Proteinuria (protein in your urine) is a sign of kidney damage caused by IgA nephropathy. Treatment can help reduce proteinuria and preserve your kidney function longer.
IgA nephropathy (IgAN) is a type of chronic kidney disease. While health experts don’t yet fully understand its cause, IgAN develops as a result of problems with the antibody immunoglobulin A (IgA).
Your immune system makes IgA to fight off infections. When IgA works as it should, it protects you by fighting off viruses and bacteria. But if your body makes too much IgA, the excess starts to build up in your glomeruli (the tiny filters in your kidneys), causing IgAN.
IgA deposits in the glomeruli lead to inflammation and damage. And kidney damage can result in protein in your urine, called proteinuria.
Your kidneys have many jobs, including filtering toxins out of your blood. Each kidney contains about 1 million tiny filters called glomeruli. Healthy glomeruli are very good at removing waste products and extra fluid from your blood, and those products leave your body in your urine.
The glomeruli hold on to the nutrients your body needs, including vitamins, minerals, and protein. These nutrients return to your bloodstream for use throughout your body.
When you have IgAN, high levels of IgA start to build up in your kidneys. This buildup damages your glomeruli, so they don’t work as well. They are then less able to properly separate the substances that should stay in your body from those that end up in your urine.
Typically, protein should stay in your body. But when the glomeruli are damaged, some protein can leak into your urine.
In the early stages of proteinuria, you may not have any symptoms. Sometimes, the results of a urine test are the only way you’ll find out about protein in your urine.
If proteinuria continues, you might start to see some changes in your urine. Proteinuria can make your urine look foamy or frothy. You might see blood in your urine or notice changes in the color. Proteinuria can make your urine look pink or cola-colored.
Proteinuria is a sign of kidney damage, which can have other symptoms. You may experience fatigue, muscle cramping, nausea, and swelling in your legs, feet, stomach, or face.
You might find out there’s protein in your urine only after your doctor shares the results of a urine test with you.
In some cases, you might notice changes in your urine. It might look foamy or be pink or the color of cola.
The most reliable way to find out whether you have proteinuria or kidney damage is through urine and blood testing. Urine testing will show how much protein is present in your urine, and blood tests can give you other information about the health of your kidneys.
Proteinuria is a sign of kidney damage, and higher levels of protein in your urine indicate greater kidney damage.
There’s no cure for IgAN, but treatments can help reduce proteinuria and help you maintain kidney function longer. Here are some treatment options.
ACE inhibitors or ARBs
Angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), two large classes of blood pressure medications, are
The generic names of ACE inhibitors end in “-pril.” Brand names of ACE inhibitors include Altace, Coversyl, and Vasotec.
The generic names of ARBs all end in “-sartan.” Some of the brand names of ARBs are Avapro, Atacand, and Micardis.
Blood pressure and kidney health are interconnected. Even if you don’t have high blood pressure, a healthcare professional might recommend an ACE inhibitor or an ARB for you.
Both ACE inhibitors and ARBs help relax the glomeruli. Healthy kidneys filter your blood at a higher pressure, pushing more blood through your glomeruli. ACE inhibitors and ARBs slow down this process slightly.
With a slower filtration rate, the glomeruli are better able to keep up, so your kidneys can filter out more protein, preventing it from leaking into your urine.
SGLT2 inhibitors
Sodium-glucose cotransporter-2 (SGLT2) inhibitors are a type of medication used for type 2 diabetes. Examples of SGLT2 inhibitors include canagliflozin (Invokana), dapagliflozin (Forxiga), empagliflozin (Jardiance), and ertugliflozin (Steglatro).
These medications also have a role in managing IgAN. They help preserve kidney function by reducing the stress on your glomeruli. As with ACE inhibitors and ARBs, this reduced pressure helps your kidneys capture more protein to prevent it from leaking into your urine.
In a small 2023 study involving 93 people who still had proteinuria despite treatment with an ACE inhibitor or an ARB, SGLT2 inhibitors led to a significant reduction in proteinuria. SGLT2 inhibitors are often used as an add-on to an ACE inhibitor or an ARB.
Endothelin receptor type A antagonists (ERAs)
ERAs are a newer class of medications that block a type of endothelin, a compound that increases pressure in the kidneys. In the United States, two ERAs are available for use in people with IgAN: sparsentan (Filspari) and atrasentan (Vanrafia).
ERAs slow the progression of kidney disease and decrease proteinuria.
Corticosteroids
Corticosteroids are powerful anti-inflammatories. They can significantly reduce proteinuria, but they’re not intended for long-term use because they can cause side effects. A doctor might prescribe them for
Corticosteroids can slow the progression of IgAN by reducing the amount of IgA your immune system produces and decreasing inflammation in your kidneys to preserve their function. Longer use of corticosteroids is linked to some severe side effects, but sometimes the benefits of corticosteroids in IgAN outweigh the risks.
Some new targeted corticosteroids are available to treat IgAN, including TRF-budesonide (Tarpeyo). Targeted corticosteroids are exciting because they work better than systemic steroids and have fewer side effects when treating specific conditions.
Hydroxychloroquine
Hydroxychloroquine is known for treating malaria. It’s also used to treat some autoimmune conditions, including lupus and rheumatoid arthritis.
This medication helps regulate your immune system and decrease inflammation, so it may be helpful for IgAN. Research shows that hydroxychloroquine is nearly as effective as systemic corticosteroids in lowering proteinuria and has fewer side effects.
Lifestyle measures
In addition to taking any medications your doctor has prescribed, it’s important to do what you can to take care of your kidneys.
Depending on your health history, this may include:
- reducing the amount of sodium (salt) in your diet
- managing your blood pressure
- managing your blood sugar levels
- managing your cholesterol levels
- quitting or cutting down on smoking
Untreated proteinuria can cause problems in your kidneys and other parts of your body. As kidney damage progresses, IgAN can lead to kidney failure. About 20% of people with IgAN experience kidney failure within 10 years after diagnosis.
In addition to filtering your blood, your kidneys have a role in regulating your blood pressure. Therefore, kidney damage can lead to high blood pressure and heart disease.
When your kidneys are inflamed, those inflammatory proteins can affect other parts of your body. Inflammation contributes to heart disease by increasing the buildup of plaque. Plaque buildup in your arteries causes them to harden, increasing the risk of a heart attack or stroke.
IgA nephropathy is a type of chronic kidney disease that occurs when your immune system makes too much IgA, which builds up in your kidneys. This buildup causes damage and inflammation, which can lead to proteinuria. Several medications and self-care strategies can help you reduce proteinuria and maintain your kidney function longer.