What is acquired cystic kidney disease?

Acquired cystic kidney disease happens when a person's kidneys develop fluid-filled sacs, called cysts, over time. Acquired cystic kidney disease is not the same as polycystic kidney disease (PKD), another disease that causes the kidneys to develop multiple cysts.

Acquired cystic kidney disease occurs in children and adults who have

• chronic kidney disease (CKD)—a condition that develops over many years and may lead to end-stage kidney disease, or ESRD. The kidneys of people with CKD gradually lose their ability to filter wastes, extra salt, and fluid from the blood properly.
• end-stage kidney disease—total and permanent kidney failure that requires a kidney transplant or blood-filtering treatments called dialysis.

The cysts are more likely to develop in people who are on kidney dialysis. The chance of developing acquired cystic kidney disease increases with the number of years a person is on dialysis. However, the cysts are caused by CKD or kidney failure, not dialysis treatments.

More information is provided in the NIDDK health topics, kidney failure and dialysis.

What are the differences between acquired cystic kidney disease and polycystic kidney disease?

Acquired cystic kidney disease differs from PKD in several ways. Unlike acquired cystic kidney disease, PKD is a genetic, or inherited, disorder that can cause complications such as high blood pressure and problems with blood vessels in the brain and heart.

The following chart lists the differences:

People with Polycystic Kidney Disease

• are born with a gene that causes the disease
• have enlarged kidneys
• develop cysts in the liver and other parts of the body

People with Acquired Cystic Kidney Disease

• do not have a disease-causing gene
• have kidneys that are normal-sized or smaller
• do not form cysts in other parts of the body

In addition, for people with PKD, the presence of cysts marks the onset of their disease, while people with acquired cystic kidney disease already have CKD when they develop cysts.

More information is provided in the NIDDK health topic, Polycystic Kidney Disease.

How common is acquired cystic kidney disease?

Acquired cystic kidney disease becomes more common the longer a person has CKD.

• About 7 to 22 percent of people with CKD already have acquired cystic kidney disease before starting dialysis treatments.
• Almost 60 percent of people on dialysis for 2 to 4 years develop acquired cystic kidney disease.¹
• About 90 percent of people on dialysis for 8 years develop acquired cystic kidney disease.¹

What causes acquired cystic kidney disease?

Researchers do not fully understand what causes cysts to grow in the kidneys of people with CKD. The fact that these cysts occur only in the kidneys and not in other parts of the body, as in PKD, indicates that the processes that lead to cyst formation take place primarily inside the kidneys.²

What are the signs and symptoms of acquired cystic kidney disease?

A person with acquired cystic kidney disease often has no symptoms. However, the complications of acquired cystic kidney disease can have signs and symptoms.

What are the complications of acquired cystic kidney disease?

People with acquired cystic kidney disease may develop the following complications:

• an infected cyst, which can cause fever and back pain.
• blood in the urine, which can signal that a cyst in the kidney is bleeding.
• tumors in the kidneys. People with acquired cystic kidney disease are more likely than people in the general population to have cancerous kidney tumors. However, the chance of cancer spreading is lower in people with acquired cystic kidney disease than that of other kidney cancers not associated with acquired cystic kidney disease, and the long-term outlook is better.¹

How is acquired cystic kidney disease diagnosed?

A health care provider may diagnose a person with acquired cystic kidney disease based on

• medical history
• imaging tests

Medical History

Taking a medical history may help a health care provider diagnose acquired cystic kidney disease. A health care provider may suspect acquired cystic kidney disease if a person who has been on dialysis for several years develops symptoms such as fever, back pain, or blood in the urine.

Imaging Tests

To confirm the diagnosis, the health care provider may order one or more imaging tests. A radiologist—a doctor who specializes in medical imaging—interprets the images from these tests, and the patient does not need anesthesia.

• Ultrasound uses a device, called a transducer, that bounces safe, painless sound waves off organs to create an image of their structure. A specially trained technician performs the procedure in a health care provider's office, an outpatient center, or a hospital. The images can show cysts in the kidneys as well as the kidneys' size and shape.
• Computerized tomography (CT) scans use a combination of x-rays and computer technology to create images. For a CT scan, a nurse or technician may give the patient a solution to drink and an injection of a special dye, called contrast medium. CT scans require the patient to lie on a table that slides into a tunnel-shaped device where an x-ray technician takes the x-rays. An x-ray technician performs the procedure in an outpatient center or a hospital. CT scans can show cysts and tumors in the kidneys.
• Magnetic resonance imaging (MRI) is a test that takes pictures of the body's internal organs and soft tissues without using x-rays. A specially trained technician performs the procedure in an outpatient center or a hospital. Although the patient does not need anesthesia, a health care provider may give people with a fear of confined spaces light sedation, taken by mouth. An MRI may include the injection of contrast medium. With most MRI machines, the patient will lie on a table that slides into a tunnel-shaped device that may be open-ended or closed at one end. Some machines allow the patient to lie in a more open space. During an MRI, the patient, although usually awake, must remain perfectly still while the technician takes the images, which usually takes only a few minutes. The technician will take a sequence of images from different angles to create a detailed picture of the kidneys. During the test, the patient will hear loud mechanical knocking and humming noises from the machine.

Sometimes a health care provider may discover acquired cystic kidney disease during an imaging exam for another condition. Images of the kidneys may help the health care provider distinguish acquired cystic kidney disease from PKD.

How is acquired cystic kidney disease treated?

If acquired cystic kidney disease is not causing complications, a person does not need treatment. A health care provider will treat infections with antibiotics—medications that kill bacteria. If large cysts are causing pain, a health care provider may drain the cyst using a long needle inserted into the cyst through the skin.

When a surgeon transplants a new kidney into a patient's body to treat kidney failure, acquired cystic kidney disease in the damaged kidneys, which usually remain in place after a transplant, often disappears.

A surgeon may perform an operation to remove tumors or suspected tumors. In rare cases, a surgeon performs an operation to stop cysts from bleeding.

Eating, Diet, and Nutrition

No specific diet will prevent or delay acquired cystic kidney disease. In general, a diet designed for people on hemodialysis or peritoneal dialysis reduces the amount of wastes that accumulate in the body between dialysis sessions.

More information is provided in the NIDDK health topics, Eat Right to Feel Right on Hemodialysis and Nutrition for Advanced Chronic Kidney Disease in Adults.

Points to Remember

• Acquired cystic kidney disease happens when a person's kidneys develop fluid-filled sacs, called cysts, over time.
• Acquired cystic kidney disease occurs in children and adults who have
  • chronic kidney disease (CKD)
  • end-stage kidney disease (ESRD)
• People with acquired cystic kidney disease may develop the following complications:
  • an infected cyst, which can cause fever and back pain
  • blood in the urine, which can signal that a cyst in the kidney is bleeding
  • tumors in the kidneys
• To confirm the diagnosis, the health care provider may order one or more imaging tests:
  • Ultrasound
  • Computerized tomography (CT) scan
  • Magnetic resonance imaging (MRI)
• If acquired cystic kidney disease is not causing complications, a person does not need treatment.
• A health care provider will treat infections with antibiotics—medications that kill bacteria.
• If large cysts are causing pain, a health care provider may drain the cyst using a long needle inserted into the cyst through the skin.
• A surgeon may perform an operation to remove tumors or suspected tumors. In rare cases, a surgeon performs an operation to stop cysts from bleeding.

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

What is albuminuria?

Albuminuria is a sign of kidney disease and means that you have too much albumin in your urine. Albumin is a protein found in the blood. A healthy kidney doesn’t let albumin pass from the blood into the urine. A damaged kidney lets some albumin pass into the urine. The less albumin in your urine, the better.

Sometimes albuminuria is also called proteinuria.

More information is provided in the NIDDK health topics, Diabetic Kidney Disease and High Blood Pressure and Kidney Disease.

Why is urine albumin important?

Measurement of urine albumin is an important tool for

• diagnosing kidney disease
• monitoring the progression of kidney disease

Health care providers regularly test people for albuminuria as part of a routine medical exam and will closely monitor urine albumin in people with kidney disease.

A urine albumin level that stays the same or goes down may mean that treatments are working. Treatment that lowers the urine albumin level may lower the chances that kidney disease will progress to kidney failure.

People who have diabetes, high blood pressure, heart disease, or a family history of kidney failure are at risk for kidney disease. Talk with your health care provider about how often you should get a urine test for albumin.

How is albuminuria detected?

A health care provider often tests for albuminuria using a urine dipstick test followed by a urine albumin and creatinine measurement.

You will be asked to collect a urine sample in a special container in your health care provider’s office or a commercial facility. The office or facility tests the sample onsite or sends it to a lab for analysis.

Dipstick test for albumin. A dipstick test performed on a urine sample can detect the presence of albumin in the urine. For the test, a nurse or technician places a dipstick, a strip of chemically treated paper, into the urine. The dipstick changes color if albumin is present in the urine.

Albumin and creatinine measurement. A health care provider uses this measurement to determine the ratio between the albumin and creatinine in the urine and to estimate the amount of albumin excreted in 24 hours. Creatinine is a waste product that is filtered in the kidneys and excreted in the urine. Health care providers consider a urine albumin-to-creatinine ratio above 30 mg/g higher than normal.

How can albuminuria be reduced?

You may be able to reduce the amount of albumin in your urine by taking medicines that lower blood pressure called ACE inhibitors or ARBs. The names of these medicines end in -pril or -sartan.

You may also be able to protect your kidneys and reduce albuminuria by working with a registered dietitian who can help you plan meals and change your eating habits. The meal plan may help you

• lose weight, if you are overweight
• avoid foods high in sodium or salt
• eat the right amounts and types of protein

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

What is amyloidosis?

Amyloidosis is a rare disease that occurs when amyloid proteins are deposited in tissues and organs. Amyloid proteins are abnormal proteins that the body cannot break down and recycle, as it does with normal proteins. When amyloid proteins clump together, they form amyloid deposits. The buildup of these deposits damages a person’s organs and tissues. Amyloidosis can affect different organs and tissues in different people and can affect more than one organ at the same time. Amyloidosis most frequently affects the kidneys, heart, nervous system, liver, and digestive tract. The symptoms and severity of amyloidosis depend on the organs and tissues affected.

What are the kidneys and what do they do?

The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the two kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid. The urine flows from the kidneys to the bladder through tubes called ureters. The bladder stores urine. When the bladder empties, urine flows out of the body through a tube called the urethra, located at the bottom of the bladder. In men, the urethra is long, while in women it is short.

What types of amyloidosis affect the kidneys?

Primary amyloidosis and dialysis-related amyloidosis are the types of amyloidosis that can affect the kidneys.

Primary Amyloidosis of the Kidneys

The kidneys are the organs most commonly affected by primary amyloidosis. Amyloid deposits damage the kidneys and make it harder for them to filter wastes and break down proteins. When the kidneys become too damaged, they may no longer be able to function well enough to maintain health, resulting in kidney failure. Kidney failure can lead to problems such as high blood pressure, bone disease, and anemia—a condition in which the body has fewer red blood cells than normal.

Dialysis-related Amyloidosis

People who suffer from kidney failure and have been on long-term dialysis may develop dialysis-related amyloidosis. This type of amyloidosis occurs when a certain protein, called beta-2 microglobulin, builds up in the blood because dialysis does not remove it completely. The two types of dialysis are

• hemodialysis. Hemodialysis uses a special filter called a dialyzer to remove wastes and extra fluid from the blood.
• peritoneal dialysis. Peritoneal dialysis uses the lining of the abdominal cavity—the space in the body that holds organs such as the stomach, intestines, and liver—to filter the blood.

Dialysis-related amyloidosis is a complication of kidney failure because neither hemodialysis nor peritoneal dialysis effectively filters beta-2 microglobulin from the blood. As a result, elevated amounts of beta-2 microglobulin remain in the blood. Dialysis-related amyloidosis is relatively common in people with kidney failure, especially adults older than 60 years of age, who have been on dialysis for more than 5 years.¹

More information is provided in the NIDDK health topics:

• Treatment Methods for Kidney Failure: Hemodialysis
• Treatment Methods for Kidney Failure: Peritoneal Dialysis

What are the signs and symptoms of primary amyloidosis of the kidneys?

The most common sign of primary amyloidosis of the kidneys is nephrotic syndrome––a collection of signs that indicate kidney damage. The signs of nephrotic syndrome include

• albuminuria—an increased amount of albumin, a protein, in the urine. A person with nephrotic syndrome excretes more than half a teaspoon of albumin per day.
• hyperlipidemia—a condition in which a person’s blood has more-than-normal amounts of fats and cholesterol.
• edema—swelling, typically in a person’s legs, feet, or ankles and less often in the hands or face.
• hypoalbuminemia—a condition in which a person’s blood has less-than-normal amounts of albumin.

More information is provided in the NIDDK health topic, Nephrotic Syndrome in Adults.

Other signs and symptoms of primary amyloidosis may include

• fatigue, or feeling tired
• shortness of breath
• low blood pressure
• numbness, tingling, or a burning sensation in the hands or feet
• weight loss

What are the symptoms of dialysis-related amyloidosis?

The symptoms of dialysis-related amyloidosis may include

• pain, stiffness, and fluid in the joints.
• abnormal, fluid-containing sacs, called cysts, in some bones.
• carpal tunnel syndrome, caused by unusual buildup of amyloid proteins in the wrists. The symptoms of carpal tunnel syndrome include numbness or tingling, sometimes associated with muscle weakness, in the fingers and hands.

Dialysis-related amyloidosis most often affects bones, joints, and the tissues that connect muscle to bone, called tendons. The disease may also affect the digestive tract and organs such as the heart and lungs. Bone cysts caused by dialysis-related amyloidosis can lead to bone fractures. Dialysis-related amyloidosis can also cause tears in tendons and ligaments. Ligaments are tissues that connect bones to other bones.

How is primary amyloidosis of the kidneys diagnosed?

A health care provider diagnoses primary amyloidosis of the kidneys with

• a medical and family history
• a physical exam
• urinalysis
• blood tests
• a kidney biopsy

Medical and Family History

Taking a medical and family history may help a health care provider diagnose amyloidosis of the kidneys. He or she will ask the patient to provide a medical and family history.

Physical Exam

A physical exam may help diagnose primary amyloidosis of the kidneys. During a physical exam, a health care provider usually

• examines a patient’s body to check for swelling
• uses a stethoscope to listen to the lungs
• taps on specific areas of the patient’s body

Urinalysis

A health care provider may use urinalysis—the testing of a urine sample—to check for albumin and amyloid proteins in urine. The patient provides a urine sample in a special container at a health care provider’s office or a commercial facility. A nurse or technician can test the sample in the same location or send it to a lab for analysis. More-than-normal amounts of albumin in urine may indicate kidney damage due to primary amyloidosis. Amyloid proteins in urine may indicate amyloidosis.

Blood Tests

The health care provider may use blood tests to see how well the kidneys are working and to check for amyloid proteins and hyperlipidemia. A blood test involves drawing a patient’s blood at a health care provider’s office or a commercial facility and sending the sample to a lab for analysis. Blood tests for kidney function measure the waste products in the blood that healthy kidneys normally filter out. Hyperlipidemia may indicate nephrotic syndrome. Amyloid proteins in blood may indicate amyloidosis.

Kidney Biopsy

Only a biopsy can show the amyloid protein deposits in the kidneys. A health care provider may recommend a kidney biopsy if other tests show kidney damage. A kidney biopsy is a procedure that involves taking a piece of kidney tissue for examination with a microscope. A health care provider performs a kidney biopsy in a hospital with light sedation and local anesthetic. The health care provider uses imaging techniques such as ultrasound or a computerized tomography (CT) scan to guide the biopsy needle into the kidney and take the tissue sample. A pathologist—a doctor who specializes in diagnosing diseases––examines the tissue in a lab for amyloid proteins and kidney damage.

The biopsy results can help the health care provider determine the best course of treatment. More information is provided in the NIDDK health topic, Kidney Biopsy.

How is dialysis-related amyloidosis diagnosed?

A health care provider diagnoses dialysis-related amyloidosis with

• urinalysis
• blood tests
• imaging tests

A health care provider can use urinalysis and blood tests to detect the amount of amyloid proteins in urine and blood. Imaging tests, such as x-rays and CT scans, can provide pictures of bone cysts and amyloid deposits in bones, joints, tendons, and ligaments. An x-ray technician performs imaging tests in a health care provider’s office, an outpatient center, or a hospital. A radiologist—a doctor who specializes in medical imaging—interprets the images. A patient does not require anesthesia.

How is primary amyloidosis of the kidneys treated?

A health care provider treats primary amyloidosis of the kidneys with the following:

• medication therapy, including chemotherapy
• a stem cell transplant
• treating other conditions

Medication therapy. The goal of medication therapy, including chemotherapy, is to reduce amyloid protein levels in the blood. Many health care providers recommend combination medication therapy such as

• melphalan (Alkeran), a type of chemotherapy
• dexamethasone (Decadron), an anti-inflammatory steroid medication

These medications can stop the growth of the cells that make amyloid proteins. These medications may cause hair loss and serious side effects, such as nausea, vomiting, and fatigue.

Stem cell transplant. A stem cell transplant is a procedure that replaces a patient’s damaged stem cells with healthy ones. Stem cells are found in the bone marrow and develop into three types of blood cells the body needs. To prepare for a stem cell transplant, the patient receives high doses of chemotherapy. The actual transplant is like a blood transfusion. The transplanted stem cells travel to the bone marrow to make healthy new blood cells. The chemotherapy a patient receives to prepare for the transplant can have serious side effects, so it is important to talk with the health care provider about the risks of this procedure.

Read more in What Is a Blood and Marrow Stem Cell Transplant? at www.nhlbi.nih.gov/health/health-topics/topics/bmsct.

Treating other conditions. Primary amyloidosis has no cure, so treating some of the side effects and other conditions seen with the disease is essential. Other conditions may include

• anemia—treatment may include medications
• depression—treatment may include talking with a mental health counselor and taking medications
• fatigue—treatment may include changes in diet and activity level
• kidney disease—treatment may include medications to help maintain kidney function or slow the progression of kidney disease

A patient and his or her family should talk with the health care provider about resources for support and treatment options.

More information about kidney disease is provided in the NIDDK health topic, Kidney Disease.

How is dialysis-related amyloidosis treated?

A health care provider treats dialysis-related amyloidosis with

• medication therapy
• newer, more effective hemodialysis filters
• surgery
• a kidney transplant

The goal of medication therapy and the use of newer, more effective hemodialysis filters is to reduce amyloid protein levels in the blood. Medication therapy can help reduce symptoms such as pain and inflammation. A health care provider may treat a person with dialysis-related amyloidosis who has bone, joint, and tendon problems, such as bone cysts and carpal tunnel syndrome, using surgery.

Dialysis-related amyloidosis has no cure; however, a successful kidney transplant may stop the disease from progressing.

More information is provided in the NIDDK health topic, Treatment Methods for Kidney Failure: Transplantation.

Eating, Diet, and Nutrition

Researchers have not found that eating, diet, and nutrition play a role in causing or preventing primary amyloidosis of the kidneys or dialysis-related amyloidosis. People with nephrotic syndrome may make dietary changes such as

• limiting dietary sodium, often from salt, to help reduce edema and lower blood pressure
• decreasing liquid intake to help reduce edema and lower blood pressure
• eating a diet low in saturated fat and cholesterol to help control more-than-normal amounts of fats and cholesterol in the blood

Health care providers may recommend that people with kidney disease eat moderate or reduced amounts of protein. Proteins break down into waste products that the kidneys filter from the blood. Eating more protein than the body needs may burden the kidneys and cause kidney function to decline faster. However, protein intake that is too low may lead to malnutrition, a condition that occurs when the body does not get enough nutrients.

People with kidney disease on a restricted protein diet should receive blood tests that can show low nutrient levels. People with primary amyloidosis of the kidneys or dialysis-related amyloidosis should talk with a health care provider about dietary restrictions to best manage their individual needs.

Points to Remember

• Amyloidosis is a rare disease that occurs when amyloid proteins are deposited in tissues and organs.
• Primary amyloidosis and dialysis-related amyloidosis are the types of amyloidosis that can affect the kidneys.
• The most common sign of primary amyloidosis of the kidneys is nephrotic syndrome.
• The signs of nephrotic syndrome include
  • albuminuria—an elevated amount of albumin in the urine. A person with nephrotic syndrome excretes more than half a teaspoon of albumin per day.
  • hyperlipidemia—a condition in which a person’s blood has more-than-normal amounts of fats and cholesterol.
  • edema—swelling, typically in a person’s legs, feet, or ankles and less often in the hands or face.
  • hypoalbuminemia—a condition in which a person’s blood has less-than-normal amounts of albumin.
• Other signs and symptoms of primary amyloidosis may include
  • fatigue, or feeling tired
  • shortness of breath
  • low blood pressure
  • numbness, tingling, or a burning sensation in the hands or feet
  • weight loss
• The symptoms of dialysis-related amyloidosis may include
  • pain, stiffness, and fluid in the joints.
  • abnormal, fluid-containing sacs, called cysts, in some bones.
  • carpal tunnel syndrome, caused by unusual buildup of amyloid proteins in the wrists. The symptoms of carpal tunnel syndrome include numbness or tingling, sometimes associated with muscle weakness, in the fingers and hands.
• A health care provider diagnoses primary amyloidosis of the kidneys with
  • a medical and family history
  • a physical exam
  • urinalysis
  • blood tests
  • a kidney biopsy
• A health care provider diagnoses dialysis-related amyloidosis with
  • urinalysis
  • blood tests
  • imaging tests
• A health care provider treats primary amyloidosis of the kidneys with the following:
  • medication therapy, including chemotherapy
  • a stem cell transplant
  • treating other conditions
• A health care provider treats dialysis-related amyloidosis with
  • medication therapy
  • newer, more effective hemodialysis filters
  • surgery
  • a kidney transplant

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

About the Kidney Failure Series

You and your doctor will work together to choose a treatment that's best for you. The publications of the NIDDK Kidney Failure Series can help you learn about the specific issues you will face.

Booklets

• What I need to know about Kidney Failure and How it’s Treated
• Treatment Methods for Kidney Failure: Hemodialysis
• Treatment Methods for Kidney Failure: Peritoneal Dialysis
• Treatment Methods for Kidney Failure: Kidney Transplantation
• Kidney Failure: Eat Right to Feel Right on Hemodialysis

Fact Sheets

• Kidney Failure: What to Expect
• Vascular Access for Hemodialysis
• Hemodialysis Dose and Adequacy
• Peritoneal Dialysis Dose and Adequacy
• Amyloidosis and Kidney Disease
• Anemia in Chronic Kidney Disease
• Chronic Kidney Disease-Mineral and Bone Disorder
• Financial Help for Treatment of Kidney Failure

Learning as much as you can about your treatment will help make you an important member of your health care team.

What is anemia?

Anemia is a condition in which the body has fewer red blood cells than normal. Red blood cells carry oxygen to tissues and organs throughout the body and enable them to use energy from food. With anemia, red blood cells carry less oxygen to tissues and organs—particularly the heart and brain—and those tissues and organs may not function as well as they should.

How is anemia related to chronic kidney disease?

Anemia commonly occurs in people with chronic kidney disease (CKD)—the permanent, partial loss of kidney function. Anemia might begin to develop in the early stages of CKD, when someone has 20 to 50 percent of normal kidney function. Anemia tends to worsen as CKD progresses. Most people who have total loss of kidney function, or kidney failure, have anemia.¹ A person has kidney failure when he or she needs a kidney transplant or dialysis in order to live. The two forms of dialysis include hemodialysis and peritoneal dialysis. Hemodialysis uses a machine to circulate a person’s blood through a filter outside the body. Peritoneal dialysis uses the lining of the abdomen to filter blood inside the body.

What are the kidneys and what do they do?

The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine.

Healthy kidneys produce a hormone called erythropoietin (EPO). A hormone is a chemical produced by the body and released into the blood to help trigger or regulate particular body functions. EPO prompts the bone marrow to make red blood cells, which then carry oxygen throughout the body.

What causes anemia in chronic kidney disease?

When kidneys are diseased or damaged, they do not make enough EPO. As a result, the bone marrow makes fewer red blood cells, causing anemia. When blood has fewer red blood cells, it deprives the body of the oxygen it needs.

Other common causes of anemia in people with kidney disease include blood loss from hemodialysis and low levels of the following nutrients found in food:

• iron
• vitamin B12
• folic acid

These nutrients are necessary for red blood cells to make hemoglobin, the main oxygen-carrying protein in the red blood cells.

If treatments for kidney-related anemia do not help, the health care provider will look for other causes of anemia, including

• other problems with bone marrow
• inflammatory problems—such as arthritis, lupus, or inflammatory bowel disease—in which the body’s immune system attacks the body’s own cells and organs
• chronic infections such as diabetic ulcers
• malnutrition

What are the signs and symptoms of anemia in someone with chronic kidney disease?

The signs and symptoms of anemia in someone with CKD may include

• weakness
• fatigue, or feeling tired
• headaches
• problems with concentration
• paleness
• dizziness
• difficulty breathing or shortness of breath
• chest pain

Anyone having difficulty breathing or with shortness of breath should seek immediate medical care. Anyone who has chest pain should call 911.

What are the complications of anemia in someone with chronic kidney disease?

Heart problems are a complication of anemia and may include

• an irregular heartbeat or an unusually fast heartbeat, especially when exercising.
• the harmful enlargement of muscles in the heart.
• heart failure, which does not mean the heart suddenly stops working. Instead, heart failure is a long-lasting condition in which the heart can’t pump enough blood to meet the body’s needs.

How is anemia in chronic kidney disease diagnosed?

A health care provider diagnoses anemia based on

• a medical history
• a physical exam
• blood tests

Medical History

Taking a medical history is one of the first things a health care provider may do to diagnose anemia. He or she will usually ask about the patient’s symptoms.

Physical Exam

A physical exam may help diagnose anemia. During a physical exam, a health care provider usually examines a patient’s body, including checking for changes in skin color.

Blood Tests

To diagnose anemia, a health care provider may order a complete blood count, which measures the type and number of blood cells in the body. A blood test involves drawing a patient’s blood at a health care provider’s office or a commercial facility. A health care provider will carefully monitor the amount of hemoglobin in the patient’s blood, one of the measurements in a complete blood count.

The Kidney Disease: Improving Global Outcomes Anemia Work Group recommends that health care providers diagnose anemia in males older than age 15 when their hemoglobin falls below 13 grams per deciliter (g/dL) and in females older than 15 when it falls below 12 g/dL.² If someone has lost at least half of normal kidney function and has low hemoglobin, the cause of anemia may be decreased EPO production.

Two other blood tests help measure iron levels:

• The ferritin level helps assess the amount of iron stored in the body. A ferritin score below 200 nanograms (ng) per milliliter may mean a person has iron deficiency that requires treatment.²
• The transferrin saturation score indicates how much iron is available to make red blood cells. A transferrin saturation score below 30 percent can also mean low iron levels that require treatment.²

In addition to blood tests, the health care provider may order other tests, such as tests for blood loss in stool, to look for other causes of anemia.

How is anemia in chronic kidney disease treated?

Depending on the cause, a health care provider treats anemia with one or more of the following treatments:

Iron

The first step in treating anemia is raising low iron levels. Iron pills may help improve iron and hemoglobin levels. However, for patients on hemodialysis, many studies show pills do not work as well as iron given intravenously.²

Erythropoietin

If blood tests indicate kidney disease as the most likely cause of anemia, treatment can include injections of a genetically engineered form of EPO. A health care provider, often a nurse, injects the patient with EPO subcutaneously, or under the skin, as needed. Some patients learn how to inject the EPO themselves. Patients on hemodialysis may receive EPO intravenously during hemodialysis.

Studies have shown the use of EPO increases the chance of cardiovascular events, such as heart attack and stroke, in people with CKD. The health care provider will carefully review the medical history of the patient and determine if EPO is the best treatment for the patient’s anemia. Experts recommend using the lowest dose of EPO that will reduce the need for red blood cell transfusions. Additionally, health care providers should consider the use of EPO only when a patient’s hemoglobin level is below 10 g/dL. Health care providers should not use EPO to maintain a patient’s hemoglobin level above 11.5 g/dL.² Patients who receive EPO should have regular blood tests to monitor their hemoglobin so the health care provider can adjust the EPO dose when the level is too high or too low.² Health care providers should discuss the benefits and risks of EPO with their patients.

