A case of primary antiphospholipid antibody syndrome with acute renal failure showing thrombotic microangiopathy

An 18-year-old woman complained of fever and edema and was admitted to Show a University Hospital for treatment of thrombocytopenia and deteriorating r enal function. Laboratory studies demonstrated the presence of lupus antico agulant (LA), prolongation of prothrombin time, hemolytic anemia, a negativ e Coombs' test, the absence of antinuclear antibodies, and a normal fibrino gen level. Renal biopsy revealed mesangial hypercellularity, severe endocap illary cell damage, and double contour of the basement membrane walls. Immu nofluorescence studies demonstrated focal, peripheral, and finely granular deposits for IgG, IgM, and IgA but were negative for fibrinogen, Electron m icroscopy showed glomerular capillary loops with subendothelial widening an d subendothelial deposits, mesangiolysis, mesangial interposition, and mark ed luminal narrowing. Biopsy findings were consistent with thrombotic micro angiopathy. The patient was treated with hemodialysis, methylprednisolone p ulse therapy, and dipyridamole. After treatment, LA disappeared, the prothr ombin time became normal, and renal function improved. The renal lesions in this patient were caused by primary antiphospholipid antibody syndrome. Th is case strongly suggests an important causal relationship between LA and r enal lesions in thrombotic microangiopathy. We present this case to promote understanding of the pathogenesis of primary antiphospholipid antibody syn drome. Copyright (C) 1999 S. Karger AG, Basel.