acromegaly

Question 1

acromegaly pathophysiology

Answer 1

• excess growth hormone
• commonly pituitary adenoma
• rarely cancer secreting ectopic growth hormone-releasing hormone or growth hormone - paraneoplastic syndrome
• excess GNRH
• GNRH > GH > high IGF-1

Question 2

tumour pressing on local structure - vision loss

Answer 2

• optic chaiasm
• bitemporal hemianopia

Question 3

presentation of acromegaly

Answer 3

• headaches
• visual field defects
• prominent forehead and brow
• coarse, sweaty skin
• large nose
• large tongue
• large hands and feet
• large protruding jaw
• hypertrophic heart
• hypertension
• type 2 diabetes
• carpal tunnel syndrome
• arthiritis
• colorectal cancer

Question 4

investigations

Answer 4

insulin like growth factor 1 - raised
growth hormone supression test / oral glucose tolerance test - if GH not supressed
MRI - visualise adenoma

Question 5

ideal treatment

Answer 5

trans-sphenoidal surgery - through

ectopic hormones from liver / pancreatic tumours invloves surgical removal or radiotherapy

Question 6

medical options for when surgery is not available

Answer 6

pegvisomant - growth hormone receptor antagonist

somatostatin analogues - block GH release

dopamine agonists - block GH release

GH antagonist

radiotherapy

Question 7

Acromegaly in children (3)

Answer 7

• Called gigantism
• Occurs before epiphyseal fusion
• Hypopituitarism causes inhibition of puberty as gonadotrophs cannot be released

Question 8

Complications of acromegaly (6)

Answer 8

• T2DM caused by impaired glucose tolerance
• Obstructive sleep apnoea
• Cardiomyopathy
• Hypertension
• Arthropathy
• Carpal tunnel syndrome

Question 9

Other symptoms suggesting active raised growth hormone (2)

Answer 9

• Development of new skin tags
• Profuse sweating

Question 10

Why can acromegaly cause sleep apnoea?

Answer 10

Pressure around the neck due to enlargement

Question 11

Signs of acromegaly to do with GH causing organ dysfunction (4)

Answer 11

• Hypertrophic heart
• Hypertension
• Impaired glucose tolerance
• Colorectal cancer

Question 12

gold standard test for acromegaly

Answer 12

oral glucose tolerance test

Question 13

Criteria for diagnosis of acromegaly

Answer 13

Acromegaly excluded if:
random GH <0.4 ng/ml and normal IGF-I

If either abnormal proceed to:
75 gm Glucose tolerance test (GTT)

Acromegaly excluded if:
IGF-I normal
and
GTT nadir GH <0.4 ng/ml