Acromegaly

Question 1

Definition of acromegaly and gigantism?

Answer 1

Acromegaly - hypersecretion of growth hormone in adults

Gigantism - hypersecretion of growth hormone in children

Question 2

What is acromegaly usually caused by?

Answer 2

GH-secreting adenoma in the pituitary

Question 3

Pathophysiology of acromegaly?

Answer 3

Excess GH stimulates the release of IGF-1

- this results in growth of bones and soft tissue

Question 4

Presentation of acromegaly?

Answer 4

- signs of soft tissue growth
Coarse facial features (particularly protruding jaw)
Sleep apnoea
Weight gain
Headaches/visual disturbance
Carpal tunnel syndrome (transverse ligament growth)
Hypertension
Insulin resistance
Sweating
Rings/shoes become tight

Question 5

Investigations in acromegaly?

Answer 5

Screening - serum IGF-1
Diagnostic - OGTT
MRI brain (visualise pituitary tumour)

Question 6

How do acromegalics respond to OGTT?

Answer 6

Fail to suppress GH after 75g glucose load

GH doesn’t drop below 1 ng/mL

Question 7

Management of acromegaly?

Answer 7

1st line - transphenoidal hypophysectomy

2nd line - somatostatin analogue (ocreotide)

Question 8

Why is growth hormone itself an inappropriate investigation in acromegaly?

Answer 8

Release is pulsatile

Release is affected by numerous factors such as sleep, stress, age, etc