[A child case of subarachnoid hemorrhage triggered by head injury: a case report].

We report a case of basal subarachnoid hemorrhage in a child. The etiology of this lesion was difficult to diagnose. The patient was a 9-year-old boy. He sustained minor head injury followed by loss of consciousness and cardiopulmonary arrest. He was brought to our emergency room by ambulance. On arrival, he presented with cardiopulmonary arrest and deep comatose state. Basal subarachnoid hemorrhage was revealed on CAT scan. 3D-CTA documented two bulging portions: one was at the junction between the left vertebral artery and the left posterior inferior cerebellar artery. The other one was shown at the basilar artery. He died on the 7th hospital day. The autopsy revealed a laceration of the left vertebral artery. Microscopically, the wall around the laceration showed a defect in the internal elastic membrane and a decrease of smooth muscle cells with moderate fibrosis in the tunica media. These findings were compatible with the structure of a congenital aneurysm. Hence, the patient was strongly suspected to have had a congenital aneurysm whose rupture was triggered by minor head injury.