[Case of occlusion of vertebrobasilar artery after subarachnoid hemorrhage due to rupture of posterior inferior cerebellar artery aneurysm].

An autopsied case of ruptured saccular aneurysm at the junction of posterior inferior cerebellar artery and vertebral artery with which the aneurysm and basilar artery were occluded was reported. A 20-year-old female was admitted to our hospital because of consciousness disturbance and convulsion. CT scan revealed subarachnoid hemorrhage. Four vessel angiography did not show any aneurysms nor arteriovenous malformations but revealed occlusion of vertebrobasilar artery. Continuous ventricle drainage was performed but she died 5 days after the onset. On autopsy, a ruptured saccular aneurysm at the junction of right vertebral and posterior inferior cerebellar arteries, and occlusion with thrombosis of vertebrobasilar artery were found. We discussed how the aneurysm and main arteries were embolized just after the attack of subarachnoid hemorrhage. It is considered that the severe increased intracranial pressure in posterior fossa after subarachnoid hemorrhage and decreased blood pressure caused hemostasis of ruptured aneurysm while spreading the thrombosis in main trunks of vertebrobasilar artery.