Glomerulonephritis is inflammation of the filtering units of the kidneys, which are called glomeruli. This inflammation can cause too much protein and other substances to leak from the blood into the urine. Eventually, the kidney becomes less effective at filtering out waste products, water and salt from the blood, a condition called kidney failure. When this occurs, waste products build up to very high levels in the blood, and the body retains salt and water. When very large amounts of protein are lost in the urine, the person also can retain fluid and develop high cholesterol.

Glomerulonephritis can be a complication of streptococcal infections, including strep throat, particularly in children ages 6 to 10. Less often, it results from other bacterial or viral infections, especially measles, mumps, mononucleosis and human immunodeficiency virus (HIV). Other causes include some problems with the immune system (especially those involving immunoglobulin A antibodies), systemic lupus erythematosus (also called SLE or lupus), and inflammation of the kidney's blood vessels (vasculitis). Sometimes, the cause can't be identified.

Doctors divide glomerulonephritis into different types, depending on the cause of the illness, its symptoms and the kind of urine problems it causes. Three examples of these types are:

• Acute postinfectious glomerulonephritis — This form of glomerulonephritis follows an infection and often causes high blood pressure, dark urine, water retention and swelling because of kidney failure.



• Mesangial glomerulonephritis — This type seems to be related to immune-system abnormalities involving a type of antibody called immunoglobulin A (IgA). In most cases, the cause of this immune problem is not known, though it may be associated with a number of conditions, including cirrhosis of the liver, celiac disease (also called gluten enteropathy, celiac sprue or non-tropical sprue) and HIV infection. It can cause red blood cells to spill into the urine, but rarely causes high blood pressure, leg swelling or kidney failure.



• Membranous glomerulonephritis —In this disease, the glomeruli leak large amounts of protein into the urine from the blood.

If glomerulonephritis is mild, it will not cause any symptoms. When that happens, the disease is discovered only if protein or blood is found in the urine during a routine test. In other people, the first clue can be the development of high blood pressure. If symptoms appear, they can include swelling around the eyes, reduced urination and dark urine from the presence of red blood cells in the urine. If high blood pressure develops, some people will have headaches. If a large amount of protein is lost in the urine, there also can be swelling, particularly of the face, abdomen, lower legs, ankles or feet.

Severe or chronic (long-lasting) forms of the disease can cause kidney failure. When this happens, the person passes very small amounts of urine, feels generally ill and has swelling.

Your doctor will look for a history of infection, evidence of kidney problems and other medical disorders that can affect the kidneys. He or she also will ask how often you are urinating, how much urine you are producing and the color of the urine. To check for a history of swelling, your doctor may ask whether you've noticed puffiness around your eyes, unusual tightness in your shoes or waistband or a feeling of heaviness in your legs or ankles.

Your doctor will examine you. He or she will measure your blood pressure, weigh you to check for weight gain resulting from water retention, and check for swelling in your legs or elsewhere. To confirm the diagnosis, he or she will evaluate your kidney function through blood tests and a urinalysis, an analysis of urine that detects blood, protein or signs of infection. You also may need specialized blood testing to check for specific immune problems and a kidney biopsy, in which a tiny piece of kidney tissue is removed and examined in a laboratory.

How long glomerulonephritis lasts depends on its cause and on the severity of kidney damage. When glomerulonephritis follows an infection, the problem usually goes away within weeks to months. In other cases, glomerulonephritis becomes a chronic (long-lasting) condition that lasts for years and eventually can lead to renal failure.

To prevent glomerulonephritis following an infection, the infection must be treated promptly. Most forms of glomerulonephritis cannot be prevented.

When glomerulonephritis is caused by an infection, the first step in treatment is to eliminate the infection. If bacteria caused the infection, antibiotics may be given. However, children who develop the disease following a streptococcal infection often recover without any specific treatment.

When glomerulonephritis has slowed the amount of urine a person is producing, he or she may be given medications called diuretics, which help the body to rid itself of excess water and salt by producing more urine. More severe forms of the disease are treated with medications to control high blood pressure, as well as changes in diet to reduce the work of the kidneys. A small percentage of people with severe glomerulonephritis may be treated with medications called immunosuppressive drugs, which decrease the activity of the immune system, such as corticosteroids and/or cyclophosphamide (Cytoxan). If glomerulonephritis progresses to end-stage renal failure, treatment options include dialysis and a kidney transplant.

Call your doctor if you or your child is putting out less urine then normal or if urine looks bloody or abnormally dark. Also call your doctor if you notice unusual swelling, particularly around the eyes or in the legs or feet. If you have a history of a kidney problem and you develop any of these symptoms, you should seek medical assistance without delay.

Children with glomerulonephritis usually recover completely if their illness is mild or if it develops following a strep infection. Although adults often have a poorer outlook, some recover completely. More severe forms of the disease may eventually lead to kidney failure, which may ultimately require lifelong treatment with dialysis or a kidney transplant.

National Institute of Diabetes and Digestive and Kidney Disorders
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American Foundation for Urologic Disease
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Fax: (410) 689-3998
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National Kidney Foundation
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Phone: (212) 889-2210
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Fax: (212) 689-9261
E-Mail: info@kidney.org
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