Growth Hormone disorder (Acromegaly) (Gigantism) (↓GH) Flashcards
growth hormone normal functions?
-5
grows muscles & bones
stimulates IGF release
GH has glucose sparing effect
↑lipolysis
IGF effects?
-4
grows muscle + bones
protects bone
protects cartilage
which cells make growth hormone?
where are they located?
somatotrophs
Ant. pituitary gland
somatotrophs make up & wise how much on the endocrine cells in Ant. pituitary gland?
50%
problem with measuring growth hormone?
so what can you measure instead to give you a decent idea?
GH serum levels fluctuate a lot in the day
measure IGF
other name for growth hormone?
somatotropin
IGF released where?
liver
main cause for ↑GH in adult?
% wise how many times is this the cause?
Pituitary adenoma
95%
↑GH in adult called what?
Acromegaly
other causes of ↑GH (aside from Pituitary adenoma)?
-2
ectopic tumour
multiple endocrine neoplasia
ectopic tumour at which organ can commonly ↑GH levels?
pancreas
Acromegaly features around the face and mouth?
-3
Thick lips + tongue
Big gap between teeth
Protruding jaw
Thick tongue medical name?
macroglossia
Protruding jaw medical name?
prognathism
Acromegaly features/symptoms?
-7
Big hands Big feet Thick lips + tongue – macroglossia Big gap between teeth Protruding jaw – prognathism Sweaty skin Oily skin
sign on eye examination?
why?
bitemporal hemianopia
pituitary adenoma hits on optic chiasm
what happens to blood glucose?
↑BG
Suspect Acromegaly,
1st line Ix?
+ve result?
Serum Insulin growth factor (IGF-1)
↑↑
Suspect Acromegaly.
Insulin growth factor (IGF-1) is up.
next Ix to confirm diagnosis?
Oral Glucose Tolerance Test
Suspect Acromegaly.
Insulin growth factor (IGF-1) is up.
Oral Glucose Tolerance Test is abnormal.
next Ix?
why do you do this Ix?
MRI head
look for pituitary adenoma
which blood test basically look at the all/most of the hormones that come from the pituitary?
Pituitary hormone screen
in acromegaly, along with high GH, what other hormone can be high?
how often is it high in acromegaly pts %?
prolactin
20%
main Ix to look for ectopic tumour causing acromegaly?
CT
which blood test to check for high prolactin?
Pituitary hormone screen
pt has confirmed acromegaly.
1st line Mx?
method used to get to the pituitary?
resect pituitary
trans sphenoidal - up nose
pt has confirmed acromegaly.
what do you give to combat high prolactin?
give Dopamine
pt has confirmed acromegaly.
surgery done, but still growth hormone is raised.
1st line drug to combat high GH?
-name
octreotide
1st line drug to combat high GH?
-name
this drug is analogue of what hormone?
octreotide
somatostatin
somatostatin effect on growth hormone?
suppression/inhibition
2nd line drug to combat high GH?
- name
why is this drug used less than octreotide?
pegvisomant
expensive
pegvisomant class?
GH receptor antagonist – blocks GH
is surgery usually curative or not?
usually curative
Prognosis for acromegaly?
decent - Life expectancy near normal once disease treated
define gigantism?
high GH in a child
usual cause of gigantism?
Pituitary adenoma
extra features/ symptoms of gigantism not seen in acromegaly?
tall + delayed puberty
why does gigantism cause increased height but acromegaly does not?
epiphyseal growth places not closed
why is there delayed puberty in gigantism?
-step by step
↑GH in child > -ve feedback on HPA axis > less GnRH > hypogonadal > delayed puberty
Growth Hormone Deficiency.
what happens to GH levels?
↓GH
Diagnostic test for growth hormone deficiency?
result?
IGF blood test
low IGF
1st line Mx for growth hormone deficiency?
give Synacthen (growth hormone)
