Mitral Valve Endocarditis Due to Whipple Disease: A Rare Cause of Subacute Endocarditis

Background: Whipple disease is a rare chronic infection caused by Tropheryma whipplei, which can manifest as culture-negative infective endocarditis, primarily affecting the aortic valve. Case Summary: A 45-year-old man presented with chronic diarrhea, significant weight loss, and arthralgias, and later developed heart failure with a new mitral systolic murmur. Echocardiography showed a heterogeneous mitral valve mass. Blood cultures were negative. Duodenal biopsy revealed macrophages with positive periodic acid–Schiff stain, confirming Whipple disease. Treatment with doxycycline and hydroxychloroquine led to clinical and echocardiographic improvement. Discussion: T whipplei endocarditis should be considered in culture-negative endocarditis with systemic symptoms. Diagnosis requires histopathology or polymerase chain reaction analysis, and treatment involves prolonged antibiotics and can involve surgery. This case highlights the importance of recognizing this rare etiology for timely management. Take-Home Messages: Whipple disease should be considered in culture-negative endocarditis, particularly with chronic arthralgias or gastrointestinal symptoms. Importantly, T whipplei endocarditis may also occur without classic systemic features.