Acromegaly

Question 1

Definition

Answer 1

· Constellation of signs and symptoms caused by hypersecretion of GH in adults

o Excess GH before puberty results in GIGANTISM

Question 2

Aetiology/Risk factors

Answer 2

· Most cases are caused by a GH-secreting pituitary adenoma

· RARELY caused by excess GHRH causing somatotroph hyperplasia from hypothalamic ganglioneuroma, bronchial carcinoid or pancreatic tumours

Question 3

Epidemiology

Answer 3

· RARE
· 5/1,000,000
· Age affected: 40-50 yrs

Question 4

Presenting symptoms

Answer 4

· Very gradual progression of symptoms over many years

· Rings and shoes becoming tight

· Increased sweating

· Headaches

· Carpal tunnel syndrome

· Hypopituitary symptoms:
o Hypogonadism
o Hypothyroidism
o Hypoadrenalism

· Visual disturbances (due to compression of optic chiasm by tumour)

· Hyperprolactinaemia leading to:
o Irregular periods
o Decreased libido
o Impotence

Question 5

Signs on physical examination (hands)

Answer 5

Hands

o Large spade-like hands
o Thick greasy skin
o Carpel tunnel syndrome signs
o Premature osteoarthritis

Question 6

Signs on physical examination (face)

Answer 6

Face

o Prominent eyebrow ridge
o Prominent cheeks
o Broad nose bridge
o Prominent nasolabial folds
o Thick lips
o Increased gap between teeth
o Large tongue
o Prognathism
o Husky resonant voice (due to thickening of vocal cords)

Question 7

Signs on physical examination (other)

Answer 7

· Visual Field Loss
o Bitemporal superior quadrantopia progressing to bitemporal hemianopia

· Neck
o Multinodular goitre

· Feet
o Enlarged

Question 8

Investigations

Answer 8

· Serum IGF-1 - useful screening test
o GH stimulates IGF-1 secretion

· Oral Glucose Tolerance Test (OGTT)
o Positive result: failure of suppression of GH after 75 g oral glucose load

· Pituitary Function Tests
o 9am cortisol
o Free T4 and TSH
o LH and FSH
o Testosterone
o Prolactin

· MRI of Brain - visualise the pituitary adenoma

Question 9

Management plan (medical)

Answer 9

· Medical - if surgery is contraindicated or refused

o Subcutaneous Somatostatin Analogues
· Examples: octreotide, lanreotide
· Side-effects: abdominal pain, steatorrhoea, glucose intolerance, gallstones

o Oral Dopamine Agonists
· Examples: bromocriptine, cabergoline
· Side-effects: nausea, vomiting, constipation, postural hypotension, psychosis (RARE)

o GH Antagonist (pegvisomant)

o Monitor
· GH and IGF1 levels can be used to monitor disease control

Question 10

Management plan (other)

Answer 10

· Surgical - trans-sphenoidal hypophysectomy

· Radiotherapy - adjunctive to surgery

Question 11

Possible complications (of surgery)

Answer 11

· Complications of Surgery

o Nasoseptal perforation
o Hypopituitarism
o Adenoma recurrence
o CSF leak
o Infection

Question 12

Possible complications (CVS)

Answer 12

o Cardiomegaly

o Hypertension

Question 13

Possible complications (respiratory)

Answer 13

o Obstructive sleep apnoea

Question 14

Possible complications (GI)

Answer 14

o Colonic polyps

Question 15

Possible complications (reproductive)

Answer 15

o Hyperprolactinaemia (in 30% of cases)

Question 16

Possible complications (metabolic)

Answer 16

o Hypercalcaemia

o Hyperphosphataemia

o Renal stones

o Diabetes mellitus

o Hypertriglyceridaemia

Question 17

Possible complications (physiological)

Answer 17

o Depression

o Psychosis (from dopamine agonists)

Question 18

Prognosis

Answer 18

· GOOD with early diagnosis and treatment

· Physical changes are irreversible