蛛网膜下隙出血（SAH）系指脑底部或脑表面的血管破裂，血液直接流入蛛网膜下隙，即原发性SAN，约占全部脑卒中病人的5％～10％。先天性颅内动脉瘤和动-静脉血管畸形是SAH的主要原因（60％）。脑底异常血管网症，中毒、血液病和药源性因素等所致的SAN者亦不少见。大约20％的SAH Subarachnoid hemorrhage (SAH) refers to the rupture of blood vessels in the bottom of the brain or on the surface of the brain. The blood flows directly into the subarachnoid space, which is the primary SAN, accounting for about 5% to 10% of all stroke patients. Congenital intracranial aneurysms and arteriovenous malformations are the major causes of SAH (60%). Brain abnormalities at the end of the brain network, poisoning, blood diseases and drug-induced SAN factors are not uncommon. About 20% of SAH