Adult Nephrotic Syndrome

What is nephrotic syndrome?

Nephrotic syndrome is a condition marked by

• very high levels of protein in the urine, a condition called proteinuria
• low levels of protein in the blood
• swelling, especially around the eyes, feet, and hands
• high cholesterol

What causes nephrotic syndrome?

Nephrotic syndrome results from damage to the kidneys' glomeruli—tiny blood vessels that filter wastes and excess water from the blood and send them to the bladder as urine.

When the glomeruli are working properly, they keep protein in the blood from leaking into the urine. Healthy kidneys allow less than 1 gram of protein to escape through the urine in a day. In nephrotic syndrome, the damaged glomeruli allow 3 grams or more of protein to leak into the urine during a 24-hour period.

As a result of this protein loss, the blood is deficient. Normal amounts of blood protein are needed to help regulate fluid throughout the body. Protein acts like a sponge to soak up fluid into the bloodstream. When blood is low in protein, fluid accumulates in the body’s tissues rather than circulating. The fluid causes swelling and puffiness.

Nephrotic syndrome can occur with many diseases. In adults, the most common causes are diabetic nephropathy and membranous nephropathy. In older adults, the most common cause is amyloidosis. Prevention of nephrotic syndrome relies on controlling these diseases. Frequently, however, the cause of nephrotic syndrome is unknown.

How is nephrotic syndrome diagnosed?

Your doctor will need blood and urine samples to evaluate your condition.

A high level of protein in a spot urine sample may indicate nephrotic syndrome. The doctor may order a 24-hour collection of urine in order to get a more precise measurement.

Blood tests may show low levels of protein. If kidney damage is advanced, waste products such as creatinine and urea nitrogen may build up in the blood.

Once nephrotic syndrome is established, the doctor may recommend a kidney biopsy—a procedure in which tiny pieces of the kidney are removed for examination with a microscope. The biopsy may reveal the underlying disease so that the doctor can determine a course of treatment. If a person has had diabetes for some time, and the patient history and laboratory tests are consistent with diabetic nephropathy, a biopsy is rarely necessary.

How is nephrotic syndrome treated?

In addition to addressing the underlying cause, treatment of nephrotic syndrome focuses on reducing high cholesterol, blood pressure, and protein in urine through diet, medications, or both. Two groups of blood pressure medications—angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs)—also protect the kidneys by reducing proteinuria.

Some people may benefit from limiting protein in their diet to reduce the buildup of wastes in the blood.

Nephrotic syndrome may go away once the underlying cause, if known, has been treated. In children, 80 percent of cases of nephrotic syndrome are caused by a condition called minimal change disease, which can be successfully treated with prednisone. However, in adults, most of the time the underlying cause is a kidney disease such as membranous nephropathy or focal segmental glomerulonephritis, diseases that are treated with corticosteroids, immunosuppressive drugs, and, in some cases, cytotoxic agents. Unfortunately, these treatments do not always bring about remission of nephrotic syndrome. Depending on the disease, as many as half of the patients may develop chronic kidney disease that progresses to end-stage renal disease. In these cases, the kidneys gradually lose their ability to filter wastes and excess water from the blood. If kidney failure occurs, the person will need dialysis or a kidney transplant.

NIH

Ectopic Kidney

What is an ectopic kidney?

An ectopic kidney is a birth defect in which a kidney is located in an abnormal position. In most cases, people with an ectopic kidney have no complaints. In other cases, the ectopic kidney may create urinary problems, such as urine blockage, infection, or urinary stones. Researchers estimate that ectopic kidney occurs once in every 1,000 births.

What are the kidneys?

Kidneys are bean-shaped organs, each about the size of your fist. Most people have two kidneys located near the middle of the back, just below the rib cage. The kidneys filter wastes and extra fluid from your blood. The wastes and extra fluid become urine, which drains from the kidneys to the bladder through tubes called ureters. Urine is stored in the bladder until it is released from the body when you urinate.

What causes an ectopic kidney?

During fetal development, a baby’s kidneys first appear as buds inside the pelvis, near the bladder. As the fetal kidneys develop, they climb gradually toward their normal position near the rib cage in the back. Sometimes, one of the kidneys fails to make the climb. It may stop after making part of the climb. Or it may remain in the pelvis. Rarely does a child have two ectopic kidneys.

An ectopic kidney may remain in the pelvis, close to the bladder.

An ectopic kidney may cross over and become fused with the other kidney.

Some kidneys climb toward the rib cage, but one may cross over so that both kidneys are on the same side of the body. When a crossover occurs, the two kidneys may grow together and become fused.

What are the symptoms of an ectopic kidney?

An ectopic kidney may not cause any symptoms and may function normally, even though it is not in its usual position. Many people have an ectopic kidney and do not discover it until they have tests done for other reasons. Sometimes, a doctor may discover an ectopic kidney after feeling a lump in the abdomen during an examination. In other cases, an ectopic kidney may cause abdominal pain or urinary problems.

What are the possible complications of an ectopic kidney?

When a kidney is out of the normal position, drainage problems are likely. Sometimes, urine can even flow backwards from the bladder to the kidney, a problem called vesicoureteral reflux, or simply reflux. Abnormal urine flow can set the stage for a number of problems.

Infection. Normally, urine flow washes out bacteria and keeps them from growing in the kidneys and urinary tract. When a kidney is out of the normal position, urine may get trapped in the ureter or in the kidney itself. Urine that remains in the urinary tract gives bacteria the chance to grow and spread. Symptoms of a urinary tract infection include frequent or painful urination, back or abdominal pain, fever, and chills. The urine may be cloudy or have an unusual smell.

Stones. Urinary stones form from substances found in the urine, such as calcium and oxalate. Urine that remains too long in the urinary tract increases the risk that these substances will have time to form stones. Symptoms of urinary stones include extreme pain in the back, side, or pelvis; blood in the urine; fever or chills; vomiting; and burning during urination.

