Acromegaly

Question 1

what is acromegaly

Answer 1

• excessive growth hormone release from ant. pit.

- GH –> IGF from liver, causing symptoms

Question 2

when is gigantism caused

Answer 2

when excess GH prod prior to end of puberty (before epiphyseal plate fusion) causing linear increased growth

Question 3

describe presentation of Px w/ acromegaly

Answer 3

• large nose, tongue, hands, feet
• arthritis, carpal tunnel syndrome
• frontal bossing
• large protruding jaw
• headache
• lower pitch voice
• bitemporal hemianopia (if compression by adenoma)

Question 4

give some causes of acromegaly

Answer 4

• pituitary adenoma

- GHRH prod from bronchial carcinoid

Question 5

what is most common cause of acromegaly

Answer 5

pituitary adenoma

Question 6

what investigations can be done in suspected acromegaly

Answer 6

• IGF-1 screening test; correlates w/ GH level
• oral glucose tolerance test
• MRI to visualise tumour

Question 7

what its IGF-1

Answer 7

insulin-like growth factor 1; growth factor produced by liver in response to GH release

Question 8

give some complications of acromegaly

Answer 8

• increased CVD risk
• hypertension
• diabetes mellitus
• increased risk of colon cancer
• erectile dysfunction

Question 9

why is oral glucose tolerance test used as an investigation of acromegaly

Answer 9

• normally GH levels are surpassed by glucose load

- in acromegaly, glucose fails to suppress excessive GH

Question 10

why is serum GH level not measured as investigation of acromegaly

Answer 10

GH levels by themselves vary throughout the day so unreliable in making diagnosis

Question 11

outline management of acromegaly

Answer 11

medical:
- somatostatin analogues (GH inhibitors) e.g. octreotide
- dopamine agonist (inhibitory effect) e.g. cabergoline
- GH receptor antagonist e.g. pegvisomant

surgical:
- trans-sphenoidal surgical resection of adenoma