Lupus and the Kidney

Lupus and the Kidney
Alan G. Wasserstein, M.D.

LEARNING ABOUT LUPUS: A USER FRIENDLY GUIDEFrom the Lupus Foundation of Delaware Valley, Inc.Edited by: Mary E. Moore, Ph.D., M.D., Carolyn H. McGrory, MS, RN, Robert S. Rosenthal, M.D.

Lupus does not always cause kidney disease, but when it does, kidney involvement can be one of its most significant problems. In all of these cases, the kidney problems are due to the production of abnormal autoantibodies. These antibodies are directed against the patient's own tissue, for example, against DNA, the material of which the genes are made. The formation of immune complexes (combinations of these antibodies joining with normal body substances) appears to set up an inflammatory reaction in the kidney.

Several serious clinical disorders can result. The kidney may leak large amounts of protein, a condition called the nepbrotic syndrome. In the nephrotic syndrome, the ability of the kidneys to remove salt and water from the body is impaired. Excess fluid accumulates in the legs and abdomen and around the eyes, causing discomfort and inconvenience. Patients can not fit into their clothes or shoes. Diuretics are usually prescribed to help eliminate the excess fluid by increasing urination. The most feared complication is kidney failure. Kidney failure may or may not be preceded by nephrotic syndrome. Minor abnormalities in the results of urine or blood tests often provide the clue that damage to the kidney exists. Such abnormalities include excessive amounts of protein in the urine, red blood cells in the urine, or a slight loss of kidney function indicated by a rise in the serum creatinine (a blood study).

Sometimes kidney damage is more severe than the clinical symptoms reveal. A kidney biopsy should be done early if such problems are suspected. If kidney damage caused by lupus is diagnosed and treated early, the treatment is usually more effective. There is no doubt that the biopsy is the best way to determine the extent of disease and the need for treatment. After the kidney has been located with ultrasound or a CAT scan, a biopsy is done with the patient lying on his or her abdomen. Only a local anesthetic is required. A tiny cylinder of kidney tissue is withdrawn with a special needle. This tissue is examined under a microscope. Since there is a risk of bleeding from the kidney, the patient must stay in the hospital for observation for 12 hours or overnight following the biopsy.

A treatment plan is developed on the basis of the biopsy. Mild abnormalities are present in practically all lupus patients, even those with no other clinical or laboratory evidence of kidney involvement. These do not require treatment. Corticosteroids, such as prednisone, have been the basis of treatment for a long time. Their use may result in some improvement in lupus kidney disease, but the improvement is not as long lasting as we would like. (They are very effective, however, for other lupus problems such as arthritis, rash, fever, etc.) A significant advance in the treatment of lupus-related kidney disease has been the use of immunosuppressive drugs, specifically Cytoxan (cyclophosphamide).

Immunosuppressive drugs reduce the production of antibodies which cause inflammation. Cytoxan is usually given in combination with prednisone. In many cases it has led to clear improvement in lupus kidney disease. This has been demonstrated by observing improvement in biopsy specimens, reduction in the amount of protein in the urine, and increase in kidney function. Cytoxan is a toxic drug, however, which has many side effects. These include a decrease in the white blood cell count which makes a patient more susceptible to bacterial and other infections. It can also cause bleeding from the bladder (hemorrhagic cystitis), hair loss, sterility, and, years later, some patients may even develop cancer from its use. Sometimes kidney failure occurs very rapidly in patients with lupus (acute renal failure). in these cases, extremely large doses of corticosteroids and/or Cytoxan given intravenously (pulse therapy) may be helpful.

Patients who do not respond to treatment may progress to kidney failure, requiring dialysis or a kidney transplant. Although these are unfortunate outcomes, both dialysis and kidney transplants may have favorable results. Patients who have kidney failure which is advanced enough to require dialysis develop a natural immunosuppression and their lupus improves. As a result, dialysis patients with lupus do as well as other dialysis patients without systemic disease. Similarly, there has been success with kidney transplants in lupus patients. For the best outcome, a patient's lupus should be in remission at the time of the transplant. Kidneys for transplantation may come from either relatives or organ donors. In order to minimize the chance of rejection, the tissue type of the donated kidney should match the tissue type of the patient as closely as possible.

Cyclosporine, a new immunosuppressive drug given to kidney transplant patients, has significantly improved the success rate of transplants. Once the new kidney has been accepted by the body, recurrence of lupus in the kidney is rare.

=========================================================== This information is for "informational purposes" and is not meant to be used for medical diagnosis. Always consult your physician on matters such as this.