Many people with lupus—about 1 in 3—have kidney disease. Doctors who treat kidney problems are called nephrologists. Rheumatologists who treat lupus also screen for kidney disease.
The kidneys have the important job of cleaning (filtering) toxins and waste from the blood and helping to control blood pressure. In some people with lupus, the kidneys become so inflamed that they cannot do their job properly. This condition is called lupus nephritis, and it needs to be carefully treated in order to prevent or minimize permanent damage to the kidneys.
No simple single test can show how the kidneys are doing, so all people with lupus should have their urine examined for the presence of protein or blood cells, and their blood checked to assess kidney function, on a regular basis. The development of high blood pressure can also be a sign that the kidneys are inflamed. These are important tests for every person with lupus to have again and again, even if the kidneys have always been healthy in the past.
Some people with lupus kidney disease have pain in their side, darker urine than usual, weight gain (from extra fluid), and swelling around the eyes, hands, or feet. But it sounds like you are one of many people with this problem who does not notice anything unusual. That’s normal, and it’s OK—and one of the reasons why it’s so important to see a doctor regularly if you have lupus.
Many people with lupus have mild kidney disease that needs ongoing care with lifestyle changes such as not eating salty foods. They should visit the doctor regularly because blood pressure and lab tests are needed to monitor the disease and adjust treatment. If blood pressure is high, it can speed up kidney damage.
If the doctor suspects lupus kidney disease, he or she may biopsy the kidney to find out the amount of inflammation and damage. The treatment will then depend on symptoms and the biopsy results.
Medicines such as “diuretics” (water pills) can help remove fluid and increase comfort. For kidney disease that is more severe, other medicines may be prescribed, such as corticosteroids and immunosuppressive drugs (CellCept (mycophenolate mofetil), Imuran (azathioprine), Cytoxan (cyclophosphamide)), and blood pressure medicines.
Even with careful watching and treatment, the kidneys sometimes stop working well enough to do their job. This is called kidney failure. If this happens, tests and possibly another kidney biopsy are done to make sure that lupus is the cause.
If the kidneys no longer work, a procedure called dialysis usually is needed. With dialysis, a connection is made from a person’s blood vessels to a machine for several hours two or three times a week, so that the machine can clean the blood—a job that the kidneys normally do. Sometimes a kidney from another person (a kidney transplant) is a choice for treating kidney failure.
Thankfully, because more and more people know about lupus, it is easier to get a diagnosis and to start the necessary treatment. With quick and early diagnosis, important organs such as the kidneys are less likely to get severely damaged.
The prognosis of lupus is better today than it was many years ago. Scientists and doctors are doing research on the many complications of lupus to find drugs that will work better and cause fewer side effects.
Daniele J. Wallace, MD