What is nephrotic syndrome?
Nephrotic syndrome is not considered one specific kidney disease.
Rather, it is a disorder that occurs when another kidney disease — or a systemic disease that affects the entire body, such as lupus or diabetes — damages the glomeruli, or the clusters of small blood vessels in the kidneys that filter waste and excess water from the blood.
Due to this damage, large amounts of protein leak into the urine, reducing the amount of protein in the blood. The protein in the blood plays an important role in maintaining fluid in the bloodstream and so, when nephrotic syndrome occurs, some of this fluid leaks out of the bloodstream into the tissues, which causes swelling (known as edema). Complications from nephrotic syndrome include blood clots, malnutrition, high blood pressure, acute kidney failure (for which emergency dialysis is often required), risk for developing chronic kidney disease and increased risk for infections, such as pneumonia, cellulitis, peritonitis and meningitis.
Signs and symptoms
Common signs and symptoms of nephrotic syndrome include:
- swelling, especially around the eyes and in the ankles and feet;
- foamy urine due to excess protein in the urine;
- weight gain from excess fluid retention;
- fatigue; and
- loss of appetite.
There are several methods used to diagnose nephrotic syndrome, including urine and blood tests. Urine samples may be used to determine if the amounts of protein and blood in the urine indicate kidney damage. A blood test may be used to check kidney function. In addition, the doctor will test for other diseases known to cause nephrotic syndrome. A kidney biopsy may be required.
The first, and most important, step in treating nephrotic syndrome is addressing the underlying cause. Depending on the specific cause, treatment will vary. No matter the cause, it is necessary to monitor and reduce high blood pressure, edema, high cholesterol and the risks for infection. These treatments include medications and changes in diet, such as limiting intake of dietary sodium, saturated fat and cholesterol.
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