Introduction: Culture-negative endocarditis (CNE) remains a diagnostic and therapeutic challenge. Bartonella henselae is a rare but important cause of CNE, often presenting with systemic embolization and neurologic symptoms, and frequently requiring serologic testing for diagnosis in the absence of positive blood or valve cultures. Description: A 55-year-old man with a history of diabetes, hypertension, and depression was brought to the hospital after being found confused and immobile in a hotel room. On presentation, he was encephalopathic with significant lower extremity weakness. Imaging revealed multiple splenic infarcts, and MRI of the brain showed scattered supra- and infratentorial embolic infarcts. Transesophageal echocardiogram revealed a large vegetation on the anterior mitral leaflet and a smaller, more mobile one on the posterior leaflet, with associated severe mitral regurgitation. Multiple blood cultures and subsequent mitral valve tissue cultures were negative. He was initially started on empiric ceftriaxone and vancomycin for suspected CNE. Further infectious workup returned a positive Bartonella henselae IgG titer, prompting transition to doxycycline and rifampin. His encephalopathy, renal function, and inflammatory markers gradually improved with therapy, and Bartonella titers trended negative. He eventually underwent mitral valve replacement; valve tissue cultures remained negative. His post-operative course was complicated by atrial flutter with 2:1 AV block, necessitating permanent pacemaker placement. Despite a prolonged hospitalization, the patient showed steady neurologic improvement and was discharged to rehabilitation in stable condition. Discussion: This case highlights the importance of considering Bartonella in patients with systemic emboli and culture-negative vegetations. Diagnosis required high clinical suspicion and appropriate serologic testing, as blood and tissue cultures remained sterile. The embolic burden and multisystem involvement reflect the potential severity of Bartonella-associated endocarditis and the importance of early recognition. Bartonella henselae is a rare but serious cause of CNE. In patients with systemic emboli and negative cultures, early serologic testing and empiric therapy are key to preventing irreversible complications.
Mundluru et al. (Sun,) studied this question.