Flashcards in Pituitary physiology Deck (48)
What hormone produced in the hypothalamus stimualtes the release of ACTH?
What hormone produced in the hypothalamus stimulates release of TSH?
What hormone produced by the hypothalamus stimualtes release of LH/ FSH?
What hormone produced by the hypothalamus inhibits the release of prolactin?
What are dynamic tests?
if theres too much hormone- do test that tries to suppress the hormone; is theres too little hormone- do test that tries to stimulate the hormone
What is synacthen?
Who shouldnt be given an insulin stress test?
patients with cardiac histories or epilepsy
How do insulin stress tests work?
supposed to induce severe hypoglycaemia and stimulate growth hormone and ACTH as part of the stress mechanism
What is a microadenoma defined as?
less than or equal to 1cm
What is a macroadenoma defined as?
greater than 1cm
What are physiological causes of raised prolactin?
breast-feeding; pregnancy; stress; sleep
What drugs can cause a raised prolactin?
dopamine antagonists; antipsychotics;antidepressants
What are pathological causes of raised prolactin?
hypothyroidism; stalk lesions; prolactinoma
What are the symptoms of a raised prolactin in females?
galactorrhoea; menstrual irregularity; ammenorrhoea; infertility
Who has the earlier presentation, males of females?
What are the sympomts of raised prolactin in males?
impotence; visual field abnormal; headache; anterior pituitary malfunction
How does hypothyroidism cause a raised prolactin?
no thyroxine so no negative deedback so high levels of TRH which also stimualtes PRL
What is homonymous hemianopia?
complete loss of vision in one side
What is the treatment for prolactinoma?
drugs- dopamine agonist: cabergoline
What is acromegaly caused by?
What are the symptoms of acromegaly?
giant (before epiphyseal fusion); thickened soft tissues; HT; cardiac failure; headaches; snoring/sleep apnoea; DM; local pituitary effeects (visual fields ;hypopituitarism; early CV death; colonic polyps and colon cancer
What causes the headaches in acromegaly?
hyperdynamic blood supply
How is acromegaly diagnosed?
IGF1 meausred; GTT (suppression test)- GH should suppress to less than 0.4 after glucose but in acromegaly there is no suppession
What is the treatment for acromegaly?
pituitary surgery; external radiotherpathy to ptiuitary fossa
What are the effects of somatostatin analogues in acromegaly (octreotide)?
reduces GH; shrinks tumour; relieves headaches and improves op outcomes
What are the SE of somatostatin analogues?
local stinging (injection); flatulence; diarrhoea; abdo pain; gastritis; gallstones
Why do gallstones occur with somatostatin analogues?
inhibiti GB contraction and theres a risk of biliary colic
What is pegvisomant?
a GH antagonist which binds to the GH receptor to block GH activity
What is the follow up for acromegaly?
cancer surveillance-colon; CVS risk factors; sleep apnoea; check otehr pituitary hormones