pituitary tumours

Question 1

what are the types of cells in pituitary and hormones they release?

Answer 1

somatotrophs: GH, corticotrophs: ACTH (corticotrophin) , thyrotrophs (TSH) thyrotrophin, gonadotrophs LH FSH, lactotrophs: PROLACTIN

Question 2

what happens when you have a functioining pituitary tumour arising from a somatotroph?

Answer 2

acromegaly

Question 3

what happens when you have a pituitary tumour arising from a lactotroph?

Answer 3

prolactinoma

Question 4

what happens when you have a pituitary tumour arising from a thyrotroph?

Answer 4

TSHoma

Question 5

is a TSHoma common?

Answer 5

no

Question 6

what happens when you have a pituitary tumour arising from a gonadotroph?

Answer 6

gonadotrophinoma

Question 7

what happens when you have a pituitary tumour arising from a corticotroph?

Answer 7

cushings disease (corticotroph adenoma)

Question 8

what are th etwo pit cell types for wchich a pit tumour leads to a NAMED disease and what are the diseases

Answer 8

corticotrophs: cushings, somatotrophs: acromegaly

Question 9

what can you find out about pit tumours in MRI

Answer 9

when you want to find out 1) size and 2) location

Question 10

classifications on size

Answer 10

microadenoma < 1cm
macro adenoma> 1cm

Question 11

how common is it to have a microadenoma?

Answer 11

1/5 ppl have one

Question 12

3 classifications/ standard considerations based on location

Answer 12

1) sellar (in sella turnica) and supprasellar (above sella turnica)
2) compressing optic chiasm or not
3) invading cavernous sinus or not

Question 13

pit tumour classifications based on function

Answer 13

functional if they lead to increased pit hormone release, and non functioning adenoma if they dont

Question 14

what is a malignant pituitary tumour called?

Answer 14

pituitary carcinoma

Question 15

how common are pit carcinomas?

Answer 15

very rare <0.5% of pit tumours

Question 16

what index is used to measur emitotic index and below what percentage is a tumour considered beingn?

Answer 16

ki67 index <3%

Question 17

can benign pituitary adenomas invade nearby structures in the brain?

Answer 17

yes, because even though they have benign histology they can display malignant behaviour

Question 18

what does the excess prolactin do in hyperprolactinaemia?

Answer 18

binds to prolactin receptors on kisspeptin neurons in hypothalamus inhibiting kisspeptin release

Question 19

what chain of hormones is stimulated by kisspeptin?

Answer 19

kisspeptin stimulates GnRH release from hypothalamus, which stimulates LH and FSH release from gonadotrophs in anterior pituitary which stimulates oestrogen progesterone in reproductibe organs

Question 20

what are the end symptoms of kisspeptin inhibition by prolactin?

Answer 20

oligomenorrhoea/ low libido (in both genders) / infertility / osteoporosis

Question 21

what is the most common type of functional pit adenoma?

Answer 21

prolactinoma

Question 22

what is the usual prolactin serum level in prolactinomas?

Answer 22

prolactin> 5000 mU/L

Question 23

does an increase in size of the prolactinoma affect the prolactin serum levels?

Answer 23

yes they increase

Question 24

presenting symptoms of prolactinomas:

Answer 24

only women:
1)mentrual disturbance
2)subfertility

3 related to sex and reproduciton:
erectile dysfunction
low libido
subfertility

Question 25

do men or women more usually present with larger prolactinomas?

Answer 25

Men: big (bc no clear syptoms just low libido) Women: usually smaller bc picked earlier bc you notice irregular periods also women try to have babies so

Question 26

other physiological causes of elevated prolactin? (3 categories 5 specifics)

Answer 26

breastfeeding, "stress" stimulus: 1)exercise 2)seizure 3) venepuncture nipple/ chest wall stimulation

Question 27

3 pathological causes of high prolactin other than prolactinoma

Answer 27

primary hypothyroidism polycystic ovarian syndrome chronic renal failure

Question 28

what type of drugs usually cause high prolactin?

Answer 28

dopamine antagonists

Question 29

what are 5 specific drugs that cause high prolactin? (iatrogenic causes of high prolact)

Answer 29

1) antipsychotics 2) selective serotonin re-uptake inhibitors 3) anti-emetics 4) high dose oestrogen 5) opiates

Question 30

WHEN should you order a pituitary MRI for prolactinaemia?

Answer 30

only once you have confirmed PATHOLOGICAL elevation of serum prolactin

Question 31

is the first line treatment of prolactinomas medical or surgical?

Answer 31

medical

Question 32

what type of drug do you give as a first line treatment of prolactinomas?

Answer 32

dopamine receptor agonists

Question 33

what is the currently commonly used dopamine receptor agonist?

Answer 33

cabergoline

Question 34

which specific dopamine receptor does cabergoline attack?

Answer 34

D2 receptor

Question 35

is cabergoline safe in pregnancy?

