Pupillary sparing and aberrant regeneration in chronic third nerve palsy secondary to a posterior communicating artery aneurysm

We present an unusual case of a chronic pupil-sparing third nerve palsy due to a posterior communicating artery aneurysm with aberrant regeneration of the right upper eyelid and worsening symptoms after minor head trauma. A 53-year-old woman presented with a chronic pupil-sparing third nerve palsy due to a posterior communicating artery aneurysm with aberrant regeneration of her right upper eyelid. Three months prior to presentation, the patient experienced worsening of her symptoms after minor head trauma. Most patients with pupil-sparing third nerve palsies progress to pupil involvement; however, our patient never exhibited efferent pupillary dysfunction. A 53-year-old woman with a medical history of a remote transient ischaemic attack and myocardial infarction presented for evaluation of worsening headaches and double vision after a box fell and hit the back of her head 3 months prior to presentation. On further questioning, the right-sided headaches and intermittent horizontal binocular diplopia started 4 months prior to …