IgA Nephropathy

IgA nephropathy (IgAN) is a type of kidney disease where antibodies build up in your kidneys and cause damage to your glomeruli (small filters inside your kidneys). Antibodies are a type of protein made by your immune system to protect against things like bacteria and viruses.

The name is a combination of two parts:

• IgA is the specific type of antibody involved, the full name being: “immunoglobulin A”
• Nephropathy is a word to describe damage to the glomeruli (small filters inside your kidneys)

IgAN is also known as Berger’s disease.

Many people with IgAN may not have any symptoms at first. As the disease advances, symptoms usually start to appear. If symptoms are present, you may notice one or more of the following:

• Foamy urine
• Puffiness around the eyes (especially in the morning)
• Swelling of your legs, feet, ankles, belly area, or face
• Hematuria (blood in your urine), especially if it starts during or soon after a cold, sore throat, or respiratory infection (an infection in your sinus, throat, airways, or lungs)
• Change in the color of urine – either pink, dark brown, or cola-colored urine
• High blood pressure

The exact causes of IgAN are not well understood. Leading research suggests it may be caused by a mix of your genes and environment. For most people, the disease process usually starts with a cold, sore throat, or respiratory infection. As your immune system fights the infection, some people make very high levels of IgA antibodies. When you have too many of these antibodies in your blood, they can get stuck in your glomeruli (small filters in your kidneys). When they get stuck, it causes inflammation, scarring, and kidney damage.

Although anybody can develop IgAN, it is usually more common in people who:

• Have a family history of IgAN or IgA vasculitis
• Have celiac disease (gluten allergy), inflammatory bowel disease (IBD), hepatitis, cirrhosis (liver failure), or HIV (human immunodeficiency virus)
• Are between the ages of 10 and 40 years old
• Are male
• Are of Asian, Pacific Island, or White European ancestry

Healthy kidneys keep blood cells and albumin (protein) from getting into the urine. So, one of the earliest signs of kidney damage from IgAN is the leaking of blood and/or protein (albumin) into your urine. Without treatment, this can get worse over time and lead to complications.

Complications of IgA nephropathy can include:

• High blood pressure: Your kidneys also play a role in balancing your blood pressure. When they are damaged by IgA nephropathy, it gets harder for your kidneys to continue maintaining this balance.
• Cardiovascular disease: High amounts of protein in your urine increase your risk for heart failure, heart attack, and/or stroke.
• Chronic kidney disease (CKD): Over time, the IgAN disease process can cause the slow loss of your kidney function. Your risk is even higher if you also have other risk factors for CKD like diabetes or high blood pressure.
• Kidney failure: When your kidneys don’t work well enough to support your body’s needs. Around 1 in 5 people with IgA nephropathy develop kidney failure within 10 years of diagnosis.

As part of the diagnosis process, your health care professional will likely review your symptoms, conduct a physical exam, and request lab tests.

Tests

Several tests may be used to get the complete picture of your kidney health and see whether you have IgAN:

• Urinalysis: a general urine (pee) test that looks for blood and/or protein in your urine.
• Urine protein-creatinine ratio (uPCR): a urine test that measures the level of protein and creatinine (waste product) in your urine. This test is very similar to the urine albumin-creatinine ratio (uACR) but measures all the different proteins that may be present (not just albumin).
• Estimated glomerular filtration rate (eGFR): a blood test that helps estimate how well your kidneys are removing waste products from the blood.
• Kidney biopsy: a test in which one or more tiny pieces (samples) of your kidney is removed and then looked at with a microscope. These results can also help predict your long-term risk for kidney failure.

Overview

There is no cure for IgAN. So, treatment is focused on managing symptoms, managing your blood pressure, and slowing the kidney disease process. Newer medications that directly target the IgAN disease process are also available, with more being studied in clinical trials.

Medications

• ACE inhibitors or ARBs: these medicines lower the amount of protein in your urine, lower your blood pressure, and help slow down the CKD disease process. Even if you don’t have high blood pressure, they can help slow the kidney damage caused by IgAN. These medicines have been used the longest for treating IgAN and are considered “first line”.
• SGLT2 inhibitors: these medicines also lower the amount of protein in your urine and help slow down the CKD disease process. They can also help you manage your blood sugar levels if you have diabetes. SGLT2 inhibitors can be used together with an ACE inhibitor or ARB.
• Endothelin receptor [type A] antagonists (ERAs): this is a newer class of medicines approved for IgAN that helps the blood vessels in your kidneys relax. This lowers the amount of protein in your urine and is expected to help slow down the CKD disease process.
  • The only drug currently available from this class (sparsentan) happens to be BOTH an ERA and an ARB, so should not be used in combination with an ACE inhibitor or ARB.
• Corticosteroids (often called “steroids”): these medicines help to calm your immune system (your body’s defense system), so it makes less IgA. This helps give your kidneys a chance to relax and try to recover. Steroids are usually only recommended for a short period of time (6-9 months). This helps to maximize the benefits while trying to minimize the risk of side effects like high blood sugar, weight gain, and bone weakening.
  • To lower the risk of side effects from steroids even more, a “targeted release” version of budesonide is available. It is a capsule that is taken by mouth and delivers budesonide (a steroid) directly to the

There are many other steps you can take to help manage your IgAN and lower your risk of worsening CKD:

• If you smoke and/or use tobacco products, stop. Smoking can speed up the kidney disease process and increase your risk of getting kidney failure. It also increases your risk for other serious health problems, including high blood pressure, heart disease, cancers, and stroke.
• If you are overweight, losing weight through a balanced diet and physical activity can help improve your health in many ways.
• Exercise regularly. Remember, it’s okay to start slowly – taking short walks is a great way to begin.
• Limit your sodium (salt) intake to less than 2300 mg per day (about 1 teaspoon of salt from all the food and drinks you consume each day). Your healthcare provider may advise an even lower target depending on your other health conditions. This means a lot more than not using a saltshaker, but also limiting foods with high levels of sodium listed on their nutrition facts label. Some foods that don’t taste salty can have a surprising amount of sodium when you check their nutrition facts label.

Questions to ask

• What was my most recent uPCR or uACR result? If my last result was not at goal, what can I do to make it lower?
• What is my risk of developing kidney failure because of my IgAN?
• When should I follow up to have my labs rechecked?
• What lifestyle changes do you suggest I make to help prevent complications?
• What symptoms should I watch for that might indicate my condition is worsening?
• What warning signs should prompt me to seek immediate medical attention?

• NKF KidneyCARE (Community Access to Research Equity) Study
• Kidney Disease and Albuminuria/Proteinuria
• IgA Nephropathy Foundation
• National Institutes of Health (NIH) Genetic and Rare Diseases Information Center

This content is provided for informational use only and is not intended as medical advice or as a substitute for the medical advice of a healthcare professional.