The renal system includes 2 kidneys, 2 ureters, the bladder, and the urethra. This system can be attacked by lupus the same as any other organs or joints. When lupus attacks the kidneys, the most common complication is lupus nephritis or inflammation of the kidneys.
Lupus nephritis is a serious and potentially life-threatening type of kidney disease caused by lupus. About half of people with lupus will develop lupus nephritis. One out of 10 will develop end-stage renal disease due to lupus nephritis. It usually develops in the first 5 years after lupus symptoms first appear.1,2
Lupus nephritis symptoms
In the early stages of lupus nephritis, there may be no signs or mild signs that anything is wrong. The first symptoms a person notices are usually:1
- Weight gain
- Puffiness in the feet, ankles, legs, hands, or eyelids. This swelling usually gets worse throughout the day.
- Urine may be foamy or red or brown colored.
- Blood pressure may increase. Many people report an increased need to urinate, especially at night.
- A blood test will show protein in the urine, a condition called proteinuria.
Lupus nephritis diagnosis
One of the reasons your doctor will test your urine at every visit is that lupus nephritis can cause serious damage before symptoms appear. The tests used to diagnose lupus nephritis include:1
- Urine test (urinalysis)
- Blood tests
- Kidney biopsy (minimally invasive surgery to take a small sample of kidney tissue)
A biopsy is only ordered if serious kidney damage is suspected.
Your doctor may also order a blood test to look for certain antibodies. Having a positive dsDNA antibody greatly increases the chances of developing nephritis. Black and Hispanic people with lupus develop lupus nephritis at higher rates, at younger ages, and have worse outcomes. This suggests there may be high-risk genes in these populations.2
Lupus nephritis stages
There are 6 stages or classes of lupus nephritis. There may be few if any, noticeable symptoms in the early stages. Treatment may not be needed until a certain amount of protein or blood is found in the urine during testing.3
As nephritis enters the more advanced stages, symptoms get more severe as the kidneys become more damaged. Eventually, nephritis can cause end-stage renal disease or kidney failure, especially if left untreated.3
Lupus nephritis treatments
There is no cure for lupus nephritis, but there are many treatments. The most common drugs used to treat lupus nephritis are immunosuppressants. Immunosuppressants help stop the body from attacking healthy cells. The most common of these drugs include:1,3,4
- Mycophenolate mofetil (CellCept) or mycophenolic acid used with a steroid such as prednisone
- Cyclophosphamide (Cytoxan)
- Azathioprine (Imuran)
- Cyclosporin A
Biologics such as belimumab (Benlysta) and rituximab are usually used in more serious cases when other drugs are controlling symptoms. Biologics change the way a certain process in the body works by altering cell actions or reactions. Belimumab is the only biologic treatment approved to treat lupus and lupus nephritis.6
Other drugs for lupus nephritis are used off-label or currently being studied and include:1,3-5
- Rituximab (Rituxan is generally only used when multiple other drugs have failed)
- Eculizumab (Soliris)
- Leflunomide (Arava)
- Obinutuzumab (Gazyva is taken with certain other immunosuppressants)
In cases of severe kidney disease, a kidney transplant may be needed. The good news is that 10-year survival improves from 46 percent to 95 percent if lupus nephritis can be pushed into remission.2
Other kidney complications of lupus
While lupus nephritis is the most common renal complication of lupus, other kidney problems also crop up, including:1,3
- Kidney and urinary tract infections often occur in people who take drugs to suppress the immune system. This makes them more vulnerable to infections of all types, including kidney infections.
- Interstitial nephritis, or inflammation of the glomerulus (the filtration system inside the kidneys) which may be caused by antibiotics or anti-inflammatory drugs.
- Lupus cystitis, or inflammation of the lining of the bladder.
- Thrombosis and vasculitis, which are blood-related disorders caused by lupus, can damage the kidneys.
Several drugs used to treat lupus can cause symptoms that are confused with lupus nephritis.
If you notice any new symptoms related to a kidney complication, contact your doctor quickly. Quick action can help stop more kidney damage and reduce your discomfort.