From negative echocardiography to cardiac tamponade: A case report of late-onset prosthetic valve endocarditis

Prosthetic valve endocarditis (PVE) occurring decades after valve replacement is rare and diagnostically challenging, particularly when presenting as culture-negative PVE (CN-PVE). We report a 47-year-old man who presented with persistent fever and misleading urinary symptoms 26 years after double mechanical mitral and aortic valve replacement. Initial transthoracic and transesophageal echocardiography were negative despite ongoing clinical suspicion. Repeat transesophageal echocardiography on day 19 revealed a new mitral valve vegetation, followed by subsequent involvement of the aortic valve. Despite escalation to quadruple antimicrobial therapy, the patient developed embolic complications, including an M2 segment ischemic stroke and splenic infarction. The course was further complicated by cardiac tamponade requiring emergent pericardiocentesis. A multidisciplinary team stabilized the patient and managed him as a bridge to urgent surgical intervention, and he was transferred for redo double-valve replacement. This case highlights the persistent risk of infective endocarditis in patients with mechanical valves and the limitations of early imaging in culture negative PVE, emphasizing the need for sustained clinical suspicion and timely surgical intervention.