Oculomotor nerve palsy from posterior communicating artery aneurysm.

The mortality rate for posterior communicating artery (PCA) aneurysm with oculomotor nerve palsy is 33 per 100. The incidence of oculomotor palsy with PCA aneurysm varies from 34% to 56%. The classic presentation of a PCA aneurysm involving the oculomotor nerve is sudden onset of severe unilateral frontal headache, ptosis, a dilated and fixed pupil, and limitations of adduction, depression, and elevation of the eye. Carotid arteriography is diagnostic. This case is presented because of the high probability of being seen first by a primary care physician. Delay in clinical recognition and treatment can have dire consequences for the patient.