Childhood nephrotic syndrome is a group of symptoms that occur because of damage to the kidneys. Nephrotic syndrome can occur in children at any age, but usually is found in children between 18 months and 5 years of age. You should check with your child’s pediatrician or a pediatric kidney disease specialist if your child has signs of nephrotic syndrome.
Glomeruli are tiny blood vessels in the kidneys that in healthy individuals filter salt, water and waste products from the blood. When working properly, glomeruli do not filter out protein, which helps them absorb water from tissues.
Each of the body's two kidneys has about one million glomeruli. When these filters are damaged, protein leaks from blood into the urine, resulting in decreased levels of protein in the blood (hypoalbuminemia) and increased levels of protein in the urine (proteinuria), which leaves the kidneys unable to absorb the excess water. Over time these imbalances can damage the kidney.
Nephrotic syndrome may be the first sign of a disease that damages the glomeruli.
Minimal change disease is the most common type of nephrotic syndrome in children, which gets its name from the fact that kidney biopsies taken from most of these children appear to be normal or nearly normal.
Some children have one of two common conditions that damage the glomeruli, the structures in the kidney that filter the blood. It's the second leading cause of nephrotic syndrome in children.
Membranoproliferative glomerulonephritis is much less common in children than in adults. Very rarely, a child is born with congenital nephropathy (kidney disease) which usually is inherited.
Signs or symptoms of childhood nephrotic syndrome occur because of damage to the kidneys. You should check with your child’s pediatrician or a pediatric kidney disease specialist if your child has signs of nephrotic syndrome.
Your child’s doctor will ask questions about your child’s medical history and symptoms, and perform a physical examination of your child to assess signs and symptoms.
Using a urine sample, your doctor can detect the presence of excess protein in your child’s urine and discover information about kidney function. The doctor may recommend a 24-hour collection of urine to more fully measure the amount of protein and other substances in your child’s urine.
The doctor also may want a blood sample to help determine or rule out causes for the symptoms and to check levels of cholesterol, creatinine, and a blood protein called albumin. Blood samples can also be used to determine how well the kidneys are functioning.
Glomerular filtration rate is a test that estimates the amount of blood that passes through the glomeruli each minute. The glomeruli help filter blood in the kidneys. This test provides information about how well your child’s kidneys are working.
In some cases, the doctor may request a renal ultrasound. This test provides the doctor with information about the size and shape of the kidney and helps detect cysts, kidney stones, obstructions, masses in the kidney, and other problems. The test is painless and noninvasive. A technologist moves a probe over the kidney from outside your child’s body, which creates sound waves that bounce back from the kidney, forming an image on a video screen.
If a kidney disease or other problem is causing the nephrotic syndrome, the doctor may want to look at a piece of kidney tissue under a microscope to try to pinpoint the precise problem. For a biopsy, which involves an overnight hospital stay, your child will receive a light sedative and local anesthesia. The doctor will view the kidney and, guided either by an ultrasound or a computed tomography (CT) scans, direct a biopsy needle into the kidney. The kidney tissue will be examined to diagnose an underlying disease that is causing blood in the urine.
Nephrotic syndrome is caused by damage to the glomeruli, the tiny blood vessels in the kidneys that filter blood.
Although nephrotic syndrome is more a set of signs and symptoms of kidney problems in your child, it is important to seek treatment for your child, often from a doctor who specializes in treating childhood kidney diseases, called a pediatric nephrologist.
Doctors will treat your child’s nephrotic syndrome to prevent the kidneys from losing protein and to increase the release of urine from the body. Your child might have to be hospitalized during the first episode of symptoms if your child has high blood pressure, breathing difficulties or severe edema (swelling).
Some children may experience only one episode of nephrotic syndrome, but for others, the symptoms return. Relapses are most common in the first two years after the initial episode and often follow a viral illness. Doctors may use several medications to treat initial symptoms and relapses. The most commonly used medications are
If your child has minimal change disease, your doctor will probably prescribe a corticosteroid drug called prednisone to stop the leakage of protein from the blood into the urine. Prednisone is taken over a period of weeks or months. When protein is no longer found in the blood, the dosage of prednisone will be tapered. Intravenous (IV) albumin also may be administered to restore levels of protein, and the doctor may prescribe a diuretic—a drug that will help your child urinate more frequently, which will cause the swelling to subside.
Your child may receive immunosuppressive drug therapy to control frequent relapses or side effects from prednisone. If your child does not respond to prednisone or experiences frequent relapses, the doctor may suspect that the syndrome is cause by a condition called focal segmental glomerulosclerosis, not minimal change disease. A biopsy, or sample of your child’s kidney tissue, can help doctors determine the cause.
Maintaining a healthy diet is another aspect of treatment. Your child’s doctor may provide recommendations for a particular balance of protein and fluid intake. A diet low in salt, saturated fat, and cholesterol also may be helpful. The reduction in your child’s intake of sodium may help reduce swelling.
During the course of treatment, your child should not be given live vaccines because the medications for nephrotic syndrome weaken the immune system. However, a chicken pox vaccine may be recommended if your child has not been exposed to the disease.
The doctor may also use ACE inhibitors (which are usually used to treat hypertension) to control the leakage of protein into urine and prevent kidney damage.
In extremely rare cases of nephrotic syndrome caused by congenital nephropathy, a child needs a kidney transplant by age 2 or 3, and in some cases, the kidneys will need to be removed and the child will require dialysis.
American Board of Pediatrics/Nephrology
Nephrotic syndrome is not a disease. It is a collection of symptoms that are indications that a disease may be present.
Nephrotic syndrome can occur at any age, but it appears most frequently in children between the ages of 2 and 6.
A urine test will determine the presence of excess protein in the urine and will provide other information about kidney function.
Your child’s doctor may want to perform blood tests to rule out other causes for symptoms and to test for levels of cholesterol, creatinine, and a blood protein called albumin. In some cases, in order to pinpoint the cause of the damage to the kidneys, the doctor may order an ultrasound of the kidneys (a renal ultrasound). Less commonly, a biopsy of the kidney may be necessary.
Most children who have nephrotic syndrome have minimal change disease, named because people with the condition have normal or nearly normal- appearing kidneys on biopsy.
Although children with minimal change disease are likely to experience relapses of nephrotic syndrome throughout childhood, the condition tends to be well managed and most outgrow the disease before reaching adulthood, without lasting kidney damage.
A variety of medications may be used to treat initial symptoms and relapses. The most commonly used medications are corticosteroids, diuretics, and immunosuppressive drugs. Most children with nephrotic syndrome and minimal change disease respond to these drugs.
If your child has high blood pressure, breathing difficulties, or severe edema (swelling), hospitalization may be necessary during treatment for the first episode.
Your child’s doctor may suspect that the syndrome is cause by focal segmental glomerulosclerosis (FSGS)—the second leading cause of nephrotic syndrome in children after minimal change disease—and may order a biopsy. Focal segmental glomerulosclerosis is more difficult to treat and may eventually lead to the need for dialysis or transplantation rather than minimal change disease.
Only in rare cases will a child with nephrotic syndrome develop kidney failure requiring dialysis or transplantation.
Maintaining a healthy diet is another aspect of treatment. Your child’s doctor may provide recommendations for a particular balance of protein and fluid intake, and a diet low in salt, saturated fat, and cholesterol may be helpful. The reduction in your child’s intake of sodium may help reduce swelling.
During the course of treatment, your child should not be given live vaccines because the medications for nephrotic syndrome weaken the immune system. However, a chicken pox vaccine may be recommended if your child has not been exposed to the disease. Discuss vaccinations with your child’s doctor.