IgA nephropathy — also called Berger's disease — is a common kidney disease that occurs when an antibody called IgA lodges in your kidneys. This hampers your kidneys' ability to filter waste and excess water from your blood. Over time, IgA nephropathy can lead to blood and protein in your urine, high blood pressure, and swollen hands and feet.

IgA nephropathy usually progresses slowly over many years, and although some people eventually achieve complete remission, others develop end-stage kidney failure. No cure exists for IgA nephropathy, but certain medications can slow its course.

Keeping your blood pressure under control, limiting protein in your diet and reducing your cholesterol levels also may help keep IgA nephropathy in check.

IgA nephropathy usually doesn't cause symptoms in the early stages. The disease can go unnoticed for decades and is sometimes first suspected when routine tests reveal protein and microscopic red blood cells in your urine.

The first visible sign is often cola- or tea-colored urine — the result of urinary blood that you can see.

Signs and symptoms of IgA nephropathy include:

• Repeated episodes of cola-colored or tea-colored urine, usually during or following an upper respiratory infection
• Pain in your side(s)
• Foam in the toilet water from protein in your urine
• Swelling (edema) in your hands and feet
• High blood pressure
• Low-grade fever

When to see a doctor
Make an appointment with your doctor if you have blood in your urine. Urinary bleeding often isn't serious and can result from strenuous exercise and some foods and medications. But prolonged bleeding may indicate a medical problem and should always be evaluated. Also see your doctor if your urine is foamy or you develop unaccustomed swelling in your hands and feet.

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Kidney cross section

Your kidneys are two bean-shaped, fist-sized organs located at the small of your back, one on either side of your spine. Each kidney contains approximately 1 million glomeruli — tiny blood vessels that filter waste and excess water from your blood as it passes through your kidneys. The filtered blood re-enters your bloodstream, while the waste material passes into your bladder and out of your body when you urinate. Every day about 2 quarts of water, along with waste products, leave your body as urine.

Immunoglobulin A (IgA) is an antibody that plays a key role in your immune system by attacking invading pathogens. But in IgA nephropathy, this antibody collects in the glomeruli, affecting their filtering ability.

Researchers don't know exactly what causes IgA deposits in the kidneys, although IgA nephropathy appears to have a genetic component in some people.

IgA nephropathy is also sometimes associated with other conditions, including:

• Cirrhosis, a condition in which scar tissue replaces normal tissue within the liver
• Celiac disease, a digestive condition triggered by eating gluten, a protein found in most grains
• Dermatitis herpetiformis, an itchy, blistering skin disease that stems from gluten intolerance
• Infections, including HIV infection and bacterial infections
• Henoch-Schonlein purpura, a condition that results from inflammation of the small blood vessels of the skin, joints, intestine and kidneys

Although the exact cause of IgA nephropathy is unknown, some factors may increase your risk of developing this condition:

• Age. IgA nephropathy can affect people of all ages, including children, but it's most likely to strike people in their 20s and 30s.
• Your sex. In the West, IgA nephropathy affects about twice as many men as it does women.
• Ethnicity. IgA nephropathy is more common in Caucasians and Asians than it is in blacks.
• Family history. In some cases, IgA nephropathy appears to run in families, indicating that genetic factors may contribute to the disease.

The course of IgA nephropathy varies considerably from person to person. Some people have the disease for years with few problems; many cases, in fact, may go undiagnosed. Other people develop one or more of the following complications:

• High blood pressure. Damage to your kidneys from IgA deposits can raise your blood pressure.
• Acute kidney failure. If your kidneys lose their filtering ability due to IgA deposits, waste products build up quickly in your blood. When this happens, you may need to undergo temporary hemodialysis — an artificial way of cleansing your blood when your kidneys aren't able to do so. During hemodialysis, a needle is inserted into your arm through a special access point. Your blood is then directed through the needle and tubing to a machine called a dialyzer, which filters your blood a few ounces at a time. The filtered blood returns to your body, through another needle.
• Chronic kidney failure. IgA nephropathy can cause your kidneys to gradually stop functioning. Kidney function at less than 10 to 15 percent of normal capacity is considered end-stage kidney disease. In such cases, permanent dialysis or a kidney transplant is needed to sustain life.
• Nephrotic syndrome. This is a group of problems that can be caused by damage to the glomeruli, including high urine protein levels, low blood protein levels (hypoalbuminemia), high cholesterol and swelling of your eyelids, feet and abdomen.

