A 55 year-old African American male with a history of homelessness, hepatitis B, and no known history of renal insufficiency presented with complaints of bilateral lower extremity swelling, and hematuria for five days. Physical examination was significant for a 1/6 systolic ejection murmur, bibasilar crackles, and bilateral 2+ lower extremity pitting edema up to the knees. Laboratory findings demonstrated elevated serum creatinine of 5.51 mg/dL on admission (baseline of 0.7 mg/dL) and 2.96g proteinuria. Echocardiogram revealed vegetations on aortic and mitral valves with associated aortic and mitral regurgitations. Serological testing showed a Bartonella quintana IgG titer of 1:1024 and IgM titer of greater than 1:20, both suggesting recent infection. Work up for the new onset renal insufficiency revealed a serum cytoplasmic anti-neutrophil cytoplasmic antibody (ANCA) titer of 1:1024, and a subsequent kidney biopsy showed focal proliferative glomerulonephritis with a single crescent.
Bartonella quintana is a gram negative aerobic bacterium that is primarily transmitted by the human body louse and has been found to cause culture negative endocarditis, particularly in homeless patients. To our knowledge, there have been only three reported cases in English literature detailing an association between B. quintana endocarditis with masquerading C-ANCA associated vasculitis. This report explores a case in which differentiation between this phenomenon and true small vessel vasculitis was imperative in terms of management, as treatment for the latter consists of immunosuppressive therapy that could cause dissemination of B. quintana endocarditis and consequent detrimental clinical outcomes. Patients with B. quintana endocarditis present with typical features of culture negative endocarditis but may also presents with clinical features suggesting glomerulonephritis and vasculitis. Echocardiography may reveal valvular vegetations. Diagnosis can be confirmed with serum antibody titers, serum B. quintana polymerase chain reaction (PCR) levels, or PCR levels of tissue extracted from the affected valve. Treatment for confirmed B. quintana endocarditis usually consists of antibiotic therapy with gentamicin for 14 days and doxycycline for 6 weeks, but can also include valvular surgery. Treatment of the endocarditis usually leads to the resolution of the vasculitis.
A falsely positive C-ANCA titer should be considered in the setting of a homeless patient presenting with Bartonella quintana endocarditis and concurrent symptoms of small vessel vasculitis.
To cite this abstract:Chang J, Keogh A, Khan S, Li M. Culture Negative Bartonella Quintana Endocarditis with Mimicking Pauci-Immune Anti-Neutrophil Cytoplasmic Antibody (Anca) Associated Glomerulonephritis in a Homeless Male. Abstract published at Hospital Medicine 2015, March 29-April 1, National Harbor, Md. Abstract 474. Journal of Hospital Medicine. 2015; 10 (suppl 2). https://www.shmabstracts.com/abstract/culture-negative-bartonella-quintana-endocarditis-with-mimicking-pauci-immune-anti-neutrophil-cytoplasmic-antibody-anca-associated-glomerulonephritis-in-a-homeless-male/. Accessed November 20, 2019.