Many people with kidney disease need iron supplements and EPO to raise their red blood cell count to a level that will reduce the need for red blood cell transfusions. In some people, iron supplements and EPO will improve the symptoms of anemia.

Red Blood Cell Transfusions

If a patient’s hemoglobin falls too low, a health care provider may prescribe a red blood cell transfusion. Transfusing red blood cells into the patient’s vein raises the percentage of the patient’s blood that consists of red blood cells, increasing the amount of oxygen available to the body.

Vitamin B12 and Folic Acid Supplements

A health care provider may suggest vitamin B12 and folic acid supplements for some people with CKD and anemia. Using vitamin supplements can treat low levels of vitamin B12 or folic acid and help treat anemia. To help ensure coordinated and safe care, people should discuss their use of complementary and alternative medical practices, including their use of dietary supplements, with their health care provider.

Read more about vitamin B12 and folic acid on the MedlinePlus website at www.nlm.nih.gov/medlineplus. Read more about complementary and alternative medicine at nccih.nih.gov/.

Eating, Diet, and Nutrition

A health care provider may advise people with kidney disease who have anemia caused by iron, vitamin B12, or folic acid deficiencies to include sources of these nutrients in their diets. Some of these foods are high in sodium or phosphorus, which people with CKD should limit in their diet. Before making any dietary changes, people with CKD should talk with their health care provider or with a dietitian who specializes in helping people with kidney disease. A dietitian can help a person plan healthy meals.

Read more about nutrition for people with CKD on the National Kidney Disease Education Program page.

The following chart illustrates some good dietary sources of iron, vitamin B12, and folic acid.

Food	Serving Size	Iron	Vitamin B12	Folic Acid
Recommended Daily Value		18 mg	6 mcg	400 mcg
100 percent fortified breakfast cereal	¾ cup (1 oz)	18 mg	6 mcg	394 mcg
beans, baked	1 cup (8 oz)	8 mg	0 mcg	37 mcg
beef, ground	3 oz	2 mg	2 mcg	8 mcg
beef liver	3 oz	5 mg	67 mcg	211 mcg
clams, fried	4 oz	3 mg	1 mcg	66 mcg
spinach, boiled	1 cup (3 oz)	2 mg	0 mcg	115 mcg
spinach, fresh	1 cup (1 oz)	1 mg	0 mcg	58 mcg
trout	3 oz	0 mg	5 mcg	16 mcg
tuna, canned	3 oz	1 mg	1 mcg	2 mcg

Points to Remember

• Anemia is a condition in which the body has fewer red blood cells than normal. Red blood cells carry oxygen to tissues and organs throughout the body and enable them to use energy from food.
• Anemia commonly occurs in people with chronic kidney disease (CKD)—the permanent, partial loss of kidney function. Most people who have total loss of kidney function, or kidney failure, have anemia.
• When kidneys are diseased or damaged, they do not make enough erythropoietin (EPO). As a result, the bone marrow makes fewer red blood cells, causing anemia.
• Other common causes of anemia in people with kidney disease include blood loss from hemodialysis and low levels of the following nutrients found in food:
  • iron
  • vitamin B12
  • folic acid
• The first step in treating anemia is raising low iron levels.
• If blood tests indicate kidney disease as the most likely cause of anemia, treatment can include injections of a genetically engineered form of EPO.
• Many people with kidney disease need iron supplements and EPO to raise their red blood cell count to a level that will reduce the need for red blood cell transfusions.
• A health care provider may suggest vitamin B12 and folic acid supplements for some people with CKD and anemia.
• A health care provider may advise people with kidney disease who have anemia caused by iron, vitamin B12, or folic acid deficiencies to include sources of these nutrients in their diets.

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

About the Kidney Failure Series

You and your doctor will work together to choose a treatment that's best for you. The publications of the NIDDK Kidney Failure Series can help you learn about the specific issues you will face.

Booklets

• Treatment Methods for Kidney Failure: Hemodialysis
• Treatment Methods for Kidney Failure: Peritoneal Dialysis
• Treatment Methods for Kidney Failure: Kidney Transplantation
• Kidney Failure: Eat Right to Feel Right on Hemodialysis

Fact Sheets

• Kidney Failure: What to Expect
• Vascular Access for Hemodialysis
• Hemodialysis Dose and Adequacy
• Peritoneal Dialysis Dose and Adequacy
• Amyloidosis and Kidney Disease
• Anemia in Chronic Kidney Disease
• Chronic Kidney Disease-Mineral and Bone Disorder
• Financial Help for Treatment of Kidney Failure

How can chronic kidney disease (CKD) affect children and their families?

The lives of children with serious and long-lasting conditions such as CKD are affected in many ways. CKD is any condition that causes reduced kidney function over an extended period of time. Children with CKD may have a negative self-image and may have relationship problems with family members due to the stress of living with a chronic disease. The condition can lead to behavior problems and make participating in school and extracurricular activities more difficult. CKD can cause learning problems because the buildup of wastes in the body can slow down nerve and brain function. Children with CKD may have trouble concentrating and may develop language and motor skills more slowly than their peers. The most severe problems occur when CKD is present starting early in infancy.

CKD that leads to kidney failure—described as end-stage kidney disease or ESRD when treated with a kidney transplant or blood-filtering treatments called dialysis—can increase these challenges. Fortunately, a kidney transplant can reverse or improve most of these problems. Dialysis can also improve or correct these problems. Most children with CKD who receive appropriate treatment can attend school, graduate from high school, and go on to college or vocational school. However, families of children with CKD or kidney failure need to recognize that these children may need additional guidance and understanding.

More information about kidney disease in children and its treatment is provided in the NIDDK health topics, Overview of Kidney Disease in Children and Treatment Methods for Kidney Failure in Children.

How can parents and other adults help children with chronic kidney disease in daily life?

Parents and other adults can help children with CKD fit in at school, deal with low self-esteem, make friends, be physically active, and follow their treatment regimen. As children with CKD approach adulthood, they may need help with preparing to enter the workforce.

Attending School

School attendance is vital in helping children with CKD lead the best life possible. Many people are unaware of how CKD affects children. School administrators, teachers, and classmates should receive education and information about the effects of CKD.

Children with kidney failure may miss school each week because of dialysis and medical appointments. These absences can compound the learning problems many children with CKD face. Parents or guardians should make every effort to schedule treatments outside of school hours.

The Individuals with Disabilities Education Act Public Law 94-142 states that every child is entitled to an appropriate education and directs school districts to provide special services to ensure children with disabilities can participate in regular classrooms to the fullest extent possible. Children with CKD may need

• tutoring
• vocational rehabilitation
• special accommodations

To receive special education services, children must be evaluated to see if they have a disability and must receive an Individualized Education Program—a written document that details the services each child will receive. Parents or guardians of children with CKD should talk with the school counselor about having their child evaluated.

Dealing with Low Self-esteem

Having a chronic illness can make a child feel depressed and powerless. Learning and growth problems may also contribute to low self-esteem. One way to help children feel empowered is to give them as much control and responsibility over their own care as possible:

• Children can learn more about their medications, including doses.
• Children on dialysis should be encouraged to take an active part in their treatments.
• Parents or guardians should allow children to participate in treatment decision making.

Urinary incontinence—the loss of bladder control, which results in the accidental loss of urine—is common in children with CKD. Urinary incontinence can be embarrassing for children and can make it harder to build relationships with their peers. However, several strategies and treatment options are available to help prevent urinary incontinence.

More information is provided in the NIDDK health topic, Urinary Incontinence in Children.

Making Friends

Children with CKD may have trouble fitting in with children their own age because of their small stature or delayed mental development. For children who have had a transplant, the side effects—such as a full face, weight gain, acne, or facial hair—of some of the medications they take may make it harder to make friends and may also lower self-esteem. Participating in regular classroom and extracurricular activities may help children improve their social skills. Summer camps and recreational programs for children with special needs can be a good place to make new friends.

Participating in Physical Activities and Sports

Children with CKD should be encouraged to participate in physical activities, including exercise and sports. In general, exercise has physical and psychological benefits. Parents or guardians may feel protective of children with CKD; however, they should not try to limit activities unless instructed to by a health care provider. Some children may even need to be encouraged to get outside and play. Parents or guardians should talk with their child’s health care provider about the right activity level and appropriate sports for their child.

Children who have had a kidney transplant can compete in sports. Every year the Transplant Games, sponsored by the National Kidney Foundation, allow people with transplants to participate in friendly competition and show the world that transplantation provides a new lease on life and health.

Following Treatment Regimens

Children with CKD may need to take multiple medications, eat a specific diet, and follow their health care provider’s orders to help control their disease. Many children have a hard time following the treatment regimen. Health care providers use the term nonadherence to describe the failure or refusal to take prescribed medications or follow a health care provider’s directions. Adherence can be improved with a combination of health education, motivational techniques, and behavioral skill methods. Strategies need to be tailored to each child and the child’s family. The health care provider should

• teach the child about the condition and treatment regimen
• talk with the child to learn about the child’s wishes, beliefs, and feelings to find ways to improve motivation
• suggest methods for remembering to take medications, such as a calendar, a pillbox, or text message reminders

Preparing to Enter the Work Force

Young adults who have been treated for CKD during childhood have to overcome a number of barriers to prepare for a career and find a job. Completing the training required for employment takes more effort, and some people with CKD report that their small stature creates problems fitting into adult environments. Employers may have trouble understanding kidney problems and the accommodations that need to be made for people with CKD. The employment section of the U.S. Department of Labor’s Disability website offers a variety of resources for employers and job seekers about career planning, workplace accommodations, work incentive programs, and other related issues.

Who can help families deal with issues related to chronic kidney disease in children?

Many skilled professionals are available to ensure that children with CKD get the best possible care. The family may want to talk with a social worker, mental health professional, financial counselor, and dietitian. If a child reaches kidney failure, the medical staff at the dialysis center or transplantation clinic can provide help.

Social Worker

A social worker can help families locate services such as transportation and family counseling. The social worker can provide information about

• finding support groups in the community
• helping a child with a chronic illness rejoin school activities
• reducing the stress of caring for a child with a chronic illness

The social worker can also help families submit applications for Medicare and Medicaid. Medicare is a program that helps people older than 65 and people with disabilities, including people of any age with kidney failure, pay for medical care. Medicaid is a health care program for certain low-income individuals and families who fit into an eligibility group that is recognized by federal and state law.

Mental Health Professional

A mental health professional, such as a psychologist, can help children with CKD find ways to deal with the emotional turmoil caused by having a chronic illness. Some child psychologists also specialize in helping children with disabilities and medical problems rejoin school activities. They may also be able to suggest techniques that reinforce adherence with taking medication and following the health care provider’s instructions.

Family members may also find that counseling helps them handle the conflicts and stresses they face. Many couples report increased tension in their marriage when their child has a serious illness such as CKD. Siblings may resent the amount of attention given to their sibling with CKD and feel guilty about having bad thoughts about their sibling.

Financial Counselor

A financial counselor can help families meet the financial obligations that chronic illness creates. Medical bills can strain family finances; in some cases, a parent or guardian may need to stop working to care for a child full time.

More information is provided in the NIDDK health topic, Financial Help for Treatment of Kidney Failure.

Dietitian

Proper nutrition is extremely important for children with CKD. Every dialysis clinic has a dietitian to help people understand how the food they eat affects their health. The dietitian

• helps develop meal plans to fit a child’s restricted diet
• provides information about possible nutritional deficiencies caused by kidney disease
• recommends special dietary supplements or formulas to improve the child’s nutrition
• provides recipes and recommends cookbooks appropriate for people with kidney disease

Following the restrictions of a kidney disease diet might be hard at first; however, making tasty and satisfying meals is possible with just a little creativity.

Eating, Diet, and Nutrition

For children with CKD, learning about nutrition is vital because their diet can affect how well their kidneys work. Parents or guardians should always consult with their child’s health care team before making any dietary changes. Staying healthy with CKD requires paying close attention to the following elements of a diet:

• Protein. Children with CKD should eat enough protein for growth while limiting high protein intake. Too much protein can put an extra burden on the kidneys and cause kidney function to decline faster. Protein needs increase when a child is on dialysis because the dialysis process removes protein from the child’s blood. The health care team recommends the amount of protein needed for the child. Foods with protein include
  • eggs
  • milk
  • cheese
  • chicken
  • fish
  • red meats
  • beans
  • yogurt
  • cottage cheese
• Sodium. The amount of sodium children need depends on the stage of their kidney disease, their age, and sometimes other factors. The health care team may recommend limiting or adding sodium and salt to the diet. Foods high in sodium include
  • canned foods
  • some frozen foods
  • most processed foods
  • some snack foods, such as chips and crackers
• Potassium. Potassium levels need to stay in the normal range for children with CKD, because too little or too much potassium can cause heart and muscle problems. Children may need to stay away from some fruits and vegetables or reduce the number of servings and portion sizes to make sure they do not take in too much potassium. The health care team recommends the amount of potassium a child needs. Low-potassium fruits and vegetables include
  • apples
  • cranberries
  • strawberries
  • blueberries
  • raspberries
  • pineapple
  • cabbage
  • boiled cauliflower
  • mustard greens
  • uncooked broccoli
  High-potassium fruits and vegetables include
  • oranges
  • melons
  • apricots
  • bananas
  • potatoes
  • tomatoes
  • sweet potatoes
  • cooked spinach
  • cooked broccoli
• Phosphorus. Children with CKD need to control the level of phosphorus in their blood because too much phosphorus pulls calcium from the bones, making them weaker and more likely to break. Too much phosphorus also can cause itchy skin and red eyes. As CKD progresses, a child may need to take a phosphate binder with meals to lower the concentration of phosphorus in the blood. Phosphorus is found in high-protein foods. Foods with low levels of phosphorus include
  • liquid nondairy creamer
  • green beans
  • popcorn
  • unprocessed meats from a butcher
  • lemon-lime soda
  • root beer
  • powdered iced tea and lemonade mixes
  • rice and corn cereals
  • egg whites
  • sorbet
• Fluids. Early in CKD, a child’s damaged kidneys may produce either too much or too little urine, which can lead to swelling or dehydration. As CKD progresses, children may need to limit fluid intake. The health care provider will tell the child and parents or guardians the goal for fluid intake.

More information is provided in the NIDDK health topics, Nutrition for Chronic Kidney Disease in Children and Kidney Failure: Eat Right to Feel Right on Hemodialysis.

Points to Remember

• Children with chronic kidney disease (CKD) may have a negative self-image and may have relationship problems with family members due to the stress of living with a chronic disease. The condition can lead to behavior problems and make participating in school and extracurricular activities more difficult.
• CKD can cause learning problems because the buildup of wastes in the body can slow down nerve and brain function. Children with CKD may have trouble concentrating and may develop language and motor skills more slowly than their peers.
• Parents and other adults can help children with CKD fit in at school, deal with low self-esteem, make friends, be physically active, and follow their treatment regimen. As children with CKD approach adulthood, they may need help with preparing to enter the workforce.
• School attendance is vital in helping children with CKD lead the best life possible.
• One way to help children feel empowered is to give them as much control and responsibility over their own care as possible:
  • Children can learn more about their medications, including doses.
  • Children on dialysis should be encouraged to take an active part in their treatments.
  • Parents or guardians should allow children to participate in treatment decision making.
• Participating in regular classroom and extracurricular activities may help children improve their social skills. Summer camps and recreational programs for children with special needs can be a good place to make new friends.
• Parents or guardians may feel protective of children with CKD; however, they should not try to limit activities unless instructed to by a health care provider.
• Children with CKD may need to take multiple medications, eat a specific diet, and follow their health care provider’s orders to help control their disease. Many children have a hard time following the treatment regimen. Health care providers use the term nonadherence to describe the failure or refusal to take prescribed medications or follow a health care provider’s directions.
• Adherence can be improved with a combination of health education, motivational techniques, and behavioral skill methods.
• Many skilled professionals are available to ensure that children with CKD get the best possible care. The family may want to talk with a social worker, mental health professional, financial counselor, and dietitian. If a child reaches kidney failure, the medical staff at the dialysis center or transplantation clinic can provide help.
• For children with CKD, learning about nutrition is vital because their diet can affect how well their kidneys work. Parents or guardians should always consult with their child’s health care team before making any dietary changes.

Resources

American Society of Transplantation

Facts about Kidney Transplantation: Pediatric Patient Education Brochure (PDF, 312 KB)

National Kidney Foundation

Children with Chronic Kidney Disease: Tips for Parents

Family Focus newsletter

Employers’ Guide

Nemours KidsHealth Website

When Your Child Has a Chronic Kidney Disease

What’s the Deal with Dialysis?

Nephkids

Cyber-support group

United Network for Organ Sharing

Organ Transplants: What Every Kid Needs to Know (PDF, 1.67 MB)

U.S. Department of Health and Human Services, Centers for Medicare & Medicaid Services

Medicare Coverage of Kidney Dialysis & Kidney Transplant Services (PDF, 743 KB)

U.S. Social Security Administration

Benefits for Children with Disabilities (PDF, 413 KB)

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

What is childhood nephrotic syndrome?

Childhood nephrotic syndrome is not a disease in itself; rather, it is a group of symptoms that

• indicate kidney damage—particularly damage to the glomeruli, the tiny units within the kidney where blood is filtered
• result in the release of too much protein from the body into the urine

When the kidneys are damaged, the protein albumin, normally found in the blood, will leak into the urine. Proteins are large, complex molecules that perform a number of important functions in the body.

The two types of childhood nephrotic syndrome are

• primary—the most common type of childhood nephrotic syndrome, which begins in the kidneys and affects only the kidneys
• secondary—the syndrome is caused by other diseases

A health care provider may refer a child with nephrotic syndrome to a nephrologist—a doctor who specializes in treating kidney disease. A child should see a pediatric nephrologist, who has special training to take care of kidney problems in children, if possible. However, in many parts of the country, pediatric nephrologists are in short supply, so the child may need to travel. If traveling is not possible, some nephrologists who treat adults can also treat children.

What are the kidneys and what do they do?

The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid. Children produce less urine than adults and the amount produced depends on their age. The urine flows from the kidneys to the bladder through tubes called ureters. The bladder stores urine. When the bladder empties, urine flows out of the body through a tube called the urethra, located at the bottom of the bladder.

Kidneys work at the microscopic level. The kidney is not one large filter. Each kidney is made up of about a million filtering units called nephrons. Each nephron filters a small amount of blood. The nephron includes a filter, called the glomerulus, and a tubule. The nephrons work through a two-step process. The glomerulus lets fluid and waste products pass through it; however, it prevents blood cells and large molecules, mostly proteins, from passing. The filtered fluid then passes through the tubule, which sends needed minerals back to the bloodstream and removes wastes.

What causes childhood nephrotic syndrome?

While idiopathic, or unknown, diseases are the most common cause of primary childhood nephrotic syndrome, researchers have linked certain diseases and some specific genetic changes that damage the kidneys with primary childhood nephrotic syndrome.

The cause of secondary childhood nephrotic syndrome is an underlying disease or infection. Called a primary illness, it’s this underlying disease or infection that causes changes in the kidney function that can result in secondary childhood nephrotic syndrome.

Congenital diseases—diseases that are present at birth—can also cause childhood nephrotic syndrome.

Primary Childhood Nephrotic Syndrome

The following diseases are different types of idiopathic childhood nephrotic syndrome:

• Minimal change disease involves damage to the glomeruli that can be seen only with an electron microscope. This type of microscope shows tiny details better than any other microscope. Scientists do not know the exact cause of minimal change disease.
  Minimal change disease is the most common cause of idiopathic childhood nephrotic syndrome.¹
• Focal segmental glomerulosclerosis is scarring in scattered regions of the kidney:
  • “Focal” means that only some of the glomeruli become scarred.
  • “Segmental” means damage affects only part of an individual glomerulus.
• Membranoproliferative glomerulonephritis is a group of disorders involving deposits of antibodies that build up in the glomeruli, causing thickening and damage. Antibodies are proteins made by the immune system to protect the body from foreign substances such as bacteria or viruses.

Secondary Childhood Nephrotic Syndrome

Some common diseases that can cause secondary childhood nephrotic syndrome include

• diabetes, a condition that occurs when the body cannot use glucose—a type of sugar—normally
• Henoch-Schönlein purpura, a disease that causes small blood vessels in the body to become inflamed and leak
• hepatitis, inflammation of the liver caused by a virus
• human immunodeficiency virus (HIV), a virus that alters the immune system
• lupus, an autoimmune disease that occurs when the body attacks its own immune system
• malaria, a disease of the blood that is spread by mosquitos
• streptococcal infection, an infection that results when the bacteria that causes strep throat or a skin infection is left untreated

Other causes of secondary childhood nephrotic syndrome can include certain medications, such as aspirin, ibuprofen, or other nonsteroidal anti-inflammatory drugs, and exposure to chemicals, such as mercury and lithium.

Congenital Diseases and Childhood Nephrotic Syndrome

Congenital nephrotic syndrome is rare and affects infants in the first 3 months of life.² This type of nephrotic syndrome, sometimes called infantile nephrotic syndrome, can be caused by

• inherited genetic defects, which are problems passed from parent to child through genes
• infections at the time of birth

More information about underlying diseases or infections that cause changes in kidney function is provided in the NIDDK health topic, Glomerular Diseases.

Which children are more likely to develop childhood nephrotic syndrome?

In cases of primary childhood nephrotic syndrome for which the cause is idiopathic, researchers are unable to pinpoint which children are more likely to develop the syndrome. However, as researchers continue to study the link between genetics and childhood nephrotic syndrome, it may be possible to predict the syndrome for some children.

Children are more likely to develop secondary childhood nephrotic syndrome if they

• have diseases that can damage their kidneys
• take certain medications
• develop certain types of infections

What are the signs and symptoms of childhood nephrotic syndrome?

The signs and symptoms of childhood nephrotic syndrome may include

• edema—swelling, most often in the legs, feet, or ankles and less often in the hands or face
• albuminuria—when a child’s urine has high levels of albumin
• hypoalbuminemia—when a child’s blood has low levels of albumin
• hyperlipidemia—when a child’s blood cholesterol and fat levels are higher than normal

In addition, some children with nephrotic syndrome may have

• blood in their urine
• symptoms of infection, such as fever, lethargy, irritability, or abdominal pain
• loss of appetite
• diarrhea
• high blood pressure

What are the complications of childhood nephrotic syndrome?

The complications of childhood nephrotic syndrome may include

• infection. When the kidneys are damaged, a child is more likely to develop infections because the body loses proteins that normally protect against infection. Health care providers will prescribe medications to treat infections. Children with childhood nephrotic syndrome should receive the pneumococcal vaccine and yearly flu shots to prevent those infections. Children should also receive age-appropriate vaccinations, although a health care provider may delay certain live vaccines while a child is taking certain medications.
• blood clots. Blood clots can block the flow of blood and oxygen through a blood vessel anywhere in the body. A child is more likely to develop clots when he or she loses proteins through the urine. The health care provider will treat blood clots with blood-thinning medications.
• high blood cholesterol. When albumin leaks into the urine, the albumin levels in the blood drop. The liver makes more albumin to make up for the low levels in the blood. At the same time, the liver makes more cholesterol. Sometimes children may need treatment with medications to lower blood cholesterol levels.

How is childhood nephrotic syndrome diagnosed?

A health care provider diagnoses childhood nephrotic syndrome with

• a medical and family history
• a physical exam
• urine tests
• a blood test
• ultrasound of the kidney
• kidney biopsy

Medical and Family History

Taking a medical and family history is one of the first things a health care provider may do to help diagnose childhood nephrotic syndrome.

Physical Exam

A physical exam may help diagnose childhood nephrotic syndrome. During a physical exam, a health care provider most often

• examines a child’s body
• taps on specific areas of the child’s body

Urine Tests

A health care provider may order the following urine tests to help determine if a child has kidney damage from childhood nephrotic syndrome.

Dipstick test for albumin. A dipstick test performed on a urine sample can detect the presence of albumin in the urine, which could mean kidney damage. The child or a caretaker collects a urine sample in a special container. For the test, a nurse or technician places a strip of chemically treated paper, called a dipstick, into the child’s urine sample. Patches on the dipstick change color when albumin is present in urine.

Urine albumin-to-creatinine ratio. A health care provider uses this measurement to estimate the amount of albumin passed into the urine over a 24-hour period. The child provides a urine sample during an appointment with the health care provider. Creatinine is a waste product filtered in the kidneys and passed in the urine. A high urine albumin-to-creatinine ratio indicates that the kidneys are leaking large amounts of albumin into the urine.

Blood Test

A blood test involves drawing blood at a health care provider’s office or a commercial facility and sending the sample to a lab for analysis. The lab tests the sample to estimate how much blood the kidneys filter each minute, called the estimated glomerular filtration rate, or eGFR. The test results help the health care provider determine the amount of kidney damage. Health care providers may also order other blood tests to help determine the underlying disease that may be causing childhood nephrotic syndrome.

Ultrasound of the Kidney

Ultrasound uses a device, called a transducer, that bounces safe, painless sound waves off organs to create an image of their structure. A specially trained technician performs the procedure in a health care provider’s office, an outpatient center, or a hospital. A radiologist—a doctor who specializes in medical imaging—interprets the images to see if the kidneys look normal; a child does not need anesthesia.

Kidney Biopsy

Biopsy is a procedure that involves taking a small piece of kidney tissue for examination with a microscope. A health care provider performs the biopsy in an outpatient center or a hospital. The health care provider will give the child light sedation and local anesthetic; however, in some cases, the child will require general anesthesia. A pathologist—a doctor who specializes in diagnosing diseases—examines the tissue in a lab. The test can help diagnose childhood nephrotic syndrome.

When the health care provider suspects a child has minimal change disease, he or she often starts treatment with medications without performing a biopsy. If the medication is effective, the child does not need a biopsy. In most cases, a health care provider does not perform a biopsy on children younger than age 12 unless he or she thinks that another disease is the cause.

How is childhood nephrotic syndrome treated?

Health care providers will decide how to treat childhood nephrotic syndrome based on the type:

• primary childhood nephrotic syndrome: medications
• secondary childhood nephrotic syndrome: treat the underlying illness or disease
• congenital nephrotic syndrome: medications, surgery to remove one or both kidneys, and transplantation

Primary Childhood Nephrotic Syndrome

Health care providers treat idiopathic childhood nephrotic syndrome with several types of medications that control the immune system, remove extra fluid, and lower blood pressure.

• Control the immune system. Corticosteroids are a group of medications that reduce the activity of the immune system, decrease the amount of albumin lost in the urine, and decrease swelling. Health care providers commonly use prednisone or a related corticosteroid to treat idiopathic childhood nephrotic syndrome. About 90 percent of children achieve remission with daily corticosteroids for 6 weeks and then a slightly smaller dose every other day for 6 weeks.² Remission is a period when the child is symptom-free.
  
  Many children relapse after initial therapy, and health care providers treat them with a shorter course of corticosteroids until the disease goes into remission again. Children may have multiple relapses; however, they most often recover without long-term kidney damage.
  
  When a child has frequent relapses or does not respond to treatment, a health care provider may prescribe other medications that reduce the activity of the immune system. These medications prevent the body from making antibodies that can damage kidney tissues. They include
  • cyclophosphamide
  • mycophenolate (CellCept, Myfortic)
  • cyclosporine
  • tacrolimus (Hecoria, Prograf)
  A health care provider may use these other immune system medications with corticosteroids or in place of corticosteroids.
• Remove extra fluid. A health care provider may prescribe a diuretic, a medication that helps the kidneys remove extra fluid from the blood. Removing the extra fluid can often help to lower blood pressure.
• Lower blood pressure. Some children with childhood nephrotic syndrome develop high blood pressure and may need to take additional medications to lower their blood pressure. Two types of blood pressure-lowering medications, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, have the additional benefit of slowing the progression of kidney disease. Many children with nephrotic syndrome require two or more medications to control their blood pressure.