Kidney failure. If urine backs up all the way to the kidneys, damage to the kidneys can occur. As a result, the kidneys can’t filter wastes and extra fluid from the blood. Symptoms of kidney failure include swelling in the legs or abdomen, feeling very tired, headaches, or nausea. If total kidney failure occurs, you will need dialysis or a kidney transplant. Total kidney failure happens only when both kidneys are damaged. One ectopic kidney, even when it has no function, won’t cause kidney failure.

Trauma. If the ectopic kidney is in the lower abdomen, or pelvis, it may be susceptible to injury from blunt trauma. People with ectopic kidney who want to participate in body contact sports may wish to wear protective gear.

What tests will the doctor order?

Your doctor can get the most information about your condition by looking at pictures of the ectopic kidney. Several different imaging tests are available.

Ultrasound. During an ultrasound examination, a medical technician will glide a device called a transducer over your skin—either on your side, your abdomen, or your pelvis—depending on the location of the kidney. The transducer sends harmless sound waves into your body. The sound waves bounce off your kidney and back to the transducer. The equipment reads the sound waves and creates a black and white image of the kidney on a television screen.

X ray. Your doctor may use conventional x-ray equipment to perform an intravenous pyelogram (IVP) or a voiding cystourethrogram (VCUG). In an IVP, a special dye is injected into a vein, usually in the arm. The radiologist takes a series of snapshots as the dye circulates through the blood and reaches the kidneys. The structures of the kidneys show up on the x rays as the dye is filtered from the blood and passes through the kidneys to the ureters. An IVP can show whether urine is backing up into the ectopic kidney. In children, ultrasounds are usually done instead of IVPs.

In a VCUG, a thin hollow tube called a catheter is placed into the bladder so that it can be filled with x-ray contrast material. X rays are then taken as the patient urinates. The VCUG gives information about the bladder and reveals whether urine is backing up toward the kidneys during urination.

Nuclear scan. In a nuclear scan, a small amount of a radioactive drug is injected into a vein, and pictures are taken of the kidney over a period of time after the injection. Sometimes a diuretic medicine is also given to increase urine flow. This test can reveal whether the ureters—tubes that drain urine from the kidneys—are blocked and how well the kidneys work. Sometimes, a nuclear scan may be done to find the location of an ectopic kidney.

Computerized tomography (CT) scan. A CT scan uses multiple x-ray images to create a cross-section view of your body on a computer screen. You will lie on a table that passes through a doughnut-shaped machine where the scanning takes place. CT scans aren’t usually needed in the evaluation of an ectopic kidney, but they may be done in a few cases.

Magnetic resonance imaging (MRI). MRI technology uses radio waves and magnets to create pictures of internal organs. No exposure to radiation is required. With most MRI machines, you lie on a table that slides into a tunnel that may be open-ended or closed at one end. Some newer machines are designed to allow you to lie in a more open space. Like CT scans, MRIs are rarely needed to evaluate an ectopic kidney.

In addition to imaging tests, the doctor may order blood tests to determine how well your kidneys are working. These tests are almost always normal in patients with an ectopic kidney, even if it is badly damaged, because the other kidney usually has completely normal function.

What are the treatments for an ectopic kidney?

If your urinary function is normal and the doctor finds no blockage, no treatment for ectopic kidney is needed. Your doctor should continue to monitor your condition in case a change occurs.

If tests show that obstruction is present, you may need surgery to correct the position of the kidney to allow for better drainage of urine. To correct reflux, the surgeon may reattach the ureter to the bladder so that urine can’t reflux into the kidney.

If extensive kidney damage has occurred, the surgeon may need to remove the kidney. As long as the other kidney is working properly, losing one kidney is not a problem. Many people live a normal life after donating a kidney for transplant. Some people are even born with only one kidney and lead full, healthy lives without discovering their condition.

With the right testing and treatment, if needed, an ectopic kidney should cause no serious long-term health problems.

NIH

Simple Kidney Cysts

A cyst is a closed pocket or pouch of tissue that can form anywhere in the body. Cysts can be filled with air or fluid. Cysts that form on the kidneys usually contain fluid. One or more cysts may develop on small tubes in the kidneys. The simple kidney cyst is different from the cysts that develop when a person has polycystic kidney disease, which is a genetic disease. Although its cause is not fully understood, the simple cyst is not an inherited condition. Simple kidney cysts become more common as people age. Nearly 30 percent of people over the age of 70 have at least one simple kidney cyst.

Most often, simple cysts do not cause symptoms or harm the kidney. In some cases, however, pain can occur when cysts enlarge and press on other organs. Sometimes cysts become infected or suddenly start to bleed. Less often the cysts impair kidney function. People with simple cysts are often found to have high blood pressure, although the cause-and-effect relationship is not well understood.

Kidney cysts are found by taking pictures of the kidneys using computerized tomography (CT) scans and ultrasonography. When simple cysts are found but no complications are present, no treatment is needed.

If cysts cause symptoms, treatment may be needed. One procedure involves puncturing the cyst using a long needle inserted through the skin. The doctor uses ultrasonography to guide the needle to the cyst. The cyst is drained and then filled with a solution containing alcohol to make the tissue harder.

If the cyst is large, surgery may be needed. Most procedures can be performed using a laparoscope, which allows for a smaller incision and quicker recovery. The surgeon drains the cyst then removes or burns away its outer tissue. Most patients stay in the hospital 1 or 2 days.

NIH

Chronic Kidney Disease (CKD)

Who is at risk?
Risk factors are conditions that make you more likely to develop a disease. The leading risk factors for CKD are

diabetes

high blood pressure

family history of kidney failure
Having diabetes increases your risk of developing CKD. In fact, diabetes is the leading cause of kidney failure. High blood pressure is the second leading cause.

