From Lice to the Heart and Kidneys

Introduction: Bartonella henselae and quintana, accounting for more than 95% of all Bartonella infections, are the most common cause of culture negative endocarditis in the US. There are many case reports of proteinase-3 (PR3) ANCA vasculitis associated with Bartonella endocarditis. Here we present a case of Bartonella-associated dual-positive myeloperoxidase (MPO) and PR3 renal-limited ANCA vasculitis Case Description: A 55-year-old male with a history of stage 3 chronic kidney disease, heart failure with preserved ejection fraction (HFpEF), severe mitral regurgitation (MR), Hepatitis B on entecavir, and Hepatitis C presented with shortness of breath, lower extremity edema, and abdominal distention. Initial labs were consistent with a nephritic presentation, acute renal failure with Cr 9.32 mg/dL (baseline 1.7 mg/dL), hematuria, proteinuria, hypocomplementemia, elevated BNP, and hypoalbuminemia. Serologies were notable for strongly positive MPO and PR3 titers. Echocardiogram revealed severe MR with vegetations. Initial blood cultures were negative, but subsequent Bartonella quintana IgG (> 1:1,024) and microbial cell–free DNA were positive. The patient required urgent initiation of hemodialysis and underwent mitral valve replacement. Tissue confirmed Bartonella endocarditis and he was started on doxycycline and rifampin. Renal biopsy showed diffuse crescentic pauci-immune GN and diffuse podocyte foot process effacement. ANCA associated vasculitis (AAV) treatment included pulse dose steroids and induction therapy with RTX ten days following the initiation of definitive antimicrobial therapy and Avacopan two weeks following the completion of rifampin therapy. He demonstrated early signs of renal recovery at dischage Discussion: We present a case of dual positive MPO/PR3 AAV associated with Bartonella endocarditis leading to diffuse crescentic pauci-immune GN. The severity of findings on renal biopsy prompted an aggressive approach to management despite underlying endocarditis and planned valvular surgery. Treatment with immunosuppression began within days of starting antimicrobial therapy and resulted in early signs of renal recovery nearing discharge. Early initiation of Avacopan therapy (post completion of rifampin to avoid its inducing effects) can be utilized to expedite a prednisone taper in patients with underlying infectious complications or need for adequate wound-healing10x magnification of PAS stain showing diffuse cellular crescents