Culture Negative Infective Endocarditis Presenting as Renal Infarction in a Low-risk Young Woman: A Case Report.

Culture-negative infective endocarditis is difficult to diagnose because it often presents with vague symptoms, delaying recognition and worsening outcomes. Renal infarction is rare but may be the first clue. A previously healthy 32-year-old woman had intermittent fever for six weeks and sudden right-sided flank pain for two days. Examination revealed a holosystolic murmur and right costovertebral angle tenderness. Investigations showed raised inflammatory markers and a positive rheumatoid factor, while repeated blood cultures were negative. Echocardiography showed severe mitral regurgitation without visible vegetations, and computed tomography angiography confirmed right renal infarction. Using modified Duke criteria, the diagnosis was made and empiric intravenous vancomycin and ceftriaxone were started. Despite intensive care and aggressive therapy, she deteriorated and died from refractory heart failure due to severe valvular dysfunction. This case shows the disease can be insidious even in low-risk patients, stressing early suspicion, multidisciplinary care, and timely surgical evaluation when appropriate.