Acromegaly

Question 1

What?

Answer 1

Excess GH secondary to pituitary adenoma in over 95% of cases
Minority caused by ectopic GHRH or GH production by tumours e.g. pancreatic

Question 2

Features

Answer 2

Coarse facial features appearance, spade-like hands, increase in shoe size
Large tongue, prognathism, interdental spaces
Excessive sweating and oily skin
Features of pituitary tumour: hypopituitarism, headaches, bitemporal hemianopia
Raised prolactin in 1/3 of cases - galactorrho
6% of patient’s have MEN-1

Question 3

Complications

Answer 3

HTN
Diabetes (>10%)
Cardiomyopathy
Colorectal cancer

Question 4

Investigations

Answer 4

GH levels may vary during the day and therefor are not diagnostic
Definitive test is OGTT with serial GH measurements
Serum IGF-1 may also be used as a screening test and may be used to monitor disease

OGTT:
In normal patients GH is suppressed to < 2 with hyperglycaemia
Acromegaly - no suppression of GH, may also demonstrate impaired glucose tolerance

Pituitary MRI may show pituitary adenoma

Question 5

Management

Answer 5

Trans-sphenoidal surgery first line in majority

Dopamine agonists e.g. Bromocriptine. Effective only in minority of patients.

Somatostatin analogues e.g. Octreotide. Effective in 50-70% of patients. May be used as an adjunct to surgery.

Pegvisomant - GH receptor antagonist. OD SC injections. Very effective. Doesn’t reduce tumour size.