男11例,女8例,55～78岁,活动中发病10例,特点:无1例有剧烈头痛,亦未出现颈强、克氏征等脑膜刺激征,出现意识障碍者多达8例,精神障碍7例,首发症状为癫痫者2例。CT 扫描阳性者15例,4例阴性者凭腰穿见血性脑脊液确诊。指出老年人不明原因的昏迷,嗜睡、突然出现精神症状等均应想到蛛网膜下腔出血。不可全靠 CT 诊断。 There were 11 males and 8 females, ranging from 55 to 78 years old. Ten cases were active. Among them, there was no severe headache in one case and no meningeal irritation such as cervical syndrome or Kirschner’s syndrome. Up to 8 cases , 7 cases of mental disorders, the first symptom of epilepsy in 2 cases. CT scan positive in 15 cases, 4 cases of negative by blood see the bloody cerebrospinal fluid confirmed. Pointed out that the elderly unexplained coma, lethargy, sudden mental symptoms should think of subarachnoid hemorrhage. Can not rely on CT diagnosis.