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
