Culture-Negative Transcatheter Pulmonary Valve Endocarditis.

CLINICAL CONDITION: We present a case of transcatheter pulmonary valve endocarditis in a 38-year-old woman with a history of atrial septal defect, pulmonary stenosis, and bicuspid aortic valve, all previously repaired with mechanical and bioprosthetic valve replacements. Despite negative initial studies, 18F-fluorodeoxyglucose positron emission tomography-computed tomography revealed septic pulmonary emboli and abnormal uptake at the pulmonary valve. Metagenomic sequencing identified Haemophilus parainfluenzae as the pathogen. KEY QUESTIONS: What is the differential diagnosis of a cardiac mass in this context? How should imaging and laboratory testing be approached in prosthetic valve endocarditis with negative studies? What surgical factors matter in patients with prior cardiac repairs? OUTCOME: The patient underwent successful replacement of the pulmonary and aortic valves and completed a course of antibiotics, with full recovery. TAKE-HOME MESSAGE: Consider bioprosthetic valve endocarditis in patients with persistent fevers and negative cultures. Use advanced diagnostics early when the clinical suspicion is high.