Perimesencephalic subarachnoid hemorrhage associated with a painless, pupillary-involving third cranial nerve palsy: Case report and literature review

[...]cranial nerve palsy in the setting of PNSH is rare, with only two previous cases documented in the literature [3,4]. [...]though less likely, we cannot exclude the possibility that our patient suffered a radiographically-occult microinfarct to either the midbrain or peripheral portion of the nerve, although this typically results in a pupillary-sparing third cranial nerve palsy. [...]our MR imaging data do not support this hypothesis given the lack of diffusion restriction in the area of the third cranial nerve nucleus in the midbrain (Fig. 3A).