Sepsis in the Structurally-Vulnerable Heart: A Case of Infective Endocarditis Masquerading as a Urinary Tract Infection in Pediatric Rheumatic Heart Disease.

We present a case of a six-year-old female patient with a history of rheumatic heart disease (RHD), including mitral stenosis, mitral regurgitation, and pulmonary hypertension, who presented with fever, abdominal pain, and urinary findings. Although urinalysis and imaging confirmed bilateral pyelonephritis, the admitting provider noted concerning physical exam findings, including Janeway lesions and systemic features that raised suspicion for concurrent infective endocarditis (IE). In the context of her underlying valvular disease, these exam clues broadened the differential beyond a presumed urinary source and prompted an endocarditis-focused evaluation. This case underscores the enduring value of a careful physical examination, the need to maintain a wide diagnostic lens, and the importance of tailoring sepsis management for pediatric patients with complex cardiac comorbidities.