Secondary Childhood Nephrotic Syndrome

Health care providers treat secondary childhood nephrotic syndrome by treating the underlying cause of the primary illness. For example, a health care provider may treat children by

• prescribing antibiotics for an infection
• adjusting medications to treat lupus, HIV, or diabetes
• changing or stopping medications that are known to cause secondary childhood nephrotic syndrome

While treating the underlying cause, the health care provider will also treat the child to improve or restore kidney function with the same medications used to treat primary childhood nephrotic syndrome.

Caretakers should make sure that children take all prescribed medications and follow the treatment plan recommended by their health care provider.

More information about specific treatments for secondary childhood nephrotic syndrome is provided in the NIDDK health topic, Glomerular Diseases.

Congenital Nephrotic Syndrome

Researchers have found that medications are not effective in treating congenital nephrotic syndrome, and that most children will need a kidney transplant by the time they are 2 or 3 years old. A kidney transplant is surgery to place a healthy kidney from someone who has just died or a living donor, most often a family member, into a person’s body to take over the job of the failing kidney. To keep the child healthy until the transplant, the health care provider may recommend the following:

• albumin injections to make up for the albumin lost in urine
• diuretics to help remove extra fluid that causes swelling
• antibiotics to treat the first signs of infection
• growth hormones to promote growth and help bones mature
• removal of one or both kidneys to decrease the loss of albumin in the urine
• dialysis to artificially filter wastes from the blood if the kidneys fail

More information is provided in the NIDDK health topic, Treatment Methods for Kidney Failure in Children.

How can childhood nephrotic syndrome be prevented?

Researchers have not found a way to prevent childhood nephrotic syndrome when the cause is idiopathic or congenital.

Eating, Diet, and Nutrition

Children who have nephrotic syndrome may need to make changes to their diet, such as

• limiting the amount of sodium, often from salt, they take in each day
• reducing the amount of liquids they drink each day
• eating a diet low in saturated fat and cholesterol to help control elevated cholesterol levels

Parents or caretakers should talk with the child’s health care provider before making any changes to the child’s diet.

More information is provided in the NIDDK health topic, Nutrition for Chronic Kidney Disease in Children.

Points to Remember

• Childhood nephrotic syndrome is not a disease in itself; rather, it is a group of symptoms that
  • indicate kidney damage—particularly damage to the glomeruli, the tiny units within the kidney where blood is filtered
  • result in the release of too much protein from the body into the urine
• The two types of childhood nephrotic syndrome are
  • primary—the most common type of childhood nephrotic syndrome, which begins in the kidneys and affects only the kidneys
  • secondary—the syndrome is caused by other diseases
• The signs and symptoms of childhood nephrotic syndrome may include
  • edema—swelling, most often in the legs, feet, or ankles and less often in the hands or face
  • albuminuria—when a child’s urine has high levels of albumin
  • hypoalbuminemia—when a child’s blood has low levels of albumin
  • hyperlipidemia—when a child’s blood cholesterol and fat levels are higher than normal
• A health care provider may order urine tests to help determine if a child has kidney damage from childhood nephrotic syndrome.
• Health care providers will decide how to treat childhood nephrotic syndrome based on the type:
  • primary childhood nephrotic syndrome: medications
  • secondary childhood nephrotic syndrome: treat the underlying illness or disease
  • congenital nephrotic syndrome: medications, surgery to remove one or both kidneys, or transplantation

Resources

National Kidney Foundation
Children with Chronic Kidney Disease: Tips for Parents
www.kidney.org

Family Focus newsletter
www.kidney.org

Employers’ Guide
www.kidney.org

Nemours KidsHealth Website
When Your Child Has a Chronic Kidney Disease
www.kidshealth.org

What’s the Deal With Dialysis?
www.kidshealth.org

Nephkids
Cyber-support group
www.cybernephrology.ualberta.ca

United Network for Organ Sharing
Organ Transplants: What Every Kid Needs to Know
www.unos.org (PDF, 1.67 MB)

U.S. Department of Health and Human Services, Centers for Medicare & Medicaid Services
Medicare Coverage of Kidney Dialysis & Kidney Transplant Services
www.medicare.gov (PDF, 1,080 KB)

U.S. Social Security Administration
Benefits For Children With Disabilities
www.ssa.gov (PDF, 413 KB)

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

Many diseases affect kidney function by attacking the glomeruli, the tiny units within the kidney where blood is cleaned. Glomerular diseases include many conditions with a variety of genetic and environmental causes, but they fall into two major categories:

• Glomerulonephritis (gloh-MEHR-yoo-loh-nef-RY-tis) describes the inflammation of the membrane tissue in the kidney that serves as a filter, separating wastes and extra fluid from the blood.
• Glomerulosclerosis (gloh-MEHR-yoo-loh-skleh-ROH-sis) describes the scarring or hardening of the tiny blood vessels within the kidney.

Although glomerulonephritis and glomerulosclerosis have different causes, they can both lead to kidney failure.

What are the kidneys and what do they do?

The two kidneys are bean-shaped organs located just below the rib cage, one on each side of the spine. Everyday, the two kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid.

Blood enters the kidneys through arteries that branch inside the kidneys into tiny clusters of looping blood vessels. Each cluster is called a glomerulus, which comes from the Greek word meaning filter. The plural form of the word is glomeruli. There are approximately 1 million glomeruli, or filters, in each kidney. The glomerulus is attached to the opening of a small fluid-collecting tube called a tubule. Blood is filtered in the glomerulus, and extra fluid and wastes pass into the tubule and become urine. Eventually, the urine drains from the kidneys into the bladder through larger tubes called ureters.

Each glomerulus-and-tubule unit is called a nephron. Each kidney is composed of about 1 million nephrons. In healthy nephrons, the glomerular membrane that separates the blood vessel from the tubule allows waste products and extra water to pass into the tubule while keeping blood cells and protein in the bloodstream.

How do glomerular diseases interfere with kidney function?

Glomerular diseases damage the glomeruli, letting protein and sometimes red blood cells leak into the urine. Sometimes a glomerular disease also interferes with the clearance of waste products by the kidney, so they begin to build up in the blood. Furthermore, loss of blood proteins like albumin in the urine can result in a fall in their level in the bloodstream. In normal blood, albumin acts like a sponge, drawing extra fluid from the body into the bloodstream, where it remains until the kidneys remove it. But when albumin leaks into the urine, the blood loses its capacity to absorb extra fluid from the body. Fluid can accumulate outside the circulatory system in the face, hands, feet, or ankles and cause swelling.

What are the symptoms of glomerular disease?

The signs and symptoms of glomerular disease include

• albuminuria: large amounts of protein in the urine
• hematuria: blood in the urine
• reduced glomerular filtration rate: inefficient filtering of wastes from the blood
• hypoproteinemia: low blood protein
• edema: swelling in parts of the body

One or more of these symptoms can be the first sign of kidney disease. But how would you know, for example, whether you have proteinuria? Before seeing a doctor, you may not. But some of these symptoms have signs, or visible manifestations:

• Proteinuria may cause foamy urine.
• Blood may cause the urine to be pink or cola-colored.
• Edema may be obvious in hands and ankles, especially at the end of the day, or around the eyes when awakening in the morning, for example.

How is glomerular disease diagnosed?

Patients with glomerular disease have significant amounts of protein in the urine, which may be referred to as "nephrotic range" if levels are very high. Red blood cells in the urine are a frequent finding as well, particularly in some forms of glomerular disease. Urinalysis provides information about kidney damage by indicating levels of protein and red blood cells in the urine. Blood tests measure the levels of waste products such as creatinine and urea nitrogen to determine whether the filtering capacity of the kidneys is impaired. If these lab tests indicate kidney damage, the doctor may recommend ultrasound or an x-ray to see whether the shape or size of the kidneys is abnormal. These tests are called renal imaging. But since glomerular disease causes problems at the cellular level, the doctor will probably also recommend a kidney biopsy—a procedure in which a needle is used to extract small pieces of tissue for examination with different types of microscopes, each of which shows a different aspect of the tissue. A biopsy may be helpful in confirming glomerular disease and identifying the cause.

What causes glomerular disease?

A number of different diseases can result in glomerular disease. It may be the direct result of an infection or a drug toxic to the kidneys, or it may result from a disease that affects the entire body, like diabetes or lupus. Many different kinds of diseases can cause swelling or scarring of the nephron or glomerulus. Sometimes glomerular disease is idiopathic, meaning that it occurs without an apparent associated disease.

The categories presented below can overlap: that is, a disease might belong to two or more of the categories. For example, diabetic nephropathy is a form of glomerular disease that can be placed in two categories: systemic diseases, since diabetes itself is a systemic disease, and sclerotic diseases, because the specific damage done to the kidneys is associated with scarring.

Autoimmune Diseases

When the body's immune system functions properly, it creates protein-like substances called antibodies and immunoglobulins to protect the body against invading organisms. In an autoimmune disease, the immune system creates autoantibodies, which are antibodies or immunoglobulins that attack the body itself. Autoimmune diseases may be systemic and affect many parts of the body, or they may affect only specific organs or regions.

Systemic lupus erythematosus (SLE) affects many parts of the body: primarily the skin and joints, but also the kidneys. Because women are more likely to develop SLE than men, some researchers believe that a sex-linked genetic factor may play a part in making a person susceptible, although viral infection has also been implicated as a triggering factor. Lupus nephritis is the name given to the kidney disease caused by SLE, and it occurs when autoantibodies form or are deposited in the glomeruli, causing inflammation. Ultimately, the inflammation may create scars that keep the kidneys from functioning properly. Conventional treatment for lupus nephritis includes a combination of two drugs, cyclophosphamide, a cytotoxic agent that suppresses the immune system, and prednisolone, a corticosteroid used to reduce inflammation. A newer immunosuppressant, mychophenolate mofetil (MMF), has been used instead of cyclophosphamide. Preliminary studies indicate that MMF may be as effective as cyclophosphamide and has milder side effects.

Goodpasture's Syndrome involves an autoantibody that specifically targets the kidneys and the lungs. Often, the first indication that patients have the autoantibody is when they cough up blood. But lung damage in Goodpasture's Syndrome is usually superficial compared with progressive and permanent damage to the kidneys. Goodpasture's Syndrome is a rare condition that affects mostly young men but also occurs in women, children, and older adults. Treatments include immunosuppressive drugs and a blood-cleaning therapy called plasmapheresis that removes the autoantibodies.

IgA nephropathy is a form of glomerular disease that results when immunoglobulin A (IgA) forms deposits in the glomeruli, where it creates inflammation. IgA nephropathy was not recognized as a cause of glomerular disease until the late 1960s, when sophisticated biopsy techniques were developed that could identify IgA deposits in kidney tissue.

The most common symptom of IgA nephropathy is blood in the urine, but it is often a silent disease that may go undetected for many years. The silent nature of the disease makes it difficult to determine how many people are in the early stages of IgA nephropathy, when specific medical tests are the only way to detect it. This disease is estimated to be the most common cause of primary glomerulonephritis—that is, glomerular disease not caused by a systemic disease like lupus or diabetes mellitus. It appears to affect men more than women. Although IgA nephropathy is found in all age groups, young people rarely display signs of kidney failure because the disease usually takes several years to progress to the stage where it causes detectable complications.

No treatment is recommended for early or mild cases of IgA nephropathy when the patient has normal blood pressure and less than 1 gram of protein in a 24-hour urine output. When proteinuria exceeds 1 gram/day, treatment is aimed at protecting kidney function by reducing proteinuria and controlling blood pressure. Blood pressure medicines—angiotensin—converting enzyme inhibitors (ACE inhibitors) or angiotensin receptor blockers (ARBs)—that block a hormone called angiotensin are most effective at achieving those two goals simultaneously.

Hereditary Nephritis—Alport Syndrome

The primary indicator of Alport syndrome is a family history of chronic glomerular disease, although it may also involve hearing or vision impairment. This syndrome affects both men and women, but men are more likely to experience chronic kidney disease and sensory loss. Men with Alport syndrome usually first show evidence of renal insufficiency while in their twenties and reach total kidney failure by age 40. Women rarely have significant renal impairment, and hearing loss may be so slight that it can be detected only through testing with special equipment. Usually men can pass the disease only to their daughters. Women can transmit the disease to either their sons or their daughters. Treatment focuses on controlling blood pressure to maintain kidney function.

Infection-related Glomerular Disease

Glomerular disease sometimes develops rapidly after an infection in other parts of the body. Acute post-streptococcal glomerulonephritis (PSGN) can occur after an episode of strep throat or, in rare cases, impetigo (a skin infection). The Streptococcus bacteria do not attack the kidney directly, but an infection may stimulate the immune system to overproduce antibodies, which are circulated in the blood and finally deposited in the glomeruli, causing damage. PSGN can bring on sudden symptoms of swelling (edema), reduced urine output (oliguria), and blood in the urine (hematuria). Tests will show large amounts of protein in the urine and elevated levels of creatinine and urea nitrogen in the blood, thus indicating reduced kidney function. High blood pressure frequently accompanies reduced kidney function in this disease.

PSGN is most common in children between the ages of 3 and 7, although it can strike at any age, and it most often affects boys. It lasts only a brief time and usually allows the kidneys to recover. In a few cases, however, kidney damage may be permanent, requiring dialysis or transplantation to replace renal function.

Bacterial endocarditis, infection of the tissues inside the heart, is also associated with subsequent glomerular disease. Researchers are not sure whether the renal lesions that form after a heart infection are caused entirely by the immune response or whether some other disease mechanism contributes to kidney damage. Treating the heart infection is the most effective way of minimizing kidney damage. Endocarditis sometimes produces chronic kidney disease (CKD).

HIV, the virus that leads to AIDS, can also cause glomerular disease. Between 5 and 10 percent of people with HIV experience kidney failure, even before developing full-blown AIDS. HIV-associated nephropathy usually begins with heavy proteinuria and progresses rapidly (within a year of detection) to total kidney failure. Researchers are looking for therapies that can slow down or reverse this rapid deterioration of renal function, but some possible solutions involving immunosuppression are risky because of the patients' already compromised immune system.

Sclerotic Diseases

Glomerulosclerosis is scarring (sclerosis) of the glomeruli. In several sclerotic conditions, a systemic disease like lupus or diabetes is responsible. Glomerulosclerosis is caused by the activation of glomerular cells to produce scar material. This may be stimulated by molecules called growth factors, which may be made by glomerular cells themselves or may be brought to the glomerulus by the circulating blood that enters the glomerular filter.

Diabetic nephropathy is the leading cause of glomerular disease and of total kidney failure in the United States. Kidney disease is one of several problems caused by elevated levels of blood glucose, the central feature of diabetes. In addition to scarring the kidney, elevated glucose levels appear to increase the speed of blood flow into the kidney, putting a strain on the filtering glomeruli and raising blood pressure.

Diabetic nephropathy usually takes many years to develop. People with diabetes can slow down damage to their kidneys by controlling their blood glucose through healthy eating with moderate protein intake, physical activity, and medications. People with diabetes should also be careful to keep their blood pressure at a level below 140/90 mm Hg, if possible. Blood pressure medications called ACE inhibitors and ARBs are particularly effective at minimizing kidney damage and are now frequently prescribed to control blood pressure in patients with diabetes and in patients with many forms of kidney disease.

Focal segmental glomerulosclerosis (FSGS) describes scarring in scattered regions of the kidney, typically limited to one part of the glomerulus and to a minority of glomeruli in the affected region. FSGS may result from a systemic disorder or it may develop as an idiopathic kidney disease, without a known cause. Proteinuria is the most common symptom of FSGS, but, since proteinuria is associated with several other kidney conditions, the doctor cannot diagnose FSGS on the basis of proteinuria alone. Biopsy may confirm the presence of glomerular scarring if the tissue is taken from the affected section of the kidney. But finding the affected section is a matter of chance, especially early in the disease process, when lesions may be scattered.

Confirming a diagnosis of FSGS may require repeat kidney biopsies. Arriving at a diagnosis of idiopathic FSGS requires the identification of focal scarring and the elimination of possible systemic causes such as diabetes or an immune response to infection. Since idiopathic FSGS is, by definition, of unknown cause, it is difficult to treat. No universal remedy has been found, and most patients with FSGS progress to total kidney failure over 5 to 20 years. Some patients with an aggressive form of FSGS reach total kidney failure in 2 to 3 years. Treatments involving steroids or other immunosuppressive drugs appear to help some patients by decreasing proteinuria and improving kidney function. But these treatments are beneficial to only a minority of those in whom they are tried, and some patients experience even poorer kidney function as a result. ACE inhibitors and ARBs may also be used in FSGS to decrease proteinuria. Treatment should focus on controlling blood pressure and blood cholesterol levels, factors that may contribute to kidney scarring.

Other Glomerular Diseases

Membranous nephropathy, also called membranous glomerulopathy, is the second most common cause of the nephrotic syndrome (proteinuria, edema, high cholesterol) in U.S. adults after diabetic nephropathy. Diagnosis of membranous nephropathy requires a kidney biopsy, which reveals unusual deposits of immunoglobulin G and complement C3, substances created by the body's immune system. Fully 75 percent of cases are idiopathic, which means that the cause of the disease is unknown. The remaining 25 percent of cases are the result of other diseases like systemic lupus erythematosus, hepatitis B or C infection, or some forms of cancer. Drug therapies involving penicillamine, gold, or captopril have also been associated with membranous nephropathy. About 20 to 40 percent of patients with membranous nephropathy progress, usually over decades, to total kidney failure, but most patients experience either complete remission or continued symptoms without progressive kidney failure. Doctors disagree about how aggressively to treat this condition, since about 20 percent of patients recover without treatment. ACE inhibitors and ARBs are generally used to reduce proteinuria. Additional medication to control high blood pressure and edema is frequently required. Some patients benefit from steroids, but this treatment does not work for everyone. Additional immunosuppressive medications are helpful for some patients with progressive disease.

Minimal change disease (MCD) is the diagnosis given when a patient has the nephrotic syndrome and the kidney biopsy reveals little or no change to the structure of glomeruli or surrounding tissues when examined by a light microscope. Tiny drops of a fatty substance called a lipid may be present, but no scarring has taken place within the kidney. MCD may occur at any age, but it is most common in childhood. A small percentage of patients with idiopathic nephrotic syndrome do not respond to steroid therapy. For these patients, the doctor may recommend a low-sodium diet and prescribe a diuretic to control edema. The doctor may recommend the use of nonsteroidal anti-inflammatory drugs to reduce proteinuria. ACE inhibitors and ARBs have also been used to reduce proteinuria in patients with steroid-resistant MCD. These patients may respond to larger doses of steroids, more prolonged use of steroids, or steroids in combination with immunosuppressant drugs, such as chlorambucil, cyclophosphamide, or cyclosporine.

What are renal failure and end-stage renal disease?

Renal failure is any acute or chronic loss of kidney function and is the term used when some kidney function remains. Total kidney failure, sometimes called end-stage renal disease (ESRD), indicates permanent loss of kidney function. Depending on the form of glomerular disease, renal function may be lost in a matter of days or weeks or may deteriorate slowly and gradually over the course of decades.

Acute Renal Failure

A few forms of glomerular disease cause very rapid deterioration of kidney function. For example, PSGN can cause severe symptoms (hematuria, proteinuria, edema) within 2 to 3 weeks after a sore throat or skin infection develops. The patient may temporarily require dialysis to replace renal function. This rapid loss of kidney function is called acute renal failure (ARF). Although ARF can be life-threatening while it lasts, kidney function usually returns after the cause of the kidney failure has been treated. In many patients, ARF is not associated with any permanent damage. However, some patients may recover from ARF and subsequently develop CKD.

Chronic Kidney Disease

Most forms of glomerular disease develop gradually, often causing no symptoms for many years. CKD is the slow, gradual loss of kidney function. Some forms of CKD can be controlled or slowed down. For example, diabetic nephropathy can be delayed by tightly controlling blood glucose levels and using ACE inhibitors and ARBs to reduce proteinuria and control blood pressure. But CKD cannot be cured. Partial loss of renal function means that some portion of the patient's nephrons have been scarred, and scarred nephrons cannot be repaired. In many cases, CKD leads to total kidney failure.

Total Kidney Failure

To stay alive, a patient with total kidney failure must go on dialysis—hemodialysis or peritoneal dialysis—or receive a new kidney through transplantation. Patients with CKD who are approaching total kidney failure should learn as much about their treatment options as possible so they can make an informed decision when the time comes. With the help of dialysis or transplantation, many people continue to lead full, productive lives after reaching total kidney failure.

Points to Remember

• The kidneys filter waste and extra fluid from the blood.
• The filtering process takes place in the nephron, where microscopic blood vessel filters, called glomeruli, are attached to fluid-collecting tubules.
• A number of different disease processes can damage the glomeruli and thereby cause kidney failure. Glomerulonephritis and glomerulosclerosis are broad terms that include many forms of damage to the glomeruli.
• Some forms of kidney failure can be slowed down, but scarred glomeruli can never be repaired.
• Treatment for the early stages of kidney failure depends on the disease causing the damage.
• Early signs of kidney failure include blood or protein in the urine and swelling in the hands, feet, abdomen, or face. Kidney failure may be silent for many years.

The Nephrotic Syndrome

• The nephrotic syndrome is a condition marked by very high levels of protein in the urine; low levels of protein in the blood; swelling, especially around the eyes, feet, and hands; and high cholesterol.
• The nephrotic syndrome is a set of symptoms, not a disease in itself. It can occur with many diseases, so prevention relies on controlling the diseases that cause it.
• Treatment of the nephrotic syndrome focuses on identifying and treating the underlying cause, if possible, and reducing high cholesterol, blood pressure, and protein in the urine through diet, medication, or both.
• The nephrotic syndrome may go away once the underlying cause, if known, is treated. However, often a kidney disease is the underlying cause and cannot be cured. In these cases, the kidneys may gradually lose their ability to filter wastes and excess water from the blood. If kidney failure occurs, the patient will need to be on dialysis or have a kidney transplant.

What is growth failure in children with chronic kidney disease (CKD)?

Growth failure is a complication of CKD in which children do not grow as expected. When a child is below the third percentile—meaning 97 percent of children the same age and gender are taller—he or she has growth failure.¹ CKD is kidney disease that does not go away with treatment and tends to get worse over time.

Health care providers use charts to monitor the growth of children with CKD and look for signs of growth failure. Growth charts for children use percentiles to compare a particular child’s height with the height of children the same age and gender. For example, a child whose height is at the 50th percentile on a growth chart means half the children in the United States are taller than that child and half the children are shorter.

About one-third of children with CKD have growth failure.¹ Children diagnosed with CKD at a younger age

• have a higher chance of developing growth failure
• have more health issues related to growth failure and CKD

What are the kidneys and what do they do?

The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the two kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid. Children produce less urine than adults and the amount produced depends on their age. The urine flows from the kidneys to the bladder through tubes called ureters. The bladder stores urine. When the bladder empties, urine flows out of the body through a tube called the urethra, located at the bottom of the bladder.

What causes growth failure in children with chronic kidney disease?

Researchers have found that many factors cause growth failure in children with CKD. In addition to removing wastes and extra fluid from the blood, the kidneys perform important functions for a child’s growth. Understanding normal kidney function and growth helps families understand what causes growth failure in children with CKD.

Normal kidney function helps maintain the

• balance of nutrients and minerals, such as calcium and phosphorus, in the blood. These minerals are essential for normal bone growth. The kidneys use a hormone called calcitriol, a form of vitamin D, to help bones absorb the right amount of calcium from the blood. The kidneys also remove extra phosphorus, helping balance phosphorus and calcium levels in the blood.
• body’s ability to use growth hormone. Growth hormone is necessary during childhood to help bones grow and stay healthy. The pituitary gland naturally produces growth hormone, which acts as a messenger to help the body grow. Growth hormone tells the liver to produce another hormone, called insulin-like growth factor, that travels to muscles, organs, and bones and tells them to grow.
• correct levels of erythropoietin in the body. Erythropoietin is a hormone that helps bone marrow make red blood cells.
• proper balance of sodium, also called salt; potassium; and acid-base levels in the blood. Acid-base balance refers to the amount of acid in the blood.

Damaged kidneys can slow a child’s growth by

• causing mineral and bone disorder, which occurs when
  • vitamin D is not turned into calcitriol, which starves the bones of calcium.
  • phosphorus levels rise in the blood and draw calcium out of the bones and into the blood, causing the bones to weaken.
• creating an imbalance of sodium, potassium, and acid-base levels in the blood, also called acidosis. When blood is not balanced, the body slows growth to focus energy on restoring the balance.
• decreasing appetite. A child with CKD may not be hungry, or he or she may not have the energy to eat, which may lead to poor nutrition and slower growth.
• decreasing the production of erythropoietin. When erythropoietin levels are low, a child may develop anemia—a condition that develops when the blood does not have enough healthy red blood cells to carry oxygen to cells throughout the body. Anemia can cause growth to slow or stop.
• making an abnormally large amount of urine, called polyuria, which disrupts the body’s fluid balance. A child with polyuria loses minerals as well. The body slows growth to make up for the lost fluid and minerals.
• preventing the body from correctly using growth hormone. When the kidneys are damaged, waste builds up in the blood and the body does not properly process growth hormone.

How is growth failure treated in children with chronic kidney disease?

Health care providers treat growth failure in children with CKD with

• changes in eating, diet, and nutrition
• medications
• growth hormone therapy

Most children with growth failure grow to about one-third of their adult height within the first two years of life; therefore, it is important to start treatment for growth failure early.¹

Eating, Diet, and Nutrition

Children with CKD may lose their appetite or lack the energy to eat. To treat growth failure in children, a health care provider may recommend dietary changes, such as

• adding calcium. Children with CKD should get the recommended level of calcium for their age from their diet or from calcium supplements.
• monitoring liquids. Balancing the child’s liquid intake based on his or her kidney disease is important. Some children will need to increase liquid intake, while other children will need to restrict liquid intake.
• limiting phosphorus. Children with CKD may need to limit phosphorus intake if they have mineral and bone disorder.
• monitoring protein. Children with CKD should eat enough protein for growth; however, they should avoid high protein intake, which can put an extra burden on the kidneys.
• monitoring sodium. The amount of sodium children with CKD need depends on the stage of their kidney disease, their age, and sometimes other factors. The health care provider may recommend either limiting or adding sodium, often from salt, to the child’s diet.
• adding vitamin D. Children who do not get enough vitamin D through diet may need to take vitamin D supplements.

To help ensure coordinated and safe care, parents and caregivers should discuss the use of complementary and alternative medical practices, including the use of dietary supplements, with the child’s health care provider. Read more at nccih.nih.gov/.

Some children will use a feeding tube to receive all their nutrition. A feeding tube is a small, soft plastic tube placed through the nose or mouth into the stomach. The child will receive supplements through the tube to provide a full supply of fluid and nutrients to help him or her grow and develop. Feeding tubes are most often used in infants; however, sometimes older children and adolescents benefit from them as well.

Encouraging children to develop healthy eating habits can help prevent poor nutrition and promote healthy growing. The health care team will work with parents or caretakers to develop a healthy diet tailored to meet the needs of their child.

More information about diet and kidney disease is provided in the NIDDK health topic, Nutrition for Chronic Kidney Disease in Children.

Medications

A health care provider may prescribe medications that can help correct the underlying problems causing growth failure.

• A health care provider may prescribe phosphate binders when phosphorus levels in the blood rise and interfere with bone formation and normal growth. In the intestine, the medications bind, or attach, to some of the phosphorus found in food, causing the phosphorus to move through the intestine without being absorbed and exit the body in the stool. This process can decrease blood phosphorus levels and increase blood calcium levels. Phosphate binders come as chewable tablets, liquids, capsules, and pills.
• A health care provider may prescribe alkaline agents such as sodium bicarbonate to restore the acid-base balance in a child with acidosis.
• Synthetic erythropoietin is a man-made form of erythropoietin given by injection to treat anemia.

Growth Hormone Therapy

When a health care provider diagnoses a child with CKD and the child begins to show signs of growth failure, the health care provider may prescribe daily human growth hormone injections. The injections are a man-made growth hormone that mimics the natural hormone found in the body. Researchers have shown that using growth hormone therapy is effective in helping children reach normal adult height.

