title: Infective endocarditis by Bartonella quintana masquerading as antineutrophil cytoplasmic antibody-associated small vessel vasculitis.
abstract: The Bartonella species have been recently recognized as important causative agents of culture-negative bacterial endocarditis. Antineutrophil cytoplasmic antibodies (ANCAs) have been associated with the spectrum of idiopathic small vessel vasculitis. However, a variety of infections can result in a false-positive ANCA test, and especially subacute bacterial endocarditis (SBE) with the presence of ANCAs occasionally mimics the clinical manifestations of an ANCA-associated vasculitis such as skin purpura and glomerulonephritis. In contrast, noninfectious endocardial involvement is known to be part of the spectrum of the manifestations of the ANCA-associated vasculitis. Therefore, it is crucial to distinguish an ANCA-positive SBE from an ANCA-associated vasculitis with endocardial compromise, because the misdiagnosis of an SBE as an ANCA-associated vasculitis can lead to an inappropriate immunosuppressive therapy with catastrophic consequences. The differential diagnosis is sometimes difficult, especially in the case of culture-negative infective endocarditis with a positive ANCA test. We describe here a case of a culture-negative SBE caused by Bartonellaquintana, accompanied with a positive cytoplasmic ANCA test and clinical findings masquerading as ANCA-associated vasculitis. Both a serological test for Bartonella and polymerase chain reaction restriction fragment length polymorphism analysis were helpful for a correct diagnosis and appropriate treatment.
authors: Department of Cardiovascular Medicine, University of Tokyo Hospital, Tokyo, Japan. hsugiyama-tky@umin.ac.jp
authors: Hiroaki
authors: H
authors: Sugiyama
authors: Makoto
authors: M
authors: Sahara
authors: Yasushi
authors: Y
authors: Imai
authors: Minoru
authors: M
authors: Ono
authors: Koh
authors: K
authors: Okamoto
authors: Ken
authors: K
authors: Kikuchi
authors: Ryozo
authors: R
authors: Nagai
mesh_terms: D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000175:diagnosis; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood*; D001474:Bartonella Infections / Q000097:blood / Q000175:diagnosis*; D018413:Bartonella quintana / Q000302:isolation & purification*; D003937:Diagnosis, Differential; D004696:Endocarditis / Q000097:blood / Q000175:diagnosis / Q000382:microbiology*; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic