Recurrent Perimesencephalic Nonaneurysmal Subarachnoid Hemorrhage: Case Report and Review of the Literature.

BACKGROUND: Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSAH) is a benign form of subarachnoid hemorrhage (SAH) with a favorable prognosis. The risk of recurrent hemorrhage of this benign entity is extremely low.

CASE DESCRIPTION: We describe a rare case of recurrent, spontaneous PNSAH in a 56-year-old man. This hypertensive patient suffered a recurrent episode of PNSAH 1 month after its first ictus, suggesting rebleeding can still occur in the setting of PNSAH; however, the risk is much less than that in aneurysmal SAH. No source of the hemorrhage was identified in the imaging examinations, even with the performance of a 6-vessel angiography.

CONCLUSIONS: Despite the PNSAH owning benign clinical manifestations and a favorable outcome, this distinct case of recurrent PNSAH demonstrated that the risk of recurrent hemorrhage of PNSAH does exist, although it is rather low. A conservative approach with close follow-up is still warranted for PNSAH patients.