Carotid artery dissection: a challenging diagnosis.

Spontaneous extracranial internal carotid artery dissection (ICAD) is a rare vascular event. Even in the presence of existing signs and symptoms, the diagnosis can be missed by experienced clinicians of all specialties. This is a report of a patient who presented with symptomatic bilateral dissection manifested as partial Horner's syndrome. The diagnosis was made after several clinical evaluations with the use of duplex ultrasound and angiography.