Answer 35

yes

Question 36

what (2 things) do dopamine receptor agonists do?

Answer 36

1) reduce prolactin serum levels 2) shrink prolactinomas

Question 37

what would you do differently in temrs of drug administration for micro and macroprolactinomas?

Answer 37

lesser and greater dose equivalently

Question 38

how do dopamine receptor agonists work?

Answer 38

bind to D2 (dopamine) receptors on lactotrophs, immitating the effect of dopamine and blocking prolactin release

Question 39

what is the consequence of excess GH in adults

Answer 39

acromegaly

Question 40

what is the consequence of excess GH in children

Answer 40

gigantism

Question 41

what is the meantime of diagnosis from onset of sympotms from acromegaly and why?

Answer 41

10 yrs bc it comes on gradually and ppl dont notice it

Question 42

sympotms of acromegaly other than enlarged stuff

Answer 42

sweating headache hypertension impaired glucose tolerance/ diabetes melitus

Question 43

symptoms of acromegaly linjed to enlarged stuff

Answer 43

1)coarsening of facial features: macroglossia, prominent nose, large jaw: prognathnism 2)increased hand and feet size 3)snoring and obstructive sleep apnea (cartilage on throat enlarges)

Question 44

what is the mechanism of GH action that leads to imparied glucose tolerance in acromegaly?

Answer 44

GH stimulates release of insulin like growth factor (somatomedin: a version of growth factor that is structurally a lot like insulin) from the liver

Question 45

what system is at risk if acromegaly is left untreated?

Answer 45

cardiovascular

Question 46

is the first line treatment of acromegaly surgical or medical and what is it spesifically?

Answer 46

surgical: transsphenoidal pit surgery (through nose)

Question 47

what is the aim of surgical intervention for acromegaly?

Answer 47

lower GH and IGF-1 LEVELS

Question 48

WHEN CAN YOU use medical treatment in treating acromegaly and with what purpose?

Answer 48

before surgery to shrink tumour or after surgery if surgical resection is incomplete

Question 49

what drugs are used to treat acromegaly: types and 1 ex each

Answer 49

somatostatin analogues eg octreotide dopamine agonists eg cabergoline

Question 50

why do dopamine agonists work for acromegaly treatment?

Answer 50

bc GH pit tumours frequently exoress d2 receptors

Question 51

what other mehtod of treatign other than surg and drugs and what is disadvanatge

Answer 51

radiotherapy

Question 52

which biovhemical test confirms acromegaly?

Answer 52

rise in GH after glucose load

Question 53

skin related symptoms in cushings syndrome

Answer 53

easy bruising red cheecks poor wound healing thin skin: (easily pulled )

Question 54

fat related symptoms in cushings syndrome

Answer 54

moon face fat pads (buffalo bump - bit afto pou ehei i mama stin plati pano pano ) purple/ red striae (stretch marks) pendulus abdomen (hanging over pubis)

Question 55

other cushings syndrome symptoms

Answer 55

1) osteoporosis 2) proximal myopathy (you can also tell by thin arms and legs) 3) impaired glucose tolerance 4) high bp 5) mental changes

Question 56

differencee between cushings disease and syndrome

Answer 56

disease: caused by pit adenoma, syndrome is just the symtpoms, may have any cause

Question 57

what are the 3 investigations you carry out for cushings disease

Answer 57

1) test for free cortisol in urine -24h round bc of incr cortisol secretion 2) cortisol in blood or saliva at midnight 3) give oral dexamethasone (exogenous glucocorticoid) ull see failure to supress cortisol: incr cortisol secr

Question 58

what causes of cushings SYNDROME are acth independent?

Answer 58

oral steroids (common) adrenal adenoma or carcinoma

Question 58

why do you need to measure cortisol at midnight? what does high at midninght mean ?

Answer 58

(bc cortisol is low at night, if its high midnight means loss of diurnal rhythm)

Question 58

what causes of cushings SYNDROME are acth dependent?

Answer 58

cushings disease, (pituitary corticotroph adneoma) ectopic acth: lung cancer

Question 59

what do you do once you confirm hypercotisolism?

Answer 59

measure ACTH

Question 60

when should you order a pituitary MRI (cushigs syndrome related)

Answer 60

when you find high acth after high cortisol

Question 61

what do non functioning pit adenomas often present with?

Answer 61

visual disturbance (bitemporal hemianopia)

Question 62

can a non funtioning pituitary adenoma affect pit hormones?

Answer 62

typically doesnt but it CAN cause 1)hypopituitarism or 2) raised serum prolactin

Question 63

how do pituitary adenomas sometimes raise serum prolactin?

Answer 63

they squeeze the pituitary stalk and dopamine cant travel down from hypithalamus

Question 64

what treatment is needed for pituitary adenomas?

Answer 64

trans-sphenoidal surgery for larger tumors epsecially if they are causing a visual disturbance