More information is provided in the NIDDK health topic, Treatment Methods for Kidney Failure in Children.

Points to Remember

• Growth failure is a complication of chronic kidney disease (CKD) in which children do not grow as expected.
• Health care providers use charts to monitor the growth of children with CKD and look for signs of growth failure.
• Researchers have found that many factors cause growth failure in children with CKD.
• Health care providers treat growth failure in children with CKD with
  • changes in eating, diet, and nutrition
  • medications
  • growth hormone therapy
• Encouraging children to develop healthy eating habits can help prevent poor nutrition and promote healthy growing.
• The health care team will work with parents or caretakers to develop a healthy diet tailored to meet the needs of their child.
• When a health care provider diagnoses a child with CKD and the child begins to show signs of growth failure, the health care provider may prescribe daily human growth hormone injections.

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

If I have kidney disease, why should I learn about heart disease?

If you have kidney disease, you are more likely to get heart disease. Heart disease is the most common cause of death among people who have kidney disease. However, learning about kidney disease and heart disease can help you find ways to stay healthy.

What is kidney disease?

Kidney disease means that the kidneys are damaged and can’t filter blood as they should. This damage can cause wastes to build up in the body. For most people, kidney damage occurs slowly over many years. This gradual loss of kidney function is called chronic kidney disease (CKD).

Most patients with CKD have no symptoms until kidney damage is advanced. After many years, you may start to feel sick or tired all of the time. Kidney failure is when you need a kidney transplant or a blood filtering treatment called dialysis to stay alive. Before you reach that stage, other health problems may develop. One of these problems is heart disease.

What is heart disease?

Heart disease includes any problem that keeps your heart from pumping blood as well as it should. The problem might start in your blood vessels or your heart. Heart and blood vessel problems include

• the buildup of a substance called plaque in the walls of the blood vessels
• a blood clot that blocks the flow of blood to the heart
• heart attack—heart damage caused by a lack of blood and oxygen to the heart

The buildup of plaque is often the first step in making other problems. Plaque can block blood flow.

	Normal blood vessel
	Blood vessel with plaque
	Blood vessel with plaque and blood clot

The early symptoms of plaque in your blood vessels include

• pain in your chest, called angina
• pain in your legs when walking
• sudden numbness or weakness in your arms or legs
• temporary signs of a stroke—a blockage of blood to the brain—such as having a hard time speaking or drooping muscles in your face
• feeling dizzy at times

A blood clot may form in a blood vessel that carries blood to the heart muscle. Then your heart muscle does not get the oxygen and nutrients it needs from the blood. The muscle becomes damaged. The damage to your heart caused by this blockage and lack of oxygen is called a heart attack.

Each person may have different heart attack symptoms. Symptoms can include

• chest pains or discomfort, or often a sense of chest pressure
• pain or discomfort in one or both arms—often the left arm—or in the back, jaw, neck, or stomach
• shortness of breath
• heavy sweating
• nausea or vomiting
• light-headedness

Women may not have chest pain. However, women may be more likely to have shortness of breath, nausea, or back and jaw pain.

If you have any of these symptoms, call 911 right away. You can start getting treatment in the ambulance on your way to the emergency room.

How are kidney disease and heart disease related?

Kidney disease and heart disease share two of the same main causes:

• diabetes
• high blood pressure

Diabetes

If you have diabetes, you have too much glucose, also called sugar, in your blood. Too much glucose in your blood for a long time can damage many parts of your body, including your heart and kidneys. More information is provided in the following NIDDK health topics:

• Diabetic Kidney Disease
• Diabetes, Heart Disease, and Stroke

High Blood Pressure

Blood pressure is the force of your blood pushing against the walls of your blood vessels. With high blood pressure, your heart works harder to pump blood, which can strain your heart. High blood pressure can damage your blood vessels. If high blood pressure damages the small blood vessels in your kidneys, your kidneys will not filter your blood as well as they should.

Blood pressure is written as two numbers separated by a slash. A doctor will say a blood pressure reading of 120/80 as “120 over 80.” The top number represents the force of blood pressing against the blood vessel walls when the heart is contracting. The bottom number represents the pressure when the heart is at rest between contractions. You should keep your blood pressure below 140/90 unless your doctor sets a different goal. Controlling your blood pressure can help protect your heart and kidneys.

High blood pressure is not only a cause of kidney disease; kidney disease is also a cause of high blood pressure. When you have damaged kidneys, they may be unable to filter extra water and salt from your body. The high blood pressure that results can then make kidney disease worse. Worsening kidney disease can raise blood pressure again. A dangerous cycle results as each disease makes the other worse. More information is provided in the NIDDK health topic, High Blood Pressure and Kidney Disease.

Who gets kidney disease?

You are more likely to develop kidney disease if you have

• diabetes
• high blood pressure
• heart disease
• lupus
• a family member who has kidney failure

African Americans, Hispanics/Latinos, American Indians, and Alaska Natives are also more likely to develop kidney disease.

Who gets heart disease?

You are more likely to develop heart disease if you have

• high blood pressure
• high blood cholesterol, a blood fat
• diabetes
• kidney disease
• a family history of early heart disease

You are also more likely to develop heart disease if you

• smoke
• eat a diet high in the wrong kinds of fats
• have too much sodium—often from salt—in your diet
• are overweight
• don’t exercise
• are a man age 45 or older
• are a woman age 55 or older

What are the tests for kidney disease?

Tests for kidney disease include a blood test and a urine test. Both tests can be done in your doctor’s office or at a commercial facility.

• The blood test checks your GFR, which tells how well your kidneys are filtering. GFR stands for glomerular filtration rate.
• The urine test checks for albumin in your urine. Albumin is a protein that can pass into the urine when the kidneys are damaged.

If these tests show you have kidney disease, you may need to repeat these tests on a regular basis. More information is provided in the NIDDK health topic, Testing for Kidney Disease.

What are the tests for heart disease?

You can get several routine tests for heart disease in your doctor’s office or at an outpatient center, including

• a blood pressure test
• a blood test for cholesterol
• an electrocardiogram—a test using sensors stuck to your skin to record the electrical signals that keep your heart beating

Another test, called a stress test, measures how your heart works during physical activity, such as walking, running on a treadmill, or riding a bike. This test usually takes place in a hospital or a specialized outpatient center.

If these tests show that you have heart disease, your doctor may want to do more tests.

How are kidney disease and heart disease treated?

If you have kidney disease or heart disease, your health care provider will want you to control your blood glucose if you have diabetes and your blood pressure if you have high blood pressure. Your health care provider may prescribe medicines to keep your blood glucose and blood pressure under control. Medicines for blood glucose control can include insulin injections and pills. Certain medicines for blood pressure may also keep your kidney disease from getting worse.

Another important part of treating kidney disease and heart disease includes living a healthy lifestyle. Staying active can help protect your kidneys and your heart. Try to be active for 30 minutes or more most days of the week. Start with easy activities such as walking slowly or raking leaves. Later, try some activities that get your heart pumping, such as walking briskly or swimming. Always talk with your health care provider before starting any new exercise program. You can find more information about about weight control and physical activity at NIDDK's Weight Control Information Network. See the “Eating, Diet, and Nutrition” section below for tips on eating a healthy diet that will protect your heart and kidneys.

How can I prevent kidney disease and heart disease?

You cannot always prevent kidney disease and heart disease. However, you can lower your chance of having kidney disease and heart disease by taking the following steps:

• See your health care provider as directed.
• Keep your blood pressure below 140/90. Follow your provider’s advice on how to stay at or below your target.
• Control your blood glucose if you have diabetes.
• Have your blood and urine checked as your provider instructs.
• Try to keep your cholesterol numbers in a healthy range. Talk with your provider about your cholesterol goals.
• Control your weight. If you are overweight, talk with your provider about how you can lose weight.
• Be physically active 30 minutes a day most days of the week.
• Take all medicines as prescribed.
• Eat healthy—see “Eating, Diet, and Nutrition.”

Eating, Diet, and Nutrition

A healthy diet can help protect you from heart disease and kidney disease. Keep your heart and kidneys healthy by eating plenty of the following foods:

• fruits and vegetables
• whole-grain breads and cereals
• low-fat milk and milk products such as yogurt and cheese
• lean meats or meat substitutes such as tofu
• fish
• unsaturated fats such as olive oil or corn oil
• low-sodium foods

People with advanced chronic kidney disease may need to adjust their diet to avoid high potassium. If you have advanced kidney disease, you may need to limit foods such as bananas, oranges, potatoes, and tomatoes and eat apples, berries, grapes, and peaches instead. Check with your provider to find out if you should cut back on your potassium. Do not alter your diet without checking because you might eat less of these healthy fruits and vegetables unnecessarily.

More information is provided in the NIDDK health topic, Potassium: Tips for People with Chronic Kidney Disease.

You need protein. However, protein breaks down into wastes that your kidneys need to remove. Most people eat more protein than they need. Large amounts of protein make your kidneys work harder. High-quality proteins such as meat, fish, and eggs make fewer wastes than other sources of protein. Beans, whole grains, soy products, nuts and nut butters, and dairy products can also be good sources of protein.

More information is provided in the NIDDK health topic, Protein: Tips for People with Chronic Kidney Disease.

Phosphorus is a mineral that helps keep your bones healthy. Phosphorus also helps blood vessels and muscles work. Phosphorus is found naturally in foods rich in protein, such as meat, poultry, fish, nuts, beans, and dairy products. Phosphorus is also added to many processed foods. When you have kidney disease, phosphorus can build up in your blood, making your bones thin, weak, and more likely to break. Many people with kidney disease need to eat foods with less phosphorus than they are used to eating.

More information is provided in the NIDDK health topic, Phosphorous: Tips for People with Chronic Kidney Disease.

Sodium is a part of salt. Sodium is found in many canned, packaged, and “fast” foods. Sodium is also found in many seasonings and meats. You should limit the amount of sodium you get to 2,300 mg or less each day.

More information is provided in the NIDDK health topic, Sodium: Tips for People with Chronic Kidney Disease.

A dietitian is a health care provider who helps people with kidney disease choose the right foods and plan healthy meals. Talk with a dietitian about foods that might harm you and foods you should add to your diet.

More information is provided in the NIDDK health topic, Eating Right for Kidney Health: Tips for People with Chronic Kidney Disease.

What should I ask my doctor about kidney disease and heart disease?

Some questions to ask your doctor include

• What is my blood pressure? What should it be?
• How often should I have my blood pressure checked?
• Should I be taking medicines to control my blood pressure?
• Should I be on a special diet?
• What are my cholesterol numbers? What should they be?
• How much exercise should I be getting?
• Where can I get help to quit smoking?

Points to Remember

• If you have kidney disease, you are more likely to get heart disease. Heart disease is the most common cause of death among people who have kidney disease.
• Kidney disease means that the kidneys are damaged and can’t filter blood as they should. This damage can cause wastes to build up in the body.
• Heart disease includes any problem that keeps your heart from pumping blood as well as it should. The problem might start in your blood vessels or your heart.
• Tests for kidney disease include a blood test and a urine test.
• You can get several routine tests for heart disease in your doctor’s office or at an outpatient center, including
  • a blood pressure test
  • a blood test for cholesterol
  • an electrocardiogram
  • a stress test
• If you have kidney disease or heart disease, you will want to control your blood glucose if you have diabetes, and your blood pressure if you have high blood pressure.
• You can lower your chance of having kidney disease and heart disease by taking the following steps:
  • See your health care provider as directed.
  • Keep your blood pressure below 140/90. Follow your provider’s advice on how to stay at or below your target.
  • Control your blood glucose if you have diabetes.
  • Have your blood and urine checked as recommended.
  • Try to keep your cholesterol numbers in a healthy range.
  • Control your weight. If you are overweight, talk with your provider about how you can lose weight.
  • Be physically active 30 minutes a day most days of the week.
  • Take all medicines as prescribed.
  • Eat healthy.
• You should limit the amount of sodium you get to 2,300 mg or less each day. Sodium is a part of salt.

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

What is hemolytic uremic syndrome?

Hemolytic uremic syndrome, or HUS, is a kidney condition that happens when red blood cells are destroyed and block the kidneys' filtering system. Red blood cells contain hemoglobin—an iron-rich protein that gives blood its red color and carries oxygen from the lungs to all parts of the body.

When the kidneys and glomeruli—the tiny units within the kidneys where blood is filtered—become clogged with the damaged red blood cells, they are unable to do their jobs. If the kidneys stop functioning, a child can develop acute kidney injury—the sudden and temporary loss of kidney function. Hemolytic uremic syndrome is the most common cause of acute kidney injury in children.

What are the kidneys and what do they do?

The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the two kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid. Children produce less urine than adults and the amount produced depends on their age. The urine flows from the kidneys to the bladder through tubes called ureters. The bladder stores urine. When the bladder empties, urine flows out of the body through a tube called the urethra, located at the bottom of the bladder.

The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the two kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid. Children produce less urine than adults and the amount produced depends on their age. The urine flows from the kidneys to the bladder through tubes called ureters. The bladder stores urine. When the bladder empties, urine flows out of the body through a tube called the urethra, located at the bottom of the bladder.

What causes hemolytic uremic syndrome in children?

The most common cause of hemolytic uremic syndrome in children is an Escherichia coli (E. coli) infection of the digestive system. The digestive system is made up of the gastrointestinal, or GI, tract—a series of hollow organs joined in a long, twisting tube from the mouth to the anus—and other organs that help the body break down and absorb food.

Normally, harmless strains, or types, of E. coli are found in the intestines and are an important part of digestion. However, if a child becomes infected with the O157:H7 strain of E. coli, the bacteria will lodge in the digestive tract and produce toxins that can enter the bloodstream. The toxins travel through the bloodstream and can destroy the red blood cells. E.coli O157:H7 can be found in

• undercooked meat, most often ground beef
• unpasteurized, or raw, milk
• unwashed, contaminated raw fruits and vegetables
• contaminated juice
• contaminated swimming pools or lakes

Less common causes, sometimes called atypical hemolytic uremic syndrome, can include

• taking certain medications, such as chemotherapy
• having other viral or bacterial infections
• inheriting a certain type of hemolytic uremicsyndrome that runs in families

More information about foodborne illnesses and the digestive system is provided in the NIDDK health topic, foodborne illnesses.

Which children are more likely to develop hemolytic uremic syndrome?

Children who are more likely to develop hemolytic uremic syndrome include those who

• are younger than age 5 and have been diagnosed with an E. coli O157:H7 infection
• have a weakened immune system
• have a family history of inherited hemolyticuremic syndrome

Hemolytic uremic syndrome occurs in about two out of every 100,000 children.

What are the signs and symptoms of hemolytic uremic syndrome in children?

A child with hemolytic uremic syndrome may develop signs and symptoms similar to those seen with gastroenteritis—an inflammation of the lining of the stomach, small intestine, and large intestine— such as

• vomiting
• bloody diarrhea
• abdominal pain
• fever and chills
• headache

As the infection progresses, the toxins released in the intestine begin to destroy red blood cells. When the red blood cells are destroyed, the child may experience the signs and symptoms of anemia—a condition in which red blood cells are fewer or smaller than normal, which prevents the body's cells from getting enough oxygen.

Signs and symptoms of anemia may include

• fatigue, or feeling tired
• weakness
• fainting
• paleness

As the damaged red blood cells clog the glomeruli, the kidneys may become damaged and make less urine. When damaged, the kidneys work harder to remove wastes and extra fluid from the blood, sometimes leading to acute kidney injury.

Other signs and symptoms of hemolytic uremic syndrome may include bruising and seizures.

When hemolytic uremic syndrome causes acute kidney injury, a child may have the following signs and symptoms:

• edema—swelling, most often in the legs, feet, or ankles and less often in the hands or face
• albuminuria—when a child's urine has high levels of albumin, the main protein in the blood
• decreased urine output
• hypoalbuminemia—when a child's blood has low levels of albumin
• blood in the urine

How is hemolytic uremic syndrome in children diagnosed?

A health care provider diagnoses hemolytic uremic syndrome with

• a medical and family history
• a physical exam
• urine tests
• a blood test
• a stool test
• kidney biopsy

Medical and Family History

Taking a medical and family history is one of the first things a health care provider may do to help diagnose hemolytic uremic syndrome.

Physical Exam

A physical exam may help diagnose hemolytic uremic syndrome. During a physical exam, a health care provider most often

• examines a child's body
• taps on specific areas of the child's body

Urine Tests

A health care provider may order the following urine tests to help determine if a child has kidney damage from hemolytic uremic syndrome.

Dipstick test for albumin. A dipstick test performed on a urine sample can detect the presence of albumin in the urine, which could mean kidney damage. The child or caretaker collects a urine sample in a special container in a health care provider's office or a commercial facility. For the test, a nurse or technician places a strip of chemically treated paper, called a dipstick, into the child's urine sample. Patches on the dipstick change color when albumin is present in the urine.

Urine albumin-to-creatinine ratio. A health care provider uses this measurement to estimate the amount of albumin passed into the urine over a 24-hour period. The child provides a urine sample during an appointment with the health care provider. Creatinine is a waste product that is filtered in the kidneys and passed in the urine. A high urine albumin-to-creatinine ratio indicates that the kidneys are leaking large amounts of albumin into the urine.

Blood Test

A blood test involves drawing blood at a health care provider's office or a commercial facility and sending the sample to a lab for analysis. A health care provider will test the blood sample to

• estimate how much blood the kidneys filter eachminute, called the estimated glomerular filtrationrate, or eGFR. The test results help the healthcare provider determine the amount of kidneydamage from hemolytic uremic syndrome.
• check red blood cell and platelet levels.
• check for liver and kidney function.
• assess protein levels in the blood.

Stool Test

A stool test is the analysis of a sample of stool. The health care provider will give the child's parent or caretaker a container for catching and storing the stool. The parent or caretaker returns the sample to the health care provider or a commercial facility that will send the sample to a lab for analysis. Stool tests can show the presence of E. coli O157:H7.

Kidney Biopsy

Biopsy is a procedure that involves taking a small piece of kidney tissue for examination with a microscope. A health care provider performs the biopsy in an outpatient center or a hospital. The health care provider will give the child light sedation and local anesthetic; however, in some cases, the child will require general anesthesia. A pathologist—a doctor who specializes in diagnosing diseases—examines the tissue in a lab. The pathologist looks for signs of kidney disease and infection. The test can help diagnose hemolytic uremic syndrome.

What are the complications of hemolytic uremic syndrome in children?

Most children who develop hemolytic uremic syndrome and its complications recover without permanent damage to their health.¹

However, children with hemolytic uremic syndrome may have serious and sometimes life-threatening complications, including

• acute kidney injury
• high blood pressure
• blood-clotting problems that can lead to bleeding
• seizures
• heart problems
• chronic, or long lasting, kidney disease
• stroke
• coma

How is hemolytic uremic syndrome in children treated?

A health care provider will treat a child with hemolytic uremic syndrome by addressing

• urgent symptoms and preventing complications
• acute kidney injury
• chronic kidney disease (CKD)

In most cases, health care providers do not treat children with hemolytic uremic syndrome with antibiotics unless they have infections in other areas of the body. With proper management, most children recover without long-term health problems.²

Treating Urgent Symptoms and Preventing Complications

A health care provider will treat a child's urgent symptoms and try to prevent complications by

• observing the child closely in the hospital
• replacing minerals, such as potassium and salt, and fluids through an intravenous (IV) tube
• giving the child red blood cells and platelets— cells in the blood that help with clotting—through an IV
• giving the child IV nutrition
• treating high blood pressure with medications

Treating Acute Kidney Injury

If necessary, a health care provider will treat acute kidney injury with dialysis—the process of filtering wastes and extra fluid from the body with an artificial kidney. The two forms of dialysis are hemodialysis and peritoneal dialysis. Most children with acute kidney injury need dialysis for a short time only.

Treating Chronic Kidney Disease

Some children may sustain significant kidney damage that slowly develops into CKD. Children who develop CKD must receive treatment to replace the work the kidneys do. The two types of treatment are dialysis and transplantation.

In most cases, health care providers treat CKD with a kidney transplant. A kidney transplant is surgery to place a healthy kidney from someone who has just died or a living donor, most often a family member, into a person's body to take over the job of the failing kidney. Though some children receive a kidney transplant before their kidneys fail completely, many children begin with dialysis to stay healthy until they can have a transplant.

More information is provided in the NIDDK health topic, Treatment Methods for Kidney Failure in Children.

How can hemolytic uremic syndrome in children be prevented?

Parents and caregivers can help prevent childhood hemolytic uremic syndrome due to E. coli O157:H7 by

• avoiding unclean swimming areas
• avoiding unpasteurized milk, juice, and cider
• cleaning utensils and food surfaces often
• cooking meat to an internal temperature of at least 160° F
• defrosting meat in the microwave or refrigerator
• keeping children out of pools if they have had diarrhea
• keeping raw foods separate
• washing hands before eating
• washing hands well after using the restroom and after changing diapers

When a child is taking medications that may cause hemolytic uremic syndrome, it is important that the parent or caretaker watch for symptoms and report any changes in the child's condition to the health care provider as soon as possible.

Eating, Diet, and Nutrition

At the beginning of the illness, children with hemolytic uremic syndrome may need IV nutrition or supplements to help maintain fluid balance in the body. Some children may need to follow a low-salt diet to help prevent swelling and high blood pressure.

Health care providers will encourage children with hemolytic uremic syndrome to eat when they are hungry. Most children who completely recover and do not have permanent kidney damage can return to their usual diet.

Points to Remember

• Hemolytic uremic syndrome, or HUS, is a kidney condition that happens when red blood cells are destroyed and block the kidneys' filtering system.
• The most common cause of hemolytic uremic syndrome in children is an Escherichia coli (E. coli) infection of the digestive system.
• Normally, harmless strains, or types, of E. coli are found in the intestines and are an important part of digestion. However, if a child becomes infected with the O157:H7 strain of E. coli, the bacteria will lodge in the digestive tract and produce toxins that can enter the bloodstream.
• A child with hemolytic uremic syndrome may develop signs and symptoms similar to those seen with gastroenteritis, an inflammation of the lining of the stomach, small intestine, and large intestine.
• Most children who develop hemolytic uremic syndrome and its complications recover without permanent damage to their health.
• Some children may sustain significant kidney damage that slowly develops into chronic kidney disease (CKD).
• Parents and caregivers can help prevent childhood hemolytic uremic syndrome due to E. coli O157:H7 by
  • avoiding unclean swimming areas
  • avoiding unpasteurized milk, juice, and cider
  • cleaning utensils and food surfaces often
  • cooking meat to an internal temperature of at least 160° F
  • defrosting meat in the microwave or refrigerator
  • keeping children out of pools if they have had diarrhea
  • keeping raw foods separate
  • washing hands before eating
  • washing hands well after using the restroom and after changing diapers

Resources

National Kidney Foundation
Children with Chronic Kidney Disease: Tips for Parents
www.kidney.org

Family Focus newsletter
www.kidney.org

Employers' Guide
www.kidney.org

Nemours KidsHealth Website
When Your Child Has a Chronic Kidney Disease
www.kidshealth.org

What's the Deal With Dialysis?
www.kidshealth.org

Nephkids
Cyber-support group
www.cybernephrology.ualberta.ca

United Network for Organ Sharing
Organ Transplants: What Every Kid Needs to Know
www.unos.org (PDF, 1.67 MB)

U.S. Department of Health and Human Services, Centers for Medicare & Medicaid Services
Medicare Coverage of Kidney Dialysis & Kidney Transplant Services
www.medicare.gov (PDF, 1,080 KB)

U.S. Social Security Administration
Benefits For Children With Disabilities
www.socialsecurity.gov (PDF, 413 KB)

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

What is high blood pressure?

Blood pressure is the force of blood pushing against blood vessel walls as the heart pumps out blood, and high blood pressure, also called hypertension, is an increase in the amount of force that blood places on blood vessels as it moves through the body. Factors that can increase this force include higher blood volume due to extra fluid in the blood and blood vessels that are narrow, stiff, or clogged.

Blood pressure test results are written with two numbers separated by a slash. For example, a health care provider will write a blood pressure result as 120/80. A health care provider will say this blood pressure result as “120 over 80.” The top number is called the systolic pressure and represents the pressure as the heart beats and pushes blood through the blood vessels. The bottom number is called the diastolic pressure and represents the pressure as blood vessels relax between heartbeats.

Most people without chronic health conditions have a normal blood pressure if it stays below 120/80. Prehypertension is a systolic pressure of 120 to 139 or a diastolic pressure of 80 to 89. High blood pressure is a systolic pressure of 140 or above or a diastolic pressure of 90 or above.¹

People should talk with their health care provider about their individual blood pressure goals and how often they should have their blood pressure checked.

What are the kidneys and what do they do?

The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the two kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid. The urine flows from the kidneys to the bladder through tubes called ureters. The bladder stores urine. When the bladder empties, urine flows out of the body through a tube called the urethra, located at the bottom of the bladder. In men the urethra is long, while in women it is short.

Kidneys work at the microscopic level. The kidney is not one large filter. Each kidney is made up of about a million filtering units called nephrons. Each nephron filters a small amount of blood. The nephron includes a filter, called the glomerulus, and a tubule. The nephrons work through a two-step process. The glomerulus lets fluid and waste products pass through it; however, it prevents blood cells and large molecules, mostly proteins, from passing. The filtered fluid then passes through the tubule, which sends needed minerals back to the bloodstream and removes wastes. The final product becomes urine.

How does high blood pressure affect the kidneys?

High blood pressure can damage blood vessels in the kidneys, reducing their ability to work properly. When the force of blood flow is high, blood vessels stretch so blood flows more easily. Eventually, this stretching scars and weakens blood vessels throughout the body, including those in the kidneys.

If the kidneys’ blood vessels are damaged, they may stop removing wastes and extra fluid from the body. Extra fluid in the blood vessels may then raise blood pressure even more, creating a dangerous cycle.

High blood pressure is the second leading cause of kidney failure in the United States after diabetes, as illustrated in Figure 1.² In addition, the rate of kidney failure due to high blood pressure increased 7.7 percent from 2000 to 2010.³

Figure 1. Causes of kidney failure in the United States

What are the symptoms of high blood pressure and kidney disease?

Most people with high blood pressure do not have symptoms. In rare cases, high blood pressure can cause headaches.

Kidney disease also does not have symptoms in the early stages. A person may have swelling called edema, which happens when the kidneys cannot get rid of extra fluid and salt. Edema can occur in the legs, feet, or ankles and less often in the hands or face. Once kidney function decreases further, symptoms can include

• appetite loss
• nausea
• vomiting
• drowsiness or feeling tired
• trouble concentrating
• sleep problems
• increased or decreased urination
• generalized itching or numbness
• dry skin
• headaches
• weight loss
• darkened skin
• muscle cramps
• shortness of breath
• chest pain

How are high blood pressure and kidney disease diagnosed?

A health care provider diagnoses high blood pressure when multiple blood pressure tests—often repeated over several visits to a health care provider’s office—show that a systolic blood pressure is consistently above 140 or a diastolic blood pressure is consistently above 90. Health care providers measure blood pressure with a blood pressure cuff. People can also buy blood pressure cuffs at discount chain stores and drugstores to monitor their blood pressure at home.

Kidney disease is diagnosed with urine and blood tests.

Urine Tests

Dipstick test for albumin. A dipstick test performed on a urine sample can detect the presence of albumin in the urine. Albumin is a protein in the blood that can pass into the urine when the kidneys are damaged. A patient collects the urine sample in a special container in a health care provider’s office or a commercial facility. The office or facility tests the sample onsite or sends it to a lab for analysis. For the test, a nurse or technician places a strip of chemically treated paper, called a dipstick, into the urine. Patches on the dipstick change color when blood or protein is present in urine.

Urine albumin-to-creatinine ratio. A health care provider uses the albumin and creatinine measurement to determine the ratio between the albumin and creatinine in the urine. Creatinine is a waste product in the blood that is filtered in the kidneys and excreted in the urine. A urine albumin-to-creatinine ratio above 30 mg/g may be a sign of kidney disease.

