Abstract: FR-PO0763
Hidden in the Crescents: Bartonella henselae Infective Endocarditis Mimicking ANCA-Associated Vasculitis
Session Information
- Glomerular Diseases: ANCA Vasculitis, Anti-GBM Disease, and Crescentic GN
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Chau, Matthew Kwun-Ting, Northwell Health, New Hyde Park, New York, United States
- Pagan, Ricardo Alberto, Northwell Health, New Hyde Park, New York, United States
- Oltorik, Christopher David, Northwell Health, New Hyde Park, New York, United States
- Varghese, Jeny, Northwell Health, New Hyde Park, New York, United States
Introduction
Anti-neutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV) accounts for ~10% of acute kidney injury cases, but ANCA positivity may also occur in infection. Discordance between ANCA immunofluorescence and antigen-specific assays has been described in infection-related disease. Bartonella species are an important cause of blood culture–negative infective endocarditis (IE), representing up to 28% of cases in the United States and Europe. We report a case of Bartonella henselae IE presenting as rapidly progressive glomerulonephritis (RPGN) with discordant ANCA serologies.
Case Description
A 60-year-old man without prior kidney disease presented with confusion, hyponatremia, peripheral edema, nephrotic-range proteinuria, and progressive renal failure. Serologic evaluation revealed p-ANCA by immunofluorescence, elevated PR3 antibodies, and Bartonella henselae titers of 1:2560. Blood cultures were negative for organism growth. Kidney biopsy demonstrated crescentic glomerulonephritis with sparse immune-type electron-dense deposits. Transesophageal echocardiography identified vegetations on the mitral and aortic valves. A diagnosis of Bartonella IE–associated glomerulonephritis was made. Antibiotic therapy was initiated; however, due to continued renal decline, hemodialysis and prednisone were started without renal recovery.
Discussion
Infection should be considered in patients with RPGN and discordant ANCA results. IE-associated glomerulonephritis (IE-GN) frequently mimics primary AAV, complicating diagnosis. Up to a third of IE-GN cases demonstrate ANCA positivity, most commonly PR3, likely due to infection-induced polyclonal B-cell activation. While antimicrobials are the mainstay of treatment, immunosuppression may be considered in some cases, though its benefit remains uncertain. This case highlights the importance of recognizing infection-related mimics of AAV to guide therapy and avoid premature immunosuppression.
Fig 1: Renal biopsy showing crescent formation