Pediatric nephrotic syndrome

What is pediatric 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.

What are the different types of pediatric nephrotic syndrome?

• 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.

• Focal segmental glomerulosclerosis -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.

What are the signs and symptoms of pediatric nephrotic syndrome?

• Edema

• Fatigue and irritability

• Foam in the urine

• Hypoalbuminemia

• Hyperlipidemia

• Less frequent urination

• Pale appearance

• Poor appetite

• Proteinuria

• Weight gain from fluid retention

How is pediatric nephrotic syndrome diagnosed?

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.

Laboratory tests

Using a urine sample, your doctor can detect the presence of excess protein (proteinuria) 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.

Glofil (GFR) test

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.

Ultrasound

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.

Biopsy

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.

What are the causes of pediatric nephrotic syndrome?

Nephrotic syndrome is caused by damage to the glomeruli, the tiny blood vessels in the kidneys that filter blood.

• Primary, or idiopathic, nephrotic syndrome - when the cause of that damage is unknown

• Secondary nephrotic syndrome - in some cases, the damage is caused by a disease that originates outside of the kidney

How is pediatric nephrotic syndrome treated?

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: 

• Corticosteroids

• Diuretics

• Immunosuppressive drugs, drugs that suppress, or halt, natural immune responses

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.