上矢状窦血栓形成致蛛网膜下腔出血（ＳＡＨ）临床上较少见，现报告１例如下。患者，男，２９岁。因头痛、呕吐５天入院。曾于４个月前因发热、头痛、呕吐３周，发作性四肢抽搐２天，诊断为“散发性脑炎”，经抗癌剂、激素、脱水剂和抗菌素治疗痊愈。无高血压、高粘血症、动脉 Upper sagittal sinus thrombosis caused by subarachnoid hemorrhage (SAH) clinically rare, a report is as follows. Patient, male, 29 years old. Due to a headache, vomiting 5 days admitted. Had 4 months ago because of fever, headache, vomiting for 3 weeks, episodes of limbs twitch 2 days, diagnosed as “sporadic encephalitis,” the anti-cancer agents, hormones, dehydration agents and antibiotics cured. No high blood pressure, hyperviscosity, arterial