Acromegaly

Question 1

What is the pathophysiology?

Answer 1

XS secretion of GH = xs production of IGF-1 = causes an overgrowth of all organ systems, bones, joints and soft tissues

Question 2

What are the causes?

Answer 2

Usually secondary to a pituitary adenoma = secretes xs GH

Rarely caused by ectopic GHRH of GH production by tumours e.g. pancreatic

Question 3

How does it present?

Answer 3

Begins with headache/ VFD (bitemporal hemianopia), sweating (sweat gland hypertrophy), HTN
Acral enlargement (spade-like hands, increase in shoe size, prominent jaw)
Large tongue
Proganthism
Interdental spaces
Hypopituitarism/ hypogonadism - low libido
Galactorrhoea (due to raised prolactin in 1/3 cases)

Question 4

Name 4 complications

Answer 4

HTN
DM - acanthosis nigricans (sign)
Cardiomyopathy
Colorectal cancer

Question 5

What is the first-line investigation?

Answer 5

Serum IGF-1

Question 6

What Ix used to confirm the dx?

How can it be intepreted?

Answer 6

OGTT

(Perform OGTT if IGF-1 levels abnormal)

• in normal pt GH is suppressed to <2 mu/L with hyperglycaemia
• in acromegaly there is no suppression of GH

Question 7

Why are GH levels NOT diagnostic?

Answer 7

GH levels vary during the day and night

Question 8

Name another Ix and why?

Answer 8

Pituitary MRI - to see pituitary tumour

Question 9

What is the 1st line Mx?

What is the difference between microadenoma and macroadenoma?

Answer 9

Trans-sphenoidal surgery

Microadenoma <1cm - higher success rate
Macroadenoma >1cm

Question 10

Name 3 drugs used in medical therapy and their order of preference

Answer 10

2nd line - Somatostatin analogue (IM ocreotide OR lanreotide)
- Can be used as an adjunct to surgery

Dopamine agonists - BROMOCRIPTINE, CABERGOLINE

GH antagonist - PEGVISOMANT

Older pts OR failed surgical/medical Rx = external irradiation