Acromegaly
• Excess growth hormone (GH) → ↑ IGF-1
• Features: large hands/feet, coarse facial features, prognathism (large jaw), sweating, visual field defects
(bitemporal hemianopia), glucose intolerance/diabetes
• Diagnosis:
o Screening: ↑ IGF-1
o Confirmatory: oral glucose tolerance test – GH fails to suppress
o Pituitary MRI to localise adenoma
• Treatment:
o First-line: trans-sphenoidal surgery
o Alternatives: somatostatin analogues (octreotide), GH receptor antagonists (pegvisomant), radiotherapy
Prolactinoma
• Most common functioning pituitary tumour
• Features: galactorrhoea, amenorrhoea, infertility, low libido, visual field defects (if large)
• Diagnosis:
o ↑ serum prolactin (rule out pregnancy, hypothyroidism, drugs)
o Pituitary MRI
• Treatment:
o First-line: dopamine agonists – cabergoline > bromocriptine
o Surgery if medical therapy fails or compressive symptoms
Hypopituitarism
• Deficiency of one or more pituitary hormones
• Features: fatigue, loss of libido, amenorrhoea, cold intolerance, hypotension
• Labs: ↓ cortisol, ↓ TSH/FT4, ↓ LH/FSH, ↓ GH/IGF-1
• Causes: pituitary tumours, apoplexy, Sheehan’s, trauma, irradiation
• Treatment:
o Replace hormones in correct order: hydrocortisone first, then thyroxine ± sex steroids/GH
Diabetes Insipidus (Cranial)
• ADH deficiency → inability to concentrate urine
• Features: polyuria, polydipsia, nocturia
• Diagnosis:
o Water deprivation test: no urine concentration
o Responds to desmopressin (confirms cranial DI)
• Causes: idiopathic, neurosurgery, trauma, tumours
• Treatment: desmopressin (DDAVP)
Pituitary Apoplexy
• Sudden haemorrhage/infarction of pituitary (often into adenoma)
• Features: sudden headache, visual loss, ophthalmoplegia, shock
• Emergency: MRI brain, immediate IV hydrocortisone, supportive care ± surgery
Non-Functioning Pituitary Adenoma
• Most common type of pituitary adenoma
• No hormone excess
• Features: mass effect – headache, bitemporal hemianopia, hypopituitarism
• Diagnosis: MRI + full pituitary hormone panel
• Treatment: trans-sphenoidal resection ± radiotherapy
Cushing’s Disease (Pituitary ACTH Excess)
• ACTH-secreting pituitary adenoma → ↑ cortisol
• Features: central obesity, moon face, purple striae, proximal weakness, hypertension
• Diagnosis:
o 1 mg dexamethasone suppression test: no suppression
o Confirm with high-dose dexamethasone or CRH test
o MRI pituitary
• Treatment: trans-sphenoidal resection ± ketoconazole/metyrapone
Empty Sella Syndrome
• Herniation of subarachnoid space into sella → compressed/flattened pituitary
• Primary: idiopathic (often incidental)
• Secondary: post-surgery/radiation
• May cause hypopituitarism or be asymptomatic
Sheehan’s Syndrome
• Postpartum pituitary infarction due to massive blood loss/hypotension
• Features: failure to lactate, amenorrhoea, fatigue
• May progress to full hypopituitarism
• Requires lifelong hormone replacement
Kallmann Syndrome
• Congenital GnRH deficiency + anosmia
• Features: delayed puberty, infertility, hypogonadotropic hypogonadism
• Often associated with midline defects (cleft lip/palate)
• More common in males
Investigation Principles
• Visual field testing – essential in macroadenomas
• Hormone panels – test all axes: cortisol, TSH/FT4, LH/FSH, prolactin, IGF-1
• MRI pituitary – gold standard for structural lesions
• Dynamic testing – suppression/stimulation tests where needed (e.g. OGTT for GH, dexamethasone for ACTH)
Treatment Principles
• Trans-sphenoidal surgery – first-line for macroadenomas
• Medical therapy – somatostatin analogues (acromegaly), dopamine agonists (prolactinoma),
steroidogenesis blockers (Cushing’s)
• Hormone replacement – replace cortisol before thyroxine in hypopituitarism
• Long-term follow-up: regular TFTs, cortisol, IGF-1, visual fields, MRI
