Carotid artery dissection presenting with isolated headache and Horner syndrome after minor head injury.

A woman aged 31 years presented to the emergency department after a minor head injury. She reported mild headache and a metallic taste in her mouth. Full neurologic examination was remarkable only for left-sided Horner syndrome. Left internal carotid artery dissection was confirmed on magnetic resonance imaging. She was treated with aspirin. Symptoms and signs persisted 3 months later, but there was no additional neurologic deficit. We stress the importance of early detection of Horner syndrome to minimize the risk of disabling stroke.