CKD runs in families, so you may have an increased risk if your mother, father, sister, or brother has kidney failure.

Some racial groups are also at increased risk for CKD.

African Americans are nearly four times as likely to develop kidney failure as white Americans.

American Indians have nearly three times the risk compared to whites.

Hispanic Americans have nearly twice the risk of non-Hispanic whites.

Screening for kidney disease includes simple blood and urine tests.

If you have diabetes or high blood pressure, or a close family member with kidney failure, you should get checked for kidney disease, especially if you're a member of one of the racial or ethnic groups at higher risk for CKD.

How can I find out if I have CKD?

Since early CKD has no symptoms, the only way to find out if you have it is through simple medical tests.

Blood pressure. High blood pressure can lead to kidney damage, and it can also be a sign that kidney damage has already occurred. If your blood pressure is high, you'll want to get it under control to make sure your kidneys remain healthy.

Blood. The glomerular filtration rate (GFR) measures how efficiently the kidneys are filtering waste from the blood. The new method of calculating GFR requires only a measurement of the creatinine (kree-AT-ih-nin) in a blood sample. Creatinine is a waste product in the blood created by the normal breakdown of muscle cells during activity. When kidneys are not working well, creatinine builds up in the blood.

Urine. Measuring the amount of a protein called albumin in the urine can show a kidney problem. A large amount of protein in the urine is known as proteinuria and is a sign of kidney damage. Your doctor may test for protein using a dipstick in a sample of your urine taken in the doctor's office. The color of the dipstick indicates the level of protein.

A test that can show smaller amounts of protein or albumin in the urine is called a microalbumin test and also uses a dipstick in the urine.

Your doctor may also do a calculation of the protein-to-creatinine or albumin-to-creatinine ratio. Healthy kidneys move creatinine from the blood into the urine. A ratio greater than 30 milligrams of albumin per 1 gram of creatinine indicates that the kidneys are leaking helpful substances from the blood and failing to filter out harmful substances. This test should be used in people at high risk, especially those with diabetes.

If your first laboratory test shows high levels of protein, another test should be done 1 to 2 weeks later. If the second test also shows high levels of protein, you have persistent protein in the urine (proteinuria) and should have additional tests to test your kidney function.
A 24-hour urine collection is no longer necessary. Small samples of urine and blood, which can easily be taken in the doctor's office, are all the new methods require.

Several organizations offer free screenings for kidney disease. You may be able to have your kidney function measured at a local health fair. The National Kidney Foundation's KEEP (Kidney Early Evaluation Program) initiative offers blood and urine testing, onsite consultation with a physician, and referral and followup services for people whose test results are outside the normal range. The American Kidney Fund's MIKE (Minority Intervention and Kidney Education) Program offers educational sessions and medical screenings. The American Association of Kidney Patients' Finding Your Strength program offers education about your kidneys, tests to expect, and ways to stay healthy with CKD.

What can I do to slow down or avoid kidney failure?

Learning about reduced kidney function allows you to take steps to keep your kidneys healthy as long as possible. You can control many of the things that can make CKD worse and may lead to kidney failure.

If you have diabetes, control your blood glucose, also called blood sugar. Studies show that keeping tight control of blood glucose can delay or prevent kidney failure.

If you have high blood pressure, keep your blood pressure below 140/90 mm Hg.

If you have high blood pressure with CKD, keep your blood pressure below 130/80 mm Hg. Blood pressure medicines called ACE (angiotensin-converting enzyme) inhibitors and ARBs (angiotensin receptor blockers) protect the kidneys better than other medicines. You may need a combination of two or more drugs to keep your blood pressure below 130/80. In many cases, a medicine that lowers blood pressure by increasing urination, called a diuretic, should also be part of the plan.

If you have CKD, don't eat too much protein. Protein breaks down into the waste products the kidneys must excrete. Reducing those waste products by eating less protein means the kidneys don't have to work so hard. But eating too little protein can lead to poor nutrition. Work with a dietitian to make sure you get the right amounts of protein and other nutrients.

What can I do to avoid the complications of CKD?

CKD can lead to many other health problems well before kidney failure occurs.

Anemia. Anemia develops when the kidneys fail to produce enough erythropoietin, or EPO, the hormone that directs the bones to make red blood cells. Anemia can cause heart problems.

Bone problems. Healthy kidneys help keep your bones strong by balancing the levels of calcium and phosphorus in the blood. CKD can lead to bone problems by throwing those minerals out of balance.

Acidosis. The kidneys also maintain the acid/base balance in the blood. Kidney problems may lead to acidosis, a condition in which the blood is too acidic. Acidosis can disrupt body functions.

Cardiovascular disease (CVD). Patients with CKD are more likely to die from a heart attack or stroke than from kidney failure. Even a small loss of kidney function can double a person's risk of developing CVD.
If you have CKD, you will need to have regular checkups to monitor blood levels of creatinine, urea nitrogen, potassium, phosphorus, parathyroid hormone, hemoglobin, and cholesterol. If your blood tests show abnormal levels of any of these substances several times, your doctor will prescribe medicines. For example, if you have anemia indicated by low levels of hemoglobin on repeated tests, your doctor can prescribe a synthetic form of EPO (erythropoietin) to help your body make more red blood cells.

You have the power to prevent kidney failure.

Work with your doctor to manage the health problems that CKD can cause. Taking charge of your health can make your kidneys last longer. You have the power to prevent kidney failure.

Points to Remember

Chronic kidney disease (CKD) is a growing problem in the United States. Some 20 million Americans with reduced kidney function are at increased risk for kidney failure and cardiovascular disease.

The leading causes of CKD are diabetes and high blood pressure. If you have either one of these conditions, you should have your kidney function checked regularly.

