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