Aortic Valve Endocarditis in an Intravenous Drug User With Psychiatric History: A Diagnostic Challenge.

Infective endocarditis (IE), a life-threatening cardiac infection, can present atypically, complicating diagnosis. We present a case of a 45-year-old male patient with schizophrenia and intravenous drug use (IVDU) who presented with suicidal ideation. Though afebrile, he exhibited tachycardia, bilateral pedal edema, bronchial breath sounds, and a diastolic murmur. Echocardiography identified an extensive aortic valve vegetation and a reduced ejection fraction. Despite negative resected valve cultures and Gram staining, emergency aortic valve replacement and left atrial appendage clipping were performed, followed by a six-week antibiotic course. This case underscores the diagnostic challenge of afebrile, culture-negative IE, likely due to prior antibiotics or fastidious organisms, particularly in high-risk populations like those with IVDU. Psychiatric presentations may obscure typical IE symptoms, necessitating heightened clinical suspicion and comprehensive evaluation, including echocardiography, even without classic signs like fever or leukocytosis. Timely intervention and individualized diagnostics are critical to improving outcomes in such complex cases.