What is it?
IgA nephropathy, also called Berger’s disease, is a chronic kidney disease that occurs when deposits of immunoglobulin A (IgA) build up in the kidneys.
Immunoglobulins are normal parts of the immune system that help your body get rid of infections. People with IgA nephropathy have a defective version of immunoglobulin A. The defective IgA forms chains that get stuck in the kidneys.
IgA nephropathy affects millions of people worldwide. While IgA nephropathy is a lifelong disease, for most people it doesn’t progress to anything serious.
Treatment typically involves controlling your blood pressure and cholesterol levels with medications. Some people with IgA nephropathy will eventually need a kidney transplant.
What are the symptoms?
In the early stages of IgA nephropathy, the main symptom is blood in the urine. In medical terms, this is called hematuria. Symptoms usually start between the ages of 15 and 35, but they may go unnoticed for years because the amount of blood in the urine is very small.
If the disease progresses and starts to impair the function of your kidneys, you may also experience:
- brown or tea-colored urine
- pain on the side of your back (flank pain)
- protein in the urine (proteinuria)
- high blood pressure (hypertension)
- swelling of the hands and feet
What causes it?
An immunoglobulin or antibody is a large protein that the immune system uses to kill harmful bacteria and viruses. One type of immunoglobulin is immunoglobulin A or IgA. When someone has IgA nephropathy, their IgA doesn’t work properly. Instead of binding only to bacteria and viruses, the IgA mistakenly attaches to other IgA molecules and creates long chains.
As the chains circulate in the blood, they eventually get deposited in the kidney’s filters (glomeruli). These IgA deposits result in an inflammatory reaction in the body. This inflammation can eventually cause kidney damage.
At the moment, it’s not fully understand why a person’s IgA acts this way. Researchers believe there is a genetic component to the disease because it sometimes runs in families.
Certain factors can also increase a person’s risk of developing IgA nephropathy. Men are two to three times more likely to have it than women. The condition is also more common in Native Americans, Caucasians, and Asians.
Other conditions that are associated with IgA nephropathy include:
- liver diseases, including cirrhosis and hepatitis B and C
- celiac disease
- dermatitis herpetiformis
- infections, including HIV, viral infections in the upper respiratory tract, and stomach viruses
- Henoch-Schönlein purpura
How it’s diagnosed
IgA nephropathy may first be noticed when a routine test reveals protein and red blood cells in your urine.
A doctor will review your medical and family history and perform a physical exam. They may also ask you about your symptoms, including if you’ve ever noticed that your urine is dark or reddish in color, or if you have a history of urinary tract infections (UTIs).
To help confirm a diagnosis and differentiate your condition from other diseases, the following tests may also be done:
- kidney biopsy to look for IgA deposits (a biopsy is the only way to confirm a diagnosis)
- urinalysis[WB1] to check for protein and blood in the urine
- serum creatinine test to find out if creatinine is building up in your blood
- estimated glomerular filtration rate (GFR) to determine how well your kidneys are filtering waste
- blood pressure test
- cholesterol blood test
There’s no cure for IgA nephropathy and no standard way of treating it. Some people won’t need treatment at all. They’ll still need to go in for regular checkups to check their kidney function.
For others, treatment is aimed at slowing the progress of the condition and managing blood pressure, swelling, and protein levels in the urine.
This might include one or more of the following:
- blood pressure medications known as angiotensin receptor blockers (ARBs) or angiotensin-converting enzyme (ACE) inhibitors; these can lower blood pressure as well as lower the protein levels in the urine
- immunosuppressant drugs, such as oral steroids
- omega-3 fatty acid supplements, like a prescription-strength fish oil
- cholesterol medications, known as statins
- diuretics, which help remove excess fluid from the blood
In some people, IgA nephropathy progresses over the course of a few decades and can eventually lead to kidney failure.
People with kidney failure will need to have dialysis, a process where the blood is filtered with a machine, or a kidney transplant. Even after a transplant, it’s possible for the condition to come back in the new kidney.
Managing IgA nephropathy with diet
You may be able to slow down the progression of IgA nephropathy by making a few changes to your diet. This includes:
- eating a diet low in saturated fats and cholesterol
- limiting your intake of sodium
- reducing the amount of protein in your diet
- including sources of omega-3 fatty acids, such as flaxseeds, canola oil, cod liver oil, walnuts, and fish oil supplements
To reduce your sodium and cholesterol intake, you can try following a diet similar to the DASH diet. DASH stands for dietary approaches to stop hypertension. This diet focuses on fruits, vegetables, whole grains, and lean meats and reducing your intake of sodium.
Since the DASH diet is meant to help people lower their blood pressure, it may be helpful for people with IgA nephropathy who need to keep their blood pressure levels within normal ranges.
A low-protein diet is also recommended to help slow the progression of IgA nephropathy. However, clinical studies haven’t been able to show conclusively that limiting protein intake is beneficial for people with IgA nephropathy.
What are the complications?
IgA nephropathy varies greatly from person to person. Some people won’t experience any complications at all and the disease may even go into remission on its own.
Other people, however, develop complications as their condition progresses. These include:
- high blood pressure
- high cholesterol (hypercholesterolemia)
- acute kidney failure
- chronic kidney disease
- end-stage renal disease (ESRD)
- [WB2] heart problems
Prognosis and life expectancy
There’s no cure for IgA nephropathy and no reliable way to tell how it will affect each person individually. For most people, the disease progresses very slowly.
Up to 70 percent of people can expect to have a normal life expectancy without complications. This is especially true for people who only have minimal proteinuria and normal kidney function at the time of their diagnosis.
On the other hand, roughly 15 percent of people with IgA nephropathy will develop ESRD within 10 years of onset, and over 30 percent of people will develop ESRD within 20 years. The prognosis is least favorable for people with long-term hypertension, persistent hematuria, and prolonged proteinuria (above 1 gram/day).
People with ESRD require dialysis treatment or a kidney transplant. A kidney transplant is typically successful, but it’s possible for IgA nephropathy to come back (recur) in the new kidney.
About 40 percent of people who have a recurrence will eventually lose their kidney again, but it can take up to 10 years after the transplant for that to occur.
Your doctor will work with you to develop a treatment plan if you’re diagnosed with IgA nephropathy.