Lesson of the month (1). Homonymous left hemianopia secondary to traumatic extracranial vertebral artery dissection.

This lesson reports the case of a 32-year-old female presenting with left-sided homonymous hemianopia after a road traffic accident. A diagnosis of vertebral artery dissection (VAD) was missed at presentation after an initial computed tomography head scan was normal. Later, VAD was confirmed on neck magnetic resonance imaging. VAD is an uncommon cause of stroke in the young and, to date, there are no current emergency guidelines available for the management of patients with the condition.