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Endo yr 2 > pituitary tumours > Flashcards

pituitary tumours Flashcards

1
Q

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

A

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

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2
Q

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

A

acromegaly

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3
Q

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

A

prolactinoma

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4
Q

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

A

TSHoma

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5
Q

is a TSHoma common?

A

no

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6
Q

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

A

gonadotrophinoma

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7
Q

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

A

cushings disease (corticotroph adenoma)

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8
Q

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

A

corticotrophs: cushings, somatotrophs: acromegaly

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9
Q

what can you find out about pit tumours in MRI

A

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

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10
Q

classifications on size

A

microadenoma < 1cm
macro adenoma> 1cm

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11
Q

how common is it to have a microadenoma?

A

1/5 ppl have one

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12
Q

3 classifications/ standard considerations based on location

A

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

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13
Q

pit tumour classifications based on function

A

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

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14
Q

what is a malignant pituitary tumour called?

A

pituitary carcinoma

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15
Q

how common are pit carcinomas?

A

very rare <0.5% of pit tumours

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16
Q

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

A

ki67 index <3%

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17
Q

can benign pituitary adenomas invade nearby structures in the brain?

A

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

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18
Q

what does the excess prolactin do in hyperprolactinaemia?

A

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

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19
Q

what chain of hormones is stimulated by kisspeptin?

A

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

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20
Q

what are the end symptoms of kisspeptin inhibition by prolactin?

A

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

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21
Q

what is the most common type of functional pit adenoma?

A

prolactinoma

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22
Q

what is the usual prolactin serum level in prolactinomas?

A

prolactin> 5000 mU/L

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23
Q

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

A

yes they increase

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24
Q

presenting symptoms of prolactinomas:

A

only women:
1)mentrual disturbance
2)subfertility

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

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25
Q

do men or women more usually present with larger prolactinomas?

A

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

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26
Q

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

A

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

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27
Q

3 pathological causes of high prolactin other than prolactinoma

A

primary hypothyroidism
polycystic ovarian syndrome
chronic renal failure

28
Q

what type of drugs usually cause high prolactin?

A

dopamine antagonists

29
Q

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

A

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

30
Q

WHEN should you order a pituitary MRI for prolactinaemia?

A

only once you have confirmed PATHOLOGICAL elevation of serum prolactin

31
Q

is the first line treatment of prolactinomas medical or surgical?

A

medical

32
Q

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

A

dopamine receptor agonists

33
Q

what is the currently commonly used dopamine receptor agonist?

A

cabergoline

34
Q

which specific dopamine receptor does cabergoline attack?

A

D2 receptor

35
Q

is cabergoline safe in pregnancy?

A

yes

36
Q

what (2 things) do dopamine receptor agonists do?

A

1) reduce prolactin serum levels
2) shrink prolactinomas

37
Q

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

A

lesser and greater dose equivalently

38
Q

how do dopamine receptor agonists work?

A

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

39
Q

what is the consequence of excess GH in adults

A

acromegaly

40
Q

what is the consequence of excess GH in children

A

gigantism

41
Q

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

A

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

42
Q

sympotms of acromegaly other than enlarged stuff

A

sweating
headache
hypertension
impaired glucose tolerance/ diabetes melitus

43
Q

symptoms of acromegaly linjed to enlarged stuff

A

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)

44
Q

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

A

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

45
Q

what system is at risk if acromegaly is left untreated?

A

cardiovascular

46
Q

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

A

surgical: transsphenoidal pit surgery (through nose)

47
Q

what is the aim of surgical intervention for acromegaly?

A

lower GH and IGF-1 LEVELS

48
Q

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

A

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

49
Q

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

A

somatostatin analogues eg octreotide
dopamine agonists eg cabergoline

50
Q

why do dopamine agonists work for acromegaly treatment?

A

bc GH pit tumours frequently exoress d2 receptors

51
Q

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

A

radiotherapy

52
Q

which biovhemical test confirms acromegaly?

A

rise in GH after glucose load

53
Q

skin related symptoms in cushings syndrome

A

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

54
Q

fat related symptoms in cushings syndrome

A

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)

55
Q

other cushings syndrome symptoms

A

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

56
Q

differencee between cushings disease and syndrome

A

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

57
Q

what are the 3 investigations you carry out for cushings disease

A

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

58
Q

what causes of cushings SYNDROME are acth independent?

A

oral steroids (common)
adrenal adenoma or carcinoma

58
Q

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

A

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

58
Q

what causes of cushings SYNDROME are acth dependent?

A

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

59
Q

what do you do once you confirm hypercotisolism?

A

measure ACTH

60
Q

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

A

when you find high acth after high cortisol

61
Q

what do non functioning pit adenomas often present with?

A

visual disturbance (bitemporal hemianopia)

62
Q

can a non funtioning pituitary adenoma affect pit hormones?

A

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

63
Q

how do pituitary adenomas sometimes raise serum prolactin?

A

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

64
Q

what treatment is needed for pituitary adenomas?

A

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

Endo yr 2 (11 decks)

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