BACKGROUND: Immediate evaluation, diagnosis, and treatment of a patient with infective endocarditis, an infection of the endocardium and/or integral structures found within the heart, is essential to patient survival.

CASE REPORT: We present the case of a 41-year-old man who was brought to the Emergency Department for altered mental status and fever. He was found to have methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia complicated with severe respiratory failure and metabolic encephalopathy, necessitating intubation and mechanical ventilation. As part of the workup for persistent Staphylococcal bacteremia, 2 transthoracic echocardiograms (TTE) failed to reveal any valvular abnormalities. However, a transesophageal echocardiogram (TEE) detected a 30×30 mm large vegetation on the anterior mitral valve leaflet. Due to the overall size and risk of systemic embolization, and the fact that the patient developed new-onset heart failure, the mitral valve was replaced using an open approach. The patient tolerated the procedure well and was discharged after an extended period of hospitalization.

CONCLUSIONS: Although the literature emphasizes that the sensitivity of TTE significantly increases when the vegetation size is above 1 cm, it is of utmost importance for clinicians to keep in mind that this is not always true, and clinicians should consider performing a TEE to rule out infective endocarditis whenever a TTE is unable to detect any vegetation in a patient with persistent Staphylococcal bacteremia. This is clearly demonstrated by the present case, in which two TTEs failed to detect a 30×30 mm vegetation.

Keywords: Echocardiography, Echocardiography, Transesophageal, Endocarditis, Bacterial