Pediatric Nephrotic Syndrome

What is nephrotic syndrome?

Nephrotic syndrome is a group of symptoms that indicate the kidneys are not working properly. These symptoms include

• • Too much protein in the urine, called proteinuria
  • Low levels of a protein called albumin in the blood, called hypoalbuminemia
  • Swelling in parts of the body, called edema
  • High levels of cholesterol and other lipids (fats) in the blood, called hyperlipidemia

The kidneys are made up of about a million filtering units called nephrons. Each nephron includes a filter, called the glomerulus, and a tubule. The glomerulus filters the blood, and the tubule returns needed substances to the blood and removes wastes and extra water, which become urine. Nephrotic syndrome usually happens when the glomeruli are damaged, allowing too much protein to leak from the blood into the urine.

As blood passes through healthy kidneys, the glomeruli filter out waste products and allow the blood to keep the cells and proteins the body needs

Does nephrotic syndrome in children have another name?

Health care professionals use different terms to refer to nephrotic syndrome in children, depending on

How old the child is when symptoms begin

• • Congenital nephrotic syndrome—birth to 3 months
  • Infantile nephrotic syndrome—3 to 12 months
  • Childhood nephrotic syndrome—12 months or older

The cause of nephrotic syndrome

• • Primary nephrotic syndrome—the syndrome is caused by a kidney disease that affects only the kidneys
  • Secondary nephrotic syndrome—the syndrome develops because of other causes, such as diseases that affect other parts of the body, infections, and medicines

How common is nephrotic syndrome in children?

Nephrotic syndrome is not very common in children. On average, fewer than 5 in 100,000 children worldwide develop nephrotic syndrome each year.

Which children are more likely to develop nephrotic syndrome?

Children of all ages can develop nephrotic syndrome. But the condition most often affects children who are 2 to 7 years old, particularly boys.

What are the complications of nephrotic syndrome in children?

Losing too much protein in the urine can lead to many complications, including

• • Higher risk of infection
  • Blood clots
  • High blood pressure NIH external link, also called hypertension
  • High cholesterol
  • Brief or long-lasting kidney problems

What are the signs or symptoms of nephrotic syndrome in children?

Swelling around the eyes is the most common sign of nephrotic syndrome in children. The swelling is usually greater in the morning and, when mild, may be confused with seasonal allergies.

Other common symptoms include

• • Swelling in the lower legs, feet, abdomen, hands, face, or other parts of the body
  • Foamy urine
  • Fatigue

Some children with nephrotic syndrome may also have

• • Blood in their urine
  • Loss of appetite
  • Muscle cramps
  • Diarrhea or nausea

How do health care professionals diagnose nephrotic syndrome in children?

Nephrotic syndrome in children is diagnosed with

• • A medical and family history
  • A physical exam
  • Urine tests NIH external link, to look for excess urine proteins
  • Blood tests, to test kidney function and to look for underlying diseases

Additional tests to identify the cause of nephrotic syndrome may include

• • Ultrasound NIH external link of the kidney
  • Kidney biopsy
  • Genetic testing NIH external link

Many children with nephrotic syndrome will not need a kidney biopsy. The test is usually reserved for children who have complex disease, who have low kidney function, or who are 12 years old or older.

How can nephrotic syndrome in children be prevented?

Researchers have not found a way to prevent nephrotic syndrome in children. Knowing the symptoms can help you get your child treated early and reduce the risk of complications.

How do eating, diet, and nutrition affect nephrotic syndrome in children?

Children who have nephrotic syndrome may need to change what they eat and drink, such as

• • Limiting the amount of sodium they get, often from salt
  • Reducing the amount of liquid they drink
  • Eating foods low in saturated fat and cholesterol

In some cases, the child’s health care professional may recommend other dietary changes. Parents or other caregivers should talk with their child’s health care professional before making any changes to the child’s diet.