Acromegaly Flashcards
Definition
· Constellation of signs and symptoms caused by hypersecretion of GH in adults
o Excess GH before puberty results in GIGANTISM
Aetiology/Risk factors
· 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
Epidemiology
· RARE
· 5/1,000,000
· Age affected: 40-50 yrs
Presenting symptoms
· 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
Signs on physical examination (hands)
Hands
o Large spade-like hands
o Thick greasy skin
o Carpel tunnel syndrome signs
o Premature osteoarthritis
Signs on physical examination (face)
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)
Signs on physical examination (other)
· Visual Field Loss
o Bitemporal superior quadrantopia progressing to bitemporal hemianopia
· Neck
o Multinodular goitre
· Feet
o Enlarged
Investigations
· 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
Management plan (medical)
· 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
Management plan (other)
· Surgical - trans-sphenoidal hypophysectomy
· Radiotherapy - adjunctive to surgery
Possible complications (of surgery)
· Complications of Surgery
o Nasoseptal perforation o Hypopituitarism o Adenoma recurrence o CSF leak o Infection
Possible complications (CVS)
o Cardiomegaly
o Hypertension
Possible complications (respiratory)
o Obstructive sleep apnoea
Possible complications (GI)
o Colonic polyps
Possible complications (reproductive)
o Hyperprolactinaemia (in 30% of cases)