hypopituitarism Flashcards
what are the 5 hormones stored by anterior pituitary gland
growth hormone, prolactin, lh and fsh, tsh, acth
what are some differences between the anterior and posterior pituitary glands?
anterior pituitary is glandular as opposed to posterior which has neural origin.
posterior is continous with hypothalamus
anterior is regulated by inhibitory/ releasing factors via hypothalamic pituitary portal system
what is prolactin responsible for
milk production
what is fsh and lh responsible for
oestrogen and progesterone and testosterone production
what is tsh responsible for
production of t3 and t4 in thyroid glands
what is acth responsible for
cortisol in adrenal cortex
difference between primary and secondary pituitary disease
primary disease - gland itself fails
secondary disease - no signals from hypothalamus or anterior pituitary
what is primary hypothyroidism?
autoimmune destruction of thyroid gland, Hashimoto’s thyroiditis or iodine deficiency
t3 and t4 fall,
tsh increases because no negative feedback
what is secondary hypothyroidism
cant make tsh, tsh falls
t3 and t4 fall
e.g pituitary tumour damaging thyrotrophs
what one rare cause of hypopituitarism?
congenital( rare) - pituitary gland hasnt developed properly in utero - mutation in transcription factors e.g, prop1 mutation
tend to be deficient in gh and at least 1 other anterior hormone
typical features - short stature
hypoplastic anterior pituitary on mri
another cause of hypopituitarism
acquired (much more common) tumours radiation infection e.g meningitis traumatic brain injury pituitary surgery imflammatory - hypophytitis pituitary apoplexy - haemorrhage/ infarction shhehans syndrome - peri partum infarction
what is panhypopituitarism
total loss of anterior and posteror pituitary function
how does radiotherapy cause hypopituitarism
pituitary and hypothalamus sensitive to radiation
gh and gonadotrophins are most sensitive
prl can also increasedue to loss of hypothalamic dopamine
after how many years of radiotherapy can effects last for
persists upto 10 yrs after
what will loss of fsh/lh cause
reduced libido
secondary amenorrhoea
erectile dysfunction
reduced pubic hair
loss of acth causes..
fatigue
loss of tsh causes…
fatigue
some weight gain
loss of gh causes..
reduced quality of life
short stature in children
loss of prl causes…
Inabililty to breastfeed
what is sheehans syndrome
Hyperplasia of lactotrophs during pregnancy And post partum haemorrhage - hypotension - leads to blood loss leading to pituitary infarction - post partum hypopituitarism affects anterior pituitary more common in developing countries
what are some of the symptoms of sheehans syndrome
lethargy, anorexia
weightloss
failure of lactaction
failure to resume menses
what is pituitary apoplexy
pituitary haemorrhage
dramatic presentation
usually bleed into existing pituitary tumour
how can pituitary apoplexy be exacerbated
precipitated by anticoagulants e.g warfarin
symptoms of apoplexy
severe sudden onset of headache
visual field defects - bitemporal hemianopia
cavernous sinus involvement can lead to diplopia or ptosis
how can you diagnose hypopituitarism
dynamic pituitary function test acth and gh are stress hormones therefore induce stress by making hypoglycaemic to test for levels give insulin injection make glucose <2.2mm look for usual increase in cortisol and gh measure at diff time points can also give trh and gnrh
scan for diagnosis of hypopit..
pituitary mri
may reveal other pathology
empty sella?
treatment of gh def
assess quality of life using questionnaire - then give daily injection
measure response via improvement in qol and plasma igf1
give gh to kids
treatment of tsh deficiency
daily levothyroxine
aim for ft4 above middle of reference range
treatment of acth def
replace cortisol with prednisolone once daily 3mg
hydrocortisone 3 times 10mg 5mg 5mg
sick day rules for those with acth def
patients with addisons have risk of adrenal crisis when triggered with intercurrent illness
patients with steroid replacement must have
steroid alert pendant/bracelet
double glucocorticoid steroid dose if fever/ill
if unable to take tablets - inject im or come straight to and e.
treatment for fsh/lh def in men
if no fertility required - replace testosterone topically or intramuscular - does not restore sperm production
measure plasma testosterone
if fertility req - lh fsh injections
treatment for fsh/lh def in women
no fertility - oestrogen oral or topical
additional progesterone if intact uterus
if fertilty req - carefully times lh fsh injections
ivf
