What Is IgA Nephropathy? Causes, Symptoms, and Diagnosis

Medically reviewed by Sarika Chaudhari, M.D., Ph.D.
Written by Emily Wagner, M.S.
Posted on June 28, 2023

  • Immunoglobulin A (IgA) nephropathy is caused when IgA antibodies build up in the kidneys.
  • Symptoms of IgA nephropathy include foamy or dark urine, high blood pressure, and swollen hands and feet.
  • Your doctor can diagnose IgA nephropathy with a physical exam, blood and urine tests, and a kidney biopsy.

Your immune system does its best to protect you again infections from bacteria and viruses, but sometimes it makes mistakes. IgA nephropathy is one example of what happens when your immune system ends up doing more harm than good. This kidney disease is caused by collections of proteins known as antibodies that form in the kidneys, leading to inflammation and damage.

In this article, we’ll cover what IgA nephropathy is, what causes it, and what symptoms to look out for. We’ll also go over how your doctor or nephrologist (a physician specializing in kidney diseases) diagnoses it. The sooner you receive a diagnosis and begin treatment, the better your chances of preventing chronic kidney disease, end-stage renal disease, or even kidney failure.

What Is IgA Nephropathy?

IgA nephropathy — or Berger’s disease — affects your kidneys’ small filtering units, known as glomeruli. Your kidneys are responsible for filtering extra water and waste out of your blood. When your kidneys are damaged, they leak protein and blood into your urine.

IgA nephropathy is a glomerular disease that can progress over time. Long-term kidney damage can eventually lead to scarring. If it’s left untreated, you may eventually develop end-stage kidney disease. Each case is different — for some people, this progress can take months, and for others it can take years.

What Causes IgA Nephropathy?

To better understand what causes IgA nephropathy, it helps to first learn about antibodies. Your immune system makes five types of antibodies to protect you from getting sick. These proteins, or immunoglobulins, are found throughout your body to stop bacteria and viruses from taking hold.

IgA antibodies are located in your bloodstream and the mucosal tissues that line your mouth, nose, throat, and digestive tract. They help protect you from tiny organisms like bacteria and viruses in the air you breathe and the food you eat.

Doctors and researchers aren’t quite sure what causes IgA nephropathy, but they believe it’s an autoimmune disease. This means that your immune system starts attacking your body’s own cells and proteins. If you have IgA nephropathy, your body produces IgA antibodies that are missing a sugar known as galactose. Your immune system thinks these abnormal antibodies are foreign invaders, and it makes other antibodies to attack them.

When antibodies attach to one another, they form clumps or immune complexes. These complexes travel through your blood, which is filtered by your kidneys. When the clumps try to pass through the glomeruli, they get stuck. This creates inflammation that damages the glomeruli, eventually leading to IgA nephropathy.

Who Develops IgA Nephropathy?

According to the National Institute of Diabetes and Digestive and Kidney Diseases, certain risk factors increase your chances of developing IgA nephropathy. People with a family history of this disease are more likely to develop it, which means that certain gene changes passed down through family members may play a role.

Your age, race, and sex also affect your risk. IgA nephropathy tends to first appear in teenagers and adults into their late 30s. It’s also more common in white and Asian people and occurs in twice as many men as women, according to Mayo Clinic.

Doctors and researchers also believe that liver disease, respiratory tract infections, and celiac disease can increase the risk of IgA nephropathy. This is because IgA antibodies are found in your respiratory and digestive tracts.

When IgA antibodies come in contact with a bacteria, virus, or (in the case of celiac disease) gluten, they activate your immune system and create inflammation. As a result, more immune complexes are produced and become stuck in your kidneys.

Symptoms of IgA Nephropathy

Most people with IgA nephropathy don’t experience symptoms until the disease has progressed. It develops slowly over many years, so it can take time for you to notice any changes.

Common symptoms of IgA nephropathy include:

  • Foamy urine — This is a sign of proteinuria (protein in your urine) caused by leaky filtering units in your kidneys.
  • Red or dark urine that looks like cola — This indicates hematuria (blood in urine). In some cases, your urine may contain microscopic amounts of red blood cells that can’t be seen by eye.
  • Hypertension (high blood pressure) — Your kidneys can’t filter out water and fluid properly, so your body holds on to it, raising your blood pressure.
  • Edema (swelling) — Extra fluid can collect in your hands and feet, making them puffy or swollen.
  • Flank pain — Pain between your stomach and back where your kidneys are located.

How Is IgA Nephropathy Diagnosed?

Your doctor will diagnose IgA nephropathy using information collected from your medical history, family history, physical exam, and various tests. They’ll talk with you about your symptoms and other health conditions, and they’ll ask if anyone in your family has IgA nephropathy or another kidney disease.

Your care team will measure your temperature, blood pressure, and other vital signs. If you have high blood pressure, that may point to IgA nephropathy. During your physical exam, your doctor may check your hands and feet for swelling. Be sure to let your doctor know about any changes in your urine or pain in your sides or back.

Blood and urine tests can tell your doctor a lot about how well your kidneys are working. Your estimated glomerular filtration rate is measured with a blood test, which tells your doctor how much blood your kidneys filter over the course of one minute. The lower the number, the more your kidneys are damaged.

You’ll likely give a urine sample to be tested for blood and protein. Sometimes, blood in urine can be seen only by these tests. A special piece of paper with chemicals known as a dipstick is placed into the sample and changes color depending on how much blood is in your urine. A dipstick test can also measure urine protein levels. You may have to give just one sample or multiple samples over 24 hours.

In some cases, your doctor may order a kidney biopsy. They’ll use a long, thin needle to remove a piece of kidney tissue to look at under a microscope. A specialist known as a pathologist will look for IgA deposits, inflammation, and damage.

Talk to Your Doctor About IgA Nephropathy

If you’ve noticed any new signs of IgA nephropathy, talk to your doctor or nephrologist. They can start an evaluation that may lead to a diagnosis. It’s important to start a treatment plan to keep your kidneys working properly. The treatment’s success is usually determined by monitoring the decrease in the proteins in the urine, which reduces the risk of chronic kidney disease. If your disease does progress and you go into kidney failure, you may need dialysis to filter your blood or — in more severe cases — a kidney transplant.

Treatment options your doctor may prescribe include:

  • Blood pressure medications like ACE inhibitors and angiotensin-receptor blockers to relax blood vessels and treat high blood pressure
  • Corticosteroids or immunosuppressants to reduce inflammation
  • Statins to lower cholesterol levels
  • Diuretics to help your body clear out extra water

Find Your Team

At MyKidneyDiseaseCenter, the site for people with kidney disease and their loved ones, people come together to gain a new understanding of different kidney diseases and share their stories with others who understand life with kidney disease.

Are you or a loved one living with IgA nephropathy? Share your story in the comments below.

    Posted on June 28, 2023
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    How Would You Explain What IgA Nephropathy Is To Someone Who Is Not Familiar With This Kidney Disease?
    August 1, 2023 by MyKidneyDiseaseCenter
    Sarika Chaudhari, M.D., Ph.D. completed her medical school and residency training in clinical physiology at Government Medical College, Nagpur, India. Learn more about her here
    Emily Wagner, M.S. holds a Master of Science in biomedical sciences with a focus in pharmacology. She is passionate about immunology, cancer biology, and molecular biology. Learn more about her here

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