2026 FSA Podium and Poster Abstracts

Introduction/Background: Infective endocarditis is a serious condition associated with significant morbidity and mortality, particularly in older adults and patients with underlying structural heart disease. Members of the Streptococcus anginosus group are commensal organisms of the oral cavity, gastrointestinal tract, and genitourinary tract but have been implicated in invasive infections including bacteriemia and endocarditis. Hypertrophic obstructive cardiomyopathy (HOCM) presents unique hemodynamic challenges and may complicate the clinical course of infective endocarditis. This case describes Streptococcus anginosus infective endocarditis with a large mitral valve vegetation in a patient with HOCM following a recent dental procedure, emphasizing the importance of advanced imaging and multidisciplinary management. 

Methods: This case report describes a 74-year-old female with a medical history significant for insulin-dependent type 2 diabetes mellitus, hypertrophic obstructive cardiomyopathy, hypertension, and obesity who presented with three weeks of progressive shortness of breath and several days of non-bloody diarrhea. Diagnostic evaluation included laboratory studies, blood cultures, chest radiography, electrocardiography, and echocardiography. Blood cultures were obtained from two separate sites. Transthoracic echocardiography was initially performed, followed by transesophageal echocardiography due to persistent concern for a cardiac source of bacteremia. Additional imaging and specialty consultations were pursed based on clinical findings. 

Results: Initial laboratory evaluation demonstrated leukocytosis with neutrophil predominance, elevated inflammatory markers, and markedly elevated brain natriuretic peptide. Blood cultures grew gram-positive cocci identified as Streptococcus anginosus. Chest radiography revealed cardiomegaly without acute pulmonary pathology. Transthoracic echocardiography did not identify valvular abnormalities; however, subsequent transesophageal echocardiography demonstrated a 1.5x1.5 cm vegetation on the mitral valve. Due to the size of the vegetation and risk of embolization, the patient was transferred to a tertiary care center for surgical evaluation. Brain MRI imaging demonstrated multiple small ischemic lesions consistent with an embolic process. The patient underwent minimally invasive mitral valve replacement with concomitant septal myectomy. Intravenous ceftriaxone therapy was continued for a planned six-week course. 

Discussion/Conclusion: This case highlights the potential for Streptococcus anginosus to cause clinically significant infective endocarditis, even following minor dental procedures. It underscores the limitations of transthoracic echocardiography in detecting valvular vegetations and supports the use of transesophageal echocardiography in patients with bacteremia and underlying structural heart disease. Management of infective endocarditis in patients with HOCM requires careful attention to preload dependence and multidisciplinary coordination among internal medicine, cardiology, infectious disease, and cardiothoracic surgery teams. Early recognition and comprehensive imaging are critical to reducing complications such as embolic stroke and guiding timely surgical intervention. 

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