CKD can run in families. If you have a parent, brother, or sister with kidney failure, you should have your kidney function checked.

African Americans, American Indians, and Hispanic Americans have higher rates of CKD than white Americans. If you belong to one of these high-risk groups and have any of the other risk factors for CKD, you should have your kidney function checked.

Medical tests for kidney function should include a check for protein in the urine and a calculation of glomerular filtration rate (GFR) based on a measurement of creatinine in the blood.

If CKD is found early, you can manage it to prevent or delay kidney failure and avoid cardiovascular disease.

NIH

Childhood Nephrotic Syndrome

What is nephrotic syndrome?

Nephrotic syndrome is a set of signs or symptoms that may point to kidney problems. The kidneys are two bean-shaped organs found in the lower back. Each is about the size of a fist. They clean the blood by filtering out excess water and salt and waste products from food. Healthy kidneys keep protein in the blood, which helps the blood soak up water from tissues. But kidneys with damaged filters may leak protein into the urine. As a result, not enough protein is left in the blood to soak up the water. The water then moves from the blood into body tissues and causes swelling.

Both children and adults can have nephrotic syndrome. The causes of and treatments for nephrotic syndrome in children are sometimes different from the causes and treatments in adults. For information about nephrotic syndrome in adults, see the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) publication Nephrotic Syndrome in Adults.

Childhood nephrotic syndrome can occur at any age but is most common between the ages of 1½ and 5 years. It seems to affect boys more often than girls.

A child with nephrotic syndrome has these signs:

high levels of protein in the urine, a condition called proteinuria

low levels of protein in the blood

swelling resulting from buildup of salt and water

less frequent urination

weight gain from excess water

Nephrotic syndrome is not itself a disease. But it can be the first sign of a disease that damages the kidney’s tiny blood-filtering units, called glomeruli, where urine is made.

How is childhood nephrotic syndrome diagnosed?

To diagnose childhood nephrotic syndrome, the doctor may ask for a urine sample to check for protein. The doctor will dip a strip of chemically treated paper into the urine sample. Too much protein in the urine will make the paper change color. Or the doctor may ask for a 24-hour collection of urine for a more precise measurement of the protein and other substances in the urine.

The doctor may take a blood sample to see how well the kidneys are removing wastes. Healthy kidneys remove creatinine and urea nitrogen from the blood. If the blood contains high levels of these waste products, some kidney damage may have already occurred. But most children with nephrotic syndrome do not have permanent kidney damage.

A strip of chemically treated paper will change color when dipped in urine with too much protein.

In some cases, the doctor may want to examine a small piece of kidney tissue with a microscope to see if something specific is causing the syndrome. The procedure of collecting a small tissue sample from the kidney is called a biopsy, and it is usually performed with a long needle passed through the skin. The child will be awake during the procedure and receive calming drugs and a local painkiller at the site of the needle entry. A child who is prone to bleeding problems may require open surgery for the biopsy. General anesthesia will be used if surgery is required. For any biopsy procedure, the child will stay overnight in the hospital to rest and allow the health care team to address quickly any problems that might occur.

What conditions are associated with childhood nephrotic syndrome?

Minimal Change Disease

The condition most commonly associated with childhood nephrotic syndrome is minimal change disease. Doctors do not know what causes it. The condition is called minimal change disease because children with this form of the nephrotic syndrome have normal or nearly normal appearing kidney biopsies. If a child is diagnosed with minimal change disease, the doctor will probably prescribe prednisone, which belongs to a class of drugs called corticosteroids. Prednisone stops the movement of protein from the blood into the urine, but it does have side effects that the doctor will explain. Following the doctor’s directions exactly is essential to protect the child’s health. The doctor may also prescribe another type of drug called a diuretic, which reduces the swelling by helping the child urinate more frequently.

When protein is no longer present in the urine, the doctor will begin to reduce the dosage of prednisone. This process takes several weeks. Some children never get sick again, but most experience a relapse, developing swelling and protein in the urine again, usually following a viral illness. However, as long as the child continues to respond to prednisone and the urine becomes protein free, the child has an excellent long-term outlook without kidney damage.

Children who relapse frequently, or who seem to be dependent on prednisone or have side effects from it, may be given a second type of drug called a cytotoxic agent. The agents most frequently used are cyclophosphamide and chlorambucil. After reducing protein in the urine with prednisone, the doctor may prescribe the cyclophosphamide or chlorambucil for 8 to 12 weeks. Alternatively, cyclosporine, a drug also used in transplant patients, may be given. Treatment with cyclosporine frequently continues over an extended period.

In recent years, doctors have explored the use of mycophenolate mofetil (MMF) instead of cytotoxic agents for children who relapse frequently. MMF is an immunosuppressant used to treat autoimmune diseases and to keep the body from rejecting a transplanted organ. MMF has not been tested for treating minimal change disease in large clinical trials, but doctors report promising results with small numbers of patients. MMF has milder side effects than cytotoxic agents, but taking immunosuppressants can raise the risk of infection and other diseases. The good news is that most children outgrow minimal change disease by their late teens with no permanent damage to their kidneys.

Focal Segmental Glomerulosclerosis (FSGS) and Membranoproliferative Glomerulonephritis (MPGN)

In about 20 percent of children with nephrotic syndrome, a kidney biopsy reveals scarring or deposits in the glomeruli. The two most common diseases that damage these tiny blood-filtering units are FSGS and MPGN.

Because prednisone is less effective in treating these diseases than it is in treating minimal change disease, the doctor may use additional therapies, including cytotoxic agents. Recent experience with another class of drugs called ACE inhibitors, usually used to treat high blood pressure, indicates these drugs can help decrease the amount of protein leaking into the urine and keep the kidneys from being damaged in children with FSGS or MPGN.

