Perimesencephalic nonaneurysmal subarachnoid hemorrhage: review of the literature.

OBJECTIVE

A critical review of the literature on the incidence, presentation, diagnosis, and prognosis of perimesencephalic nonaneurysmal subarachnoid hemorrhage.

METHODS

Review of the relevant literature.

CONCLUSION

The importance of early computed tomography (< 3 d), anatomy of the perimesencephalic and neighboring cisterns, and adequate four-vessel angiography are discussed. Treatment strategies, including the avoidance of repeated angiographic studies and surgical exploration, are presented.