RELATED STORIES • Post-infectious glomerulonephritis • Membranous lupus glomerulonephritis

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Your kidneys are complex organs whose primary task is to remove wastes and excess fluid from your body. Any condition that interferes with kidney function can lead to a potentially dangerous buildup of waste products in your bloodstream.

Glomerulonephritis (glo-mer-u-lo-nuh-FRI-tis) is a type of kidney disease that hampers your kidneys' ability to remove waste and excess fluids. Also called glomerular disease, glomerulonephritis can be acute, referring to a sudden attack of inflammation, or chronic, which comes on gradually.

Glomerular disease can be part of a systemic disease, such as lupus or diabetes, or it can be a disease by itself — primary glomerulonephritis. Treatment depends on the type of glomerulonephritis you have.

Signs and symptoms of glomerulonephritis may depend on whether you have the acute or chronic form, and the cause. Your first indication that something is wrong may come from symptoms or from the results of a routine urinalysis. Signs and symptoms may include:

• Cola-colored or diluted iced-tea-colored urine from red blood cells in your urine (hematuria)
• Foam in the toilet water from protein in your urine (proteinuria)
• High blood pressure (hypertension)
• Fluid retention (edema) with swelling evident in your face, hands, feet and abdomen
• Fatigue from anemia or kidney failure
• Less frequent urination than usual

Your kidneys are two bean-shaped, fist-sized organs situated at the small of your back, just below your rib cage, one on each side of your spine. Blood enters your kidneys through arteries from your aorta, the large artery that carries blood away from your heart. Each kidney contains approximately 1 million tiny filters (glomeruli), each of which is attached to the opening of a small fluid-collecting tube (tubule). Each glomerulus and tubule form a nephron, the functional unit of the kidneys.

The glomeruli filter your blood as it passes through your kidneys. Your kidneys normally filter the equivalent of about 100 gallons of blood each day. After being filtered by the glomeruli, blood travels through veins in the kidneys back to your bloodstream. The waste, after being modified by the tubules, goes to your bladder as urine through a tube from each kidney (ureter) and passes out of your body when you urinate.

Every day about 2 quarts of waste products and extra water leave your body as urine. When your kidneys lose their filtering ability, dangerous levels of fluid and waste accumulate in your body, a condition known as kidney failure.

Many causes of glomerulonephritis
Glomerulonephritis is one disorder that can lead to kidney failure. There are many causes of glomerulonephritis. They include those related to infections, immune diseases, inflammation of the blood vessels (vasculitis) and conditions that scar the glomeruli.

Often, however, the exact cause is initially unknown. Here are some of the known causes:

Infections

• Post-streptococcal glomerulonephritis. Glomerulonephritis may develop after a strep infection in your throat or, rarely, on your skin (impetigo). Post-infectious glomerulonephritis is becoming more uncommon, however, because of rapid and complete antibiotic treatment of most streptococcal infections.
• Bacterial endocarditis. Bacteria can occasionally spread through your bloodstream and lodge in your heart, causing an infection of the valvular tissues inside the heart. Those at greatest risk are people with a heart defect, such as a damaged or artificial heart valve.
• Viral infections. Among the viral infections that may trigger glomerulonephritis are the human immunodeficiency virus (HIV), which causes AIDS, and the hepatitis B and hepatitis C viruses, which affect the liver and can become chronic infections.

Immune diseases

• Lupus. A chronic inflammatory disease, lupus can affect many parts of your body, including your skin, joints, kidneys, blood cells, heart and lungs.
• Goodpasture's syndrome. A rare immune lung disorder that may mimic pneumonia, Goodpasture's syndrome causes bleeding (hemorrhage) into your lungs as well as glomerulonephritis.
• IgA nephropathy. Characterized by recurrent episodes of blood in the urine, this condition results from deposits of the protein immunoglobulin A (IgA) in the glomeruli. IgA nephropathy can progress for years with no noticeable symptoms. Men seem more likely to develop this disorder than are women.

Vasculitis

• Polyarteritis. This form of vasculitis affects small and medium blood vessels in many parts of your body, such as your heart, kidneys and intestines.
• Wegener's granulomatosis. This form of vasculitis affects small and medium blood vessels in your lungs, upper airways and kidneys.

Conditions that cause scarring of the glomeruli

• High blood pressure. Damage to your kidneys and their ability to perform their normal functions can occur as a result of high blood pressure. Glomerulonephritis can also cause high blood pressure because it reduces kidney function.
• Diabetic kidney disease. Possibly the most common cause of end-stage kidney disease in the United States, diabetic kidney disease (diabetic nephropathy) can affect people with diabetes. It usually takes years to develop diabetic nephropathy, and damage may be slowed or prevented by maintaining good control of your blood sugar levels.
• Focal segmental glomerulosclerosis. Characterized by scattered scarring of some of the glomeruli, this condition may result from another disease or occur for no known reason.