Congenital Nephropathy

Rarely, a child may be born with congenital nephropathy, a condition that causes nephrotic syndrome. The most common form of this condition is congenital nephropathy of the Finnish type (CNF), inherited as an autosomal recessive trait—meaning the gene for CNF must be inherited from both parents.

Another condition that causes nephrotic syndrome in the first months of life is diffuse mesangial sclerosis (DMS). The pattern of inheritance for DMS is not as clearly understood as the pattern for CNF, although the condition does appear to be genetic.

Since medicines have little effect on congenital nephropathy, transplantation is usually required by the second or third year of life, when the child has grown enough to receive a kidney. To keep the child healthy, the doctor may recommend infusions of the protein albumin to make up for the protein lost in urine and prescribe a diuretic to help eliminate the extra fluid that causes swelling. The child’s immune system may be weakened, so antibiotics should be given at the first sign of infection.

Congenital nephropathy can disturb thyroid activity, so the child may need the substitute hormone thyroxine to promote growth and help bones mature. Some children with congenital nephropathy have excessive blood clotting, or thrombosis, which must be treated with a blood thinner like warfarin.

A child with congenital nephropathy may need tube feedings to ensure proper nutrition. In some cases, the diseased kidneys may need to be removed to eliminate proteinuria. Dialysis will then be required to replace kidney function until the child’s body is big enough to receive a transplanted kidney. Peritoneal dialysis is preferable to hemodialysis for young children.

In peritoneal dialysis, a catheter is surgically placed in the abdomen and then used to introduce a solution into the abdominal cavity, or peritoneum. The solution draws wastes and extra fluid from the bloodstream. After a few hours, the solution is drained and replaced with a fresh supply. The drained solution carries the wastes and extra fluid out of the body.

Points to Remember

Nephrotic syndrome is a set of signs or symptoms that may point to kidney problems.

Childhood nephrotic syndrome is most common between the ages of 1½ and 5 years.

Nephrotic syndrome causes proteinuria, low levels of protein in the blood, less frequent urination, and swelling and weight gain from the buildup of fluid.

Diagnosis of nephrotic syndrome requires urine and blood samples and may include a kidney biopsy.

Most cases of childhood nephrotic syndrome result from minimal change disease.

The two most common diseases that damage the kidneys’ tiny blood-filtering units and cause nephrotic syndrome are focal segmental glomerulosclerosis (FSGS) and membranoproliferative glomerulonephritis (MPGN).

Congenital nephropathy is a rare condition that causes nephrotic syndrome in newborns.

NIH

Analgesic Nephropathy (Painkillers and Kidneys)

An analgesic is any medicine intended to relieve pain. Over-the-counter analgesics—that is, painkillers available without a prescription—include aspirin, acetaminophen, ibuprofen, naproxen sodium, and others. These drugs present no danger for most people when taken in the recommended dosage. But some conditions make taking even these common painkillers dangerous for the kidneys. Also, taking one of these drugs regularly over a long period of time may increase the risk for kidney problems. Most drugs that can cause kidney damage are excreted only through the kidneys. That is, they are not broken down by the liver, as alcohol is, or passed out of the body through the digestive tract.

Analgesic use has been associated with two different forms of kidney damage: acute renal failure and a type of chronic kidney disease called analgesic nephropathy.

Acute Kidney Failure

Some patient case reports have attributed incidents of sudden-onset acute kidney failure to the use of over-the-counter painkillers, including aspirin, ibuprofen, and naproxen sodium. Some of these patients experienced acute illnesses involving fluid loss or decreased fluid intake. Other patients in these reports had risk factors such as systemic lupus erythematosus, advanced age, chronic kidney disease, or recent heavy alcohol consumption. These cases involved a single dose in some instances and generally short-term analgesic use of not more than 10 days.

Acute kidney failure requires emergency dialysis to clean the blood. Kidney damage is frequently reversible, with normal kidney function returning after the emergency is over and the analgesic use is stopped.

Analgesic Nephropathy

A second form of kidney damage, called analgesic nephropathy, can result from taking painkillers every day for several years. Analgesic nephropathy is a chronic kidney disease that over years gradually leads to irreversible kidney failure and the permanent need for dialysis or a kidney transplant to restore kidney function. Researchers estimate that four out of 100,000 people will develop analgesic nephropathy. It is most common in women over 30.

The painkiller phenacetin has been taken off the market because of its association with analgesic nephropathy. Recent studies have suggested that longstanding daily use of analgesics such as acetaminophen or ibuprofen may also increase the risk of chronic kidney damage, but this evidence is not as clear.

In view of these findings, people with conditions that put them at risk for acute kidney failure should check with their health care provider before taking any analgesic medicine. People who take over-the-counter painkillers regularly should check with their primary care physician to make sure the drugs are not hurting their kidneys. The physician may be able to recommend a safer alternative and can order regular tests to monitor their kidney function.

Treatment

If you have been taking analgesics regularly to control chronic pain, you may be advised to find new ways to treat your pain, such as behavior modification or relaxation techniques. Depending on how much your kidney function has declined, you may be advised to change your diet, limit the fluids you drink, or take medications to avoid anemia and bone problems caused by kidney disease. Your doctor will monitor your kidney function with regular urine and blood tests.

NIH

Acquired Cystic Kidney Disease (ACKD)

What is acquired cystic kidney disease (ACKD)?

Many people with chronic kidney disease develop ACKD, a condition in which the kidneys develop fluid-filled sacs called renal (kidney) cysts. ACKD occurs in children and adults. The cysts are more likely to develop in people who are on hemodialysis or peritoneal dialysis. Kidney failure, not dialysis, causes the cysts. However, the risk of developing ACKD increases with the number of years a person is on dialysis.

About 20 percent of people starting dialysis treatments already have ACKD.
About 60 to 80 percent of people on dialysis for 4 years develop ACKD.
About 90 percent of people on dialysis for 8 years develop ACKD.

