A Rare Case of Eustachian Valve Endocarditis in a Young Male With Poorly Controlled Type 1 Diabetes Mellitus

The eustachian valve (EV) is a vestigial structure found at the junction of the inferior vena cava and the right atrium, a remnant of the embryological sinus venosus that may persist throughout life. Right-sided infective endocarditis of the eustachian valve remains a distinctly rare and under-diagnosed entity. Commonly known risk factors of eustachian valve endocarditis (EVE) are intravenous drug use, in-dwelling intracardiac devices, and central lines, although more recently immunocompromised states, e.g. uncontrolled diabetes mellitus and old age, have been recognized as risk factors for the disease. Although Staphylococcus aureus has been the most commonly implicated organism, cases of infections with gram-negative organisms are emerging. We present a 47-year-old male with uncontrolled type 1 DM who initially presented to the ED with complaints of low back pain and dysuria and was later found to have eustachian valve endocarditis ultimately treated with intravenous antibiotics.