pituitary axis/prolactinoma/non-functioning pit. adenoma/acromegaly Flashcards
what are the 7 hormones of anterior pituitary
ACTH
TSH
GH
PRL
FSH
LH
MSH
what are the 2 hormones of posterior pituitary
oxytocin
ADH
what are the axises of the pituitary
what is a paired hormone
ie ACTH and cortisol for the steroid axis
what are you looking for in a pituitary blood test
TSH
fT4
FSH
testosterone
GH
IGF-1
Prolactin
what are you looking for in a pituitary blood test
TSH
fT4
FSH
testosterone
GH
IGF-1
Prolactin
what is the insulin stress test
it is a stimulation test that induces hypoglycaemia to measure growth hormone
which cranial nerve is affected by pituitary tumour / enlargement
2
optic nerve
what is a non-functioning pituitary adenoma
its growing large but secretions are in line
it can get:
too big - compression of potion chiasm / other structures
too small - hypoadrenalism,hypothyroidism and hypogonadism
why can you get sight problems with pituitary pathology
if mass hits the optic chiasma - can affect nerves which misinterprets light information - so need to check visual fields
what is the disease most associated with optic chiasm compression
bitemporal hemianopia
how to manage a non functioning pituitary adenoma
transphenoidal surgery
and replace hormones
what are causes of prolactinoma
physiological:
breast feeding
pregnancy
stress/anxiety
sleep
pharmacological:
dopamine antagonists
antipsychotics
antidepressants ie risperidone
other eg oestrogen
pathological:
hypothyroidism
stalk lesions - iatrogenic / rtc
prolactinoma
what is relevant about the prolactin hormone
it is the only one under inhibitory control - dopamine
what is this
and this is what is looks like pathologically
signs and symptoms of prolactinoma
in Female:
early presentation
galactorrhea
menstrual irregularity
ammenorrhoea
infertility
in Male:
late presentation
impotence
visual field abnormal
ant. pit. malfunction
ivx for prolactinoma
serum prolactin conc.
MRI of pit.
Visual fields
Pit function tests
medical mx prolactinoma
Dopamine agonists
eg cabergoline / dostinex
side effects of dopamine agonists
nausea vomitting
low mood
obsessive compulsive behaviour
how does acromegaly come about
GH excess
(growth hormone - usually due to a secreting pituitary adenoma)
clinical sigs of acromegaly
giant
large hands and feet
outward growth of jaw
increased interdental spacing & macroglossia
oily skin
thickened soft tissue
snoring/ apnea
HPT
headaches (vascular)
DM
local pit. effects
early CV death
colonic problem
what does this guy have
acromegaly
diagnostic test for acromegaly
too much GH
IGF-1 - age and sex matched
GTT (Glucose tolerance test) - would suspect GH to be suppressed but in acromegaly GH is not suppressed or can even rise
visual fields
pit. function tests
tx for acromegaly
pituitary surgery - very effective in a microadenoma
radiotherapy
drugs:
somatostatin analogues ie
Sandostatin LAR
(subcutaneous injection)
dopamine agonists can be used as well ie
Cabergoline
GH antagonists ie
Pegvisomant
(SC injection - binds to GH receptor and blocks GH activity) this is last line in therapy, in this case tumour size does not decrease
side effects of somatostatin analogues
flatulence
diarrhoea
abdominal pain
gallstones - long term
what are the somatostatin analogues
sandostatin LAR
lanreotide autogel
pasireotide LAR
what else do you need to monitor in acromegaly
cancer surveillance
CV risk
sleep apnea
pathophys. of acromegaly
the abundance of GH circulating results in excessive production of insulin-like growth factor (IGF-1) which is inappropriate for growth
physiologically, GH should be suppressed by somatostatin
excess GH causes metabolic disturbances including T2DM because of insulin resistance
main diagnostic test for acromegaly
GLUCOSE TOLERANCE TEST
and if its not suppressed/rised then MRI to check tumour size and shape
1st tx for acromegaly
trans-sphenoidal surgery
which of the following conditions is associated with pituitary adenoma?
DM
dysphonia
bitemporal hemianopia
homonymous hemianopia
cranial nerve IX X XI palsies
bitemporal hemianopia
A 34 year old lady visits her doctor because of galactorrhoea and secondary amenorrhoea. This has been going on for several months and is causing her a lot of stress and inconvenience. She has a background history of high blood pressure, mental health problems and is an ex IV drug abuser. There is no family history of note.
A blood test reveals that she has a serum prolactin level of 950 nmol/l. A scan of her brain / pituitary is normal.
Which of the following is the most likely cause of her hyperprolactinaemia?
what is the initial screening test for acromegaly
serum IGF-1
why can you get sleep apnea with acromegaly
upper airway obstruction secondary to macroglossia and soft tissue swelling
