Acromegaly Flashcards
what is it?
a condition caused by an excess of growth hormone
how does it present?
giant - before epiphyseal fusion
thickened soft tissues - skin, large jaw, sweaty, large hands
snoring/sleep apnoea (thickened nasopharynx)
hypertension (heart) - cardiac failure
headaches (vascular)
diabetes mellitus
local pituitary effects - visual fields, hypopituitarism
early CV death
colonic polyps and colon cancer
how is diagnosed?
GTT suppression test (give 75g oral glucose and check GH levels at 0, 30, 60, 90 and 120 mins)
after 2 hrs GH should be suppressed
normal - GH suppresses to <0.4ug/l after glucose
acromegaly
- GH unchanged/no suppression
- paradoxical rise
can also CT/MRI pituitary function tests on the other hormones
how is it managed?
pituitary surgery - cure 90% is microadenoma and cure 50% is macroadenoma
radiotherapy alone - 25% success at 3 yrs
somatostatin analogues
dopamine analogues
GH antagonist - pegvisomant
cancer surveillance - colon and tubule-villous adenoma
CV risk factors - BP, lipids and glucose
sleep apnoea
somatostatin analogues
sandostatin LAR (IM), lanreotide autogel (SC), pasireotide (IM)
reduces GH in most patients
tumour shrinkage - takes 6m-12m but re-expands 6 weeks after stopping
can be used pre op - relieves headache in 1 hr and marginally improves outcome
side effects
- local stinging
- short term - flatulence, diarrhoea, abdominal pains
- long term - gallstones, occur by 6m; inhibits GB contraction; risk of bilary colic
dopamine analogues
cabergoline up to 3g weekly
works better if the tumour is co-secreting prolactin
works in 10-15% of patients
GH antagonist - pegvisomant
SC injection 10-30mg per day
binds to a GH receptor and blocks GH activity
tumour size does not decrease - occasional small increase in tumour size
IGF-1 decreases but serum GH concentrations may increase
last line in therapy
20mg dose costs £36,000per yr
