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

Diagnosis:

• 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

Treatment:

• 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....