Clinical characteristics of perimesencephalic nonaneurysmal subarachnoid hemorrhage

Objective To review the experience in diagnosis and treatment of perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSH). Methods The clinical data, imaging features, treatments and prognosis of 22 PNSH patients were retrospectively investigated. Results All the patients were examined by four-vessel angiography, and as a result, no detectable aneurysm was found. All patients with PNSH were not companied with loss of consciousness or focus neurological deficits. Their symptoms were mild without consciousness disturbance and focal neurological deficits and were classified into Hunt-Hess Grade Ⅰ-Ⅱ. In the long follow-up (9 to 98 months), no patient experienced subsequent bleeding or showed permanent neurological disturbances. Except that one patient suffered from depression disorder and could not work, other patients all returned to their previous occupation. Conclusion PNSH is a special subarachnoid hemorrhage with a benign clinical course and good prognosis. Further understanding of PNSH is absolutely important to direct the clinical affairs.