IgA nephropathy is a highly variable disease whose course is often difficult to predict. For instance, having IgA deposits in your kidneys doesn't necessarily mean that you will go on to develop nephropathy. Because it's hard to know what to expect from a diagnosis of IgA nephropathy, it can be extremely helpful to take a list of questions to your appointment.

For instance, you might want to know:

• What tests do I need to determine if I have IgA nephropathy?
• Is this condition temporary or chronic?
• What is the long-term prognosis?
• What are the chances that I will develop kidney failure? Is there any way to know?
• What is the best course of action? How long will I have to take medications?
• What are the alternatives to the primary approach that you're suggesting?
• Can this disease be managed with diet and lifestyle changes alone?
• Since IgA nephropathy develops over many years, wouldn't it be a good idea just to keep an eye on it?
• Do you have any literature on this condition? Is there a Web site you can recommend where I can learn more?

Other suggestions for getting the most from your appointment include:

• Write down all your symptoms. Include key personal information, such as major stresses or recent life changes.
• Make a list of all medications, including vitamins, herbs and over-the-counter drugs, that you're taking. Even better, take the original bottles and a written list of the dosages and directions.
• If possible, take along a family member or friend. It can be difficult to absorb all the information provided to you during an appointment. The person who accompanies you may remember something that you forgot or missed.

Blood in the urine is often the first sign of IgA nephropathy. But the results of a urinalysis as part of a routine exam may alert your doctor to the possibility of IgA nephropathy long before you have signs or symptoms. The urinalysis may reveal microscopic red blood cells (microscopic hematuria) or increased protein in your urine (proteinuria), both signs of IgA nephropathy.

If your doctor suspects IgA nephropathy, he or she may recommend the following tests, in addition to urine testing:

• Blood tests. If you have IgA nephropathy, a blood test may show increased levels of the waste product creatinine in your blood. Sometimes the level of IgA in your blood also is elevated.
• Kidney biopsy. The only way for your doctor to confirm a diagnosis of IgA nephropathy is with a kidney biopsy. This procedure involves using a special biopsy needle to extract small pieces of kidney tissue for microscopic examination to determine if there are IgA deposits in the glomeruli.

There's no cure for IgA nephropathy and no definitive way of knowing what course the disease will take in any particular person. Some people experience complete remission and others live normal lives with low-grade hematuria or proteinuria. But perhaps as many as half of those affected eventually go on to develop end-stage renal disease. For this reason, treatment of IgA nephropathy focuses on slowing the progression of the disease and preventing complications.

Medications used to treat IgA nephropathy include:

• High blood pressure medications. One of the most common complications of IgA nephropathy is high blood pressure. Taking angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) can lower your blood pressure and reduce the amount of protein (albumin) in your urine.
• Immunosuppressants. Corticosteroid medications, such as prednisone and other potent immunosuppressants are sometimes used to treat severe symptoms, but their use is controversial. These drugs can cause a range of serious side effects, and their benefits must be carefully weighed against the risks.
• Omega-3 fatty acids. These beneficial fats, available in dietary fish oil supplements, can reduce inflammation in the glomeruli without harmful side effects.
• Vitamin E. Supplements of vitamin E may help reduce protein — but not blood — in the urine.

Controlling your blood pressure is one of the most important ways you can help slow kidney damage from IgA nephropathy. Your doctor may recommend changes in your diet — such as limiting your salt intake — to help manage your blood pressure. A low-salt diet can also help minimize fluid retention and swelling. Other dietary changes, such as reducing the amount of protein you eat and taking steps to decrease your cholesterol levels, also may help slow the progression of IgA nephropathy and protect your kidneys. In some cases, avoiding gluten — a protein found in most grains — may help. If your doctor doesn't discuss dietary changes with you, be sure to ask.

Coping with severe forms of IgA nephropathy can be challenging. But you don't have to do it alone. If you have questions or would like guidance, talk with a member of your health care team. You might also benefit from joining a support group, which 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.

Most cases of IgA nephropathy can't be prevented. If you have a family history of IgA nephropathy, talk with your doctor to find out if there are steps you can take to reduce your risk of developing the disease.