Children's Hospital Colorado

Immunoglobulin A (IgA) Nephropathy

What is IgA nephropathy?

Inflammation of the kidney filters is called glomerulonephritis, and it is often this group of kidney diseases that causes blood in the urine (hematuria). Immunoglobulin A (IgA) nephropathy is another disease of the kidney filters that can cause hematuria, but because it is not a “nephritis,” it is called “nephropathy,” simply meaning something is wrong with the kidney.

What causes IgA nephropathy?

Because the kidneys filter, or clean, your blood all the time, when they get sick, blood can leak into the urine. When determining the cause of blood in the urine, your child’s doctor looks for many things, like infection or injury of the kidney or urinary tract. The urinary tract is the whole system that drains urine, including the tubes (ureters) from the kidneys, the bladder and the outlet (urethra) from the bladder. If there is something wrong with the urinary tract, your child may need to see a urologist (kidney surgeon) instead of a nephrologist (medical specialist for the kidney).

No one knows why IgA nephropathy happens, but it can happen more than once and for years. The frequency and duration of the condition does not indicate much about the eventual outcome, and 85% of cases result in no long term kidney damage, with kidney function remaining normal all the while. As a result, direct treatment of the kidneys is not needed. In the majority of cases, the episodes of bloody urine will stop eventually.

What are the signs and symptoms of IgA nephropathy?

The primary sign of IgA nephropathy is blood in the urine. Most of the time, a child with IgA nephropathy doesn’t feel sick, but sometimes he or she may have a cold or virus.

What tests are used to diagnose IgA nephropathy?

Blood and urine tests are used to see how well the kidneys are working and to see if there are any abnormalities that point to more serious kidney disease. If bloody urine seems to come and go, especially at the time of colds, flu or other stress, it may be due to IgA nephropathy, but it can only be diagnosed by looking at the filters with a microscope. In order to look at the filters through a microscope, the pediatric nephrologist must perform a kidney biopsy to extract a tiny piece of kidney with a needle.

If a protein called Immunoglobulin A (IgA) is found when looking at the kidney filters under a microscope, then IgA nephropathy is diagnosed. No one knows why this blood protein gets into kidney filters, or why it causes them to leak blood. However, it is the most common cause of kidney inflammation.

What to expect

If the doctor thinks your child may have IgA nephropathy, he or she may obtain the advice of a pediatric nephrologist who can help with diagnosis and treatment. Your child may not need to see a pediatric nephrologist until some basic tests are performed to try to separate IgA nephropathy as a possibility from other kinds of kidney disease (like glomerulonephritis), and especially to prove the kidneys are working normally. IgA nephropathy is more serious if kidney function is less than normal, protein is leaking into the urine (proteinuria) and/or high blood pressure (hypertension) is present.

How do providers at Children’s Hospital Colorado make a diagnosis?

Not all kids with suspected IgA nephropathy need a biopsy. Although blood in urine can be scary and can sometimes cause backaches, IgA nephropathy doesn't cause permanent damage in 85% of cases, though the symptoms can last for years. The nephrologists at Children’s Hospital Colorado have the experience and knowledge to help, especially in severe cases where kidney function is compromised.

How is IgA nephropathy treated?

Urine and blood tests and blood pressure need to be checked on a regular basis. Depending on how well the kidneys are working, medications may be necessary. Medical steroids are used to treat severe cases, and medicines to treat high blood pressure are sometimes used as well. If your child’s treatment is going well, fewer visits are needed.


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