Unilateral oculomotor nerve paresis associated with anterior communicating artery aneurysm rupture--two case reports.

Two cases of complete unilateral oculomotor nerve palsy occurred after subarachnoid hemorrhage (SAH) due to a ruptured anterior communicating artery aneurysm. A 61-year-old female suffered left oculomotor nerve paresis after mild SAH. This paresis was probably related to pre-existing oculomotor nerve stretching caused by abnormal positioning of the posterior cerebral and superior cerebellar arteries in the premesencephalic cistern. A 70-year-old female suffered right oculomotor nerve paresis after severe SAH. Elevated intracranial pressure might have caused this paresis, but the reason for the unilateral occurrence was undetermined. Both patients were treated by clipping of the aneurysm, and the signs of oculomotor nerve paresis gradually resolved. A pattern of pupil-sparing paresis was observed during the early recovery stage in both patients.