A High-risk Case of Culture-negative Infective Endocarditis with Severe Aortic Regurgitation and Paravalvular Abscess in a 42-Year-Old Male

Infective endocarditis is a potentially life-threatening infection that may cause severe valvular and perivalvular complications, particularly when microbiological confirmation is not obtained. This case report describes a 42-year-old man who presented with progressive dyspnoea for one-month, intermittent fever, and haemoptysis, with New York Heart Association Class III functional limitation. Laboratory evaluation showed a C-reactive protein level of 73.893 mg/L, NT-proBNP of 7870 pg/mL, mild anaemia, and leucocytosis. Blood cultures remained negative after previous empirical antibiotic exposure. Chest radiography showed prominent bronchovascular markings, while high-resolution computed tomography demonstrated ground-glass opacities and patchy consolidation. Transthoracic and transoesophageal echocardiography identified multiple aortic valve vegetations, severe aortic regurgitation, and a paravalvular abscess with impending rupture. Empirical antimicrobial treatment was initiated with ceftriaxone and gentamicin, with vancomycin subsequently added; gentamicin was later discontinued. Supportive management included intravenous diuretics, ivabradine, oxygen supplementation, continuous positive airway pressure, electrolyte correction, and close clinical monitoring. Management was coordinated by cardiology and infectious disease specialists. Despite the severity of the structural cardiac findings, the patient demonstrated gradual clinical improvement with medical therapy, and surgery was not performed. The case highlights the diagnostic and management complexity of culture-negative infective endocarditis and the importance of timely echocardiographic assessment, appropriate empirical treatment, supportive care, and multidisciplinary evaluation.