Blood Test

A blood test involves having blood drawn at a health care provider’s office or a commercial facility and sending the sample to a lab for analysis. A health care provider may order a blood test to estimate how much blood the kidneys filter each minute, called the estimated glomerular filtration rate (eGFR). The results of the test indicate the following:

• eGFR of 60 or above is in the normal range
• eGFR below 60 may indicate kidney damage
• eGFR of 15 or below may indicate kidney failure

Get Screened for Kidney Disease

Kidney disease, when found early, can be treated to prevent more serious disease and other complications. The National Kidney Foundation recommends people with high blood pressure receive the following regular screenings:

• blood pressure tests
• urine albumin
• eGFR

Health care providers will help determine how often people with high blood pressure should be screened.

How can people prevent or slow the progression of kidney disease from high blood pressure?

The best way to slow or prevent kidney disease from high blood pressure is to take steps to lower blood pressure. These steps include a combination of medication and lifestyle changes, such as

• healthy eating
• physical activity
• maintaining a healthy weight
• quitting smoking
• managing stress

No matter what the cause of the kidney disease, high blood pressure can increase damage to the kidneys. People with kidney disease should keep their blood pressure below 140/90.⁴

Medication

Medications that lower blood pressure can also significantly slow the progression of kidney disease. Two types of blood pressure-lowering medications, angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), have been shown effective in slowing the progression of kidney disease. Many people require two or more medications to control their blood pressure. In addition to an ACE inhibitor or an ARB, a health care provider may prescribe a diuretic—a medication that helps the kidneys remove fluid from the blood. A person may also need beta blockers, calcium channel blockers, and other blood pressure medications.

Eating, Diet, and Nutrition

Following a healthy eating plan can help lower blood pressure. A health care provider may recommend the Dietary Approaches to Stop Hypertension (DASH) eating plan. DASH focuses on fruits, vegetables, whole grains, and other foods that are heart healthy and lower in sodium, which often comes from salt. The DASH eating plan

• is low in fat and cholesterol
• features fat-free or low-fat milk and dairy products, fish, poultry, and nuts
• suggests less red meat, sweets, added sugars, and sugar-containing beverages
• is rich in nutrients, protein, and fiber

Read more about DASH at www.nhlbi.nih.gov/health/resources/heart/hbp-dash-index.htm.

A dietitian may also recommend this type of diet for people who have already developed kidney disease. A diet low in sodium and liquid intake can help reduce edema and lower blood pressure. Reducing saturated fat and cholesterol can help control high levels of lipids, or fats, in the blood.

Health care providers may recommend that people with kidney disease eat moderate or reduced amounts of protein, though the benefits of reducing protein in a person’s diet is still being researched. Proteins break down into waste products that the kidneys filter from the blood. Eating more protein than the body needs may burden the kidneys and cause kidney function to decline faster. However, protein intake that is too low may lead to malnutrition, a condition that occurs when the body does not get enough nutrients. People with kidney disease who are on a restricted protein diet should be monitored with blood tests that can show low nutrient levels.

In addition, consuming too much alcohol raises blood pressure, so people should limit alcoholic drinks—two per day for men and one per day for women.

A health care provider can help people change their diet to meet their individual needs.

Physical Activity

Regular physical activity can lower blood pressure and reduce the chances of other health problems. A health care provider can provide information about how much and what kinds of activity are safe. Most people should try to get at least 30 to 60 minutes of activity most or all days of the week. A person can do all physical activity at once or break up activities into shorter periods of at least 10 minutes each. Moderate activities include brisk walking, dancing, bowling, riding a bike, working in a garden, and cleaning the house.

Body Weight

People who are overweight or obese should aim to reduce their weight by 7 to 10 percent during the first year of treatment for high blood pressure. This amount of weight loss can lower the chance of health problems related to high blood pressure. Overweight is defined as a body mass index (BMI)—a measurement of weight in relation to height—of 25 to 29. A BMI of 30 or higher is considered obese. A BMI lower than 25 is the goal for keeping blood pressure under control.⁵

Smoking

People who smoke should quit. Smoking can damage blood vessels, raise the chance of high blood pressure, and worsen health problems related to high blood pressure. People with high blood pressure should talk with their health care provider about programs and products they can use to quit smoking.

Stress

Learning how to manage stress, relax, and cope with problems can improve emotional and physical health. Some activities that may help reduce stress include

• exercising
• practicing yoga or tai chi
• listening to music
• focusing on something calm or peaceful
• meditating

Points to Remember

• Blood pressure is the force of blood pushing against blood vessel walls as the heart pumps out blood, and high blood pressure, also called hypertension, is an increase in the amount of force that blood places on blood vessels as it moves through the body.
• High blood pressure can damage blood vessels in the kidneys, reducing their ability to work properly. When the force of blood flow is high, blood vessels stretch so blood flows more easily. Eventually, this stretching scars and weakens blood vessels throughout the body, including those in the kidneys.
• High blood pressure is the second leading cause of kidney failure in the United States after diabetes.
• A health care provider diagnoses high blood pressure when multiple blood pressure tests—often repeated over several visits to a health care provider’s office—show that a systolic blood pressure is consistently above 140 or a diastolic blood pressure is consistently above 90.
• Kidney disease is diagnosed with urine and blood tests.
• The best way to slow or prevent kidney damage from high blood pressure is to take steps to lower blood pressure. These steps include a combination of medication and lifestyle changes, such as
  • healthy eating
  • physical activity
  • maintaining a healthy weight
  • quitting smoking
  • managing stress
• No matter what the cause of the kidney disease, high blood pressure can increase damage to the kidneys. People with kidney disease should keep their blood pressure below 140/90.

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

What is immunoglobulin A (IgA) nephropathy?

IgA nephropathy, also known as Berger’s disease, is a kidney disease that occurs when IgA deposits build up in the kidneys, causing inflammation that damages kidney tissues. IgA is an antibody—a protein made by the immune system to protect the body from foreign substances such as bacteria or viruses. Most people with IgA nephropathy receive care from a nephrologist, a doctor who specializes in treating people with kidney disease.

How does IgA nephropathy affect the kidneys?

IgA nephropathy affects the kidneys by attacking the glomeruli. The glomeruli are sets of looping blood vessels in nephrons—the tiny working units of the kidneys that filter wastes and remove extra fluid from the blood. The buildup of IgA deposits inflames and damages the glomeruli, causing the kidneys to leak blood and protein into the urine. The damage may lead to scarring of the nephrons that progresses slowly over many years. Eventually, IgA nephropathy can lead to end-stage kidney disease, sometimes called ESRD, which means the kidneys no longer work well enough to keep a person healthy. When a person’s kidneys fail, he or she needs a transplant or blood-filtering treatments called dialysis.

More information is provided in the NIDDK health topic, Glomerular Diseases Overview.

What causes IgA nephropathy?

Scientists think that IgA nephropathy is an autoimmune kidney disease, meaning that the disease is due to the body’s immune system harming the kidneys.

People with IgA nephropathy have an increased blood level of IgA that contains less of a special sugar, galactose, than normal. This galactose-deficient IgA is considered “foreign” by other antibodies circulating in the blood. As a result, these other antibodies attach to the galactose-deficient IgA and form a clump. This clump is also called an immune complex. Some of the clumps become stuck in the glomerulus of the nephron and cause inflammation and damage.

For some people, IgA nephropathy runs in families. Scientists have recently found several genetic markers that may play a role in the development of the disease. IgA nephropathy may also be related to respiratory or intestinal infections and the immune system’s response to these infections.

How common is IgA nephropathy and who is more likely to get the disease?

IgA nephropathy is one of the most common kidney diseases, other than those caused by diabetes or high blood pressure.¹

IgA nephropathy can occur at any age, although the first evidence of kidney disease most frequently appears when people are in their teens to late 30s.² IgA nephropathy in the United States is twice as likely to appear in men than in women.³ While found in people all over the world, IgA nephropathy is more common among Asians and Caucasians.⁴

A person may be more likely to develop IgA nephropathy if

• he or she has a family history of IgA nephropathy or Henoch-Schönlein purpura—a disease that causes small blood vessels in the body to become inflamed and leak
• he is a male in his teens to late 30s
• he or she is Asian or Caucasian

What are the signs and symptoms of IgA nephropathy?

In its early stages, IgA nephropathy may have no symptoms; it can be silent for years or even decades. Once symptoms appear, the most common one is hematuria, or blood in the urine. Hematuria can be a sign of damaged glomeruli. Blood in the urine may appear during or soon after a cold, sore throat, or other respiratory infection. The amount of blood may be

• visible with the naked eye. The urine may turn pink or the color of tea or cola. Sometimes a person may have dark or bloody urine.
• so small that it can only be detected using special medical tests.

Another symptom of IgA nephropathy is albuminuria—when a person’s urine contains an increased amount of albumin, a protein typically found in the blood, or large amounts of protein in the urine. Albumin is the main protein in the blood. Healthy kidneys keep most proteins in the blood from leaking into the urine. However, when the glomeruli are damaged, large amounts of protein leak out of the blood into the urine.

When albumin leaks into the urine, the blood loses its capacity to absorb extra fluid from the body. Too much fluid in the body may cause edema, or swelling, usually in the legs, feet, or ankles and less often in the hands or face. Foamy urine is another sign of albuminuria. Some people with IgA nephropathy have both hematuria and albuminuria.

After 10 to 20 years with IgA nephropathy, about 20 to 40 percent of adults develop end-stage kidney disease.⁵ Signs and symptoms of end-stage kidney disease may include

• high blood pressure
• little or no urination
• edema
• feeling tired
• drowsiness
• generalized itching or numbness
• dry skin
• headaches
• weight loss
• appetite loss
• nausea
• vomiting
• sleep problems
• trouble concentrating
• darkened skin
• muscle cramps

What are the complications of IgA nephropathy?

Complications of IgA nephropathy include

• high blood pressure
• acute kidney failure—sudden and temporary loss of kidney function
• chronic kidney failure—reduced kidney function over a period of time
• nephrotic syndrome—a collection of symptoms that indicate kidney damage; symptoms include albuminuria, lack of protein in the blood, and high blood cholesterol levels
• heart or cardiovascular problems
• Henoch-Schönlein purpura

More information is provided in the NIDDK health topics, Kidney Disease and Kidney Failure.

How is kidney disease diagnosed?

A health care provider diagnoses kidney disease with

• a medical and family history
• a physical exam
• urine tests
• a blood test

Medical and Family History

Taking a medical and family history may help a health care provider diagnose kidney disease.

Physical Exam

A physical exam may help diagnose kidney disease. During a physical exam, a health care provider usually

• measures the patient’s blood pressure
• examines the patient’s body for swelling

Urine Tests

Dipstick test for albumin and blood. A dipstick test performed on a urine sample can detect the presence of albumin and blood. The patient provides a urine sample in a special container in a health care provider’s office or a commercial facility. A nurse or technician can test the sample in the same location, or he or she can send it to a lab for analysis. The test involves placing a strip of chemically treated paper, called a dipstick, into the patient’s urine sample. Patches on the dipstick change color when albumin or blood is present in urine.

Urine albumin-to-creatinine ratio. A health care provider uses this measurement, which compares the amount of albumin with the amount of creatinine in a urine sample, to estimate 24-hour albumin excretion. A patient may have chronic kidney disease if the urine albumin-to-creatinine ratio is greater than 30 milligrams (mg) of albumin for each gram (g) of creatinine (30 mg/g). This measurement is also called UACR.

Blood Test

A blood test involves having blood drawn at a health care provider’s office or a commercial facility and sending the sample to a lab for analysis. A health care provider may order a blood test to estimate how much blood a patient’s kidneys filter each minute—a measurement called the estimated glomerular filtration rate (eGFR). Depending on the results, the test can indicate the following:

• eGFR of 60 or above is in the normal range
• eGFR below 60 may indicate kidney disease
• eGFR of 15 or below may indicate kidney failure

How is IgA nephropathy diagnosed?

Currently, health care providers do not use blood or urine tests as reliable ways to diagnose IgA nephropathy; therefore, the diagnosis of IgA nephropathy requires a kidney biopsy.

A kidney biopsy is a procedure that involves taking a small piece of kidney tissue for examination with a microscope. A health care provider performs a kidney biopsy in a hospital or an outpatient center with light sedation and a local anesthetic. The health care provider uses imaging techniques such as ultrasound or a computerized tomography scan to guide the biopsy needle into the kidney. A pathologist—a doctor who specializes in examining tissues to diagnose diseases—examines the kidney tissue with a microscope. Only a biopsy can show the IgA deposits in the glomeruli. The biopsy can also show how much kidney damage has already occurred. The biopsy results can help the health care provider determine the best course of treatment.

How is IgA nephropathy treated?

Researchers have not yet found a specific cure for IgA nephropathy. Once the kidneys are scarred, they cannot be repaired. Therefore, the ultimate goal of IgA nephropathy treatment is to prevent or delay end-stage kidney disease. A health care provider may prescribe medications to

• control a person’s blood pressure and slow the progression of kidney disease
• remove extra fluid from a person’s blood
• control a person’s immune system
• lower a person’s blood cholesterol levels

Control Blood Pressure and Slow Progression of Kidney Disease

People with IgA nephropathy that is causing high blood pressure may need to take medications that lower blood pressure and can also significantly slow the progression of kidney disease. Two types of blood pressure-lowering medications—angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs)—have proven effective in slowing the progression of kidney disease. Many people require two or more medications to control their blood pressure. A person may also need beta-blockers, calcium channel blockers, and other blood pressure medications.

Remove Extra Fluid

A health care provider may prescribe a diuretic, a medication that helps the kidneys remove extra fluid from the blood. Removing the extra fluid can improve the control of blood pressure. Taking a diuretic along with an ACE inhibitor or an ARB often increases the effectiveness of these medications.

Control the Immune System

Health care providers sometimes use medications to control a person’s immune system. Since inflammation is the immune system’s normal response, controlling the immune system can decrease inflammation. Health care providers may prescribe the following medications:

• corticosteroids, such as prednisone
• cyclophosphamide

Lower Blood Cholesterol Levels

People with IgA nephropathy may develop high blood cholesterol levels. Cholesterol is a type of fat found in the body’s cells, in blood, and in many foods. People who take medications for high blood cholesterol levels can lower their blood cholesterol levels. A health care provider may prescribe one of several cholesterol-lowering medications called statins.

How can a person prevent IgA nephropathy?

Researchers have not found a way to prevent IgA nephropathy. People with a family history of IgA nephropathy should talk with their health care provider to find out what steps they can take to keep their kidneys healthy, such as controlling their blood pressure and keeping their blood cholesterol at healthy levels.

Eating, Diet, and Nutrition

Researchers have not found that eating, diet, and nutrition play a role in causing or preventing IgA nephropathy. Health care providers may recommend that people with kidney disease, such as IgA nephropathy, make dietary changes such as

• limiting dietary sodium, often from salt, to help reduce edema and lower blood pressure
• decreasing liquid intake to help reduce edema and lower blood pressure
• eating a diet low in saturated fat and cholesterol to help control high levels of lipids, or fats, in the blood

Health care providers may also recommend that people with kidney disease eat moderate or reduced amounts of protein, although the benefit of reducing protein in a person’s diet is still being researched. Proteins break down into waste products the kidneys must filter from the blood. Eating more protein than the body needs may burden the kidneys and cause kidney function to decline faster. However, protein intake that is too low may lead to malnutrition, a condition that occurs when the body does not get enough nutrients. People with kidney disease on a restricted protein diet should receive blood tests that can show nutrient levels.

Some researchers have shown that fish oil supplements containing omega-3 fatty acids may slow kidney damage in some people with kidney disease by lowering blood pressure. Omega-3 fatty acids may help reduce inflammation and slow kidney damage due to IgA nephropathy. To help ensure coordinated and safe care, people should discuss their use of complementary and alternative medical practices, including their use of dietary supplements and probiotics, with their health care provider. Read more at nccih.nih.gov/health/supplements.

People with IgA nephropathy should talk with a health care provider about dietary changes to best manage their individual needs.

Points to Remember

• Immunoglobulin A (IgA) nephropathy, also known as Berger’s disease, is a kidney disease that occurs when IgA deposits build up in the kidneys, causing inflammation that damages kidney tissues.
• Scientists think that IgA nephropathy is an autoimmune kidney disease, meaning that the disease is due to the body’s immune system attacking tissues in the kidney.
• IgA nephropathy is one of the most common kidney diseases, other than those caused by diabetes or high blood pressure.
• In its early stages, IgA nephropathy may have no symptoms; it can be silent for years or even decades.
• Once symptoms appear, the most common one is hematuria, or blood in the urine.
• Another symptom of IgA nephropathy is albuminuria—when a person’s urine contains an increased amount of albumin, a protein typically found in the blood, or large amounts of protein in the urine.
• Currently, health care providers do not use blood or urine tests as reliable ways to diagnose IgA nephropathy; therefore, the diagnosis of IgA nephropathy requires a kidney biopsy.
• Researchers have not yet found a specific cure for IgA nephropathy.

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

How does kidney disease affect children?

Kidney disease can affect children in various ways, ranging from treatable disorders without long-term consequences to life-threatening conditions. Acute kidney disease develops suddenly, lasts a short time, and can be serious with long-lasting consequences or may go away completely once the underlying cause has been treated. Chronic kidney disease (CKD) does not go away with treatment and tends to get worse over time. CKD eventually leads to kidney failure, described as end-stage kidney disease or ESRD when treated with a kidney transplant or blood-filtering treatments called dialysis.

Children with CKD or kidney failure face many challenges, which can include

• a negative self-image
• relationship problems
• behavior problems
• learning problems
• trouble concentrating
• delayed language skills development
• delayed motor skills development

Children with CKD may grow at a slower rate than their peers, and urinary incontinence—the loss of bladder control, which results in the accidental loss of urine—is common.

More information is provided in the NIDDK health topic, Caring for a Child with Kidney Disease.

What are the kidneys and what do they do?

The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the two kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid. Children produce less urine than adults and the amount produced depends on their age. The kidneys work around the clock; a person does not control what they do. Ureters are the thin tubes of muscle—one on each side of the bladder—that carry urine from each of the kidneys to the bladder. The bladder stores urine until the person finds an appropriate time and place to urinate.

The kidney is not one large filter. Each kidney is made up of about a million filtering units called nephrons. Each nephron filters a small amount of blood. The nephron includes a filter, called a glomerulus, and a tubule. The nephrons work through a two-step process. The glomerulus lets fluid and waste products pass through it; however, it prevents blood cells and large molecules, mostly proteins, from passing. The filtered fluid then passes through the tubule, which changes the fluid by sending needed minerals back to the bloodstream and removing wastes. The final product becomes urine.

The kidneys also control the level of minerals such as sodium, phosphorus, and potassium in the body, and produce an important hormone to prevent anemia. Anemia is a condition in which the number of red blood cells is less than normal, resulting in less oxygen carried to the body’s cells.

What are the causes of kidney disease in children?

Kidney disease in children can be caused by

• birth defects
• hereditary diseases
• infection
• nephrotic syndrome
• systemic diseases
• trauma
• urine blockage or reflux

From birth to age 4, birth defects and hereditary diseases are the leading causes of kidney failure. Between ages 5 and 14, kidney failure is most commonly caused by hereditary diseases, nephrotic syndrome, and systemic diseases. Between ages 15 and 19, diseases that affect the glomeruli are the leading cause of kidney failure, and hereditary diseases become less common.¹

Birth Defects

A birth defect is a problem that happens while a baby is developing in the mother’s womb. Birth defects that affect the kidneys include renal agenesis, renal dysplasia, and ectopic kidney, to name a few. These defects are abnormalities of size, structure, or position of the kidneys:

• renal agenesis—children born with only one kidney
• renal dysplasia—children born with both kidneys, yet one does not function
• ectopic kidney—children born with a kidney that is located below, above, or on the opposite side of its usual position

In general, children with these conditions lead full, healthy lives. However, some children with renal agenesis or renal dysplasia are at increased risk for developing kidney disease.

Hereditary Diseases

Hereditary kidney diseases are illnesses passed from parent to child through the genes. One example is polycystic kidney disease (PKD), characterized by many grapelike clusters of fluid-filled cysts—abnormal sacs—that make both kidneys larger over time. These cysts take over and destroy working kidney tissue. Another hereditary disease is Alport syndrome, which is caused by a mutation in a gene for a type of protein called collagen that makes up the glomeruli. The condition leads to scarring of the kidneys. Alport syndrome generally develops in early childhood and is more serious in boys than in girls. The condition can lead to hearing and vision problems in addition to kidney disease.

Infection

Hemolytic uremic syndrome and acute post-streptococcal glomerulonephritis are kidney diseases that can develop in a child after an infection.

• Hemolytic uremic syndrome is a rare disease that is often caused by the Escherichia coli (E. coli) bacterium found in contaminated foods, such as meat, dairy products, and juice. Hemolytic uremic syndrome develops when E. coli bacteria lodged in the digestive tract make toxins that enter the bloodstream. The toxins start to destroy red blood cells and damage the lining of the blood vessels, including the glomeruli. Most children who get an E. coli infection have vomiting, stomach cramps, and bloody diarrhea for 2 to 3 days. Children who develop hemolytic uremic syndrome become pale, tired, and irritable. Hemolytic uremic syndrome can lead to kidney failure in some children.
• Post-streptococcal glomerulonephritis can occur after an episode of strep throat or a skin infection. The Streptococcus bacterium does not attack the kidneys directly; instead, the infection may stimulate the immune system to overproduce antibodies. Antibodies are proteins made by the immune system. The immune system protects people from infection by identifying and destroying bacteria, viruses, and other potentially harmful foreign substances. When the extra antibodies circulate in the blood and finally deposit in the glomeruli, the kidneys can be damaged. Most cases of post-streptococcal glomerulonephritis develop 1 to 3 weeks after an untreated infection, though it may be as long as 6 weeks. Post-streptococcal glomerulonephritis lasts only a brief time and the kidneys usually recover. In a few cases, kidney damage may be permanent.

Nephrotic Syndrome

Nephrotic syndrome is a collection of symptoms that indicate kidney damage. Nephrotic syndrome includes all of the following conditions:

• albuminuria—when a person’s urine contains an elevated level of albumin, a protein typically found in the blood
• hyperlipidemia—higher-than-normal fat and cholesterol levels in the blood
• edema—swelling, usually in the legs, feet, or ankles and less often in the hands or face
• hypoalbuminemia—low levels of albumin in the blood

Nephrotic syndrome in children can be caused by the following conditions:

• Minimal change disease is a condition characterized by damage to the glomeruli that can be seen only with an electron microscope, which shows tiny details better than any other type of microscope. The cause of minimal change disease is unknown; some health care providers think it may occur after allergic reactions, vaccinations, and viral infections.
• Focal segmental glomerulosclerosis is scarring in scattered regions of the kidney, typically limited to a small number of glomeruli.
• Membranoproliferative glomerulonephritis is a group of autoimmune diseases that cause antibodies to build up on a membrane in the kidney. Autoimmune diseases cause the body’s immune system to attack the body’s own cells and organs.

Systemic Diseases

Systemic diseases, such as systemic lupus erythematosus (SLE or lupus) and diabetes, involve many organs or the whole body, including the kidneys:

• Lupus nephritis is kidney inflammation caused by SLE, which is an autoimmune disease.
• Diabetes leads to elevated levels of blood glucose, also called blood sugar, which scar the kidneys and increase the speed at which blood flows into the kidneys. Faster blood flow strains the glomeruli, decreasing their ability to filter blood, and raises blood pressure. Kidney disease caused by diabetes is called diabetic kidney disease. While diabetes is the number one cause of kidney failure in adults, it is an uncommon cause during childhood.

More information about systemic kidney diseases is provided in the NIDDK health topics:

• Lupus Nephritis

Trauma

Traumas such as burns, dehydration, bleeding, injury, or surgery can cause very low blood pressure, which decreases blood flow to the kidneys. Low blood flow can result in acute kidney failure.

Urine Blockage or Reflux

When a blockage develops between the kidneys and the urethra, urine can back up into the kidneys and cause damage. Reflux—urine flowing from the bladder up to the kidney—happens when the valve between the bladder and the ureter does not close all the way.

How is kidney disease in children diagnosed?

A health care provider diagnoses kidney disease in children by completing a physical exam, asking for a medical history, and reviewing signs and symptoms. To confirm diagnosis, the health care provider may order one or more of the following tests:

Urine Tests

Dipstick test for albumin. The presence of albumin in urine is a sign that the kidneys may be damaged. Albumin in urine can be detected with a dipstick test performed on a urine sample. The urine sample is collected in a special container in a health care provider’s office or a commercial facility and can be tested in the same location or sent to a lab for analysis. With a dipstick test, a nurse or technician places a strip of chemically treated paper, called a dipstick, into the person’s urine sample. Patches on the dipstick change color when albumin is present in urine.

Urine albumin-to-creatinine ratio. A more precise measurement, such as a urine albumin-to-creatinine ratio, may be necessary to confirm kidney disease. Unlike a dipstick test for albumin, a urine albumin-to-creatinine ratio—the ratio between the amount of albumin and the amount of creatinine in urine—is not affected by variation in urine concentration.

Blood test. Blood drawn in a health care provider’s office and sent to a lab for analysis can be tested to estimate how much blood the kidneys filter each minute, called the estimated glomerular filtration rate or eGFR.

Imaging studies. Imaging studies provide pictures of the kidneys. The pictures help the health care provider see the size and shape of the kidneys and identify any abnormalities.

Kidney biopsy. Kidney biopsy is a procedure that involves taking a small piece of kidney tissue for examination with a microscope. Biopsy results show the cause of the kidney disease and extent of damage to the kidneys.

How is kidney disease in children treated?

Treatment for kidney disease in children depends on the cause of the illness. A child may be referred to a pediatric nephrologist—a doctor who specializes in treating kidney diseases and kidney failure in children—for treatment.

Children with a kidney disease that is causing high blood pressure may need to take medications to lower their blood pressure. Improving blood pressure can significantly slow the progression of kidney disease. The health care provider may prescribe

• angiotensin-converting enzyme (ACE) inhibitors, which help relax blood vessels and make it easier for the heart to pump blood
• angiotensin receptor blockers (ARBs), which help relax blood vessels and make it easier for the heart to pump blood
• diuretics, medications that increase urine output

Many children require two or more medications to control their blood pressure; other types of blood pressure medications may also be needed.

As kidney function declines, children may need treatment for anemia and growth failure. Anemia is treated with a hormone called erythropoietin, which stimulates the bone marrow to produce red blood cells. Children with growth failure may need to make dietary changes and take food supplements or growth hormone injections.

Children with kidney disease that leads to kidney failure must receive treatment to replace the work the kidneys do. The two types of treatment are dialysis and transplantation. More information is provided in the NIDDK health topic, Treatment Methods for Kidney Failure in Children.

Birth Defects

Children with renal agenesis or renal dysplasia should be monitored for signs of kidney damage. Treatment is not needed unless damage to the kidney occurs. More information is provided in the NIDDK health topic, Solitary Kidney.

Ectopic kidney does not need to be treated unless it causes a blockage in the urinary tract or damage to the kidney. When a blockage is present, surgery may be needed to correct the position of the kidney for better drainage of urine. If extensive kidney damage has occurred, surgery may be needed to remove the kidney. More information is provided in the NIDDK health topic, Ectopic Kidney.

Hereditary Diseases

Children with PKD tend to have frequent urinary tract infections, which are treated with bacteria-fighting medications called antibiotics. PKD cannot be cured, so children with the condition receive treatment to slow the progression of kidney disease and treat the complications of PKD. More information is provided in the NIDDK health topic, Polycystic Kidney Disease.

Alport syndrome also has no cure. Children with the condition receive treatment to slow disease progression and treat complications until the kidneys fail. More information is provided in the NIDDK health topic, Glomerular Diseases.

Infection

Treatment for hemolytic uremic syndrome includes maintaining normal salt and fluid levels in the body to ease symptoms and prevent further problems. A child may need a transfusion of red blood cells delivered through an intravenous (IV) tube. Some children may need dialysis for a short time to take over the work the kidneys usually do. Most children recover completely with no long-term consequences. More information is provided in the NIDDK health topic, Hemolytic Uremic Syndrome in Children.

