Renal tubular acidosis preceding systemic lupus erythematosus.

A 10-year-old girl with distal renal tubular acidosis (RTA) for 4 years (adequately treated for 3 years) developed clinical features suggesting systemic lupus erythematosus (SLE) with supportive laboratory evidence. She had heavy proteinuria and a decreased creatinine clearance (CCr). Renal biopsy showed diffuse proliferative and sclerosing glomerulonephritis with severe tubulointerstitial changes. Following treatment with corticosteroids and cyclophosphamide, she had a clinical remission, an increase in CCr and recovery from systemic acidosis. It is likely that distal RTA in this patient was a manifestation of SLE.