Mar. 21, 2014

Lupus and the Kidneys

By: Dr. Ballou, Chairman of the LFA, GOC Medical Advisory Board

Lupus is a mysterious disease for many reasons, one of which is because it can affect multiple parts of the body, at different times.  Which body organs are affected varies from person to person.  While the most common problems in many patients with lupus are joint pains and skin rashes, lupus affecting the kidney, often called "lupus nephritis," is the most serious manifestation.  Lupus involves the kidney in about one half of patients.  Much of the time this is somewhat mild, but a few patients have severe lupus nephritis that can even eventually lead to kidney failure.

How does a person know if lupus is affecting their kidneys?  Interestingly, this can only be determined by laboratory tests, particularly blood and urine tests.  It is a common misconception that kidney problems cause back pain.  This is not usually the case, and certainly not with lupus nephritis, where the person often has no symptoms at all.  For example, patients do not have burning with urination or increased frequency of urination like with kidney infections, and the color of the urine is usually normal.  Therefore, the doctor will often do a blood test or urine test periodically to be certain that the person does not have lupus nephritis, or if they do have lupus nephritis, to determine whether the kidney involvement is being adequately controlled with medications.

If the doctor does a urine test and detects protein in the urine, or other abnormalities, the doctor may recommend a kidney biopsy.  This is a fairly simple test that is routinely done by a radiologist as an outpatient.  The test itself usually takes about one half hour and causes only minor discomfort.  Generally the patient is observed for about 2 hours after that test, after which they may go home, without further restrictions.  The kidney biopsy can provide information regarding whether the kidney is affected and whether the involvement is mild or severe.  This type of information can help to determine what would be the best therapy for controlling the lupus nephritis.

Treatment for lupus nephritis may involve more than one type of medication.  It is exceedingly important to control the blood pressure, because elevated blood pressure can provide additional harm to the kidneys.  Many patients will receive treatment with medications called "ACE inhibitors" or “angiotensin blockers”, which are very effective for controlling blood pressure.  Sometimes these medications are used even when the blood pressure is normal, since they can help to reduce protein in the urine.  Hydroxychloroquine, often called Plaquenil, is also often used to treat patients with lupus nephritis. This medication has additional value for controlling other symptoms such as rashes and joint pains.  Prednisone, in a varying dosage, is often used early in the treatment of lupus nephritis, as this medication can have very powerful beneficial effects.  It is generally important to work closely with the doctor and gradually taper the dose of prednisone over time, since this medication can also cause numerous side effects. Recently, a number of new, more powerful medications have been found to be very effective for lupus nephritis.  These medications include mycophenolate ("CellCept"), cyclophosphamide ("Cytoxan") and azathioprine ("Imuran").  They are also called "immunosuppressive medications” or sometimes "chemotherapy" because they have also been used, often in higher doses, to treat cancer.  Each of these medications is quite powerful and generally it is important for the patient to have close follow-up by their rheumatologist or nephrologist, often with repeat laboratory tests, to be certain that these medicines are both effective and safe.

Newer medications are currently being evaluated for treatment of lupus nephritis.  Among these are belimumab (Benlysta), which was approved for treating lupus only about 2 years ago (The first new drug approved for treatment of lupus in about 50 years!).  There are at least 4 other new similar medications in the same family of so-called "biologic agents" that are being tested for lupus nephritis at this time.  We expect that some of these medications will prove to be successful for controlling lupus nephritis, and may have less side effects than some of our current medications, such as prednisone.

Unfortunately, a few patients with lupus nephritis can have very serious or rapidly progressive involvement that does not respond to any of our current therapies.  In such unusual cases, the person may develop kidney failure, requiring hemodialysis.  While patients with chronic kidney failure can enjoy a relatively normal life on dialysis, many of these patients are excellent candidates for kidney transplant.  Worldwide, there are now many lupus patients who have had a kidney transplant and have subsequently done exceedingly well for 10-20 years or even longer.  Interestingly, lupus does not seem to recur very often in the transplanted kidney.  However, the patient generally does need to continue medications to prevent rejection of the transplanted kidney.

Fortunately, the outlook for patients with lupus nephritis has progressively improved.  About 50 years ago, one half of patients with lupus nephritis died with kidney failure, often within a few months or years of the diagnosis.  Nowadays, as a result of earlier diagnosis, careful follow-up with close attention to blood pressure and urine tests, and newer treatments, more than 90% of patients can expect to live full and healthy lives.