A group of symptoms resulting from kidney damage that causes loss of protein into the urine and swelling of body tissues
- Most common in young children but can affect people of any age
- Gender, lifestyle, and genetics are not significant factors
The urine of a healthy person does not normally contain protein because the molecules are too large to pass across the glomeruli (the blood-filtering units in the kidneys). However, if the delicate glomeruli are damaged, large amounts of protein can leak into the urine from the blood. Eventually, this leakage results in low protein levels in the blood, an accumulation of fluid in body tissues, and widespread swelling.
What are the causes?
Nephrotic syndrome can be due to various kidney diseases, most commonly glomerulonephritis and diabetic kidney disease. It may also be a complication of infection elsewhere in the body, such as hepatitis B (see Acute hepatitis). Rarely, it can be due to amyloidosis, in which abnormal proteins collect in many organs throughout the body. Other possible causes include reactions to drugs and chemicals, as well as certain autoimmune disorders (in which the immune system attacks the body’s own tissues), such as systemic lupus erythematosus.
What are the symptoms?
The symptoms of nephrotic syndrome appear gradually over days or weeks and worsen as more and more protein is lost. You may notice:
Decreased urine production.
Puffiness of the face, with swelling around the eyes in the morning.
Swollen feet and legs in the evening.
Shortness of breath.
Loss of appetite and weight loss.
Swelling of the abdomen.
If you develop these symptoms, you should see a doctor immediately.
What might be done?
If your doctor suspects that you have nephrotic syndrome, he or she will first test your urine for the presence of protein. The doctor may also ask you to collect your urine over a 24-hour period so that daily protein loss can be measured. You will have a blood test to measure your protein level and to assess kidney function. In some cases, a kidney biopsy is carried out to find the cause of the condition.
Your doctor may prescribe diuretics to help to remove excess fluid from your body and may recommend a low-salt diet to prevent further fluid retention. If symptoms are severe, you may need treatment in hospital where you may be given intravenous diuretics and possibly protein-rich intravenous fluids. You may also be given corticosteroids and immunosuppressants If possible, the underlying disorder will be treated.
What is the prognosis?
The outlook for someone with nephrotic syndrome depends on the extent of the kidney damage. Children usually respond well to corticosteroids and often make a full recovery, but adults may experience recurrent episodes. In the most severe cases, chronic kidney failure and eventually end-stage kidney failure, an irreversible loss of kidney function, may develop.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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