Chronic glomerulonephritis sometimes develops after a bout of acute glomerulonephritis. In some people there's no history of kidney disease at all, and the first indication of chronic glomerulonephritis is chronic kidney failure. Infrequently, chronic glomerulonephritis runs in families. In many cases, no one knows the cause.

Talk to your doctor if you have a condition that's associated with glomerulonephritis or if you're experiencing any of the signs or symptoms of glomerulonephritis.

The first clue that you may have glomerulonephritis may come from your signs and symptoms. However, often the results of a urinalysis as part of a routine exam may alert your doctor to the possibility. The urinalysis may show red blood cells, an indicator of possible damage to the glomeruli; white blood cells, an indicator of infection; or increased protein, which may indicate nephron damage. Other indicators such as increased blood levels of creatinine or urea also may be red flags. Or, your hard-to-control high blood pressure may cause your doctor to suspect glomerulonephritis.

If your doctor suspects glomerulonephritis, you may undergo one or more of the following diagnostic procedures, in addition to urine testing:

• Blood tests. These can provide information about kidney damage and impairment of the filtering mechanisms by measuring levels of waste products, such as creatinine and blood urea nitrogen.
• Imaging tests. If your doctor detects evidence of damage, he or she may recommend diagnostic studies that allow visualization of your kidneys, such as a kidney X-ray, an ultrasound examination or a computerized tomography (CT) scan.
• Kidney biopsy. This procedure involves using a special needle to extract small pieces of kidney tissue for microscopic examination to help determine the cause of the inflammation. A kidney biopsy is almost always necessary to confirm a diagnosis of glomerulonephritis.

Complications of glomerulonephritis may include:

• Acute kidney failure. Loss of function in the filtering part of the nephron may cause waste products to accumulate rapidly. This condition may require emergency dialysis, an artificial means of removing extra fluids and waste from your blood, typically by an artificial kidney machine (dialyzer).
• Chronic kidney failure. In this extremely serious complication, the kidneys gradually lose function. Kidney function at less than 10 percent of normal capacity indicates end-stage kidney disease, which usually requires dialysis or a kidney transplant to sustain life.
• High blood pressure. Damage to your kidneys and the resultant buildup of wastes in the bloodstream can raise your blood pressure.
• Nephrotic syndrome. This is a group of signs and symptoms that may accompany glomerulonephritis and other conditions that affect the filtering ability of the glomeruli. High protein levels in the urine resulting in low protein levels in the blood, high cholesterol, and swelling of the eyelids, feet and abdomen characterize the syndrome.

Treatment and outcome of glomerulonephritis depend on whether you have an acute or chronic form of the disease, on the underlying cause, and on the type and severity of your signs and symptoms. Some cases of acute glomerulonephritis, especially those that follow a strep infection, often improve on their own and require no specific treatment.

To control your high blood pressure and slow the decline in kidney function, your doctor may prescribe one of several medications, including:

• Diuretics
• Angiotensin-converting enzyme (ACE) inhibitors
• Angiotensin II receptor agonists (ARBs)
• Calcium channel blockers
• Beta blockers

Your doctor also may prescribe drugs to treat the underlying cause of glomerulonephritis:

• Strep or other bacterial infection. Your doctor likely will prescribe an appropriate antibiotic.
• Lupus or vasculitis. Doctors often prescribe corticosteroids and immune-suppressing drugs.
• IgA nephropathy. Fish oil supplements have been successful in some people with IgA nephropathy and are under study.
• Goodpasture's syndrome. Plasmapheresis is sometimes used to treat people with Goodpasture's syndrome. Plasmapheresis is a mechanical process that removes antibodies from your blood by taking the plasma out of your blood and replacing it with fluid or donated plasma.

Therapies for associated kidney failure
For acute glomerulonephritis and acute kidney failure, temporary dialysis can help remove excess fluid and control high blood pressure. The only long-term therapies for end-stage kidney failure are kidney dialysis and kidney transplantation. When a transplant isn't possible, often because of poor general health, dialysis becomes the only option.

There's no way to prevent most forms of glomerulonephritis. However, you can seek prompt treatment of a strep infection causing a sore throat or impetigo. To prevent infections, such as HIV and hepatitis, that can lead to some forms of glomerulonephritis, follow safe sex guidelines and avoid intravenous drug use. Controlling your blood sugar may prevent diabetic nephropathy, and controlling your blood pressure makes damage to your kidneys caused by hypertension less likely.

Your doctor may recommend changes in your diet, including restricting salt intake to prevent or minimize fluid retention, swelling and hypertension. Cutting back on protein and potassium consumption may slow the buildup of wastes in your blood.

Maintaining a healthy weight and controlling your blood sugar levels if you're diabetic, may help slow the kidney damage associated with uncontrolled diabetes.

Living with chronic glomerulonephritis and chronic kidney failure can tax your emotional resources. Talk with your doctor to be sure you know your treatment options. Also, you might benefit from joining a support group. Such a group can provide both sympathetic listening and useful information. To find out about support groups in your area that deal with kidney disease, ask your doctor or contact your local chapter of the National Kidney Foundation by calling (800) 622-9010.