Thyrotoxicosis: an unusual cause of syncope.

Syncope is a common emergency department (ED) chief complaint, with many known but also unknown causes. Here we present a novel ED presentation of a young woman with new-onset hyperthyroidism that masqueraded as a syncopal event with head trauma. A 21-year-old woman arrived in the ED with head trauma as the result of seemingly unprovoked syncope, due to her history as well as the nature of her trauma. Persistent tachycardia during her ED course after an unremarkable full trauma evaluation prompted ordering of additional lab testing, which revealed evidence of thyrotoxicosis. Here we consider the possibility of thyroid dysfunction resulting in syncope.