In ACKD, the kidneys develop fluid-filled sacs called cysts.

In most cases, the cysts are harmless and require no treatment. Sometimes problems occur—including infection in the cyst, which may be associated with fever and back pain. Sometimes the cysts bleed and blood will appear in the urine. Blood in the urine should always be reported to a doctor.

Although doctors debate the exact percentage, somewhere between 10 and 20 percent of people with ACKD develop kidney tumors, which in some cases are cancerous. The rate of kidney cancer in people with ACKD is low, but it is higher than the rate in the general population.

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 on either side of the spine, just below the rib cage. The kidneys filter wastes and extra fluid from the blood to produce urine. They also release hormones that regulate blood pressure, stimulate the production of red blood cells, and regulate the body’s use of calcium to keep the bones healthy.

When the kidneys stop working, a person must receive a new kidney through transplantation or have regular blood-cleansing treatments called dialysis.

The kidneys filter wastes and extra fluid from the blood to produce urine. Urine flows from the kidneys to the bladder through the ureters.

What causes ACKD?

Dialysis filters out many, but not all, of the wastes that healthy kidneys remove. Researchers believe that an unidentified waste product not removed through dialysis causes cysts to form in the kidneys. Dialysis itself does not cause the cysts.

How does ACKD differ from polycystic kidney disease (PKD)?

ACKD differs from PKD in several ways. People with PKD often have a family history of PKD. They are born with the disease-causing gene. No disease-causing gene is associated with ACKD. PKD is associated with enlarged kidneys and cyst formation in other parts of the body. In ACKD, the kidneys are normal sized or smaller and cysts do not occur in other parts of the body. In PKD, the presence of cysts marks the onset of disease. People with ACKD already have chronic kidney disease when they develop cysts.

What are the symptoms of ACKD?

ACKD often has no symptoms. If a cyst becomes infected, a person may have back pain, fever, or even chills. If a cyst bleeds, a person will often notice blood in the urine.

How is ACKD diagnosed?

A doctor may suspect ACKD based on a patient’s history and symptoms. To confirm the diagnosis, the doctor may order one or more imaging procedures:

Ultrasound. In an ultrasound, or sonogram, a technician glides a device, called a transducer, over the abdomen. The transducer sends harmless sound waves into the body and catches them as they bounce off the internal organs to create a picture on a monitor. Abdominal ultrasounds are used to evaluate the size and shape of the kidneys.

Computerized tomography (CT) scan. CT scans use a combination of x rays and computer technology to create three-dimensional images. Sometimes a contrast dye is injected into the patient to better see the structure of the kidneys. CT scans require the patient to lie on a table that slides through a donut-shaped scanning machine. CT scans can help identify cysts and tumors in the kidneys.

Magnetic resonance imaging (MRI). MRI machines use radio waves and magnets to produce detailed pictures of internal organs and tissues. No exposure to radiation occurs. With most MRI machines, the patient lies on a table that slides into a tunnel that may be open-ended or closed at one end. Some newer machines are designed to allow the patient to lie in a more open space. Like CT scans, MRIs can help identify cysts and tumors.
Images of the kidneys may help the health care provider distinguish ACKD from PKD.

How is ACKD treated?

If ACKD is not causing pain or discomfort, no treatment is required. Infections are treated with a course of antibiotics. If large cysts are causing pain, they may be drained using a long needle inserted through the skin.

If tumors are suspected, a person may need regular examinations to monitor the kidneys for cancer. Some doctors recommend all patients be screened for kidney cancer after 3 years of dialysis. In rare cases, surgery is used to stop cysts from bleeding and to remove tumors or suspected tumors.

In transplantation, the diseased kidneys are left in place unless they are causing infection or high blood pressure. ACKD usually disappears, even in the diseased kidneys, after a person receives a transplanted kidney.

Points to Remember

Acquired cystic kidney disease (ACKD) is a condition in which the kidneys develop many fluid-filled sacs called cysts.

ACKD is most common in people who have been on dialysis for several years.

ACKD differs from polycystic kidney disease (PKD). People with PKD often have a family history of PKD. PKD is associated with enlarged kidneys and cyst formation in other parts of the body. In ACKD, the kidneys are normal sized or smaller and cysts do not form in other parts of the body.

Between 10 and 20 percent of people with ACKD develop kidney tumors, which in some cases are cancerous.

ACKD often has no symptoms.

If tumors are suspected, a person may need regular examinations to monitor the kidneys for cancer.

In rare cases, surgery is used to stop cysts from bleeding and to remove tumors or suspected tumors.

ACKD usually disappears after a person receives a transplanted kidney.

NIH

Renal Tubular Acidosis (RTA)

What is renal tubular acidosis (RTA)?

Renal tubular acidosis (RTA) is a disease that occurs when the kidneys fail to excrete acids into the urine, which causes a person’s blood to remain too acidic. Without proper treatment, chronic acidity of the blood leads to growth retardation, kidney stones, bone disease, chronic kidney disease, and possibly total kidney failure.

The body’s cells use chemical reactions to carry out tasks such as turning food into energy and repairing tissue. These chemical reactions generate acids. Some acid in the blood is normal, but too much acid—acidosis—can disturb many bodily functions. Healthy kidneys help maintain acid-base balance by excreting acids into the urine and returning bicarbonate—an alkaline, or base, substance—to the blood. This “reclaimed” bicarbonate neutralizes much of the acid that is created when food is broken down in the body. The movement of substances like bicarbonate between the blood and structures in the kidneys is called transport.

