What is lupus nephritis?
Systemic lupus erythematosus (SLE) is commonly called lupus. It’s 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 your kidney that filter your blood for waste products.
The kidneys play a vital part in your body’s functioning. They remove waste from your blood. If they’re damaged, you can become very ill.
People with damaged kidneys might have to get regular hemodialysis. This is a procedure in which your blood is cleaned by a filtration machine. People with lupus nephritis may even need a kidney transplant.
Lupus nephritis symptoms are similar to those of other kidney diseases. They include:
One of the first signs of lupus nephritis is blood in your urine or extremely foamy urine. High blood pressure and swelling in your feet also might indicate lupus nephritis. Tests that will help your doctor make a diagnosis include the following:
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. Your doctor will then test how quickly it’s 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 and also most invasive way to diagnose kidney disease. Your doctor will insert a long needle through your abdomen and into your kidney. They’ll take a sample of kidney tissue to be analyzed for signs of damage.
Ultrasounds use sound waves to create a detailed image of your kidney. Your doctor will look for anything abnormal in the size and shape of your kidney.
After diagnosis, your doctor will determine the severity of your kidney damage.
The World Health Organization (WHO) developed a system to classify the five different stages of lupus nephritis in 1964. Newer classification levels were established in 2003 by the International Society of Nephrology and the Renal Pathology Society. The new classification eliminated the original class I that had no evidence of disease and added a sixth class:
- Class I: Minimal mesangial lupus nephritis
- Class II: Mesangial proliferative lupus nephritis
- Class III: Focal lupus nephritis (active and chronic, proliferative and sclerosing)
- Class IV: Diffuse lupus nephritis (active and chronic, proliferative and sclerosing, segmental and global)
- Class V: Membranous lupus nephritis
- Class VI: Advanced sclerosis lupus nephritis
There’s 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 your intake of protein and salt
- taking blood pressure medication
- using steroids such as prednisone (Rayos) to reduce swelling and inflammation
- taking medicines to suppress your immune system such as cyclophosphamide or mycophenolate-mofetil (CellCept)
Special consideration is given to children or women who are pregnant.
Extensive kidney damage may require additional treatment.
Dialysis is usually the first choice for treatment, but it won’t work indefinitely. Most dialysis patients will eventually need a transplant. However, it may take months or years before a donor organ 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.
If you have more serious nephritis symptoms, you’re at increased risk for a loss of kidney function. Treatments can be used to slow the course of nephritis, but they aren’t always successful. Talk to your doctor about which treatment is right for you.