Acromegaly

Question 1

Aetiology of acromegaly

Answer 1

• most common → unregulated growth hormone secretion by a pituitary adenoma
• adenoma can be microscopic or can be significantly sized that causes compression of local structures
• rarely → secondary to a cancer, such as lung or pacreatic cancer, that secretes GHRH or growth hormone.

Question 2

Pathophysiology of acromegaly

Answer 2

• excessive GH (GH is produced by anterior pituitary gland)

Question 3

Clinical presentation: overgrowth of tissues

Answer 3

• Prominent forehead and brow (“frontal bossing”)
• Large nose
• Large tongue (“macroglossia”)
• Large hands and feet
• Large protruding jaw (”prognathism”)
• Arthritis from imbalanced growth of joints

Question 4

clinical presentation if SOL?

Answer 4

if pituitary tumour of sufficient size:

• starts to press on the optic chiasm → bitemporal hemaniopa (loss of vision of outer half of both eyes)

Space Occupying Lesion

• Headaches
• Visual field defect (“bitemporal hemianopia”)

Question 5

Clinical presentation: GH can cause organ dysfunction:

Answer 5

• Hypertrophic heart
• Hypertension
• Type 2 diabetes
• Colorectal cancer

Question 6

general symptoms suggesting active raised growth hormone

Answer 6

• Development of new skin tags
• Profuse sweating

Question 7

Investiagation/Diagnosis Acromegaly

Answer 7

A random growth hormone level is not helpful as it will fluctuate, giving false positives and false negatives

• Insulin-like Growth Factor 1 (IGF-1) is the initial screening test (raised)
• Oral glucose tolerance test whilst measuring growth hormone (high glucose normally suppresses growth hormone)
• MRI brain for the pituitary tumour
• Refer to ophthalmology for formal visual field testing

Question 8

Treatment of Acromegaly

Answer 8

Trans-sphenoidal (through the nose and sphenoid bone) surgical removal of thepituitary tumour is the definitive treatment of acromegaly secondary topituitary adenomas

Whereacromegalyis caused byectopichormones from a pancreatic or lung cancer, surgical removal of these cancers is the treatment.

There are medication that can be used to block growth hormone

• Pegvisomant(GH antagonist given subcutaneously and daily)
• Somatostatin analoguesto block GH release (e.g.ocreotide)
• Dopamine agoniststo block GH release (e.g.bromocriptine)