Abstract 10249: Infective Endocarditis: A Diagnostic Challenge

Abstract

Case: A healthy 30-year-old female with past medical history of eczema and no prior cardiac history presented with altered mental status, fever, neck stiffness and photophobia. Blood and CSF cultures grew methicillin susceptible Staphylococcus aureus , and the patient was started on nafcillin and linezolid. Bacteremia source was unclear, presumed to be minor skin breaks on her hands. MRI brain revealed multiple cerebral septic emboli, prompting concern for infective endocarditis. However, TTE and TEE were negative for vegetations, valve thickening, and valvular regurgitation. Blood cultures remained positive for MSSA despite dual antibiotic therapy and by hospital day 4, she began experiencing shortness of breath and new Janeway lesions were noted on exam. Repeat TTE and TEE were also negative for endocarditis. To further evaluate for an arterial source of seeding, CTA chest/abdomen was obtained which was unremarkable. Given persistence of bacteremia despite dual antibiotic therapy and unknown left-sided source, whole body PET CT scan was obtained which showed focal FDG uptake in the mitral annulus/valve region. Repeat TEE the following day showed a mitral valve ring abscess, a 1.2x0.4cm vegetation involving the P3 segment of the mitral valve, perforation at the mitral valve annulus, and new moderate mitral regurgitation. After a risk benefit discussion, the patient opted for conservative management with serial monitoring over surgical repair. She was treated with six weeks of nafcillin and four weeks of linezolid. Most recent TEE showed resolution of valvular abscess and vegetation with continued moderate mitral regurgitation. Discussion: We present a case of high grade MSSA endocarditis in a young, healthy patient without pre-existing valvular disease, causing mitral valve perforation. Infective endocarditis remains a challenging diagnosis, and this case highlights the diagnostic utility of FDG PET CT scan in such complex cases.