Children with post-streptococcal glomerulonephritis may be treated with antibiotics to destroy any bacteria that remain in the body and with medications to control swelling and high blood pressure. They may also need dialysis for a short period of time. More information about post-streptococcal glomerulonephritis is provided in the NIDDK health topic, Glomerular Diseases.

Nephrotic Syndrome

Nephrotic syndrome due to minimal change disease can often be successfully treated with corticosteroids. Corticosteroids decrease swelling and reduce the activity of the immune system. The dosage of the medication is decreased over time. Relapses are common; however, they usually respond to treatment. Corticosteroids are less effective in treating nephrotic syndrome due to focal segmental glomerulosclerosis or membranoproliferative glomerulonephritis. Children with these conditions may be given other immunosuppressive medications in addition to corticosteroids. Immunosuppressive medications prevent the body from making antibodies. More information is provided in the NIDDK health topic, Childhood Nephrotic Syndrome.

Systemic Diseases

Lupus nephritis is treated with corticosteroids and other immunosuppressive medications. A child with lupus nephritis may also be treated with blood pressure-lowering medications. In many cases, treatment is effective in completely or partially controlling lupus nephritis. More information is provided in the NIDDK health topic, Lupus Nephritis.

Diabetic kidney disease usually takes many years to develop. Children with diabetes can prevent or slow the progression of diabetic kidney disease by taking medications to control high blood pressure and maintaining normal blood glucose levels.

Trauma

The types of trauma described above can be medically treated, though dialysis may be needed for a short time until blood flow and blood pressure return to normal.

Urine Blockage and Reflux

Treatment for urine blockage depends on the cause and severity of the blockage. In some cases, the blockage goes away without treatment. For children who continue to have urine blockage, surgery may be needed to remove the obstruction and restore urine flow. After surgery, a small tube, called a stent, may be placed in the ureter or urethra to keep it open temporarily while healing occurs. More information is provided in the NIDDK health topic, Urine Blockage in Newborns.

Treatment for reflux may include prompt treatment of urinary tract infections and long-term use of antibiotics to prevent infections until reflux goes away on its own. Surgery has also been used in certain cases. More information is provided in the NIDDK health topic, Vesicoureteral Reflux.

Eating, Diet, and Nutrition

For children with CKD, learning about nutrition is vital because their diet can affect how well their kidneys work. Parents or guardians should always consult with their child’s health care team before making any dietary changes. Staying healthy with CKD requires paying close attention to the following elements of a diet:

• Protein. Children with CKD should eat enough protein for growth while limiting high protein intake. Too much protein can put an extra burden on the kidneys and cause kidney function to decline faster. Protein needs increase when a child is on dialysis because the dialysis process removes protein from the child’s blood. The health care team recommends the amount of protein needed for the child. Foods with protein include
  • eggs
  • milk
  • cheese
  • chicken
  • fish
  • red meats
  • beans
  • yogurt
  • cottage cheese
• Sodium. The amount of sodium children need depends on the stage of their kidney disease, their age, and sometimes other factors. The health care team may recommend limiting or adding sodium and salt to the diet. Foods high in sodium include
  • canned foods
  • some frozen foods
  • most processed foods
  • some snack foods, such as chips and crackers
• Potassium. Potassium levels need to stay in the normal range for children with CKD, because too little or too much potassium can cause heart and muscle problems. Children may need to stay away from some fruits and vegetables or reduce the number of servings and portion sizes to make sure they do not take in too much potassium. The health care team recommends the amount of potassium a child needs. Low-potassium fruits and vegetables include
  • apples
  • cranberries
  • strawberries
  • blueberries
  • raspberries
  • pineapple
  • cabbage
  • boiled cauliflower
  • mustard greens
  • uncooked broccoli
• High-potassium fruits and vegetables include
  • oranges
  • melons
  • apricots
  • bananas
  • potatoes
  • tomatoes
  • sweet potatoes
  • cooked spinach
  • cooked broccoli
• Phosphorus. Children with CKD need to control the level of phosphorus in their blood because too much phosphorus pulls calcium from the bones, making them weaker and more likely to break. Too much phosphorus also can cause itchy skin and red eyes. As CKD progresses, a child may need to take a phosphate binder with meals to lower the concentration of phosphorus in the blood. Phosphorus is found in high-protein foods. Foods with low levels of phosphorus include
  • liquid nondairy creamer
  • green beans
  • popcorn
  • unprocessed meats from a butcher
  • lemon-lime soda
  • root beer
  • powdered iced tea and lemonade mixes
  • rice and corn cereals
  • egg white
  • sorbet
• Fluids. Early in CKD, a child’s damaged kidneys may produce either too much or too little urine, which can lead to swelling or dehydration. As CKD progresses, children may need to limit fluid intake. The health care provider will tell the child and parents or guardians the goal for fluid intake.

More information is provided in the NIDDK health topics, Nutrition for Chronic Kidney Disease in Children and Kidney Failure: Eat Right to Feel Right on Hemodialysis.

Points to Remember

• Kidney disease can affect children in various ways, ranging from treatable disorders without long-term consequences to life-threatening conditions. Acute kidney disease develops suddenly, lasts a short time, and can be serious with long-lasting consequences, or may go away completely once the underlying cause has been treated.
• Chronic kidney disease (CKD) does not go away with treatment and tends to get worse over time.
• Kidney disease in children can be caused by
  • birth defects
  • hereditary diseases
  • infection
  • nephrotic syndrome
  • systemic diseases
  • trauma
  • urine blockage or reflux
• A health care provider diagnoses kidney disease in children by completing a physical exam, asking for a medical history, and reviewing signs and symptoms. To confirm diagnosis, the health care provider may order one or more of the following tests:
  • urine tests
  • blood test
  • imaging studies
  • kidney biopsy
• Treatment for kidney disease in children depends on the cause of the illness.
• Children with a kidney disease that is causing high blood pressure may need to take medications to lower their blood pressure. Improving blood pressure can significantly slow the progression of kidney disease. As kidney function declines, children may need treatment for anemia and growth failure.
• Children with kidney disease that leads to kidney failure must receive treatment to replace the work the kidneys do. The two types of treatment are dialysis and transplantation.
• For children with CKD, learning about nutrition is vital because their diet can affect how well their kidneys work. Parents or guardians should always consult with their child’s health care team before making any dietary changes.

Resources

National Kidney Foundation
Children with Chronic Kidney Disease: Tips for Parents 

Family Focus newsletter 

Employers’ Guide 

Nemours KidsHealth Website

When Your Child Has a Chronic Kidney Disease 

What’s the Deal with Dialysis? 

Nephkids

Cyber-support group 

United Network for Organ Sharing

Organ Transplants: What Every Kid Needs to Know (PDF, 1.67 MB)

U.S. Department of Health and Human Services, Centers for Medicare & Medicaid Services

Medicare Coverage of Kidney Dialysis & Kidney Transplant Services (PDF, 743 KB)

U.S. Social Security Administration

Benefits for Children with Disabilities (PDF, 413 KB)

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

What is kidney dysplasia?

Kidney dysplasia is a condition in which the internal structures of one or both of a fetus’ kidneys do not develop normally while in the womb. During normal development, two thin tubes of muscle called ureters grow into the kidneys and branch out to form a network of tiny structures called tubules. The tubules collect urine as the fetus grows in the womb. In kidney dysplasia, the tubules fail to branch out completely. Urine that would normally flow through the tubules has nowhere to go. Urine collects inside the affected kidney and forms fluid-filled sacs called cysts. The cysts replace normal kidney tissue and prevent the kidney from functioning.

Kidney dysplasia can affect one kidney or both kidneys. Babies with severe kidney dysplasia affecting both kidneys generally do not survive birth. Those who do survive may need the following early in life:

• blood-filtering treatments called dialysis
• a kidney transplant

Children with dysplasia in only one kidney have normal kidney function if the other kidney is unaffected. Those with mild dysplasia of both kidneys may not need dialysis or a kidney transplant for several years.

Kidney dysplasia is also called renal dysplasia or multicystic dysplastic kidney.

What are the kidneys and what do they do?

The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the two kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, which is composed of wastes and extra fluid. Children produce less urine than adults—the amount they produce depends on their age. The urine flows from the kidneys to the bladder through the two ureters, one on each side of the bladder. The bladder stores urine. The muscles of the bladder wall remain relaxed while the bladder fills with urine. As the bladder fills to capacity, signals sent to the brain tell a person to find a toilet soon. When the bladder empties, urine flows out of the body through a tube called the urethra, located at the bottom of the bladder.

The kidneys, ureters, bladder, and urethra are parts of the urinary tract. More information is provided in the NIDDK health topics, the kidneys and the urinary tract.

What causes kidney dysplasia?

Genetic factors can cause kidney dysplasia. Genes pass information from both parents to the child and determine the child’s traits. Sometimes, parents may pass a gene that has changed, or mutated, causing kidney dysplasia.

Genetic syndromes that affect multiple body systems can also cause kidney dysplasia. A syndrome is a group of symptoms or conditions that may seem unrelated yet are thought to have the same genetic cause. A baby with kidney dysplasia due to a genetic syndrome might also have problems of the digestive tract, nervous system, heart and blood vessels, muscles and skeleton, or other parts of the urinary tract.

A baby may also develop kidney dysplasia if his or her mother takes certain prescription medications during pregnancy, such as some used to treat seizures and high blood pressure. A mother’s use of illegal drugs, such as cocaine, during pregnancy may also cause kidney dysplasia in her unborn child.

How common is kidney dysplasia?

Kidney dysplasia is a common condition. Scientists estimate that kidney dysplasia affects about one in 4,000 babies.¹ This estimate may be low because some people with kidney dysplasia are never diagnosed with the condition. About half of the babies diagnosed with this condition have other urinary tract defects.²

Who is more likely to develop kidney dysplasia?

Babies who are more likely to develop kidney dysplasia include those

• whose parents have the genetic traits for the condition
• with certain genetic syndromes affecting multiple body systems
• whose mothers used certain prescription medications or illegal drugs during pregnancy

What are the signs of kidney dysplasia?

Many babies with kidney dysplasia in only one kidney have no signs of the condition. In some cases, the affected kidney may be enlarged at birth and may cause pain.

What are the complications of kidney dysplasia?

The complications of kidney dysplasia can include

• hydronephrosis of the working kidney. A baby with kidney dysplasia in only one kidney might have other urinary tract defects. When other defects in the urinary tract block the flow of urine, the urine backs up and causes the kidneys and ureters to swell, a condition called hydronephrosis. If left untreated, hydronephrosis can damage the working kidney and reduce its ability to filter blood. Kidney damage may lead to chronic kidney disease (CKD) and kidney failure.
• a urinary tract infection (UTI). A urine blockage may increase a baby’s chance of developing a UTI. Recurring UTIs can also lead to kidney damage.
• high blood pressure.
• a slightly increased chance of developing kidney cancer.

More information is provided in the NIDDK health topics, urine blockage in newborns and UTIs in children.

How is kidney dysplasia diagnosed?

Health care providers may be able to diagnose kidney dysplasia during a woman’s pregnancy using a fetal ultrasound, also called a fetal sonogram. Ultrasound uses a device, called a transducer, that bounces safe, painless sound waves off organs to create an image of their structure. Fetal ultrasound is a test done during pregnancy to create images of the fetus in the womb. A specially trained technician performs the procedure in a health care provider’s office, an outpatient center, or a hospital, and an obstetrician or a radiologist interprets the images. An obstetrician is a doctor who specializes in pregnancy and childbirth. A radiologist is a doctor who specializes in medical imaging. The patient—in this case, the fetus’ mother—does not need anesthesia for this procedure. The images can show defects in the fetus’ kidneys and other parts of the urinary tract.

Health care providers do not always diagnose kidney dysplasia before a baby is born. After birth, health care providers often diagnose kidney dysplasia during an evaluation of the child for a UTI or another medical condition. A health care provider uses ultrasound to diagnose kidney dysplasia after the baby is born.

How is kidney dysplasia treated?

If the condition is limited to one kidney and the baby has no signs of kidney dysplasia, no treatment may be necessary. However, the baby should have regular checkups that include

• checking blood pressure.
• testing blood to measure kidney function.
• testing urine for albumin, a protein most often found in blood. Albumin in the urine may be a sign of kidney damage.
• performing periodic ultrasounds to monitor the damaged kidney and to make sure the functioning kidney continues to grow and remains healthy.

How can kidney dysplasia be prevented?

Researchers have not found a way to prevent kidney dysplasia caused by genetic factors or certain genetic syndromes. Pregnant women can prevent kidney dysplasia by avoiding the use of certain prescription medications or illegal drugs during pregnancy. Pregnant women should talk with their health care provider before taking any medications during pregnancy.

What is the long-term outlook for a child with kidney dysplasia in only one kidney?

The long-term outlook for a child with kidney dysplasia in only one kidney is generally good. A person with one working kidney, a condition called solitary kidney, can grow normally and may have few, if any, health problems.

The affected kidney may shrink as the child grows. By age 10,³ the affected kidney may no longer be visible on x-ray or ultrasound. Children and adults with only one working kidney should have regular checkups to test for high blood pressure and kidney damage. A child with urinary tract problems that lead to failure of the working kidney may eventually need dialysis or a kidney transplant.

More information is provided in the NIDDK health topics, solitary kidney, dialysis, and kidney transplants.

What is the long-term outlook for a child with kidney dysplasia in both kidneys?

The long-term outlook for a child with kidney dysplasia in both kidneys is different from the long-term outlook for a child with one dysplastic kidney. A child with kidney dysplasia in both kidneys

• is more likely to develop CKD.
• needs close follow-up with a pediatric nephrologist––a doctor who specializes in caring for children with kidney disease. Children who live in areas that don’t have a pediatric nephrologist available can see a nephrologist who cares for both children and adults.
• may eventually need dialysis or a kidney transplant.

Eating, Diet, and Nutrition

Researchers have not found that eating, diet, and nutrition play a role in causing or preventing kidney dysplasia.

Points to Remember

• Kidney dysplasia is a condition in which the internal structures of one or both of a fetus’ kidneys do not develop normally while in the womb.
• Genetic factors can cause kidney dysplasia.
• Genetic syndromes that affect multiple body systems can also cause kidney dysplasia.
• A baby may also develop kidney dysplasia if his or her mother takes certain prescription medications during pregnancy, such as some used to treat seizures and high blood pressure.
• Many babies with kidney dysplasia in only one kidney have no signs of the condition.
• Health care providers may be able to diagnose kidney dysplasia during a woman’s pregnancy using a fetal ultrasound, also called a fetal sonogram.
• Health care providers do not always diagnose kidney dysplasia before a baby is born.
• If the condition is limited to one kidney and the baby has no signs of kidney dysplasia, no treatment may be necessary.
• Researchers have not found a way to prevent kidney dysplasia caused by genetic factors or certain genetic syndromes.
• Pregnant women can prevent kidney dysplasia by avoiding the use of certain prescription medications or illegal drugs during pregnancy.
• The long-term outlook for a child with kidney dysplasia in only one kidney is generally good.
• The long-term outlook for a child with kidney dysplasia in both kidneys is different from the long-term outlook for a child with one dysplastic kidney. A child with kidney dysplasia in both kidneys
  • is more likely to develop chronic kidney disease (CKD)
  • needs close follow-up with a pediatric nephrologist
  • may eventually need dialysis or a kidney transplant

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

What is Medullary Sponge Kidney?

Medullary sponge kidney, also known as Cacchi-Ricci disease, is a birth defect where changes occur in the tubules, or tiny tubes, inside a fetus’ kidneys.

In a normal kidney, urine flows through these tubules as the kidney is being formed during a fetus’ growth. In medullary sponge kidney, tiny, fluid-filled sacs called cysts form in the tubules within the medulla—the inner part of the kidney—creating a spongelike appearance. The cysts keep urine from flowing freely through the tubules.

Symptoms of medullary sponge kidney do not usually appear until the teenage years or the 20s. Medullary sponge kidney can affect one or both kidneys.

What are the complications of Medullary Sponge Kidney?

Complications of medullary sponge kidney include

• hematuria, or blood in the urine
• kidney stones
• urinary tract infections (UTIs)

Medullary sponge kidney rarely leads to more serious problems, such as chronic kidney disease or kidney failure.

What causes Medullary Sponge Kidney?

Scientists do not fully understand the cause of medullary sponge kidney or why cysts form in the tubules during fetal development. Even though medullary sponge kidney is present at birth, most cases do not appear to be inherited.

How common is Medullary Sponge Kidney?

Medullary sponge kidney affects about one person per 5,000 people in the United States. Researchers have reported that 12 to 20 percent of people who develop calcium-based kidney stones have medullary sponge kidney¹.

Who is more likely to develop Medullary Sponge Kidney?

Medullary sponge kidney affects all races and geographic regions. Among people who are more likely to develop calcium-based kidney stones, women are more likely than men to have medullary sponge kidney.²

What are the signs and symptoms of Medullary Sponge Kidney?

Many people with medullary sponge kidney have no symptoms. The first sign that a person has medullary sponge kidney is usually a UTI or a kidney stone. UTIs and kidney stones share many of the same signs and symptoms:

• burning or painful urination
• pain in the back, lower abdomen, or groin
• cloudy, dark, or bloody urine
• foul-smelling urine
• fever and chills
• vomiting

People who experience these symptoms should see or call a health care provider as soon as possible.

How is Medullary Sponge Kidney diagnosed?

A health care provider diagnoses medullary sponge kidney based on

• a medical and family history
• a physical exam
• imaging studies

Medical and Family History

Taking a medical and family history can help diagnose medullary sponge kidney. A health care provider will suspect medullary sponge kidney when a person has repeated UTIs or kidney stones.

Physical Exam

No physical signs are usually present in a patient with medullary sponge kidney, except for blood in the urine. Health care providers usually confirm a diagnosis of medullary sponge kidney with imaging studies.

Imaging Studies

Imaging is the medical term for tests that use different methods to see bones, tissues, and organs inside the body. Health care providers commonly choose one or more of three imaging techniques to diagnose medullary sponge kidney:

• intravenous pyelogram
• computerized tomography (CT) scan
• ultrasound

A radiologist—a doctor who specializes in medical imaging—interprets the images from these studies, and patients do not need anesthesia.

Intravenous Pyelogram

In an intravenous pyelogram, a health care provider injects a special dye, called contrast medium, into a vein in the patient’s arm. The contrast medium travels through the body to the kidneys. The kidneys excrete the contrast medium into urine, which makes the urine visible on an x-ray. An x-ray technician performs this procedure at a health care provider’s office, an outpatient center, or a hospital. An intravenous pyelogram can show any blockage in the urinary tract, and the cysts show up as clusters of light.

Computerized Tomography Scans

Computerized tomography scans use a combination of x-rays and computer technology to create images. For a CT scan, a health care provider may give the patient a solution to drink and an injection of contrast medium. CT scans require the patient to lie on a table that slides into a tunnel-shaped device where the x-rays are taken. An x-ray technician performs the procedure in an outpatient center or a hospital. CT scans can show expanded or stretched tubules.

Ultrasound

Ultrasound uses a device, called a transducer, that bounces safe, painless sound waves off organs to create an image of their structure. A specially trained technician performs the procedure in a health care provider’s office, an outpatient center, or a hospital. Ultrasound can show kidney stones and calcium deposits within the kidney.

How is Medullary Sponge Kidney treated?

Scientists have not discovered a way to reverse medullary sponge kidney. Once a health care provider is sure a person has medullary sponge kidney, treatment focuses on

• curing an existing UTI
• removing any kidney stones

Curing an Existing Urinary Tract Infection

To treat a UTI, the health care provider may prescribe a medication called an antibiotic that kills bacteria. The choice of medication and length of treatment depend on the person’s medical history and the type of bacteria causing the infection. More information is provided in the NIDDK health topic, Urinary Tract Infections in Adults.

Removing Kidney Stones

Treatment for kidney stones usually depends on their size and what they are made of, as well as whether they are causing pain or obstructing the urinary tract. Kidney stones may be treated by a general practitioner or by a urologist—a doctor who specializes in the urinary tract.

Small stones usually pass through the urinary tract without treatment. Still, the person may need pain medication and should drink lots of liquids to help move the stone along. Pain control may consist of oral or intravenous (IV) medication, depending on the duration and severity of the pain. People may need IV fluids if they become dehydrated from vomiting or an inability to drink.

A person with a larger stone, or one that blocks urine flow and causes great pain, may need more urgent treatment, such as

• shock wave lithotripsy. A machine called a lithotripter is used to break up the kidney stone into smaller pieces to pass more easily through the urinary tract. The patient may need local or general anesthesia.
• ureteroscopy. A ureteroscope—a long, tubelike instrument with an eyepiece—is used to find and retrieve the stone with a small basket or to break the stone up with laser energy. Local or general anesthesia may be required.
• percutaneous nephrolithotomy. In this procedure, a wire-thin viewing instrument, called a nephroscope, is used to locate and remove the stones. During the procedure, which requires general anesthesia, a tube is inserted directly into the kidney through a small incision in the patient’s back.

More information is provided in the NIDDK health topic, Kidney Stones in Adults.

Can Medullary Sponge Kidney be prevented?

Scientists have not yet found a way to prevent medullary sponge kidney. However, health care providers can recommend medications and dietary changes to prevent future UTIs and kidney stones.

Medications to Prevent Future Urinary Tract Infections and Kidney Stones

Health care providers may prescribe certain medications to prevent UTIs and kidney stones:

• A person with medullary sponge kidney may need to continue taking a low-dose antibiotic to prevent recurrent infections.
• Medications that reduce calcium in the urine may help prevent calcium kidney stones. These medications may include
  • potassium citrate
  • thiazide

Eating, Diet, and Nutrition

The following changes in diet may help prevent UTIs and kidney stone formation:

• Drinking plenty of water and other liquids can help flush bacteria from the urinary tract and dilute urine so kidney stones cannot form. A person should drink enough liquid to produce about 2 to 2.5 quarts of urine every day.³
• Reducing sodium intake, mostly from salt, may help prevent kidney stones. Diets high in sodium can increase the excretion of calcium into the urine and thus increase the chance of calciumcontaining kidney stones forming.
• Foods rich in animal proteins such as meat, eggs, and fish can increase the chance of uric acid stones and calcium stones forming. People who form stones should limit their meat consumption to 6 to 8 ounces a day.⁴
• People who are more likely to develop calcium oxalate stones should include 1,000 milligrams of calcium in their diet every day. Adults older than 50 years should consume 1,200 milligrams of calcium daily.³ Calcium in the digestive tract binds to oxalate from food and keeps it from entering the blood and the urinary tract, where it can form stones.

People with medullary sponge kidney should talk with their health care provider or a dietitian before making any dietary changes. A dietitian can help a person plan healthy meals.

Points to Remember

• Medullary sponge kidney, also known as Cacchi-Ricci disease, is a birth defect where changes occur in the tubules, or tiny tubes, inside a fetus’ kidneys.
• Symptoms of medullary sponge kidney do not usually appear until the teenage years or the 20s. Medullary sponge kidney can affect one or both kidneys.
• Complications of medullary sponge kidney include
  • hematuria, or blood in the urine
  • kidney stones
  • urinary tract infections (UTIs)
• Many people with medullary sponge kidney have no symptoms. The first sign that a person has medullary sponge kidney is usually a UTI or a kidney stone. UTIs and kidney stones share many of the same signs and symptoms:
  • burning or painful urination
  • pain in the back, lower abdomen, or groin
  • cloudy, dark, or bloody urine
  • foul-smelling urine
  • fever and chills
  • vomiting
• Health care providers commonly choose one or more of three imaging techniques to diagnose medullary sponge kidney:
  • intravenous pyelogram
  • computerized tomography (CT) scan
  • ultrasound
• Scientists have not discovered a way to reverse medullary sponge kidney. Once a health care provider is sure a person has medullary sponge kidney, treatment focuses on
  • curing an existing UTI
  • removing any kidney stones
• Scientists have not yet found a way to prevent medullary sponge kidney. However, health care providers can recommend medications and dietary changes to prevent future UTIs and kidney stones.

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

What is mineral and bone disorder in chronic kidney disease (CKD)?

Mineral and bone disorder in CKD occurs when damaged kidneys and abnormal hormone levels cause calcium and phosphorus levels in a person’s blood to be out of balance. Mineral and bone disorder commonly occurs in people with CKD and affects most people with kidney failure receiving dialysis.

In the past, health care providers used the term “renal osteodystrophy” to describe mineral and hormone disturbances caused by kidney disease. Today, renal osteodystrophy only describes bone problems that result from mineral and bone disorder in CKD. Health care providers might use the phrase “chronic kidney disease mineral and bone disorder,” or CKD-MBD, to describe the condition that affects the bones, heart, and blood vessels.

What is chronic kidney disease?

Chronic kidney disease is kidney damage that occurs slowly over many years, often due to diabetes or high blood pressure. Once damaged, the kidneys can’t filter blood as they should. This damage can cause wastes to build up in the body and other problems that can harm a person’s health, including mineral and bone disorder.

Why are hormones and minerals important?

Hormones and minerals are important because they help bones stay strong. If a person’s hormones and minerals are out of balance, his or her bones can become weak and malformed. Healthy bones continuously rebuild, sometimes taking a slightly altered shape or structure. To grow and rebuild, bones need

• the hormone calcitriol—the active form of vitamin D
• calcium
• phosphorus
• parathyroid hormone

The kidneys play an important role in maintaining healthy bone mass and structure by balancing phosphorus and calcium levels in the blood. Healthy kidneys activate a form of vitamin D that a person consumes in food, turning it into calcitriol, the active form of the vitamin. Calcitriol helps the kidneys maintain blood calcium levels and promotes the formation of bone.

The kidneys also remove extra phosphorus, helping balance phosphorus and calcium levels in the blood. Keeping the proper level of phosphorus in the blood helps maintain strong bones.

The parathyroid glands, four pea-sized glands in the neck, create parathyroid hormone, or PTH. Parathyroid hormone plays an important role in controlling calcium levels in the blood. When the kidneys do not function properly, extra parathyroid hormone is released into the blood to move calcium from inside the bones into the blood.

What causes mineral and bone disorder in chronic kidney disease?

Chronic kidney disease causes mineral and bone disorder because the kidneys do not properly balance the mineral levels in the body. The kidneys

• stop activating calcitriol. The low levels of calcitriol in the body create an imbalance of calcium in the blood.
• do not remove the phosphorus in the blood properly, so phosphorus levels rise in the blood. The extra phosphorus pulls calcium out of the bones, causing them to weaken.

Another factor contributes to the cause of mineral and bone disorder. When the kidneys are damaged, the parathyroid gland releases parathyroid hormone into the blood to pull calcium from the bones and raise blood calcium levels. This response restores the balance of phosphorus and calcium; however, it also starves the bones of much-needed calcium.

What are the signs and symptoms of mineral and bone disorder in chronic kidney disease?

In adults, symptoms of mineral and bone disorder in CKD may not appear until bone changes have taken place for many years. For this reason, people often refer to the disease as a “silent crippler.” Eventually, a person with the condition may begin to feel bone and joint pain.

Mineral and Bone Disorder in Children with Chronic Kidney Disease

Mineral and bone disorder in CKD is most serious when it occurs in children because their bones are still developing and growing. Growing children can show symptoms of mineral and bone disorder even in the early stages of CKD. Slowed bone growth leads to short stature, which may remain with a child into adulthood. One deformity caused by mineral and bone disorder in CKD occurs when the legs bend inward or outward, a condition often referred to as "renal rickets." More information is provided in the NIDDK health topic, Growth Failure in Children with Kidney Disease. Find more about children’s bone health on the Eunice Kennedy Shriver National Institute of Child Health and Human Development website at www.nichd.nih.gov.

What are the complications of mineral and bone disorder in chronic kidney disease?

The complications of mineral and bone disorder in CKD include slowed bone growth and deformities, and heart and blood vessel problems.

Slowed Bone Growth and Deformities

Damaged kidneys must work harder to clear phosphorus from the body. High levels of phosphorus cause lower levels of calcium in the blood, resulting in the following series of events:

• When a person’s blood calcium level becomes too low, the parathyroid glands release parathyroid hormone.
• Parathyroid hormone removes calcium from bones and places it into the blood, raising a person’s blood calcium level at the risk of harming bones.
• A low calcitriol level also leads to an increased level of parathyroid hormone.

