About half the people who have systemic lupus erythematosus develop some form of kidney inflammation, called lupus nephritis. This inflammation can lead to kidney failure, but the course of the lupus and the pattern of its effects on the kidneys are quite variable and hard to predict.

Initially, lupus nephritis may cause no signs or symptoms. But if inflammation is widespread and persistent, it leads to impaired kidney function indicated by:

• Foamy urine due to increased protein in the urine
• Brownish urine due to blood in the urine
• Elevated creatinine in the blood
• High blood pressure
• Swelling (edema) of the feet, lower legs and occasionally the eyelids

If you're diagnosed with lupus, your doctor will likely recommend tests to evaluate your kidney function. If a problem is detected, your doctor may recommend a kidney biopsy to help determine the severity of the kidney disease and appropriate treatment.