Acromegaly

Question 1

What is acromegaly?

Answer 1

Endocrine disorder which occurs when too much growth hormone is produced, commonly caused by a pituitary adenoma

Question 2

Symptoms of acromegaly?

Answer 2

Fatigue
Headaches
Blurred vision
Arthralgia

Question 3

Signs of acromegaly?

Answer 3

Large hands/feet
Large, prominent facial features
Prognathism
Carpel tunnel syndrome
Thick, coarse skin
Bitemporal hemianopia

Question 4

Investigations for acromegaly?

Answer 4

Serum IGF-1 levels
(GH levels vary too much throughout the day)
Oral glucose tolerance test (OGTT)

Question 5

How does OGTT work?

Answer 5

1. Start of test – measure glucose + GH level
2. Give 75mg glucose
3. Re-check glucose + GH over next 30, 60, 90 and 120 mins.

Results:
In normal patients GH is suppressed to < 2 mu/L with hyperglycaemia
In acromegaly there is no suppression of GH

Question 6

Management of acromegaly?

Answer 6

1. Surgery = trans-sphenoidal resection, post-op radiotherapy
2. Medical: somatostatin analogues e.g. octreotide
3. GH antagonist e.g. pegvisomont

Question 7

How does acromegaly cause bitemporal hemianopia?

Answer 7

If a pituitary adenoma is large enough, it may press on the optic chiasm leading to the visual defect.