Thursday, 28 October 2010

MRCP revision battle 36.3: Acromegaly

Acromegaly is caused by excess growth hormone.  99% of cases are due to a pituitary tumour.  5% of cases are associated with MEN 1 (now might be a good time to re-revise battle 20.1 which covers MEN...)

For the purposes of revision I'll divide features into 'classical' and 'MRCP smaller print'

Classical features:
  • soft tissue growth
    • large tongue
    • large hands
    • big ears
    • coarsening facial features
    • widening of gaps between teeth
  • impaired glucose tolerance (40%)/diabetes (20%)
  • raised blood pressure
  • horse voice

MRCP features:
  • raised phosphate
  • raised triglycerides
  • pseudogout
  • colonic polyps
  • proximal muscle weakness
  • arthralgia

  • failure of GH to decrease (to a lab-specific level) after oral glucose tolerance test
    • false positives to this test may occur in puberty, pregnancy, DM, renal/liver impairment
  • serum IGF-1 is a screening test only

  • transphenoidal surgery (40-70% cure)
  • ocreotide = somatostatin analogue
  • bromocriptine (<20% effective)
  • pegvisomant = GH receptor antagonist, conclusive data on effectiveness still awaited

Now for a little vitamin C....