Endo - Hypopituitarism Flashcards
The anterior pit is …. in origin
The posterior pit is …. in origin
glandular
neural
The five anterior pituitary hormones ?
- Somatotrophin
- Prolactin
- TSH
- LH and FSH
- ACTH
hypothalamo releasing /inhib factors travel in …. to ant pit
portal circulation
Primary hypothyroidism vs secondary ?
- eg autoimmune destruction of thyroid gland - TSH inc TRH inc, T3 + T4 fall
- eg pit tumour damaging thyrotrophs (ant pit that releases TSH) TSH falls, T3 + T4 fall
Primary vs secondary hypoadrenalism
- eg destruction of adrenal cortex , CRH inc, ACTH inc, cortisol falls
- eg pit tumour damaging corticotrophs, can’t make ACTH which falls, cortisol falls
Primary vs secondary hypogonadism?
- eg destruction of testes, GnRH inc, LH and FSH inc, testos, oes and prog fall
- eg pit tumour damaging gonadotrophs , can’t make LH and FSh which fall, testos etc falls
Congenital causes of hypopituitarism ?
Congenital
- rare
- result of mutations of transcrip factors for ant pit developm
- deficient in GH so short and one other aph
- hypoplastic - ant pit underdeverloped on MRI
Acquired
- tumours
- radiation
- infection
- traumatic brain injury
- pit surgery
- inflam (hypophytis)
- pit apoplexy
- peri partum infarction (Sheehan’s syndrome)
What is pituitary apoplexy ? dramatic in those with ? preceipitated by ? symp?
Haemorrhage or less commonly infarction
dramatic in patients with pit adenomas (can be first sign)
can be precipitated by anticoagulants
severe sudden onset headache
bitemp hemianopia
cavernous sinus involve- diplopia, ptosis
what is Hypopituitarism
- ant (most often) or post pit dysfunction
- post pit dysf usually as result of inflam or surgery
What is panhypopituitarism
total loss of ant and post pit function
radiotherapy induced hypopituitarism occurs due to …..
radiotherap can be … or … to pit
extend depends on
which part of ant pit most sensitive ?
What increases after radiotherapy
What is recommended with radiotherapy ?
pit and hypothalamus both sensitive to radiation
direct or indirect
dose
GH and gonadatrophin
Prolactin due to loss of hypothal dop
risk stays for 10 years after radiot so annual assessment
presentations of hypopituitarism with FSH /LH
FSH /LH
- reduced libido
- 2* amenorhhea
- erectile dysfunction
- redcued pubic hari
Hypopit presentation ACTH
fatigue
hypopit presentation with TSh
fatigue
hypopit presentation with Gh
reduced qol
(short stature only in kids)
hypopit presentation with prolactin
Inability to breastfeed
what is sheehan’s syndrome ?
- hypotension during or after birth (post partum haemorrage which can lead to pituitary infarction) - low bp / severe blood loss
- ant pit enlarges in pregnancy (lactotroph hyperplasia)
- so blood loss will destroy hormone producing tissue
- causing post partum hypopituitarism
DOEs sheehans affect both ant and post pit ?Why?
Blood supply affected so post pit not usually affected
BEst way to visualise pit gland ?
MRI
Symptoms of sheehans syndrome
- lethargy , anorexia, weight loss due to TSH/ ACTH/ GH deficiency
- failure to lactate - prl defic
- no periods after delivery
WHy is biochem diagnosis of hypopit difficult ?
cortisol - dependent on time of day
FSH /LH - cyclical
CH/ACTH - pulsatile
how do we diagnose hypopit?
- biodynamic pit funciton test (series of hormone measurements over series of time pts)
- radilogically via pit MRI
Dynamic tests for hypopit ?
Trigger pit hormones to be produced - if hypopit levels stay low
ACTH & GH
- insulin induce hypoglycaemia (<2.2)
- induces stress
- stress hormones released- ACTH (cortisol measured) & GH
- low in hypopit
TSH
- TRH stimulates TSH release
FSH/LH
- GnRH stimulates FSH/LH release
