Chempath 22: Pituitary Flashcards
Why is blood pressure low in Addison’s disease ?
Low aldosterone levels
less aldosterone binds to mineralocorticoid receptors in collecting duct. Less Na+ reabsorbed so less water reabsorbed
List the hormones that are released by the Anterior pituitary gland ?
GH Prolactin TSH LH FSH ACTH
The hypothalamus releases TRH which acts on the anterior pituitary causing release of ……… and ……….
TSH
Prolactin
Dopamine causes reduced secretion of ……….. That’s why the drug Cabergoline or ………… can be used to treat a …………..
Prolactin
Bromocriptine
Prolactinoma
Why do people with hypothyroidism get hyperprolactinaemia ?
In primary hypothyroidism the Hypothalamus secretes more TRH which causes increased TSH and prolactin release.
How does hyperprolactinaemia cause infertility ?
Prolactin has a negative feedback loop with GnRH which means it can switch off release of FSH and LH.
Post partum haemorrhage can cause infarction of the pituitary. This is known as ………… syndrome.
Sheehans.
Transphenoidal hypophysectomy is the surgery to treat a ………
Prolactinoma in the optic chiasm
Which hormones are released by the hypothalamus and pituitary in response to hypoglycaemia ?
CRF - ACTH
GHRH - GH
Describe pituitary function testing?
Use a combined rapid anterior pituitary panel (CPFT):
- Induce hypoglycaemia (fasting + insulin) and measure if levels of GH and Cortisol rise.
- Give TRH and measure if Prolactin and TSH levels rise
- Give GnRH and see if LH and FSH levels rise
Which pituitary hormone should be replaced most urgently in case of pituitary failure?
A)TSH B)LH & FSH C)Cortisol D)Prolactin E)Aldosterone
C) Cortisol
Cortisol must be replaced with Hydrocortisone urgently as it is required to respond to stress and maintain cell integrity and electrolyte balance.
Aldosterone should still be produced by the adrenals
Explain why secondary hyperprolactinaemia requires surgery ?
Secondary hyperprolactinaemia is most commonly caused by a non functioning pituitary adenoma. This blocks Dopamine from causing negative feedback on prolactin release. This does not respond to Bromocriptine so requires surgery.
In slow growing children you should initially do a plasma ……. level. Otherwise an ……….. test can be done to see if …… levels rise.
GH
exercise
GH
Which syndrome is associated with adrenal failure due to haemorrhage into the adrenals?
This is mainly caused by ………infection
Waterhouse-friderichsen syndrome
N.meningitidis (meningococcal infection)
Acromegaly is diagnosed using the …………………… and …………. test
Oral glucose tolerance test
IGF-1 level