Encephalopathy, chiasmal compression, ophthalmoplegia, and diabetes insipidus in pituitary apoplexy

Pituitary apoplexy with haemorrhage is a potentially life-threatening condition, and a rare cause of third nerve palsies. The range of vision loss and ophthalmoplegia seen in cases of apoplexy reflects the variability of cranial structures compressed by mass effect. The pathophysiology of extraocular muscle limitation and facial paraesthesia occurs with compression of the cavernous sinus, which contains cranial nerves III, IV, VI, and the ophthalmic branch of V. Blood supply to adjacent structures may be also compromised, causing additional loss of function. This case report of a patient with diabetes insipidus and a third nerve palsy illustrates the anatomic basis of the presenting signs of pituitary apoplexy, and the necessity for prompt neuroimaging if it is suspected.