Headache in the emergency department: importance of history in identifying secondary etiologies.

Headache is a common emergency department complaint and has a broad differential diagnosis. Most commonly the headache is without serious underlying cause, but occasionally can be the manifestation of a more catastrophic illness. History may be the most important aspect in the evaluation of headache patients and careful attention to historical clues or atypical symptoms may point to a diagnosis. We present a patient with a first-time headache, which was ultimately found to be secondary to a carotid cavernous fistula. Historical features that require a more aggressive work-up of headache are discussed.