Mastication steal: an unusual precipitant of cerebrovascular insufficiency.

An 83-year-old man had episodic dizziness, visual disturbance, and facial and extremity weakness associated with eating. Occlusion of the ipsilateral common carotid artery and stenosis or occlusion of the major collateral sources were demonstrated. We believe this anatomic configuration, combined with increases in demand for external carotid artery blood flow necessitated by the act of chewing, resulted in a vascular steal syndrome. An extended carotid endarterectomy was performed, and there were no additional episodes.