If mineral and bone disorder in CKD remains untreated in adults, bones gradually become thin and weak, and a person with the condition may begin to feel bone and joint pain. Mineral and bone disorder in CKD also increases a person’s risk of bone fractures.

Heart and Blood Vessel Problems

In addition to harming bones, mineral and bone disorder in CKD can cause problems in the heart and blood vessels:

• High levels of blood calcium can damage blood vessels and lead to heart problems.
• High phosphorus levels also can cause blood vessels to become like bone, leading to hardening of the arteries.
• High phosphorus levels also cause abnormal hormone regulation, even if the calcium level is acceptable.

Parathyroid hormone and another hormone made in the bones called FGF23 can also affect bone and heart health, leading to the following series of problems:

• When parathyroid hormone or FGF23 levels are high, a person can have heart problems.
• The complex hormone abnormalities that cause bone deformities can also harm a person’s heart and blood vessels.

How is mineral and bone disorder in chronic kidney disease diagnosed?

A health care provider diagnoses mineral and bone disorder in CKD with

• a family and medical history
• a physical exam
• a blood test
• a bone biopsy
• an x-ray

Family and Medical History

Taking a medical and family history is one of the first things a health care provider may do to help diagnose mineral and bone disorder in CKD. He or she will ask the patient or caretaker questions about when the patient was first diagnosed with CKD and whether any family members have also had mineral and bone disorder with or without CKD.

Physical Exam

A physical exam may help diagnose mineral and bone disorder in CKD. During a physical exam, a health care provider usually examines a patient’s body for changes in bone structure.

Blood Test

A blood test involves drawing blood at a health care provider’s office or a commercial facility and sending the sample to a lab for analysis. The blood test shows levels of calcium, phosphorus, parathyroid hormone, and sometimes vitamin D.

Bone Biopsy

A bone biopsy is a procedure that removes a piece of bone tissue for examination with a microscope. A health care provider performs the biopsy in a hospital with light sedation and local anesthetic. The health care provider uses imaging techniques such as ultrasound or a computerized tomography scan to guide the biopsy needle into the hip bone. A pathologist—a doctor who specializes in diagnosing diseases—examines the bone tissue in a lab. The test can show whether a person’s bone cells are building normal bone.

X-ray

An x-ray is a picture created by using radiation and recorded on film or on a computer. The amount of radiation used is small. A radiographer performs the x-ray at a hospital or an outpatient center, and a radiologist—a doctor who specializes in medical imaging—interprets the images. Patients do not need anesthesia. The patient will lie on a table or stand during the x-ray. The technician will position the x-ray machine over the bone area. The patient will hold his or her breath as the x-ray machine takes the picture so that the picture will not be blurry. The radiographer may ask the patient to change position for additional pictures. An x-ray can show extra calcium in blood vessels.

Each of these tests can help the health care provider determine whether CKD or some other condition is causing the mineral and bone disorder and decide on a course of treatment.

How is mineral and bone disorder in chronic kidney disease treated?

Treating mineral and bone disorder in CKD includes preventing damage to bones by controlling parathyroid hormone levels through changes in eating, diet, and nutrition; medications and supplements; and dialysis. If these treatments do not bring parathyroid hormone levels under control, a health care provider may remove a person’s parathyroid glands surgically, a procedure called a parathyroidectomy.

Eating, Diet, and Nutrition

Changes in diet can treat mineral and bone disorder in CKD. Reducing dietary intake of phosphorus is one of the most important steps in preventing bone disease. Most foods contain phosphorus; however, processed and packaged foods contain especially high levels of phosphorus. Food producers use phosphorus as an additive to preserve the food on the shelf. People who have CKD or are on dialysis should avoid packaged foods containing ingredients that include the letters PHOS. A renal dietitian can help develop a dietary plan to control phosphorus levels in the blood. Some drinks and natural foods also contain high amounts of phosphorus, including

• beer
• cheese
• cocoa
• dark sodas
• dried beans
• milk
• nuts
• peanut butter
• peas

More information is provided in the NIDDK health topics, How To Read a Food Label: Tips for People with Chronic Kidney Disease and Phosphorus: Tips for People with Chronic Kidney Disease.

Medications and Supplements

Medications protect the bones by restoring the proper balance of minerals and hormones. If the kidneys do not make adequate amounts of calcitriol, a health care provider may prescribe synthetic calcitriol as a pill (Rocaltrol) or, for dialysis patients, in an injectable form (Calcijex). Calcitriol helps reduce parathyroid hormone levels. Medications called doxercalciferol (Hectorol) and paricalcitol (Zemplar) act like calcitriol because they are also activated forms of vitamin D. A health care provider may prescribe a calcium supplement in addition to calcitriol or another activated form of vitamin D.

Certain forms of vitamin D—available by prescription or as over-the-counter vitamin supplements—require activation by a person’s kidneys before they can act as calcitriol does. However, the benefits of some of these not-yet-activated forms of vitamin D—for example, ergocalciferol (Calciferol, Drisdol) or cholecalciferol (Delta D3)—are unclear. To help ensure coordinated and safe care, people should discuss their use of alternative medications, including use of vitamin and mineral supplements, with their health care provider.

Cinacalcet hydrochloride (Sensipar) belongs to another class of prescription medications called calcimimetics. Cinacalcet lowers parathyroid hormone levels by imitating calcium’s effects on the parathyroid gland. Generally, this medication is used only in people on dialysis.

Often, health care providers will prescribe medications called phosphate binders—such as calcium carbonate (Tums), calcium acetate (PhosLo), sevelamer carbonate (Renvela), or lanthanum carbonate (Fosrenol)—to take with meals and snacks to bind phosphorus in the bowel. These medications decrease the absorption of phosphorus into the blood.

Dialysis

Dialysis is the process of filtering wastes and extra fluid from the body by means other than the kidneys. The two forms of dialysis are hemodialysis and peritoneal dialysis:

• Hemodialysis uses a machine to circulate a person’s blood through a filter outside the body. The blood passes from a patient’s body through a needle, at nearly 1 pint per minute. The blood then travels through a tube that takes it to the filter, called a dialyzer. Inside the dialyzer, the blood flows through thin fibers that filter out wastes and extra fluid. After the machine filters the blood, it passes back to the body through another tube. More information is provided in the NIDDK health topic, Treatment Methods for Kidney Failure: Hemodialysis.
• Peritoneal dialysis uses the lining of the abdomen to filter a person’s blood inside the body. A soft tube called a catheter is placed in the patient’s abdomen a few weeks before peritoneal dialysis begins. A person uses the catheter to fill the empty space inside the abdomen with dialysis solution—a kind of salty water—from a plastic bag. While inside the body, the dialysis solution absorbs wastes and extra fluid. After a few hours, the person drains the used dialysis solution into another bag for disposal. The person then restarts the process with a fresh bag of dialysis solution. More information is provided in the NIDDK health topic, Treatment Methods for Kidney Failure: Peritoneal Dialysis.

Increasing a person’s dialysis dose can help control the blood phosphorus level. In hemodialysis, the health care provider can adjust the dose by increasing how quickly the blood flows to and from the dialyzer. Another way to adjust the dose involves increasing the time of a person’s dialysis session or the number of sessions. In peritoneal dialysis, using more dialysis solution in each fill or increasing the number of fills each day increases the dose. More information is provided in the NIDDK health topics:

• Hemodialysis Dose and Adequacy
• Peritoneal Dialysis Dose and Adequacy

Parathyroidectomy

If diet, medications, and dialysis can’t control parathyroid hormone levels, a surgeon can remove one or more of the parathyroid glands. He or she performs the procedure using general anesthesia.

A good treatment program, including a low-phosphorus diet, appropriate medications, adequate dialysis, and, if necessary, surgery, can improve the body’s ability to repair bones damaged by mineral and bone disorder in CKD. Overall, people can improve their bone health by exercising and not smoking. People should consult a health care provider before beginning any exercise program.

Points to Remember

• Mineral and bone disorder in chronic kidney disease (CKD) occurs when damaged kidneys and abnormal hormone levels cause calcium and phosphorus levels in a person’s blood to be out of balance. Mineral and bone disorder commonly occurs in people with CKD and affects most people with kidney failure receiving dialysis.
• Chronic kidney disease is kidney damage that occurs slowly over many years, often due to diabetes or high blood pressure. Once damaged, the kidneys can’t filter blood as they should.
• Hormones and minerals are important because they help bones stay strong. If a person’s hormones and minerals are out of balance, his or her bones can become weak and malformed.
• Parathyroid hormone plays an important role in controlling calcium levels in the blood. When kidneys do not function properly, extra parathyroid hormone is released in the blood to move calcium from inside the bones into the blood.
• Chronic kidney disease causes mineral and bone disorder because the kidneys do not properly balance the mineral levels in the body. The kidneys stop activating calcitriol and do not remove the phosphorus in the blood properly.
• The complications of mineral and bone disorder in CKD include slowed bone growth and deformities, and heart and blood vessel problems.
• Treating mineral and bone disorder in CKD includes preventing damage to bones by controlling parathyroid hormone levels through changes in eating, diet, and nutrition; medications and supplements; and dialysis.
• Reducing dietary intake of phosphorus is one of the most important steps in preventing bone disease.
• If diet, medications, and dialysis can’t control parathyroid hormone levels, a surgeon can remove one or more of the parathyroid glands.

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

About the Kidney Failure Series

You and your doctor will work together to choose a treatment that's best for you. The publications of the NIDDK Kidney Failure Series can help you learn about the specific issues you will face.

Booklets

• What I need to know about Kidney Failure and How it’s Treated
• Treatment Methods for Kidney Failure: Hemodialysis
• Treatment Methods for Kidney Failure: Peritoneal Dialysis
• Treatment Methods for Kidney Failure: Kidney Transplantation
• Kidney Failure: Eat Right to Feel Right on Hemodialysis

Fact Sheets

• Kidney Failure: What to Expect
• Vascular Access for Hemodialysis
• Hemodialysis Dose and Adequacy
• Peritoneal Dialysis Dose and Adequacy
• Amyloidosis and Kidney Disease
• Anemia in Chronic Kidney Disease
• Financial Help for Treatment of Kidney Failure

Learning as much as you can about your treatment will help make you an important member of your health care team.

What is nephrotic syndrome?

Nephrotic syndrome is a collection of symptoms that indicate kidney damage. Nephrotic syndrome includes the following:

• proteinuria—large amounts of protein in the urine
• hyperlipidemia—higher than normal fat and cholesterol levels in the blood
• edema, or swelling, usually in the legs, feet, or ankles and less often in the hands or face
• hypoalbuminia—low levels of albumin in the blood

Albumin is a protein that acts like a sponge, drawing extra fluid from the body into the bloodstream where it remains until removed by the kidneys. When albumin leaks into the urine, the blood loses its capacity to absorb extra fluid from the body, causing edema.

Nephrotic syndrome results from a problem with the kidneys’ filters, called glomeruli. Glomeruli are tiny blood vessels in the kidneys that remove wastes and excess fluids from the blood and send them to the bladder as urine.

As blood passes through healthy kidneys, the glomeruli filter out the waste products and allow the blood to retain cells and proteins the body needs. However, proteins from the blood, such as albumin, can leak into the urine when the glomeruli are damaged. In nephrotic syndrome, damaged glomeruli allow 3 grams or more of protein to leak into the urine when measured over a 24-hour period, which is more than 20 times the amount that healthy glomeruli allow.

What causes nephrotic syndrome?

Nephrotic syndrome can be caused by diseases that affect only the kidneys, such as focal segmental glomerulosclerosis (FSGS) or membranous nephropathy. Diseases that affect only the kidneys are called primary causes of nephrotic syndrome. The glomeruli are usually the targets of these diseases for reasons that are not fully understood. In FSGS—the most common primary cause of nephrotic syndrome—scar tissue forms in parts of the glomeruli. In membranous nephropathy, immune molecules form harmful deposits on the glomeruli.

Nephrotic syndrome can also be caused by systemic diseases, which are diseases that affect many parts of the body, such as diabetes or lupus. Systemic diseases that affect the kidneys are called secondary causes of nephrotic syndrome. More than 50 percent of nephrotic syndrome cases in adults have secondary causes, with diabetes being the most common.¹

What are the signs and symptoms of nephrotic syndrome?

In addition to proteinuria, hyperlipidemia, edema, and hypoalbumina, people with nephrotic syndrome may experience

• weight gain
• fatigue
• foamy urine
• loss of appetite

What are the complications of nephrotic syndrome?

The loss of different proteins from the body can lead to a variety of complications in people with nephrotic syndrome. Blood clots can form when proteins that normally prevent them are lost through the urine. Blood clots can block the flow of blood and oxygen through a blood vessel. Loss of immunoglobulins—immune system proteins that help fight disease and infection—leads to an increased risk of infections. These infections include pneumonia, a lung infection; cellulitis, a skin infection; peritonitis, an abdominal infection; and meningitis, a brain and spine infection. Medications given to treat nephrotic syndrome can also increase the risk of these infections. Other complications of nephrotic syndrome include

• hypothyroidism—a condition in which the thyroid gland does not produce enough thyroid hormone to meet the body’s needs
• anemia—a condition in which red blood cells are fewer or smaller than normal, which means less oxygen is carried to the body’s cells
• coronary artery disease, also called coronary heart disease—heart disease caused by narrowing of the arteries that supply blood to the heart
• high blood pressure, also called hypertension—a condition in which blood flows through the blood vessels with a force greater than normal
• acute kidney injury—sudden and temporary loss of kidney function

How is nephrotic syndrome diagnosed?

Urine samples are taken to diagnose people suspected of having nephrotic syndrome.

Nephrotic syndrome is diagnosed when large amounts of protein are found in the urine. The blood protein albumin makes up much of the protein that is lost, though many other important proteins are also lost in nephrotic syndrome.

The presence of albumin in the urine can be detected with a dipstick test performed on a urine sample. The urine sample is collected in a special container in a health care provider’s office or commercial facility and can be tested in the same location or sent to a lab for analysis. For the test, a nurse or technician places a strip of chemically treated paper, called a dipstick, into the urine. Patches on the dipstick change color when protein is present in urine.

A more precise measurement is usually needed to confirm the diagnosis. Either a single urine sample or a 24-hour collection of urine can be sent to a lab for analysis. With the single urine sample, the lab measures both albumin and creatinine, a waste product of normal muscle breakdown. The comparison of the measurements is called a urine albumin-to-creatinine ratio. A urine sample containing more than 30 milligrams of albumin for each gram of creatinine may signal a problem. With a 24-hour collection of urine, the lab measures only the amount of albumin present. The single urine sample is easier to collect than the 24-hour sample and is usually sufficient to confirm diagnosis, though the 24-hour collection may be used in some cases.

Once nephrotic syndrome is diagnosed, blood tests are usually needed to check for systemic diseases that may be causing the nephrotic syndrome and to find out how well the kidneys are working overall. A blood test involves drawing blood at a health care provider’s office or commercial facility and sending the sample to a lab for analysis.

Though blood tests can point toward systemic diseases, a kidney biopsy is usually needed to diagnose the specific underlying disease causing the nephrotic syndrome and to determine the best treatment. A kidney biopsy is a procedure that involves taking a piece of kidney tissue for examination with a microscope. Kidney biopsies are performed by a health care provider in a hospital with light sedation and local anesthetic. A biopsy is often not needed for a person with diabetes because the person’s medical history and lab tests may be enough to diagnose the problem as being a result of diabetes.

How is nephrotic syndrome treated?

Treating nephrotic syndrome includes addressing the underlying cause as well as taking steps to reduce high blood pressure, edema, high cholesterol, and the risks of infection. Treatment usually includes medications and changes in diet.

Medications that lower blood pressure can also significantly slow the progression of kidney disease causing nephrotic syndrome. Two types of blood pressure lowering medications, angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), have proven effective in slowing the progression of kidney disease by reducing the pressure inside the glomeruli and thereby reducing proteinuria. Many people require two or more medications to control their blood pressure. In addition to an ACE inhibitor or an ARB, a diuretic—a medication that aids the kidneys in removing fluid from the blood—can also be useful in helping to reduce blood pressure as well as edema. Beta blockers, calcium channel blockers, and other blood pressure medications may also be needed.

Statin medications may be given to lower cholesterol.

People with nephrotic syndrome should receive the pneumococcal vaccine, which helps protect against a bacterium that commonly causes infection, and yearly flu shots.

Blood thinning medications are usually only given to people with nephrotic syndrome who develop a blood clot; these medications are not used as a preventive measure.

Nephrotic syndrome may go away once the underlying cause has been treated. More information about treating the underlying causes of nephrotic syndrome is provided in the NIDDK health topic, Glomerular Diseases.

Eating, Diet, and Nutrition

Eating, diet, and nutrition have not been shown to play a role in causing or preventing nephrotic syndrome in adults. For people who have developed nephrotic syndrome, limiting intake of dietary sodium, often from salt, and fluid may be recommended to help reduce edema. A diet low in saturated fat and cholesterol may also be recommended to help control hyperlipidemia.

Points to Remember

• Nephrotic syndrome includes the following:
  • proteinuria—large amounts of protein in the urine
  • hyperlipidemia—higher than normal fat and cholesterol levels in the blood
  • edema, or swelling, usually in the legs, feet, or ankles and less often in the hands or face
  • hypoalbuminia—low levels albumin in the blood
• Primary causes of nephrotic syndrome are diseases that affect only the kidneys, such as focal segmental glomerulosclerosis (FSGS). Secondary causes of nephrotic syndrome are diseases that affect many parts of the body, such as diabetes.
• In addition to proteinuria, hyperlipidemia, edema, and hypoalbumina, people with nephrotic syndrome may experience
  • weight gain
  • fatigue
  • foamy urine
  • loss of appetite
• The loss of different proteins from the body can lead to a variety of complications in people with nephrotic syndrome.
• Treating nephrotic syndrome includes addressing the underlying cause and taking steps to reduce high blood pressure, edema, high cholesterol, and the risks of infection. Treatment usually includes medications and changes in diet.

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

Why is nutrition important for someone with advanced chronic kidney disease (CKD)?

A person may prevent or delay some health problems from CKD by eating the right foods and avoiding foods high in sodium, potassium, and phosphorus. Learning about calories, fats, proteins, and fluids is important for a person with advanced CKD. Protein foods such as meat and dairy products break down into waste products that healthy kidneys remove from the blood.

As CKD progresses, nutritional needs change. A health care provider may recommend that a patient with reduced kidney function choose foods carefully.

What do the kidneys do?

The kidneys remove wastes and extra water from the blood and make urine. To keep the body working properly, the kidneys balance the salts and minerals—such as calcium, phosphorus, sodium, and potassium—that circulate in the blood. The kidneys also release hormones that help make red blood cells, regulate blood pressure, and keep bones strong.

What are the effects of CKD?

CKD usually takes a long time to develop and does not go away. In CKD, the kidneys continue to work—just not as well as they should. Wastes may build up so gradually that the body becomes used to having those wastes in the blood. Salts containing phosphorus and potassium may rise to unsafe levels, causing heart and bone problems. Anemia—low red blood cell count—can result from CKD because the kidneys stop making enough erythropoietin, a hormone that causes bone marrow to make red blood cells. After months or years, CKD may progress to permanent kidney failure, which requires a person to have a kidney transplant or regular blood filtering treatments called dialysis.

What is medical nutrition therapy (MNT)?

MNT is the use of nutrition counseling by a registered dietitian to help promote a medical or health goal. A health care provider may refer a patient to a registered dietitian to help with the patient's food plan. Many insurance policies cover MNT when recommended by a health care provider. Anyone who qualifies for Medicare can receive a benefit for MNT from a registered dietitian or nutrition professional when a health care provider provides a referral indicating that the person has diabetes or kidney disease.

One way to locate a qualified dietitian is to contact the Academy of Nutrition and Dietetics at www.eatright.org and click on "Find a Registered Dietitian." Users can enter their address or ZIP code for a list of dietitians in their area. A person looking for dietary advice to prevent kidney damage should click on "Renal (Kidney) Nutrition" in the specialty field. Dietitians who specialize in helping people with CKD are called renal dietitians.

Why is knowing about calories important for someone with advanced CKD?

As CKD progresses, people often lose their appetites because they find that foods do not taste the same. As a result, they consume fewer calories—important units of energy in food—and may lose too much weight. Renal dietitians can help people with advanced CKD find healthy ways to add calories to their diet if they are losing too much weight.

Why is knowing about protein important for someone with advanced CKD?

Protein is an essential part of any diet. Proteins help build and maintain muscle, bone, skin, connective tissue, internal organs, and blood. They help fight disease and heal wounds. But proteins also break down into waste products that must be removed from the blood by the kidneys. Eating more protein than the body needs may put an extra burden on the kidneys and cause kidney function to decline faster.

Health care providers recommend that people with CKD eat moderate or reduced amounts of protein. However, restricting protein could lead to malnutrition, so people with CKD need to be careful. The typical American diet contains more than enough protein. Learning about portion sizes can help people limit protein intake without endangering their health.

What is the right meat portion size?

Most people—with or without CKD—can get the daily protein they need by eating two 3-ounce servings of meat or meat substitute. A 3-ounce serving of meat is about the size of a deck of cards or the palm of a person’s hand.

A renal dietitian can help people learn about the amount and sources of protein in their diet. Animal protein in egg whites, cheese, chicken, fish, and red meats contain more of the essential nutrients a body needs. With careful meal planning, a well-balanced vegetarian diet can also provide these nutrients. A renal dietitian can help people with advanced CKD make small adjustments in their eating habits that can result in significant protein reduction. For example, people can lower their protein intake by making sandwiches using thinner slices of meat and adding lettuce, cucumber slices, apple slices, and other garnishes. The following table lists some higher-protein foods and suggestions for lower-protein alternatives that are better choices for people with CKD trying to limit their protein intake.

Higher- and Lower-protein Foods

Based on about a 3 oz. portion
Higher-Protein Foods	Lower-protein Alternatives
Ground beef Halibut Shrimp Salmon Tuna Chicken breast Roasted chicken	Chili con carne Beef stew Egg substitutes Tofu Imitation crab meat

When kidney function declines to the point where dialysis becomes necessary, patients should include more protein in their diet because dialysis removes large amounts of protein from the blood.

Why is knowing about fat important for someone with advanced CKD?

Everyone should know about fat sources because eating the wrong kinds of fat and too much fat increases the risk of clogged blood vessels and heart problems. Fat provides energy, helps produce hormonelike substances that regulate blood pressure and other heart functions, and carries fat-soluble vitamins. Everyone needs dietary fat, but some fats are healthier than others. People with CKD are at higher risk of having a heart attack or stroke. Therefore, people with CKD should be especially careful about how dietary fat affects their heart health.

People with advanced CKD should talk with a dietitian about healthy and unhealthy sources of fat. Saturated fats and trans-fatty acids can raise blood cholesterol levels and clog blood vessels. Saturated fats are found in animal products such as red meat, poultry, whole milk, and butter. These fats are usually solid at room temperature. Trans-fatty acids are often found in commercially baked goods such as cookies and cakes and in fried foods like doughnuts and french fries.

A dietitian can suggest healthy ways to include fat in the diet, especially if more calories are needed. Vegetable oils such as corn or safflower oil are healthier than animal fats such as butter or lard. Hydrogenated vegetable oils should be avoided because they are high in trans-fatty acids. Monounsaturated fats—olive, peanut, and canola oils—are healthy alternatives to animal fats. The table below shows the sources of fats, broken down into three types of fats that should be eaten less often and good fats that can be eaten more often.

Sources of Fats

Eat Less Often	Eat More Often
Saturated fats red meat poultry whole milk butter lard Trans-fatty acids commercial baked goods french fries doughnuts Hydrogenated vegetable oils margarine shortening	Monounsaturated fats corn oil safflower oil olive oil peanut oil canola oil

Why is knowing about sodium important for someone with advanced CKD?

Too much sodium in a person's diet can be harmful because it causes blood to hold fluid. People with CKD need to be careful not to let too much fluid build up in their bodies. The extra fluid raises blood pressure and puts a strain on the heart and kidneys. A dietitian can help people find ways to reduce the amount of sodium in their diet. Nutrition labels provide information about the sodium content in food. The U.S. Food and Drug Administration advises that healthy people should limit their daily sodium intake to no more than 2,300 milligrams (mg), the amount found in 1 teaspoon of table salt. People who are at risk for a heart attack or stroke because of a condition such as high blood pressure or kidney disease should limit their daily sodium intake to no more than 1,500 mg. Choosing sodium-free or low-sodium food products will help them reach that goal.

Sodium is found in ordinary table salt and many salty seasonings such as soy sauce and teriyaki sauce. Canned foods, some frozen foods, and most processed meats have large amounts of salt. Snack foods such as chips and crackers are also high in salt.

Alternative seasonings such as lemon juice, salt-free seasoning mixes, and hot pepper sauce can help people reduce their salt intake. People with advanced CKD should avoid salt substitutes that use potassium, such as AlsoSalt or Nu-Salt, because CKD limits the body's ability to eliminate potassium from the blood. The table below provides some high-sodium foods and suggestions for low-sodium alternatives that are healthier for people with any level of CKD who have high blood pressure.

High- and Low-sodium Foods

High-sodium Foods	Low-sodium Alternatives
Salt Regular canned vegetables Hot dogs and canned meat Packaged rice with sauce Packaged noodles with sauce Frozen vegetables with sauce Frozen prepared meals Canned soup Regular tomato sauce Snack foods	Salt-free herb seasonings Low-sodium canned foods Frozen vegetables without sauce Fresh, cooked meat Plain rice without sauce Plain noodles without sauce Fresh vegetables without sauce Homemade soup with fresh ingredients Reduced-sodium tomato sauce Unsalted pretzels Unsalted popcorn

Why is knowing about potassium important for someone with advanced CKD?

Keeping the proper level of potassium in the blood is essential. Potassium keeps the heart beating regularly and muscles working right. Problems can occur when blood potassium levels are either too low or too high. Damaged kidneys allow potassium to build up in the blood, causing serious heart problems. Potassium is found in many fruits and vegetables, such as bananas, potatoes, avocados, and melons. People with advanced CKD may need to avoid some fruits and vegetables. Blood tests can indicate when potassium levels have climbed above normal range. A renal dietitian can help people with advanced CKD find ways to limit the amount of potassium they eat. The potassium content of potatoes and other vegetables can be reduced by boiling them in water. The following table gives examples of some high-potassium foods and suggestions for low-potassium alternatives for people with advanced CKD.

High- and Low-potassium Foods

High-potassium Foods	Low-potassium Alternatives
Oranges and orange juice Melons Apricots Bananas Potatoes Tomatoes Sweet potatoes Cooked spinach Cooked broccoli Beans (baked, kidney, lima, pinto)	Apples and apple juice Cranberries and cranberry juice Canned pears Strawberries, blueberries, raspberries Plums Pineapple Cabbage Boiled Cauliflower

Why is knowing about phosphorus important for someone with advanced CKD?

Damaged kidneys allow phosphorus, a mineral found in many foods, to build up in the blood. Too much phosphorus in the blood pulls calcium from the bones, making the bones weak and likely to break. Too much phosphorus may also make skin itch. Foods such as milk and cheese, dried beans, peas, colas, canned iced teas and lemonade, nuts, and peanut butter are high in phosphorus. A renal dietitian can help people with advanced CKD learn how to limit phosphorus in their diet.

As CKD progresses, a person may need to take a phosphate binder such as sevelamer hydrochloride (Renagel), lanthanum carbonate (Fosrenol), calcium acetate (PhosLo), or calcium carbonate (Tums) to control the phosphorus in the blood. These medications act like sponges to soak up, or bind, phosphorus while it is in the stomach. Because it is bound, the phosphorus does not get into the blood. Instead, it is removed from the body in the stool.

The table below lists some high-phosphorus foods and suggestions for low-phosphorus alternatives that are healthier for people with advanced CKD.

