Pituitary physiology

Question 1

What hormone produced in the hypothalamus stimualtes the release of ACTH?

Answer 1

CRH

Question 2

What hormone produced in the hypothalamus stimulates release of TSH?

Answer 2

TRH

Question 3

What hormone produced by the hypothalamus stimualtes release of LH/ FSH?

Answer 3

GnRH

Question 4

What hormone produced by the hypothalamus inhibits the release of prolactin?

Answer 4

dopamine

Question 5

What are dynamic tests?

Answer 5

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

Question 6

What is synacthen?

Answer 6

synthetic ACTH

Question 7

Who shouldnt be given an insulin stress test?

Answer 7

patients with cardiac histories or epilepsy

Question 8

How do insulin stress tests work?

Answer 8

supposed to induce severe hypoglycaemia and stimulate growth hormone and ACTH as part of the stress mechanism

Question 9

What is a microadenoma defined as?

Answer 9

less than or equal to 1cm

Question 10

What is a macroadenoma defined as?

Answer 10

greater than 1cm

Question 11

What are physiological causes of raised prolactin?

Answer 11

breast-feeding; pregnancy; stress; sleep

Question 12

What drugs can cause a raised prolactin?

Answer 12

dopamine antagonists; antipsychotics;antidepressants

Question 13

What are pathological causes of raised prolactin?

Answer 13

hypothyroidism; stalk lesions; prolactinoma

Question 14

What are the symptoms of a raised prolactin in females?

Answer 14

galactorrhoea; menstrual irregularity; ammenorrhoea; infertility

Question 15

Who has the earlier presentation, males of females?

Answer 15

females

Question 16

What are the sympomts of raised prolactin in males?

Answer 16

impotence; visual field abnormal; headache; anterior pituitary malfunction

Question 17

How does hypothyroidism cause a raised prolactin?

Answer 17

no thyroxine so no negative deedback so high levels of TRH which also stimualtes PRL

Question 18

What is homonymous hemianopia?

Answer 18

complete loss of vision in one side

Question 19

What is the treatment for prolactinoma?

Answer 19

drugs- dopamine agonist: cabergoline

Question 20

What is acromegaly caused by?

Answer 20

GH excess

Question 21

What are the symptoms of acromegaly?

Answer 21

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

Question 22

What causes the headaches in acromegaly?

Answer 22

hyperdynamic blood supply

Question 23

How is acromegaly diagnosed?

Answer 23

IGF1 meausred; GTT (suppression test)- GH should suppress to less than 0.4 after glucose but in acromegaly there is no suppession

Question 24

What is the treatment for acromegaly?

Answer 24

pituitary surgery; external radiotherpathy to ptiuitary fossa

Question 25

What are the effects of somatostatin analogues in acromegaly (octreotide)?

Answer 25

reduces GH; shrinks tumour; relieves headaches and improves op outcomes

Question 26

What are the SE of somatostatin analogues?

Answer 26

local stinging (injection); flatulence; diarrhoea; abdo pain; gastritis; gallstones

Question 27

Why do gallstones occur with somatostatin analogues?

Answer 27

inhibiti GB contraction and theres a risk of biliary colic

Question 28

What is pegvisomant?

Answer 28

a GH antagonist which binds to the GH receptor to block GH activity

Question 29

What is the follow up for acromegaly?

Answer 29

cancer surveillance-colon; CVS risk factors; sleep apnoea; check otehr pituitary hormones

Question 30

What causes Cushings syndrome?

Answer 30

excess cortisol

Question 31

What are the ymtpoms of Cushing's syndrome?

Answer 31

protine loss- myopathy, wasting; osteoporosis- fractures; thin skin- striae, bruising; altered carbohydrate/lipid metabolism; DM; obesity; altered psyche ; hypertension and oedema; virilism; hirsutism; acne; oligo/amenorrhoea

Question 32

Why does Cushing's syndrome cause hypertension?

Answer 32

glucocorticoids bind to mineralocorticoid receptors, usually in the kidneys, an enzyme inactivates cortisol so that it is mainly aldosterone that regulates sodium balance, but with the excess cortisol, the enzyme is overwhelmed and cortisol causes sodium retention

Question 33

What is the cause of virilism; hirsutism; acne; oligo/amenorrhoea?

Answer 33

excess androgen- small amounts of androgen are also produced in the zona fasciculata (in addition to its main source from the zona reticularis)

Question 34

How can you differentiate between Cushing's and obesity?

Answer 34

Cushing's patients will have in addition: thin skin; proximal myopathy; frontal balding in women; conjuctival oedema (chemosis); osteoporosis (obesity usually protects against)

Question 35

What is the tes for too much steroid?

Answer 35

suppression test- exogenous oral high dose steroid eg dexamethasone --low serum cortisol

Question 36

What is the difference between Cushing's disease and Cushing's syndrome?

Answer 36

cushings disease when caused by a pituitary problem

Question 37

What are the causes of Cushing's syndrome?

Answer 37

adrenal adenoma; ectopic- thymus; lungl pancreas; pseudo- alcohol and depression and steroid medication

Question 38

What is the action of metyrapone?

Answer 38

block cortisol production

Question 39

What are the symptoms of anterior hypopituitarism?

Answer 39

menstrual irregularities; infertility; impotence; gynaecomastia; abdo obesity; loss of facial hair; loss of exillary and pubic hair; dry skin and hair; hypothyroid faces; growth retardation

Question 40

What are the functions of GH in adults?

Answer 40

improves well being and QOL; decreaases abdo fat; increases muscle mass, strength, exercise capacity and stamina; improves cardiac function; decreases cholesterol and increases LDL; increase bone density

Question 41

How is GH given?

Answer 41

daily SC injection

Question 42

What are the risks of testosterone replacement?

Answer 42

postate enlargement; polycythaemia; hepatitis (only for oral)

Question 43

Does testosterone replacement cause prostate cancer?

Answer 43

no- but may make it grow so do PR exam and PSA (prostate specific antigen)

Question 44

What are the features seen in familial diabetes insipidus?

Answer 44

diabetes insipidus; diabetes mellitus; optic atrophy; deaf

Question 45

How is DI diagnosed?

Answer 45

water deprivation test

Question 46

What is the treatment for DI?

Answer 46

desmopressin

Question 47

What are the rare causes of DI?

Answer 47

tumour; sarcoid; radiation; meningitis

Question 48

What are you trying to get in a water deprivation test?

Answer 48

a urine/serum osmolality ratio of greater than 2