Systemic lupus erythematosus (SLE, or, more commonly “lupus”) is a condition in which your immune system begins attacking different areas of your body.
Lupus nephritis is one of the most serious complications of lupus. It occurs when SLE causes your immune system to attack your kidneys—specifically, the parts of the kidney that filter the blood for waste products.
The kidneys play a vital part in your body’s functioning. They remove waste from your blood. If they are damaged, you can become very ill. People with damaged kidneys might have to get regular dialysis. This is a procedure in which blood is cleaned by a filtration machine. These people may even need a kidney transplant.
Research suggests that about half of those with SLE suffer from lupus nephritis (Dooley, 2007).
Lupus nephritis symptoms are similar to those of other kidney diseases. They include:
- dark urine
- blood in urine
- foamy, frothy urine
- having to urinate often at night
- puffy feet, ankles, and legs that gets progressively worse as the day goes along
- gaining weight
- high blood pressure
One of the first signs of lupus nephritis is blood in your urine or extremely foamy urine. In addition, high blood pressure and swelling in your feet might indicate lupus nephritis.
Tests that will help your doctor make a diagnosis include:
Your doctor will look for elevated levels of waste products, such as creatinine and urea. Normally these products are filtered out by the kidneys.
24-Hour Urine Collection
This test measures the kidney’s ability selectively to filter wastes. It determines how much protein appears in urine over 24 hours.
Urine tests measure kidney function. They identify levels of:
- red blood cells
- white blood cells
Iothalamate Clearance Testing
This test uses a contrast dye to see if your kidneys are filtering properly.
Radioactive iothalamate is injected into your blood. Then doctors test how quickly it is excreted in your urine. They may also directly test how quickly it leaves your blood. This is considered to be the most accurate test of kidney filtration speed.
Biopsies are the most accurate way to diagnose kidney disease. Your doctor will insert a long needle through the stomach and into your kidney. It will take a sample of kidney tissue. That sample is analyzed for signs of damage.
Ultrasounds use sound waves to create a detailed image of the kidney. Your doctor will look for anything abnormal in the size and shape of the kidney.
After diagnosis, your doctor will want to determine the severity of your kidney damage. The World Health Organization (WHO) developed a system to classify the six different stages of lupus nephritis (Weening, et al., 2004):
- Stage 1: no evidence of lupus nephritis
- Stage 2: mildest form, easily treated with corticosteroids
- Stage 3: earliest stage of advanced lupus. Treatment requires high amounts of corticosteroids. The outlook remains favorable.
- Stage 4: advanced stage of lupus. There is the risk of kidney failure. Patients require high amounts of corticosteroids and immune suppression medications.
- Stage 5: excessive protein loss and swelling. Doctors will treat with high amounts of corticosteroids. Doctors may or may not give immune-suppressing drugs.
There is no cure for lupus nephritis. The goal of treatment is to keep the problem from getting worse. Stopping kidney damage early can prevent the need for a kidney transplant.
Treatment can also provide relief from lupus symptoms.
Common treatments include:
- minimizing intake of protein and salt
- taking blood pressure medication
- using steroids to reduce swelling and inflammation
- taking immune-suppression medicines like prednisone to reduce immune system damage to the kidneys
Extensive kidney damage may require additional treatment.
The most serious complication associated with lupus nephritis is kidney failure. People with kidney failure will need either dialysis or a transplant.
Dialysis is usually the first choice for treatment, but it will not work indefinitely. Most dialysis patients will eventually need a transplant. However, it may take months or years before a transplant becomes available.
The outlook for people with lupus nephritis varies. Most people see only intermittent symptoms. Their kidney damage may be noticed only during urine tests.
However, some people do have more serious nephritis symptoms. It is these people who are at increased risk for loss of kidney function. Treatments can be used to slow the course of nephritis. Unfortunately, they are not always successful.