GRANULOMATOSIS WITH POLYANGIITIS AND SUSPECTED CONCOMITANT INFECTIVE ENDOCARDITIS: A CASE-BASED REVIEW

Abstract

The coexistence of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and infective endocarditis (IE) represents a diagnostic challenge because of substantial overlap in clinical, serological, and cardiac manifestations. We report the case of a patient with prolonged ear, nose, and throat manifestations, pulmonary nodules and cavitary lesions, markedly elevated PR3-ANCA, and small lesions adjacent to the aortic valve initially considered suspicious for infective vegetations. Despite repeatedly negative blood cultures, culture-negative IE remained an important diagnostic consideration, and antimicrobial therapy was continued. The patient subsequently developed rapidly progressive pulmonary disease and severe systemic inflammation despite broad-spectrum antimicrobial treatment. The combination of characteristic upper respiratory tract disease, pulmonary involvement, markedly elevated PR3-ANCA, and a marked clinical and radiological response to immunosuppressive therapy supported the diagnosis of granulomatosis with polyangiitis (GPA). Glucocorticoids and plasma exchange were initiated, followed by rituximab for remission induction. Conservative cardiac management with regular follow-up was chosen. This case highlights the diagnostic challenge of distinguishing PR3-ANCA-positive IE from AAV and the importance of integrating microbiological, imaging, and clinical findings to establish the diagnosis.