Nephrotic Syndrome

Topic Overview

What is nephrotic syndrome?

Nephrotic syndrome is a sign that your kidneys are not working right. You have nephrotic syndrome if you have high levels of protein in your urine, low levels of protein in the blood, and high cholesterol.
Nephrotic syndrome is not a disease. It is a warning that something is damaging your kidneys. Without treatment, that problem could cause kidney failure. So it's important to get treatment right away.
Nephrotic syndrome can occur at any age. But it is most common in children between the ages of 18 months and 8 years.

What causes nephrotic syndrome?

There are tiny blood vessels in the kidneys that filter waste and extra water from the blood. When these filters are damaged, you get nephrotic syndrome. Protein helps move water from the tissues into the blood. Healthy kidneys keep the right amount of protein in the blood. Damaged kidneys let protein slip from the blood into the urine. Without enough protein in the blood, fluid builds up in the tissues. This can cause swelling.
Many things can cause this blood vessel damage, including diabetes, lupus, infection, certain cancers, and some medicines. Sometimes doctors don't know what causes it.
A type of kidney disease called minimal change disease (also called nil disease) causes most of the cases of nephrotic syndrome in children. Doctors don't know what causes minimal change disease.

What are the symptoms?

The most common early symptom of nephrotic syndrome, in both children and adults, is swelling in the tissues around the eyes or in the feet or ankles. They may also have swelling in the lungs that can make it hard to breathe.
But many people who have nephrotic syndrome don't have symptoms.

How is nephrotic syndrome diagnosed?

Doctors diagnose nephrotic syndrome using blood and urine tests.
You may have other tests to see what is causing nephrotic syndrome. You may also have a kidney biopsy, in which the doctor takes a sample of tissue for testing.

How is it treated?

Treatment focuses on reversing, slowing, or preventing further kidney damage. The treatment you need depends on whether you are an adult or a child and what health problem caused nephrotic syndrome. You may take medicine. And your doctor may suggest a diet that is low in salt and protein.
With treatment, young children usually get better and have no lasting problems. Often treatment is not as successful in older children and adults. If the kidney damage is not stopped, it can lead to chronic kidney disease

Nephrotic Syndrome (cont.)

Cause

Nephrotic syndrome is caused by damage to the tiny blood vessels in the kidney that filter waste and excess water from the blood.
Many conditions and diseases can cause nephrotic syndrome, including:

• Minimal change disease (also called nil disease), a type of kidney disease. The cause of minimal change disease is unknown. But this disease causes most of the cases of nephrotic syndrome in children.
• Membranous glomerulopathy and focal segmental glomerulosclerosis, which are two other diseases of the kidney. Both of these diseases affect the glomeruli. The glomeruli help filter waste out of your blood. In focal segmental glomerulosclerosis, some of the parts of the glomeruli have scar tissue. This can affect how they filter the blood. In membranous glomerulopathy, the tissue wall (membrane) that separates blood and urine and acts as a filter in your kidney becomes thickened and damaged.
• Diabetes and lupus. Diabetes is the most common cause of nephrotic syndrome in adults.
• Infections, such as HIV, hepatitis B, or hepatitis C.
• Cancer
• Medicines, such as nonsteroidal anti-inflammatory drugs, penicillamine, gold therapy, or captopril.
• Illegal drugs, such as heroin.
• Conditions such as preeclampsia, chronic graft rejection following an organ transplant, and allergic reactions to bee stings.
• Unknown (idiopathic) factors.

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