Childhood nephrotic syndrome is a disease that affects the kidneys. This handout will explain childhood nephrotic syndrome, the symptoms of nephrotic syndrome, how we test for it and how we treat it.

What Is Childhood Nephrotic Syndrome?

Childhood nephrotic syndrome, or simply nephrotic syndrome, is a disease that damages the glomeruli in the kidneys. It can happen at any age, but it happens most often in babies and children ages 1-5. Nephrotic syndrome tends to affect boys more often than girls.

There are 2 types of nephrotic syndrome, which are minimal change disease (MCNS) and focal segmental glomerulosclerosis (FSGS). The first type, MCNS, is more common. The second, FSGS, is less common, but more serious than MCNS.

What Are Glomeruli?

Glomeruli are small vessels in the kidneys that help filter blood and protein throughout your body. Protein in the blood helps keep fluids from leaking into the body’s tissues. When the glomeruli are damaged, they leak large amounts of protein into urine. This leaves little protein behind for the kidneys to keep fluid from leaking into your body’s tissues. This leaking fluid causes swelling throughout your body.

What Are the Symptoms of Nephrotic Syndrome?

The most common sign of nephrotic syndrome is swelling throughout the body, but other symptoms include:

  • Swelling around your child’s eyes, belly and legs
  • Urinating less often
  • Weight gain from excess water
  • High levels of protein in the blood (proteinuria)
  • Low levels of protein in the blood from loss of protein in the urine (hypoalbuminemia)
  • High cholesterol levels in the blood (hyperlipidemia)

What Causes Nephrotic Syndrome?

In many cases, we do not know what causes nephrotic syndrome. We think it might be triggered by allergies, a cold, the flu or other viral illnesses.

Sometimes, your child can relapse, which means he or she can develop nephrotic syndrome again shortly after recovering from it. We think relapses are caused by viral illnesses or infections.