High- and Low-phosphorus Foods

High-phosphorus Foods	Low-phosphorus Alternatives
Dairy foods (milk, cheese, yogurt) Beans (baked, kidney, lima, pinto) Nuts and peanut butter Processed meats (hot dogs, canned meat) Cola Canned iced teas and lemonade Bran cereals Egg yolks	Liquid non-dairy creamer Sherbet Cooked rice Rice, wheat, and corn cereals Popcorn Peas Lemon-lime soda Root beer Powdered iced tea and lemonade mixes

Why is regulating fluid intake important for someone with advanced CKD?

People with advanced CKD may need to limit how much they drink because damaged kidneys can’t remove extra fluid. The fluid builds up in the body and strains the heart. Patients should tell their health care provider about any swelling around the eyes or in the legs, arms, or abdomen.

How can understanding and keeping track of lab reports help someone with advanced CKD make healthy food choices?

Learning how to read and understand lab reports lets a person see how different foods can affect the kidneys. A health care provider should order regular blood tests for people with CKD. Patients can ask their health care provider for copies of their lab reports and ask to have them explained, noting any results out of the normal range. Keeping track of these lab results can help people see whether they are making progress or getting worse. People with CKD should talk with their health care provider or dietitian about how they can make healthier food choices. For example, if a test shows that a person with advanced CKD has a high potassium level, that person should concentrate on reducing potassium in the diet by limiting high-potassium foods.

Points to Remember

• A person may prevent or delay some health problems from chronic kidney disease (CKD) by eating the right foods and avoiding foods high in sodium, potassium, and phosphorus.
• The kidneys remove wastes and extra water from the blood and make urine.
• Medical nutrition therapy (MNT) is the use of counseling by a registered dietitian to help promote a medical or health goal.
• Dietitians who specialize in helping people with CKD are called renal dietitians.
• People with advanced CKD often lose their appetites and consume fewer calories—important units of energy in food—and may lose too much weight.
• Eating more protein than the body needs may put an extra burden on the kidneys and cause kidney function to decline faster. Most people—with or without CKD—can get the daily protein they need by eating two 3-ounce servings of meat or meat substitute.
• People with CKD are at higher risk of having a heart attack or stroke.
• Everyone needs dietary fat, but some fats are healthier than others.
• Too much sodium in a person’s diet can be harmful because it causes blood to hold fluid. People with CKD need to be careful not to let too much fluid build up in their bodies.
• People with advanced CKD should avoid salt substitutes that use potassium because CKD limits the body’s ability to eliminate potassium from the blood.
• Damaged kidneys allow potassium to build up in the blood, causing serious heart problems. Potassium is found in many fruits and vegetables, such as bananas, potatoes, avocados, and melons.
• Too much phosphorus in the blood pulls calcium from the bones, making the bones weak and likely to break.
• People with advanced CKD may need to limit how much they drink because damaged kidneys can't remove extra fluid.
• Many patients find that keeping track of their test results helps them see how their treatment is working. Patients can ask their health care provider for copies of their lab reports and ask to have them explained, noting any results out of the normal range.

About the Nutrition for Chronic Kidney Disease Series

The NIDDK Nutrition for Chronic Kidney Disease Series includes two fact sheets:

• Nutrition for Advanced Chronic Kidney Disease in Adults
• Nutrition for Chronic Kidney Disease in Children

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

What are renal artery stenosis (RAS) and renovascular hypertension (RVH)?

Renal artery stenosis is the narrowing of one or both renal arteries. “Renal” means “kidney” and “stenosis” means “narrowing.” The renal arteries are blood vessels that carry blood to the kidneys from the aorta—the main blood vessel that carries blood from the heart to arteries throughout the body.

RVH is high blood pressure caused by RAS. Blood pressure is written with two numbers separated by a slash, 120/80, and is said as “120 over 80.” The top number is called the systolic pressure and represents the pressure as the heart beats and pushes blood through the blood vessels. The bottom number is called the diastolic pressure and represents the pressure as blood vessels relax between heartbeats. A person’s blood pressure is considered normal if it stays at or below 120/80. High blood pressure is a systolic pressure of 140 or above or a diastolic pressure of 90 or above.¹

What are the kidneys and what do they do?

The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the two kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid.

What causes RAS?

About 90 percent of RAS is caused by atherosclerosis—clogging, narrowing, and hardening of the renal arteries.² In these cases, RAS develops when plaque—a sticky substance made up of fat, cholesterol, calcium, and other material found in the blood—builds up on the inner wall of one or both renal arteries. Plaque buildup is what makes the artery wall hard and narrow.

Most other cases of RAS are caused by fibromuscular dysplasia (FMD)—the abnormal development or growth of cells on the renal artery walls—which can cause blood vessels to narrow. Rarely, RAS is caused by other conditions.

Who is at risk for RAS?

People at risk for artherosclerosis are also at risk for RAS. Risk factors for RAS caused by artherosclerosis include

• high blood cholesterol levels
• high blood pressure
• smoking
• insulin resistance
• diabetes
• being overweight or obese
• lack of physical activity
• a diet high in fat, cholesterol, sodium, and sugar
• being a man older than 45 or a woman older than 55
• a family history of early heart disease

The risk factors for RAS caused by FMD are unknown, but FMD is most common in women and people 25 to 50 years of age.³ FMD can affect more than one person in a family, indicating that it may be caused by an inherited gene.

What are the symptoms of RAS?

In many cases, RAS has no symptoms until it becomes severe.

The signs of RAS are usually either high blood pressure or decreased kidney function, or both, but RAS is often overlooked as a cause of high blood pressure. RAS should be considered as a cause of high blood pressure in people who

• are older than age 50 when they develop high blood pressure or have a marked increase in blood pressure
• have no family history of high blood pressure
• cannot be successfully treated with at least three or more different types of blood pressure medications

Symptoms of a significant decrease in kidney function include

• increase or decrease in urination
• edema—swelling, usually in the legs, feet, or ankles and less often in the hands or face
• drowsiness or tiredness
• generalized itching or numbness
• dry skin
• headaches
• weight loss
• appetite loss
• nausea
• vomiting
• sleep problems
• trouble concentrating
• darkened skin
• muscle cramps

What are the possible complications of RAS?

People with RAS are at increased risk for complications resulting from loss of kidney function or atherosclerosis occurring in other blood vessels, such as

• chronic kidney disease (CKD)—reduced kidney function over a period of time
• coronary artery disease—narrowing and hardening of arteries that supply blood to the heart
• stroke—brain damage caused by lack of blood flow to the brain
• peripheral vascular disease—blockage of blood vessels that restricts flow of blood from the heart to other parts of the body, particularly the legs

RAS can lead to kidney failure, described as end-stage renal disease when treated with blood-filtering treatments called dialysis or a kidney transplant, though this is uncommon in people who receive ongoing treatment for RAS.

How is RAS diagnosed?

A health care provider can diagnose RAS by listening to the abdomen with a stethoscope and performing imaging tests. When blood flows through a narrow artery, it sometimes makes a whooshing sound, called a bruit. The health care provider may place a stethoscope on the front or the side of the abdomen to listen for this sound. The absence of this sound, however, does not exclude the possibility of RAS.

In some cases, RAS is found when a person has a test for another reason. For example, a health care provider may find RAS during a coronary angiogram for diagnosis of heart problems. A coronary angiogram is a procedure that uses a special dye, called contrast medium, and x-rays to see how blood flows through the heart.

The following imaging tests are used to diagnose RAS:

• Duplex ultrasound. Duplex ultrasound combines traditional ultrasound with Doppler ultrasonography. Traditional ultrasound uses a device, called a transducer, that bounces safe, painless sound waves off organs to create an image of their structure. Doppler ultrasonography records sound waves reflected off of moving objects, such as blood, to measure their speed and other aspects of how they flow. The procedure is performed in a health care provider’s office, outpatient center, or hospital by a specially trained technician, and the images are interpreted by a radiologist—a doctor who specializes in medical imaging. Anesthesia is not needed. The images can show blockage in the renal artery or blood moving through nearby arteries at a lower-than-normal speed. Ultrasound is noninvasive and low cost.
• Catheter angiogram. A catheter angiogram, also called a traditional angiogram, is a special kind of x-ray in which a thin, flexible tube called a catheter is threaded through the large arteries, often from the groin, to the artery of interest—in this case, the renal artery. The procedure is performed in a hospital or outpatient center by a radiologist. Anesthesia is not needed though a sedative may be given to lessen anxiety during the procedure. Contrast medium is injected through the catheter so the renal artery shows up more clearly on the x-ray. Catheter angiogram is the “gold standard” for diagnosing RAS due to the high quality of the image produced. In addition, severe RAS can be treated during the same visit. However, a catheter angiogram is an invasive procedure, and a person may have side effects from the sedative or contrast medium or may have bleeding or injury to the artery from the catheter. The procedure is also more expensive than other imaging tests.
• Computerized tomographic angiography (CTA) scan. CTA scans use a combination of x-rays and computer technology to create images. The procedure is performed in an outpatient center or hospital by an x-ray technician, and the images are interpreted by a radiologist. Anesthesia is not needed. Contrast medium is injected into a vein in the person’s arm to better see the structure of the arteries. CTA scans require the person to lie on a table that slides into a tunnel-shaped device where the x-rays are taken. CTA scans are less invasive than catheter angiograms and take less time. However, the risks from the x-ray radiation still exist, and the test often requires more contrast medium than a catheter angiogram, so it may not be recommended for a person with poor kidney function.
• Magnetic resonance angiogram (MRA). MRA uses radio waves and magnets to produce detailed pictures of the body’s internal organs and soft tissues without using x-rays. The procedure is performed in an outpatient center or hospital by an x-ray technician, and the images are interpreted by a radiologist. Anesthesia is not needed though light sedation may be used for people with a fear of confined spaces. Contrast medium may be injected into a vein in the person’s arm to better see the structure of the arteries. With most MRA scans, the person lies on a table that slides into a tunnel-shaped device that may be open ended or closed at one end; some newer machines are designed to allow the person to lie in a more open space. In addition to providing high-quality images noninvasively, MRA can provide a functional assessment of blood flow and organ function. However, the use of contrast medium for an MRA is not advised for people with poor kidney function because of the risk of complications to the skin and other organs if the kidneys do not remove the contrast medium well enough.

How is RAS treated?

Treatment for RAS includes lifestyle changes, medications, and surgery and aims to

• prevent RAS from getting worse
• treat RVH
• relieve the blockage of the renal arteries

RAS that has not led to RVH or caused a significant blockage of the artery may not need treatment. RAS that needs to be treated, also called critical RAS, is defined by the American Heart Association as a reduction by more than 60 percent in the diameter of the renal artery.¹ However, health care providers are not exactly sure what degree of blockage will cause significant problems.

Lifestyle Changes

The first step in treating RAS is making lifestyle changes that promote healthy blood vessels throughout the body, including the renal arteries. The best ways to keep plaque from building up in the arteries are to exercise, maintain a healthy body weight, and choose healthy foods. People who smoke should quit to help protect their kidneys and other internal organs.

Medications

People with RVH may need to take medications that—when taken as prescribed by their health care provider—lower blood pressure and can also significantly slow the progression of kidney disease. Two types of blood pressure-lowering medications, angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), have proven effective in slowing the progression of kidney disease. Many people require two or more medications to control their blood pressure. In addition to an ACE inhibitor or an ARB, a diuretic—a medication that helps the kidneys remove fluid from the blood—may be prescribed. Beta blockers, calcium channel blockers, and other blood pressure medications may also be needed. Some people with RAS cannot take an ACE inhibitor or ARB due to the effects on the kidneys. People with RAS who are prescribed an ACE inhibitor or ARB should have their kidney function checked within a few weeks of starting the medication.

A cholesterol-lowering medication to prevent plaque from building up in the arteries and a blood-thinner, such as aspirin, to help the blood flow more easily through the arteries may also be prescribed.

Surgery

Although surgery has been used in the past for treatment of RAS due to atherosclerosis, recent studies have not shown improved outcomes with surgery compared with medication. However, surgery may be recommended for people with RAS caused by FMD or RAS that does not improve with medication. Different types of surgery for RAS include the following. The procedures are performed in a hospital by a vascular surgeon—a doctor who specializes in repairing blood vessels. Anesthesia is needed.

• Angioplasty and stenting. Angioplasty is a procedure in which a catheter is put into the renal artery, usually through the groin, just as in a catheter angiogram. In addition, for angioplasty, a tiny balloon at the end of the catheter can be inflated to flatten the plaque against the artery wall. A small mesh tube, called a stent, may then be positioned inside the artery to keep plaque flattened and the artery open. People with RAS caused by FMD may be successfully treated with angioplasty alone, while angioplasty with stenting has a better outcome for people with RAS caused by atherosclerosis.
• Endarterectomy or bypass surgery. In an endarterectomy, the plaque is cleaned out of the artery, leaving the inside lining smooth and clear. To create a bypass, a vein or synthetic tube is used to connect the kidney to the aorta. This new path serves as an alternate route for blood to flow around the blocked artery into the kidney. These procedures are not performed as often as in the past due to a high risk of complications during and after the procedure.

Eating, Diet, and Nutrition

Limiting intake of fats, cholesterol, sodium, and sugar can help prevent atherosclerosis, which can lead to RAS. Most sodium in the diet comes from salt. A healthy diet that prevents people from becoming overweight or obese can also help prevent atherosclerosis. People with RAS that has caused decreased kidney function should limit their intake of protein, cholesterol, sodium, and potassium to slow the progression of kidney failure. More information about nutrition for CKD is provided in the NIDDK health topics, Nutrition for Early Chronic Kidney Disease in Adults and Nutrition for Advanced Chronic Kidney Disease in Adults. People should talk with their health care provider about what diet is right for them.

Points to Remember

• Renal artery stenosis (RAS) is the narrowing of one or both renal arteries. The renal arteries are blood vessels that carry blood to the kidneys from the aorta—the main blood vessel that carries blood from the heart to arteries throughout the body.
• Renovascular hypertension (RVH) is high blood pressure caused by RAS.
• About 90 percent of RAS is caused by atherosclerosis. Most other cases of RAS are caused by fibromuscular dysplasia (FMD), which can cause blood vessels to narrow.
• RAS often has no symptoms until it becomes severe. The first symptoms of RAS are usually either high blood pressure or decreased kidney function, or both, but RAS is often overlooked as a cause of high blood pressure.
• People with RAS are at increased risk for chronic kidney disease (CKD), coronary artery disease, stroke, and peripheral vascular disease.
• Imaging tests used to diagnose RAS include duplex ultrasound, catheter angiogram, computerized tomographic angiography (CTA) scan, and magnetic resonance angiogram (MRA).
• Treatment for RAS includes lifestyle changes, medications, and surgery.

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

What are simple kidney cysts?

Simple kidney cysts are abnormal, fluid-filled sacs that form in the kidneys. Simple kidney cysts are different from the cysts that develop when a person has polycystic kidney disease (PKD), which is a genetic disorder. Simple kidney cysts do not enlarge the kidneys, replace their normal structure, or cause reduced kidney function like cysts do in people with PKD.

Simple kidney cysts are more common as people age. An estimated 25 percent of people 40 years of age and 50 percent of people 50 years of age have simple kidney cysts.¹

What are the kidneys and what do they do?

The kidneys are two bean-shaped organs, each about the size of a fist. They are located near the middle of the back, just below the rib cage, one on each side of the spine. Every day, the two kidneys process about 200 quarts of blood to filter out about 1 to 2 quarts of urine, composed of waste products and extra water. The urine flows from the kidneys to the bladder through tubes called ureters. The bladder stores urine until releasing it through urination.

What causes simple kidney cysts?

The cause of simple kidney cysts is not fully understood. Obstruction of tubules—tiny structures within the kidneys that collect urine—or deficiency of blood supply to the kidneys may play a role. Diverticula—sacs that form on the tubules—may detach and become simple kidney cysts. The role of genetic factors in the development of simple kidney cysts has not been studied.

What are the symptoms of simple kidney cysts?

Simple kidney cysts usually do not cause symptoms or harm the kidneys. In some cases, however, pain can occur between the ribs and hips when cysts enlarge and press on other organs. Sometimes cysts become infected, causing fever, pain, and tenderness. Simple kidney cysts are not thought to affect kidney function, but one study found an association between the presence of cysts and reduced kidney function in hospitalized people younger than 60 years of age.¹ Some studies have found a relationship between simple kidney cysts and high blood pressure. For example, high blood pressure has improved in some people after a large cyst was drained. However, this relationship is not well understood.²

How are simple kidney cysts diagnosed?

Most simple kidney cysts are found during imaging tests done for other reasons. When a cyst is found, the following imaging tests can be used to determine whether it is a simple kidney cyst or another, more serious condition. These imaging tests are performed at an outpatient center or hospital by a specially trained technician, and the images are interpreted by a radiologist—a doctor who specializes in medical imaging. Ultrasound may also be performed in a health care provider’s office. Anesthesia is not needed though light sedation may be used for people with a fear of confined spaces who undergo magnetic resonance imaging (MRI).

• Ultrasound. Ultrasound uses a device, called a transducer, that bounces safe, painless sound waves off organs to create an image of their structure. An abdominal ultrasound can create images of the entire urinary tract. The images can be used to distinguish harmless cysts from other problems.
• Computerized tomography (CT) scan. CT scans use a combination of x-rays and computer technology to create three-dimensional (3-D) images. A CT scan may include the injection of a special dye, called contrast medium. CT scans require the person to lie on a table that slides into a tunnel-shaped device where the x-rays are taken. CT scans can show cysts and tumors in the kidneys.
• MRI. MRI machines use radio waves and magnets to produce detailed pictures of the body’s internal organs and soft tissues without using x-rays. An MRI may include the injection of contrast medium. With most MRI machines, the person lies on a table that slides into a tunnel-shaped device that may be open ended or closed at one end; some newer machines are designed to allow the person to lie in a more open space. Like CT scans, MRIs can show cysts and tumors.

How are simple kidney cysts treated?

Treatment is not needed for simple kidney cysts that do not cause any symptoms. Simple kidney cysts may be monitored with periodic ultrasounds.

Simple kidney cysts that are causing symptoms or blocking the flow of blood or urine through the kidney may need to be treated using a procedure called sclerotherapy. In sclerotherapy, the doctor punctures the cyst using a long needle inserted through the skin. Ultrasound is used to guide the needle to the cyst. The cyst is drained and then filled with a solution containing alcohol to make the kidney tissue harder. The procedure is usually performed on an outpatient basis with a local anesthetic.

If the cyst is large, surgery may be needed. Most surgeries can be performed using a laparoscope—a special tool with a small, lighted video camera. The procedure is usually done under general anesthesia in a hospital. The surgeon drains the cyst and then removes or burns away its outer tissue. This type of surgery allows for a smaller incision and quicker recovery.

Eating, Diet, and Nutrition

Eating, diet, and nutrition have not been shown to play a role in causing or preventing simple kidney cysts.

Points to Remember

• Simple kidney cysts are abnormal, fluid-filled sacs that form in the kidneys.
• Simple kidney cysts usually do not cause symptoms or harm the kidneys.
• Most simple kidney cysts are found during imaging tests done for other reasons.
• Treatment is not needed for simple kidney cysts that do not cause any symptoms.
• Simple kidney cysts that are causing symptoms or blocking the flow of blood or urine through the kidney may need to be treated using sclerotherapy or surgery.

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

What is a solitary kidney?

When a person has only one kidney or one working kidney, this kidney is called a solitary kidney. The three main causes of a solitary kidney are

• birth defects. People with kidney agenesis are born with only one kidney. People born with kidney dysplasia have both kidneys; however, one kidney does not function. Many people with kidney agenesis or kidney dysplasia do not discover that they have a solitary kidney until they have an x-ray, an ultrasound, or surgery for an unrelated condition.
• surgical removal of a kidney. Some people must have a kidney removed to treat cancer or another disease or injury. When a kidney is removed surgically due to disease or for donation, both the kidney and ureter are removed.
• kidney donation. A growing number of people are donating a kidney to be transplanted into a family member or friend whose kidneys have failed.

In general, people with a solitary kidney lead full, healthy lives. However, some people are more likely to develop kidney disease.

What are the kidneys and what do they do?

The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid. The urine flows from the kidneys to the bladder through tubes called ureters. The bladder stores urine until releasing it through urination.

Do people with a solitary kidney need to be monitored for kidney damage?

People with a solitary kidney should be tested regularly for the following signs of kidney damage:

• albuminuria
• decreased glomerular filtration rate (GFR)
• high blood pressure

Albuminuria Testing

Albuminuria is an elevated level of the protein albumin in the urine. Albumin acts like a sponge, drawing extra fluid from the body into the bloodstream, where it remains until removed by the kidneys. When albumin leaks into the urine, the blood loses its capacity to absorb extra fluid from the body. Although the increased albumin in the urine may not cause any symptoms, it often indicates an increased chance of kidney disease.

Dipstick test for albumin. The presence of albumin in the urine can be detected with a dipstick test performed on a urine sample. The urine sample is collected in a special container in a health care provider’s office or a commercial facility and can be tested in the same location or sent to a lab for analysis. With a dipstick test, a nurse or technician places a strip of chemically treated paper, called a dipstick, into the person’s urine sample. Patches on the dipstick change color when protein is present in urine.

Albumin and creatinine measurement. A more precise measurement is usually needed to confirm albuminuria. A single urine sample or a 24-hour collection of urine is sent to a lab for analysis. With the single urine sample, the lab measures both albumin and creatinine, a waste product of normal muscle breakdown. The results are reported as a urine albumin-to-creatinine ratio. A urine sample containing more than 30 mg of albumin for each gram of creatinine may signal a problem. With a 24-hour collection of urine, the lab measures only the amount of albumin present. Although both tests are effective, the single urine sample is easier to collect than the 24-hour sample and is usually sufficient to diagnose and monitor kidney disease.

Decreased GFR Testing

Blood drawn at a health care provider’s office or a commercial facility and sent to a lab for analysis can be tested to estimate how much blood the kidneys filter each minute, called the estimated glomerular filtration rate (eGFR). The results of the test indicate the following:

• eGFR of 60 or above is in the normal range.
• eGFR below 60 may indicate kidney damage.
• eGFR of 15 or below may indicate kidney failure.

High Blood Pressure Monitoring

Blood pressure is the force of blood pushing against the blood vessel walls as the heart pumps out blood. Blood vessels are also called arteries. High blood pressure, also called hypertension, is an increase in the amount of force the blood places on the blood vessels as it moves through the body. Blood pressure is written with two numbers separated by a slash. For example, a blood pressure result of 120/80 is said as “120 over 80.” The first number is called the systolic pressure and represents the pressure as the heart beats and pushes blood through the blood vessels. The second number is called the diastolic pressure and represents the pressure as the heart rests and the blood vessels relax between heartbeats.

A person’s blood pressure is considered normal if it stays below 120/80. Prehypertension is a systolic pressure of 120 to 139 or a diastolic pressure of 80 to 89. High blood pressure is a systolic pressure of 140 or above or a diastolic pressure of 90 or above.¹ High blood pressure is diagnosed when multiple blood pressure tests—often repeated over several visits to the health care provider’s office—show that blood pressure is consistently above 140/90. Health care providers measure blood pressure with a blood pressure cuff. People can also buy blood pressure cuffs at places such as discount chain stores and drugstores to monitor their blood pressure at home.

High blood pressure can damage blood vessels in the kidneys, reducing their ability to work properly. Damaged kidneys may be less able to remove salt and extra fluid, raising blood pressure further and creating a dangerous cycle.

What steps can people with a solitary kidney take to protect their health?

People with a solitary kidney can protect their health by eating a nutritious diet, keeping their blood pressure at the appropriate level, and preventing injury to the working kidney.

Eating, Diet, and Nutrition

People with a solitary kidney do not need to eat a special diet. However, people with reduced kidney function may need to make changes to their diet to slow the progression of kidney disease. More information about recommended dietary changes is provided in the NIDDK health topics, Nutrition for Early Chronic Kidney Disease in Adults and Nutrition for Advanced Chronic Kidney Disease in Adults, and Managing Chronic Kidney Disease. People should talk with their health care provider about what diet is right for them.

Controlling Blood Pressure

People can control their blood pressure by not smoking, eating a healthy diet, and taking certain medications. Medications that lower blood pressure can also significantly slow the progression of kidney disease. Two types of blood pressure–lowering medications, angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), have proven effective in slowing the progression of kidney disease. Many people require two or more medications to control their blood pressure. In addition to an ACE inhibitor or ARB, a diuretic—a medication that helps the kidneys remove fluid from the blood—may be prescribed. Beta-blockers, calcium channel blockers, and other blood pressure medications may also be needed.

Preventing Injury

For people with a solitary kidney, loss of the remaining working kidney results in the need for dialysis or kidney transplant. People should make sure their health care providers know they have a solitary kidney to prevent injury from medications or medical procedures. People who participate in certain sports may be more likely to injure the kidney; this risk is of particular concern with children, as they are more likely to play sports. The American Academy of Pediatrics recommends individual assessment for contact, collision, and limited-contact sports. Protective equipment may reduce the chance of injury to the remaining kidney enough to allow participation in most sports, provided that such equipment remains in place during activity. Health care providers, parents, and patients should consider the risks of any activity and decide whether the benefits outweigh those risks.

Points to Remember

• When a person has only one kidney or one working kidney, this kidney is called a solitary kidney. The three main causes of a solitary kidney are birth defects, surgical removal of a kidney, and kidney donation.
• In general, people with a solitary kidney lead full, healthy lives. However, some people are more likely to develop kidney disease.
• People with a solitary kidney should be tested regularly for the following signs of kidney damage:
  • albuminuria
  • decreased glomerular filtration rate (GFR)
  • high blood pressure
• People with a solitary kidney can protect their health by eating a nutritious diet, keeping their blood pressure at the appropriate level, and preventing injury to the working kidney.

References

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.

What are the kidneys and what do they do?

The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the two kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid. The urine flows from the kidneys to the bladder through two thin tubes of muscle called ureters, one on each side of the bladder. The bladder stores urine. The muscles of the bladder wall remain relaxed while the bladder fills with urine. As the bladder fills to capacity, signals sent to the brain tell a person to find a toilet soon. When the bladder empties, urine flows out of the body through a tube called the urethra, located at the bottom of the bladder. In men the urethra is long, while in women it is short.

More information about the ureters, bladder, and urethra is provided in the NIDDK health topic, The Urinary Tract and How It Works.

Why are the kidneys important?

The kidneys are important because they keep the composition, or makeup, of the blood stable, which lets the body function. They

• prevent the buildup of wastes and extra fluid in the body
• keep levels of electrolytes stable, such as sodium, potassium, and phosphate
• make hormones that help
  • regulate blood pressure
  • make red blood cells
  • bones stay strong

How do the kidneys work?

The kidney is not one large filter. Each kidney is made up of about a million filtering units called nephrons. Each nephron filters a small amount of blood. The nephron includes a filter, called the glomerulus, and a tubule. The nephrons work through a two-step process. The glomerulus lets fluid and waste products pass through it; however, it prevents blood cells and large molecules, mostly proteins, from passing. The filtered fluid then passes through the tubule, which sends needed minerals back to the bloodstream and removes wastes. The final product becomes urine.

More information is provided in the NIDDK health topic, Questions and Answers about the Kidneys and Kidney Disease.

Points to Remember

• Every day, the two kidneys filter about 120 to 150 quarts of blood to produce about 1 to 2 quarts of urine, composed of wastes and extra fluid.
• The kidneys are important because they keep the composition, or makeup, of the blood stable, which lets the body function.
• Each kidney is made up of about a million filtering units called nephrons. The nephron includes a filter, called the glomerulus, and a tubule.
• The nephrons work through a two-step process. The glomerulus lets fluid and waste products pass through it; however, it prevents blood cells and large molecules, mostly proteins, from passing. The filtered fluid then passes through the tubule, which sends needed minerals back to the bloodstream and removes wastes.

Clinical Trials

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct and support research into many diseases and conditions.

What are clinical trials, and are they right for you?

Clinical trials are part of clinical research and at the heart of all medical advances. Clinical trials look at new ways to prevent, detect, or treat disease. Researchers also use clinical trials to look at other aspects of care, such as improving the quality of life for people with chronic illnesses. Find out if clinical trials are right for you.

What clinical trials are open?

Clinical trials that are currently open and are recruiting can be viewed at www.ClinicalTrials.gov.