蛛网膜下腔出血 ( SAH) ,常常由脑动脉瘤破裂而引起。其常见并发症有 :再出血、颅内压升高、动脉血管痉挛、脑积水、脑缺血/梗塞、脑水肿、颅内神经麻痹、癫痫、心律失常、低钠血症、血液粘滞度增加及肺水肿。这些并发症均能导致死亡 ,需要对症治疗。再出血　如果病人初次出血 Subarachnoid hemorrhage (SAH), often caused by a ruptured cerebral aneurysm. Common complications include: rebleeding, increased intracranial pressure, arterial spasm, hydrocephalus, cerebral ischemia / infarction, cerebral edema, intracranial nerve palsy, epilepsy, arrhythmia, hyponatremia, blood viscosity Degree increase and pulmonary edema. These complications can lead to death, need symptomatic treatment. Rebleeding If the patient bleeds for the first time