Pontine infarction induced by injury of the perforating branch of the basilar artery after blunt head impact: case report.

A 77-year-old male pedestrian was hit by a car. On admission, he had disturbance of consciousness and left hemiplegia. Computed tomography (CT) indicated only left frontal subcutaneous hematoma and minor hemorrhage in the left frontal lobe, suggesting axonal injury. CT on hospital day 2 revealed a low density area in the right paramedian pons, but CT angiography showed no dissection or occlusion of the vertebrobasilar artery. The diagnosis was pontine infarction resulting from shearing force injury to the paramedian branch of the basilar artery. He was transferred to another hospital for rehabilitation without improvement of symptoms on hospital day 51. Paramedian pontine infarction tends to occur in patients with risk factors for arteriosclerosis, including hypertension, diabetes mellitus, hyperlipidemia, or smoking. The present elderly patient had hypertension and hyperlipidemia, so arteriosclerosis in the paramedian branch may have contributed to his susceptibility to such injury.