Lupus nephritisDefinition: Lupus nephritis is a kidney disorder that is a complication of systemic lupus erythematosus, characterized by damage to the glomerulus and progressive loss of kidney function.
Alternative Names: Nephritis - lupus; Lupus glomerular disease
Causes, incidence, and risk factors: Lupus nephritis is one complication of�systemic lupus erythematosus (SLE ). It is related to the autoimmune process of lupus, where the immune system produces antibodies (antinuclear antibody and others) against body components. Complexes of these antibodies and complement accumulate in the kidneys and result in an inflammatory response. Lupus causes various disorders of the internal structures of the kidney, including interstitial nephritis, mesangial GN, membranous GN, membranoproliferative GN, diffuse proliferative GN, and others. It often causes nephrotic syndrome (excessive protein excretion) and may progress rapidly to renal failure. There is progressive azotemia (the accumulation of nitrogenous waste products in the bloodstream) and urinary abnormalities including protein and blood in the urine. Lupus nephritis affects approximately 3 out of 10,000 people. Systemic lupus erythematosus is most common in women 20-40 years old. It runs in families and is more common in blacks. It may be related to other autoimmune disorders including rheumatoid arthritis and scleroderma. It has been known to be triggered by pregnancy in some cases. In children with SLE, about half will have some form or degree of kidney involvement.
Symptoms: Symptoms of SLE may include the following:
Signs and tests: Examination indicates decreased kidney functioning with edema and may indicate�kidney failure. Blood pressure may be high. Abnormal sounds may be heard when the doctor listens to the heart and lungs, indicating fluid overload. Lupus nephritis is usually discovered during investigation of the causes of reduced kidney function. Fewer than half�of patients�have other symptoms of�SLE at the time of diagnosis of lupus nephritis. This disease may also alter the results of the following tests:
Treatment: The goal of treatment is improvement of kidney function. Corticosteroids or other immunosuppressive medications are often effective in reducing symptoms. Whether high doses of corticosteroids or immunosuppressives are likely to be beneficial depends on the precise findings on kidney biopsy. Dialysis may be necessary to control symptoms of acute or chronic renal failure. Renal failure may be severe enough to require dialysis even if no other symptoms of SLE are present. A kidney transplant may be recommended to treat kidney failure resulting from lupus nephritis.
Expectations (prognosis): The outcome varies. It is usually worse with diffuse proliferative lupus nephritis (one specific form of the disorder). As with SLE, the course is variable, with exacerbations (acute episodes) and remissions (symptom-free periods). Some cases of lupus nephritis may progress to chronic renal failure. Over 80% of people with lupus nephritis severe enough to require dialysis or transplantation will survive for more than 5 years after treatment. Although lupus nephritis may recur in a transplanted kidney, it rarely leads to end stage renal disease. People with active lupus should not undergo transplantation.
Prevention: There is no known prevention for lupus nephritis.
References: Harris ED. Budd RC, Genovese MC, Firestein GS, Sargent JS, Sledge CB. Kelley's Textbook of Rheumatology. 7th ed. St. Louis, Mo: WB Saunders; 2005. Noble J. Textbook of Primary Care Medicine. 3rd ed. St. Louis, Mo: Mosby; 2001.
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