Acromegaly

Question 1

What are the common causes of acromegaly?

Answer 1

GH-secreting pituitary adenoma

Ectopic GHRH/GH production from pancreatic or lung tumour

Question 2

What presentations would indicate that the tumour was macroscopic and space-occupying?

Answer 2

Headaches
Bitemporal hemianopia (tunnel vision)
-due to compression of optic chiasm by tumour

Question 3

What classical “over-growth” features might someone with acromegaly present with? What is the best way to identify these changes in patients?

Answer 3

Prominent forehead and brow (frontal bossing)
Large nose
Macroglossia 
Large hands and feet 
Prognathism (protruding jaw)
Arthritis= imbalanced growth of joints 

Look at historic photos of patient and compare now to see how the changes have developed over time

Question 4

What other conditions are people with acromegaly at increased risk of developing?

Answer 4

Hypertension
Type 2 diabetes
Colorectal cancer

Question 5

How is suspected acromegaly investigated? Why can’t you measure GH directly?

Answer 5

Insulin-like growth factor (IGF-1)= raised

OGTT (oral glucose tolerance test)
-Glucose normally suppresses GH so raised GH after OGTT indicates exogenous source of GH

MRI of brain

Visual field test

GH levels fluctuate so would not be reliable

Question 6

What are the main forms of treatment for acromegaly?

Answer 6

Trans-sphenoidal removal of pituitary adenoma

Medical:

• pegvisomant= GH antagonist
• somatostatin analogues= block GH release i.e. ocreotide
• dopamine agonists= block GH release