Lupus Nephritis Warning Signs
Lupus nephritis is a serious complication of systemic lupus erythematosus (SLE; lupus) and is a major predictor of poor outcome. Most commonly, lupus nephritis develops early in the course of disease, but it can be a late complication as well (called delayed lupus nephritis [DLN]). Mortality is higher for lupus patients who develop nephritis than for those who do not.
What Problem Was Studied?
Jaccoud’s arthropathy: a chronic deformity of the hand in the absence of destructive arthritis.
Sjögren’s syndrome: a disorder of the immune system characterized by dry eyes and a dry mouth. It can exist on its own, but often accompanies other autoimmune diseases.
Interstitial lung disease: a general term for a variety of chronic lung disorders in which the walls of the air sacs in the lungs become inflamed, scarring (or fibrosis) begins in the interstitium (tissue between the air sacs) and the lungs become stiff.
Antiphospholipid antibodies: proteins in the blood that interfere with the normal function of blood vessels. These blood vessel problems can lead to such complications as stroke, heart attack and miscarriage.
Because of the poor prognosis associated with lupus nephritis, being able to predict who may develop nephritis late in the course of disease would be of great benefit. If a person with SLE is prone to the development of kidney disease, early diagnosis of the complication and rapid treatment may prevent a poor outcome. An international team of scientists – including Arthritis Foundation-funded researchers Emily C. Somers, PhD ScM, and W. Joseph McCune, MD, of University of Michigan in Ann Arbor – came together to identify factors that can predict who may develop lupus nephritis later in the disease course.
What Was Done in the Study?
People with SLE were recruited from three hospitals: one in Medellin, Colombia, one in Catalonia, Spain and one in Ann Arbor, Mich. Those who developed kidney involvement five or more years after disease onset were classified as having DLN. The other participants were classified as having either early-onset lupus nephritis (ELN) or no lupus nephritis (those who have had lupus for 10 years or more, but with no kidney involvement). The scientists then looked at numerous clinical and demographic variables to identify possible features associated with DLN.
What Were the Study Results?
In total, 399 people participated in the study; 48 had DLN, 187 had ELN and 164 had no lupus nephritis. Jaccoud’s arthropathy was found to be a protective factor against nephritis. The presence of Sjögren’s syndrome (SS) was significantly higher in those with DLN than in the other two groups. Interstitial lung involvement and antiphospholipid antibodies were both more prevalent in the DLN group than in the early lupus nephritis group. Having both SS and SLE is associated with the possibility that renal involvement will appear after five years of disease onset.
What Does This Mean for People With Lupus?
Typically people with both SS and SLE have a milder form of lupus. However, delayed lupus nephritis is more common than previously recognized. If you have SLE and SS, kidney involvement may appear later after SLE onset than in other patients. All SLE patients should be on the lookout for signs or symptoms of kidney involvement. Signs of kidney disease include weight gain, high blood pressure, dark urine, or swelling around the eyes, legs, ankles or fingers. Most importantly, make sure you see your doctor regularly for check-ups that include urinalysis.
Varela D-C, Quintana G, Somers EC, et al. Delayed lupus nephritis. Ann Rheum Dis. Published online ahead of print April 15, 2008.
For additional information on Lupus, visit Arthritis Today.