CASE REPORT | Native Mitral Valve Infective Endocarditis From Flossing: A Case Report and Emergency Department Management

Image of point of care ultrasound mitral valve infection endocarditis contrast cardiography cardiac ultrasound    Online PoCUS Training

CASE REPORT | Native Mitral Valve Infective Endocarditis From Flossing: A Case Report and Emergency Department Management

Source: Bridwell et al. Cureus 2020; 12(12): e12144


Infective endocarditis (IE) is often classified into left (mitral and aortic), right (tricuspid and pulmonic), as well as by the nature of the affected valve (native or prosthetic). The incidence IE is 3-9/100,000, with 40% of these cases affecting the mitral valve. Due to mortality of up to 30%, rapid diagnosis and treatment is important.


A 63-year-old male with a past medical history of mitral regurgitation presented to the emergency department (ED) for three weeks of nightly fevers. The patient denied all potential risk factors for IE. However, Review of systems was otherwise unremarkable, except for vigorous flossing with bloody gingivae. Laboratory evaluation revealed leukocytosis, elevated C-reactive protein and elevated erythrocyte sedimentation rate. The patient was empirically started on intravenous antibiotics. Three separate blood cultures yielded Gram-positive cocci, which speciated to Streptococcus gordonii. Following an unremarkable transthoracic echocardiogram (TTE), a transesophageal echocardiogram (TEE) revealed a small vegetation on the posterior leaflet of the mitral valve.


Infective endocarditis is a rare but critical diagnosis that is challenging to identify due to its various subtle presentations and underlying risk factors. These risk factors traditionally include IV drug use, valvular heart disease, implantable cardiac devices, indwelling lines, unrepaired cardiac abnormalities, recent dental work, or immunocompromised state. While S. aureus is the most common cause of IE overall, native mitral endocarditis secondary to dental etiology is still most commonly caused by S. viridans species.

When evaluating patients for IE, current fever or history of recent fever is the most common presenting symptom. Dental procedures in the six weeks preceding ED presentation increase the risk of native mitral valve IE. While flossing has been associated with a decreased risk of IE, this case demonstrates that in some individuals it may be the culprit of mitral valve IE. Emergency clinicians should consider this diagnosis in patients with high risk features as well as recurrent fevers without an identified source.