Acromegaly Flashcards
What is acromegaly?
S/S caused by hypersecretion of GH in adults
What is the term used for excess GH before puberty?
GIGANTISM
What causes acromegaly?
GH-secreting pituitary adenoma (95%)
RARELY caused by ectopic GH (or GHRH) production by tumours e.g. pancreatic, lung
What condition is associated with acromegaly?
6% have MEN-1
Describe the epidemiology of acromegaly
RARE
5/ 1,000,000
Age: 40-50y
Give 3 S/S caused by pituitary tumour in acromegaly
Headache
Visual field defect: Bitemporal hemianopia
Hypopituitarism
List 6 changes in appearance that may arise in acromegaly
Enlargement of hands (spade-like) + feet (rings + shoes becoming tight)
Frontal bossing
Enlarged tongue (Macroglossia)
Coarsening of facial features
Growth of jaw (Prognathism)
How do symptoms arise in acromegaly?
Very gradual progression of symptoms over many years
Give an example of a nerve compression syndrome seen in acromegaly
Carpal tunnel syndrome
Name 4 skin features of acromegaly
Excessive sweating
Thick, oily skin
Development of skin tags
+/- mild hirsuitism in females
What arises due to articular overgrowth of synovial tissue and arthropathy in acromegaly?
Arthralgia
Osteoarthritis
Back pain
Kyphosis
What does insulin resistance in acromegaly lead to?
T2DM or glucose intolerance
Acromegaly can give symptoms of hypopituitarism. Describe these
Hypogonadism
Hypothyroidism
Hypoadrenalism
What other hormone is secreted in 1/3 of adenomas causing acromegaly? What does this result in?
Prolactin
Galactorrhoea + Amenorrhoea
What investigations should be used in acromegaly?
Serum IGF-1
(GH stimulates IGF-1 secretion)
Oral Glucose Tolerance Test confirms dx if IGF-1 levels are raised
What is a positive result in a oral glucose tolerance test?
75mg glucose load
Normal: GH suppressed to <2 mu/L with hyperglycaemia
Acromegaly: No suppression of GH (may also demonstrate impaired glucose tolerance)
Describe first line treatment for acromegaly
Trans-sphenoidal hypophysectomy
+/- adjunctive drug Tx
Only curative tx
When is acromegaly managed medically?
if tumour is inoperable or surgery unsuccessful
Describe the medical treatment of acromegaly
SC Somatostatin Analogues
Oral Dopamine Agonists
GH Antagonist (pegvisomant)
What is the MOA of somatostatin analogues?
Directly inhibit release of GH
Give an examples of subcutaneous somatostatin analogues. List 4 side effects of these medications
Octreotide
Abdominal pain
Steatorrhoea
Glucose intolerance
Gallstones
What is the MOA of Pegvisomant? How is it administered?
GH receptor antagonist, prevents dimerisation of the GH receptor
Doesn’t reduce tumour volume (surgery still needed if mass effect)
SC OD
Why have dopamine agonists been superseded by somatostatin analogues?
Dopamine agonists effective only in a minority of patients
Give 2 examples of oral dopamine agonists. List 4 side effects of these medications
Bromocriptine, Cabergoline
N+V
Constipation
Postural hypotension
Psychosis (RARE)
