[Rapidly progressive ANCA positive glomerulonephritis as the presenting feature of infectious endocarditis].

The association of positive cytoplasmic antineutrophil antibody (ANCA) necrotizing crescentic glomerulonephritis with endocarditis raises diagnostic issues. Indeed, it is often difficult to determine if the kidney injury is either secondary to an infectious disease or caused by an ANCA-associated small vessel vasculitis. We report a 59-year-old man admitted in nephrology for acute glomerular syndrome in whom the renal biopsy showed a crescentic necrotizing glomerulonephritis. A diagnosis of vasculitis was initially considered in the presence of high titer of ANCA (anti-proteinase 3). Because of associated Staphyloccocus aureus endocarditis the patient received both corticosteroids and antibiotics that allowed remission of both kidney injury and endocarditis. The renal presentation and the disappearance of ANCA support the infectious etiology of this glomerulonephritis rather than an ANCA-associated small vessel vasculitis. It is important to be cautious in the presence of ANCA positive extracapillary glomerulonephritis and endocarditis should be ruled out before initiation of corticosteroids that may be nevertheless necessary in severe acute glomerulonephritis.