Pituitary apoplexy: A rare cause of acute isolated third nerve palsy

Abstract

Isolated third cranial nerve palsies are most commonly due to microvascular ischemia in adults with atherosclerotic risk factors. Though rare, pituitary apoplexy causing ocular mononeuropathies must be recognized for prompt medical and surgical management. We highlight, with images, a 55-year old man with poorly controlled diabetes, who presents with a 3-day history of diplopia, right eye pain and ptosis. On examination, he had a third cranial nerve palsy, with a dilated pupil. Magnetic resonance imaging showed an enhancing mass in the sellar region extending laterally into the right cavernous sinus with a radiological suggestion of blood in the right cavernous sinus. Magnetic resonance angiogram showed no aneurysm, and there was no evidence of infection or hemorrhage on lumbar puncture. Hormonal testing revealed mild cortisol deficiency, but was otherwise unremarkable. Our patient was diagnosed with pituitary apoplexy. He initially elected for conservative management and was started on hydrocortisone replacement. Repeated neuroimaging 3 months’ later for non-resolving symptoms showed a persistent right sellar lesion. Endonasal endoscopic transphenoidal resection of the pituitary mass was then performed, resulting in gradual improvement in his third nerve palsy. Histology showed fibrous tissue with hemosiderin deposition, with no evidence of infection or malignancy. Our case highlights the importance of recognizing pituitary apoplexy as a rare cause of isolated third nerve palsy, even in patients with atherosclerotic risk factors. Surgical management can be considered to aid resolution of neurological complications.