Acromegaly

Question 1

What two tissues are stimulated by growth hormone

Answer 1

Skeletal & soft tissue

Question 2

Growth hormone excess is associated with two conditions depending on the patients age, state these

Answer 2

Children (before epiphyseal fusion) - gigantism
Adults (after epiphyseal fusion) - acromegaly

Question 3

Acromegaly most common cause

Answer 3

Growth hormone secreting pituitary adenoma

Question 4

Acromegaly (GH excess) clinical presentation

Answer 4

Arthropathy
- Vertebral fracture
- Osteoporosis
- Carpal tunnel syndrome

Thickened soft tissue
- thick skin
- hyperhidrosis (excess sweating)
- large jaw
- large hands

Thickened nasopharynx
- snoring/ OSA

Vascular & cardiac muscle changes
- Hypertension
- Cardiac failure
- LVH & cardiomyopathy
- vascular headaches

Gluconeogenesis & lipolysis
- Insulin resistance & diabetes mellitus
- dyslipidaemia

Tumour compression
- bitemporal hemianopia
- hypopituitarism

Question 5

Acromegaly screening/ first line test

Answer 5

IGF-1 serum levels

• IGF-1 more stable than GH & so generally preferred

Question 6

Acromegaly diagnostic/ gold standard investigation

Answer 6

Oral Glucagon Tolerance Test
- 75g oral glucose: check GH at 0, 30, 60, 90, 120 min
- Normally GH suppresses to <0.4 ug/l after glucose
- Acromegaly indicated if GH unchanged/no suppression or paradoxical rise

Question 7

Acromegaly other investigations

Answer 7

• MRI pituitary - assess size of tumour
• Visual field - assess for bitemporal hemianopia
• Pituitary function tests - assess other hormones
• Insulin stress test can also be used instead of OGTT but is much less common

Question 8

Acromegaly treatment

Answer 8

• Transphenoidal surgical tumour removal (first line)
• Radiotherapy (surgery fails/ surgical adjunct)
• Somatostatin (surgery unsuitable/ pre-surgery symptom control)

OTHER
- Tumour co-secreting prolactin - Dopamine agonist
- GH antagonist (last line) (decreases IGF-1 but not tumour)

Question 9

Apart from treating the tumour and excess GH, what else would be included in the management of patients with acromegaly (think about complications & symptoms)

Answer 9

• Cancer surveillance (colon)
• CV risk factor control (BP, lipids, glucose)
• Sleep apnoea treatment

Question 10

What are two main complications of GH excess (that can often be the presenting feature)

Answer 10

Colon polyps & cancer
Hypertension, cardiac failure & early CV death