Infective Endocarditis by <i>Bartonella</i><i>quintana</i> 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.

Antineutrophil Cytoplasmic Antibody Positivity in Gram‐Positive and Bartonella‐Induced Infective Endocarditis: Comment on the Article by Mahr et al

“…Aslangul also describes the interesting finding of ANCA positivity in 10 of 25 patients with Bartonella quintanaor Bartonella henselae-associated IE; among the 8 patients in whom the serologic diagnosis was confirmed by molecular analysis of heart valve tissue, ANCA was found in 6 (1). The possibility that Bartonella, a relatively uncommon cause of IE (2,3), has a close association with ANCA is further supported by observations described in several analogous case reports (4)(5)(6)(7)(8). Likewise, in our series of 109 patients with IE, the only 2 whose IE was caused by Bartonella species both tested positive for ANCA.…”

Reply

“…Aslangul also describes the interesting finding of ANCA positivity in 10 of 25 patients with Bartonella quintanaor Bartonella henselae-associated IE; among the 8 patients in whom the serologic diagnosis was confirmed by molecular analysis of heart valve tissue, ANCA was found in 6 (1). The possibility that Bartonella, a relatively uncommon cause of IE (2,3), has a close association with ANCA is further supported by observations described in several analogous case reports (4)(5)(6)(7)(8). Likewise, in our series of 109 patients with IE, the only 2 whose IE was caused by Bartonella species both tested positive for ANCA.…”

Bartonella henselae aortic valve endocarditis mimicking systemic vasculitis

“…Patients with IE mimicking AAV with positive cANCA and antiPR3 have been reported 2 10–12. Chirinos et al 10 reported a patient with IE and a positive cANCA whose blood and aortic valve cultures were positive for Enterococcus faecalis .…”

“…A literature review identified eight patients with IE who were positive for cANCA: seven had peripheral blood cultures positive for viridans streptococcus and one had a negative blood culture but positive valve culture 10. Culture negative B quintana endocarditis mimicking AAV has been reported 11. Peripheral blood cultures were negative for growth but B quintana was identified by PCR amplification, restriction fragment length polymorphism analysis of genomic DNA from the resected aortic valve and positive serology for B quintana and B henselae .…”