IgA Nephropathy: An Autoimmune Disease of the Kidneys

An episode of blood in your urine during a cold may be a clue

Urine testing
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Your kidneys are two bean-shaped organs located below your rib cage. Their main function is to filter blood in order to rid the body of waste and extra fluid.

Immunoglobulin A nephropathy (IgA nephropathy) is a kidney problem that affects the glomerulus, which is an intricate network of blood vessels responsible for this blood-filtering function.

Understanding IgA Nephropathy

Each of your kidneys contains about one million nephrons, and each nephron contains a glomerulus.

These glomeruli or mass networks of blood vessels delicately filter your blood. They send waste products and fluid (as urine) to the bladder and release blood and other larger molecules, like proteins, back into the bloodstream. 

Normally, a person's immune system releases the antibody, immunoglobulin A, in response to some sort of trigger like a viral infection. But in people with IgA nephropathy, the immunoglobulin A builds up and deposits itself within the glomeruli of their kidneys.

This immunoglobulin A buildup causes kidney inflammation, and eventually scarring, which makes it difficult for the glomeruli to perform their filtering function. As a result, kidney failure may occur.

Statistics About IgA Nephropathy

In North America, about twice as many males than females have IgA nephropathy, and this pertains to both children and adults. In addition to being more common in males, IgA nephropathy is more common in Caucasians and Asians and rare in African-Americans.

Lastly, in the United States, over half of adults, age 30 years or older at the time of diagnosis of IgA nephropathy, have stage 3 to stage 5 chronic kidney disease. This suggests that diagnosing IgA nephropathy earlier may be beneficial, as treatment could potentially slow down a person's kidney function decline.

How IgA Nephropathy is Diagnosed

The two most common symptoms of IgA nephropathy are blood in the urine, which causes the urine to look tea-colored, and protein in the urine, which may cause the urine to appear foamy.

However, the majority of people with IgA nephropathy have no symptoms. If a person does note gross blood in their urine, and they have IgA nephropathy, it's usually after a viral infection like a cold or the stomach flu. 

With that, a doctor may suspect you or a loved one has IgA nephropathy based on a careful history, as well as evidence on urine and blood tests. To confirm the diagnosis, a nephrologist (a doctor who specializes in kidney diseases) will remove a small piece of kidney tissue. This procedure is called a biopsy and is done by placing a needle into your back, where a kidney can be easily accessed. 

After the biopsy, a pathologist (another type of doctor) will examine the kidney tissue under a microscope and stain it to see whether or not IgA deposits are present. If there is evidence of IgA buildup, this will solidify the diagnosis of IgA nephropathy. 

It's important to note that doctors do not necessarily perform a kidney biopsy on every person who has microscopic blood or protein in their urine.

Instead, if you have blood or protein in your urine, your doctor may monitor your urine and kidney function every six to twelve months or so. He may then perform a biopsy if your kidney function begins to decline (as evidenced by an elevated creatinine level on a blood test) or you begin to have increased amounts of protein loss in your urine.

Having high blood pressure may also be a reason why your doctor performs a kidney biopsy (if there is also blood and/or protein in the urine).

How Is IgA Nephropathy Treated

In people diagnosed with IgA nephropathy, up to half will very slowly (over years to decades) develop end-stage kidney failure (called end-stage renal disease, or ESRD).

Depending on a number of factors related to your IgA nephropathy, your doctor may treat you with medications to slow down the progression of your kidney disease. These medications include angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) to control your blood pressure. Fish oil dietary supplements are also usually recommended. 

Your doctor may also treat the inflammation occurring with IgA nephropathy by giving you steroids like prednisone.

If you progress to end-stage kidney disease, you may be treated with dialysis or a kidney transplant.

While kidney transplant is an option, it's not considered a cure, as the IgA nephropathy can reoccur in the newly transplanted kidney.

A Word From Verywell

Whether you or a loved one has been diagnosed with IgA nephropathy, another kidney disease, or have been found to have blood and/or protein in your urine, be sure to follow up with your doctor as advised. 

This remains especially true with IgA nephropathy, as it's very difficult for doctors to predict who will be OK and who will develop end-stage kidney disease.  

Sources:

Cheung CK, Barratt J. (2017). Clinical presentation and diagnosis of IgA nephropathy. Glassock RJ, Fervenza FC, ed. UpToDate, Waltham, MA: UpToDate Inc. 

National Institute of Diabetes and Digestive and Kidney Diseases.(2014). Your Kidneys and How They Work.

IgA Nephropathy Foundation of America. (n.d.). FAQs - What is IgA Nephropathy?

Wyatt RJ, Julian BA. IgA nephropathy. N Engl J Med. 2013 Jun 20;368(25):2402-14.

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