A 35-year-old man was transferred to our hospital for operative repair of a perforated mitral valve due to presumed bacterial endocarditis. Two weeks prior to admission, he saw his dentist, who discovered significant periodontal disease. On the advice of his dentist, he then established care with a primary care physician to whom he reported polyuria. He was discovered to have an elevated hemoglobin A1C level and diagnosed as having diabetes mellitus. Despite initiating treatment with metformin, he reported worsening polyuria, malaise, and a 10-kg weight loss. He was eventually admitted to a local hospital where he was hypotensive to 84/59 mm Hg and was delirious on triage. Auscultation revealed a previously unknown grade 5/6 harsh late systolic murmur radiating to the axilla. Laboratory analysis was notable for a leukocytosis, acute renal insufficiency, a blood glucose level of 1100 mg/dL (61.05 mmol/L), and ketonuria. Results of a surface echocardiogram followed by a transesophageal echocardiogram (TEE) caused concern for a perforation of the posterior mitral leaflet and severe (4+) mitral regurgitation. Volume resuscitation and broad-spectrum antibiotics were initiated for presumed bacterial endocarditis given the history of recent dental cleaning and poor dentition in the setting of the leukocytosis, newly discovered systolic murmur, and echocardiographic findings