Endocrine: Acromegaly

Question 1

Acromegaly: Clinical Features (6)

Answer 1

Large hands and feet
Large tongue
Coarse facial appearance
Excessive sweating/oily skin
Features of pituitary tumour: hypopituitarism, headaches, bitemporal hemianopia
Raised prolactin in 1/3 of cases → galactorrhoea

Question 2

Acromegaly: What percentage of patient have MEN-1

Answer 2

6% of patients have MEN-1

Question 3

Acromegaly: how to investigate?

Answer 3

Serial serum IGF-1
If raised IGF-1 then confirm with OGTT
- in normal patients GH is suppressed to < 2 mu/L with hyperglycaemia
- in acromegaly there is no suppression of GH
- may also demonstrate impaired glucose tolerance which is associated with acromegaly

Question 4

Acromegaly: Most common cause?

Answer 4

Pituitary adenoma (95%)
A minority of cases are caused by ectopic GHRH or GH production by tumours e.g. pancreatic.

Question 5

Acromegaly: Managment

Answer 5

Trans-sphenoidal surgery

Somatostatin analogue
- e.g. octreotide
- effective in 50-70% of patients
- may be used as an adjunct to surgery

Pegvisomant
- Once daily s/c administration
- Very effective - decreases IGF-1 levels in 90% of patients to normal
- Doesn’t reduce tumour volume therefore surgery still needed if mass effect

Dopamine agonists
- e.g. bromocriptine
- first effective medical treatment for acromegaly, however now superseded by somatostatin analogues
- effective only in a minority of patients

External irradiation is sometimes used for older patients or following failed surgical/medical treatment

Question 6

Acromegaly: Somatostatin analogue MOA

Answer 6

Directly inhibits the release of growth hormone

Question 7

Acromegaly: Pegvisomant analogue MOA

Answer 7

GH receptor antagonist
Doesn’t reduce tumour volume therefore surgery still needed if mass effect