IgA nephropathy

DEFINITION

IgA nephropathy (nuh-FROP-uh-thee), also known as Berger’s disease, is a kidney disease that occurs when an antibody called immunoglobulin A (IgA) lodges in your kidneys. This results in local inflammation that, over time, may hamper your kidneys’ ability to filter waste, excess water and electrolytes from your blood. Kidney damage may be indicated by blood and protein in your urine, high blood pressure and swollen feet.

IgA nephropathy usually progresses slowly over many years, but the course of the disease in each person is uncertain. Some people leak blood in their urine without developing problems, some eventually achieve complete remission, and 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 and reducing your cholesterol levels also slow disease progression.

CAUSES

Your kidneys are two bean-shaped, fist-sized organs located at the small of your back, one on each side of your spine. Each kidney contains tiny blood vessels (glomeruli) that filter waste, excess water and other substances from your blood as they pass 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.

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

Researchers don’t know exactly what causes IgA deposits in the kidneys, but these conditions or factors may be associated with the development of IgA nephropathy:

• Genes, because IgA nephropathy is more common in some families and in certain ethnic groups
• Liver diseases, including cirrhosis, a condition in which scar tissue replaces normal tissue within the liver, and chronic hepatitis B and C infections
• 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 some bacterial infections

SYMPTOMS

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 red blood cells in your urine that can’t be seen without a microscope (microscopic hematuria).

Signs and symptoms of IgA nephropathy when kidney function is impaired include:

• Cola- or tea-colored urine (caused by red blood cells in the urine)

  Repeated episodes of cola- or tea-colored urine, sometimes even visible blood in your urine, usually during or after an upper respiratory or other type of infection

• Pain in the side(s) of your back below your ribs (flank)
• Foam in the toilet water from protein in your urine
• Swelling (edema) in your hands and feet
• High blood pressure

When to see a doctor

Make an appointment with your doctor if you notice blood in your urine. Urinary bleeding may be caused by strenuous exercise, some foods, medications or a urinary tract infection. But prolonged or repeated bleeding may indicate a serious medical problem and should always be evaluated. Also see your doctor if your urine is foamy or if you develop sudden swelling in your hands and feet.