One researcher has theorized that Charles Dickens may have been describing a child with RTA in the character of Tiny Tim from A Christmas Carol. Tiny Tim’s small stature, malformed limbs, and periods of weakness are all possible consequences of the chemical imbalance caused by RTA. In the story, Tiny Tim recovers when he receives medical treatment, which would likely have included sodium bicarbonate and sodium citrate, alkaline agents to neutralize acidic blood. The good news is that medical treatment can indeed reverse the effects of RTA.

How is RTA diagnosed?

To diagnose RTA, doctors check the acid-base balance in blood and urine samples. If the blood is more acidic than it should be and the urine less acidic than it should be, RTA may be the reason, but additional information is needed to rule out other causes. If RTA is the reason, additional information about the sodium, potassium, and chloride levels in the urine and the potassium level in the blood will help identify which type of RTA a person has. In all cases, the first goal of therapy is to neutralize acid in the blood, but different treatments may be needed to address the different underlying causes of acidosis.

What are the types of RTA?

Type 1: Classical Distal RTA

Type 1 is also called classical distal RTA. “Distal,” which means distant, refers to the point in the urine-forming tube of the kidney where the defect occurs—relatively distant from the point where fluid from the blood enters the tiny tube, or tubule, that collects fluid and wastes to form urine.

This disorder may be inherited as a primary disorder or may be one symptom of a disease that affects many parts of the body. Researchers have discovered abnormal genes responsible for the inherited forms of the disease. More often, however, classical distal RTA occurs as a result of systemic diseases—diseases that affect many organ systems—like the autoimmune disorders Sjögren’s syndrome and lupus, which also attack the distal tubule.

Other diseases and conditions associated with classical distal RTA include sickle cell anemia, hyperparathyroidism, hyperthyroidism, chronic active hepatitis, primary biliary cirrhosis, a hereditary form of deafness, analgesic nephropathy, rejection of a transplanted kidney, renal medullary cystic disease, obstructive uropathy, and chronic urinary tract infections. Many of these conditions cause abnormal calcium deposits to build up in the kidney and impair distal tubule function.

A major consequence of classical distal RTA is a low blood potassium level. The level drops if the kidneys excrete too much potassium into urine instead of returning it to the blood supply. Because potassium helps regulate nerve and muscle health and heart rate, low levels can cause extreme weakness, irregular heartbeat, paralysis, and even death.

Untreated classical distal RTA causes growth retardation in children and progressive kidney and bone disease in adults. Restoring normal growth and preventing kidney stones are the major goals of therapy. If acidosis is corrected with sodium bicarbonate or sodium citrate, then low blood-potassium, salt depletion, and calcium leakage into urine will be corrected. This alkali therapy also helps decrease the development of kidney stones and stabilizes kidney function so kidney failure does not progress. Infants may need potassium supplements, but older children and adults rarely do because alkali therapy prevents the kidney from excreting potassium into the urine.

Type 2: Proximal RTA

Type 2 is also called proximal RTA. The word “proximal,” which means near, indicates that the defect is closer to the point where fluid and wastes from the blood enter the tubule.

This form of RTA occurs most frequently in children as part of a disorder called Fanconi’s syndrome. The features of Fanconi’s syndrome include the abnormal excretion of glucose, amino acids, citrate, and phosphate into the urine, as well as vitamin D deficiency and low blood-potassium.

Proximal RTA can also result from inherited disorders that disrupt the body’s normal breakdown and use of nutrients. Examples include the rare disease cystinosis, in which cystine crystals are deposited in bones and other tissues; hereditary fructose intolerance; and Wilson disease.

Proximal RTA also occurs in patients treated with ifosfamide, a drug used in chemotherapy. A few older drugs—such as acetazolamide or outdated tetracycline—can also cause proximal RTA. In adults, proximal RTA may complicate diseases like multiple myeloma, or it may occur in people who experience chronic rejection of a transplanted kidney.

When possible, identifying and correcting the underlying causes are important steps in treating the acquired forms of proximal RTA. The diagnosis is based on the chemical analysis of blood and urine samples. Children with this disorder would likely receive large doses of an oral alkali, such as sodium bicarbonate or potassium citrate, to treat acidosis and prevent bone disorders, kidney stones, and growth failure. Correcting acidosis and low potassium levels restores normal growth patterns, allowing bone to mature while preventing further renal disease. Vitamin D supplements may also be needed to help prevent bone problems.

Type 3

Type 3 is rarely used as a classification because it is now thought to be a combination of type 1 and type 2.

Type 4: Hyperkalemic RTA

Type 4 is also called hyperkalemic RTA and is caused by a generalized transport abnormality of the distal tubule. The transport of electrolytes such as sodium, chloride, and potassium that normally occurs in the distal tubule is impaired. This form is distinguished from classical distal RTA and proximal RTA because it results in high levels of potassium in the blood instead of low levels. Either low potassium—hypokalemia—or high potassium—hyperkalemia—can be a problem because potassium is important in regulating heart rate.

Type 4 RTA occurs when blood levels of the hormone aldosterone are low or when the kidneys do not respond to it. Aldosterone directs the kidneys to regulate the levels of sodium, potassium, and chloride in the blood. Type 4 RTA also occurs when the tubule transport of electrolytes such as sodium, chloride, and potassium is impaired due to an inherited disorder or the use of certain drugs.

Drugs that may cause type 4 RTA include

diuretics used to treat congestive heart failure such as spironolactone or eplerenone
blood pressure drugs called angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs)
the antibiotic trimethoprim
the antibiotic pentamidine, which is used to treat pneumonia
an agent called heparin that keeps blood from clotting
a class of painkillers called nonsteroidal anti-inflammatory drugs (NSAIDs)
some immunosuppressive drugs used to prevent rejection
Type 4 RTA may also result from diseases that alter kidney structure and function such as diabetic nephropathy, HIV/AIDS, Addison’s disease, sickle cell disease, urinary tract obstruction, lupus, amyloidosis, removal or destruction of both adrenal glands, and kidney transplant rejection.

