Pituitary Apoplexy

Pituitary apoplexy is an acute neuro-endocrine emergency caused by haemorrhage or infarction of a pituitary adenoma. The sella turcica is a rigid bony compartment, so sudden bleeding or swelling can rapidly compress nearby structures rather than expanding harmlessly. Compression of the optic chiasm can produce reduced visual acuity or a visual-field defect, classically a bitemporal hemianopia. Lateral extension into the cavernous sinus can affect cranial nerves III, IV, and VI, causing diplopia, ophthalmoplegia, ptosis, or an abnormal pupil response. Damage to the remaining pituitary gland can cause abrupt loss of several anterior pituitary hormones. ACTH deficiency is the most immediately dangerous deficit. Without adequate cortisol, vascular tone and the stress response fail; hypotension, hypoglycaemia, hyponatraemia, altered consciousness, and cardiovascular collapse can follow. The patient may therefore be deteriorating from secondary adrenal insufficiency even while the neurological diagnosis is still being confirmed.