Pituitary apoplexy

Overview

Acute haemorrhage or infarction within a pituitary adenoma causing sudden expansion in the rigid sella - a rare but life-threatening endocrine emergency.

Presentation

•Sudden severe headache - thunderclap onset, retro-orbital or frontal; close mimic of subarachnoid haemorrhage (SAH)

•Vomiting - raised intracranial pressure

•Neck stiffness - meningism from subarachnoid extension of blood

•Visual field defects - classically bitemporal (superior quadrantic or hemianopia) from chiasmal compression

•Ophthalmoplegia - CN III palsy most common (ptosis, diplopia) from cavernous sinus compression

•Hypotension + tachycardia - adrenal crisis from acute ACTH deficiency; haemodynamically unstable patient is the emergency

Pituitary apoplexy vs subarachnoid haemorrhage

Feature	Pituitary apoplexy	SAH
Headache	Thunderclap	Thunderclap
Visual fields	Bitemporal defect	Usually normal
Ophthalmoplegia	Present (CN III most common)	Absent
Haemodynamic instability	Yes - adrenal crisis	No endocrine collapse
CT findings	Hyperdensity in sellar region	Subarachnoid blood

Investigations

🥇 First-line

•CT head (non-contrast) - fast, confirms haemorrhage (hyperdensity in sellar region); do NOT delay treatment to await imaging

🏆 Gold standard

•MRI pituitary - superior characterisation of haemorrhage, oedema, suprasellar extension; use once patient stabilised, NOT acutely

•Urgent bloods: serum cortisol (<100 nmol/L strongly suggests adrenal insufficiency), TSH + free T4, prolactin, LH, FSH, IGF-1

•Serum Na, K, glucose - hyponatraemia, hypoglycaemia common

•Formal visual fields - documents baseline; important for surgical decision-making but not an immediate priority

⚠️

MRI is NOT the first investigation in acute pituitary apoplexy - CT is faster and critically does not delay IV hydrocortisone. MRI is the gold standard once stabilised.

Management

•Immediate: IV hydrocortisone 100 mg bolus - the single most important step; life-saving in ACTH-deficient haemodynamically unstable patient

•IV fluids - for haemodynamic resuscitation

•Urgent MRI pituitary + neurosurgical referral once stabilised

•Surgical decompression (transsphenoidal) - definitive treatment; hypopituitarism must be corrected first

🚨

Always start hydrocortisone before levothyroxine - thyroid hormone increases cortisol clearance; initiating thyroxine without glucocorticoid cover in a cortisol-deficient patient can precipitate acute adrenal crisis.

Complications

•Adrenal crisis - most immediately life-threatening; if ACTH deficiency unrecognised and untreated

•Permanent hypopituitarism - majority of survivors require long-term hormone replacement

•Permanent visual field defects - especially if chiasmal compression prolonged before decompression

•Diabetes insipidus - posterior pituitary/stalk involvement; polyuria and polydipsia