ABSTRACT
Antineutrophil cytoplasmic antibodies (ANCA) directed against either proteinase-3 or myeloperoxidase are associated with a limited group of small vessel vasculitic syndromes. C-ANCA is regarded as highly specific for idiopathic ANCA-associated vasculitis (AAV). However, C-ANCA is not specific for Wegeners granulomatosis and has been reported in the course of a variety of infectious conditions. Sub-acute bacterial endocarditis is a notable concern because it may be associated with C-ANCA. The misdiagnosis of bacterial endocarditis as AAV and the administration of immunosuppressive treatment could aggravate the infection. We describe a patient with sub-acute bacterial endocarditis who presented with features mimicking vasculitis and positive C-ANCA by indirect immunofluorescence and for anti-PR3 antibodies by antigen-specific ELISA.