Acromegaly

Very rare Prevalence in the order of 1 in 200,000 Usually diagnosed between age 40 and 60 No difference in gender susceptibility Insidious onset

Pathogenesis Most commonly caused by pituitary adenoma  Increased secretion of growth hormone  Acts in liver to release IGF-1 (insulin-like growth factor)

So what are the symptoms? Tumour Growth hormone IGF-1

On examination Characteristic facial appearance: Coarse, Frontal bossing, ↑ sinuses, ↑ tongue, Prognathism (jaw protrusion), separation of teeth Deep voice Carpal tunnel syndrome Hand & foot enlargement Visual fields (bitemporal hemianopia) Organomegaly: Goitre, Hepatosplenomegaly

Investigations Glucose tolerance test with measurement of growth hormone level.  (Should be inhibited by glucose)  (Growth hormone secretion is episodic and so a random GH alone is unlikely to be useful) Evidence of other pituitary involvement MRI scan to identify adenoma

Management Surgery: trans-sphenoidal adenomectomy or craniotomy for very large tumours. Pituitary radiotherapy: useful if tumour is not fully removed and reduces GH progressively over years. Drugs:  Somatostatin analogues (octreotide, lanreotide) suppress GH in 60%  Dopamine agonists (bromocriptine, cabergoline) lower but rarely normalize GH  GH receptor antagonist (pegvisomant) normalizes IGF-I in >90% of pts.

Bonus marks management Management of: ↑ Cardiovascular morbidity & mortality – from HTN, impaired GTT (25%), Diabetes Mellitus (10%) ↑ Cardiac failure (heart muscle disease), ↑ IHD, ↑ CVD Obstructive sleep apnoea Arthropathy (50%) Osteoporosis Colorectal cancer Complication of treatment: hypopituitarism