Clinical features of perimesencephalic nonaneurysmal subarachnoid hemorrhage

Objective To investigate the clinical and radiological features, diagnostic criteria, and prognosis of perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSH) . Methods The authors presented a retrospective analysis of 476 patients presenting subarachchnoid hemorrhage (SAH) with whom digital subtraction angiography (DSA) was primarily taken at West China Hospital from January 1998 to December 2002. From the 97 cases with normal angiogram, 17 cases were found that the blood was confined within perimesencephalic cisterns in the reexamined CT within three days after the SAH onset, and diagnosed as PNSH. The cohort included 9 men and 8 women whose median age was 58 years (range from 38 to 72 years). Long term follow up was evaluated by reviewing the outpatient files and dedicated outpatients review. The mean fellow-up period was 44 months (range 10-70 months). Results There was no loss of consciousness and focal neurological deficit in the cohort of the 17 patients. All patients were classified Hunt and Hess Grade I or II at initial examination. During follow-up period none experienced rebleeding, cerebral artery vasopasm and hydrocephalus, and the quality of life in the long term was excellent after symptomatic care. Conclusion Patients with PNSH have even clinical condition, unique radiological features, short-term convalescence and excellent outcome with no happens of re-bleeding and cerebral ischemia. It is important that the correct diagnosis of PNSH to avoid unnecessary surgical exploration and repetition of angiographic examination.