Antineutrophil Cytoplasmic Antibody Induction due to Infection: A Patient with Infective Endocarditis and Chronic Hepatitis C

Abstract

While antineutrophil cytoplasmic antibody (ANCA) is often used as a diagnostic marker for certain vasculitides, ANCA induction in the setting of infection is much less common. In the case of infective endocarditis, patients may present with multisystem disturbances resembling an autoimmune process, cases that may be rendered even trickier to diagnose in the face of a positive ANCA. Though not always straightforward, distinguishing an infective from an inflammatory process is pivotal in order to guide appropriate therapy. We describe an encounter with a 43-year-old male with chronically untreated hepatitis C virus infection who featured ANCA positivity while hospitalized with acute bacterial endocarditis. His case serves as a reminder of two of the few infections known to uncommonly generate ANCA positivity. We also summarize previously reported cases of ANCA positivity in the context of endocarditis and hepatitis C infections.

Figure 1

(a) Photograph of the patient's resolving purpura involving his legs one week into antibiotic therapy. (b) Corresponding hematoxylin and eosin-stained histopathology at 20x magnification of a punch biopsy of one of the lesions on his leg, showing mild perivascular inflammation with focally extravasated erythrocytes consistent with a resolving purpuric process. No leukocytoclastic vasculitis was seen.