For people who produce aldosterone but cannot use it, researchers have identified the genetic basis for their body’s resistance to the hormone. To treat type 4 RTA successfully, patients may require alkaline agents to correct acidosis and medication to lower the potassium in their blood.

If treated early, most people with any type of RTA will not develop permanent kidney failure. Therefore, the goal is early recognition and adequate therapy, which will need to be maintained and monitored throughout the person’s lifetime.

Points to Remember

Renal tubular acidosis (RTA) is a disease that occurs when the kidneys fail to excrete acids into the urine, which causes a person’s blood to remain too acidic.

Without proper treatment, chronic acidity of the blood leads to growth retardation, kidney stones, bone disease, chronic kidney disease, and possibly total kidney failure.

If RTA is suspected, additional information about the sodium, potassium, and chloride levels in the urine and the potassium level in the blood will help identify which type of RTA a person has.

In all cases, the first goal of therapy is to neutralize acid in the blood, but different treatments may be needed to address the different underlying causes of acidosis.

NIH

Amyloidosis and Kidney Disease

Proteins are important building blocks for all body parts, including muscles, bones, hair, and nails. Proteins circulate throughout the body in the blood and are normally harmless. Occasionally, cells produce abnormal proteins that can settle in body tissue, forming deposits and causing disease. When these deposits of abnormal proteins were first discovered, they were called amyloid, and the disease process amyloidosis.

In recent years, researchers have discovered that different kinds of proteins can form amyloid deposits and have identified several types of amyloidosis. Two of these types are closely related to kidney disease. In primary amyloidosis, abnormal protein production occurs as a first step and can lead to kidney disease. Dialysis-related amyloidosis (DRA), on the other hand, is a result of kidney disease.

Primary Amyloidosis

Primary amyloidosis occurs when the body's antibody-producing cells do not function properly and produce abnormal protein fibers made of antibody fragments. Some people with primary amyloidosis have a condition called multiple myeloma. The antibody fragments come together to form amyloid deposits in different organs, including the kidneys, where they cause serious damage. Injured kidneys can't function effectively and may be unable to remove urea and other wastes from the blood. Elevated levels of these protein fibers can also damage the heart, lungs, brain, and digestive system.

One common sign of kidney amyloidosis is the presence of abnormally high levels of protein in the urine, a condition known as proteinuria. Healthy kidneys prevent protein from entering the urine, so the presence of protein may be a sign that the kidneys aren't working properly. A physician who finds large amounts of protein in the urine may also perform a biopsy—take a small sample of tissue for examination with a microscope—to confirm amyloidosis.

Current treatments are aimed at slowing the progression of amyloid build-up. Combination drug therapy with melphalan, a cancer drug, and prednisone, an anti-inflammatory steroid drug, may improve organ function and survival rates by interrupting the growth of the abnormal cells that produce amyloid protein. These are the same drugs used in chemotherapy to treat certain cancers, such as multiple myeloma, and they may have serious side effects, such as nausea and vomiting, hair loss, and fatigue.

Some clinics have reported promising results treating amyloidosis by transplanting the patient’s own blood stem cells to replace diseased or damaged bone marrow. The therapy also requires high doses of melphalan, so side effects can be serious. Patients with heart problems may not be considered for this treatment.

Dialysis-Related Amyloidosis

Normal kidneys filter and remove excess small proteins from the blood, thus keeping blood levels normal. When the kidneys don't work properly, as in patients receiving dialysis, one type of small protein calle beta-2-microglobulin builds up in the blood. When this occurs, beta-2-microglobulin molecules may join together, like the links of a chain, forming a few very large molecules from many smaller ones. These large molecules can form deposits and eventually damage the surrounding tissues and cause great discomfort. This condition is called dialysis-related amyloidosis (DRA).

DRA is relatively common in patients, especially older adults, who have been on hemodialysis for more than 5 years. Hemodialysis membranes that have been used for many years don't effectively remove the large, complex beta-2-microglobulin proteins from the bloodstream. Newer hemodialysis membranes, as well as peritoneal dialysis, remove beta-2-microglobulin more effectively, but not enough to keep blood levels normal. As a result, blood levels remain elevated, and deposits form in bone, joints, and tendons (the tissue that connects the muscle to the bone). DRA may result in pain, stiffness, and fluid in the joints. Patients with DRA may also develop hollow cavities, or cysts, in some of their bones; these may lead to unexpected bone fractures. Amyloid deposits may cause tears in ligaments and tendons. Most patients with these problems can be helped by surgical intervention.

Half of the people with DRA also develop a condition called carpal tunnel syndrome, which results from the unusual buildup of protein in the wrists. Patients with this condition may experience numbness or tingling, sometimes associated with muscle weakness, in their fingers and hands. This is a treatable condition.

Amyloid may build up in the wrist and cause bone cysts or carpal tunnel syndrome.
Unfortunately, no cure for DRA has been found, although a successful kidney transplant may stop the disease from progressing. However, DRA has caught the attention of dialysis engineers, who are attempting to develop new dialysis membranes that can remove larger amounts of beta-2-microglobulin from the blood.

NIH

Wegener’s Granulomatosis

Wegener’s granulomatosis is a rare disease. It is a type of vasculitis, or inflammation of the blood vessels. This limits the flow of blood to important organs, causing damage. It can affect any organ, but it mainly affects the sinuses, nose, trachea (windpipe), lungs and kidneys.

The cause of Wegener’s granulomatosis is unknown. Symptoms may include joint pain, weakness, tiredness and cold symptoms such as a runny nose that doesn’t get better. Doctors use blood tests and chest x-rays to diagnose the disease and rule out other causes of the symptoms.

Early treatment is important. Most people improve with medicines to slow or stop the inflammation.

National Institute of Allergy and Infectious Diseases

Next Page »