Pituitary Tumours Flashcards Preview

BRS Year 2 v1 > Pituitary Tumours > Flashcards

Flashcards in Pituitary Tumours Deck (25)
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1
Q

what is the most common functioning pituitary tumour

A

prolactinoma

2
Q

what is a micro vs macroadenoma

A

micro - <1cm

macro - >1cm

3
Q

what are all the classifications of pituitary tumours?

A
size
sellar/suprasellar
compressing optic chiasm or not
invading cavernous sinus or not
benign or malignant
functioning or non-functioning
4
Q

how do you measure how aggressive a pituitary tumour is

A

ki67 index - benign <3%

carcinomas are very rare

5
Q

how do prolactinomas affect fertility?

A

prolactin binds to prolactin receptors on kisspeptin neurones in hypothalamus
inhibits kisspeptin release
decreases downstream GnRH/LH/FSH/Oest/Test
Causes oligoamenorrhoea/infertility/low libido

6
Q

how do prolactinomas present?

A
menstrual disturbance
erectile dysfunction
reduced libido
galactorrhoea (less common in men)
subfertility
7
Q

what is normal serum [prolactin]

A

> 5000mU/L
men usually 300
women usually 600

8
Q

what may be physiological causes of falsely elevated prolactin?

A

pregnancy/breastfeeding
stress: exercise, seizure, venepuncture
nipple/chest wall stimulation

9
Q

what may be some pathological causes for elevated prolactin besides prolactinoma?

A
primary hypothyroidism (compensatory increase in release of TRH due to low thyroxine)
polycystic ovarian syndrome
chronic renal failure (excretion issue of uraemic toxin which reduces dopamine)
10
Q

what may be some lactogenic/drug causes of elevated prolactin besides prolactinoma (5)

A
antipsychotics
SSRIs
anti-emetics (nausea/vomiting)
high dose oestrogen
opiates
11
Q

what must you think of if you see mild serum prolactin elevation with no clinical features?

A

review the patients’ medication list
consider the stress of venepuncture
consider macroprolactin - sticky prolactin

12
Q

what is macroprolactin?

A

polymeric form of prolactin - antibody-antigen complex of monomeric prolactin and IgG (natural variation in some people)

13
Q

how do you resolve the stress of venepuncture?

A

measure sequential serum prolactin 20 mins apart with an indwelling cannula to reduce venepuncture stress

14
Q

how do you treat prolactinomas?

A

first line: medical
dopamine receptor agonists Cabergoline
dose depends upon size of tumour

15
Q

what is acromegaly?

A

excess growth hormone

16
Q

what are the symptoms of acromegaly?

A

sweatiness
headaches
macroglossia, prominent nose, prognathism, increased hand&feet size
snoring and obstructive sleep apnoea
hypertension
impaired glucose tolerance/diabetes mellitus

17
Q

how do you diagnose acromegaly?

A

elevated serum IGF-1
oral glucose tolerance test - failed suppression of GH

(growth hormone suppressed by glucose)

18
Q

treatment for acromegaly?

A

trans-sphenoidal pituitary surgery
medical treatment prior to surgery or in unsuccessful resection - somatostain analogues (octreotide) or dopamine agonists (cabergoline)
potential radiotherapy

19
Q

what is cushings syndrome?

A

excess of cortisol or other glucocorticoid

20
Q

what are the symptoms of cushings syndrome

A
red cheeks
fat pads
moon face
easy bruising, purple stridae, poor wound healing
impaired glucose tolerance
hypertension
proximal myopathy
depression
21
Q

what are the ACTH dependent causes of cushings syndrome?

A

cushings disease - corticotroph adenoma

ectopic ACTH lung cancer

22
Q

what are the ACTH independent causes of cushings syndrome?

A

steroids by mouth

adrenal adenoma/carcinoma

23
Q

diagnosis of cushings syndrome

A

24hr urine free cortisol showing increased cortisol secretion
should show elevated late night cortisol
oral dexamethasone suppression test
should show elevated cortisol (as ACTH is NOT suppressed)

once hypercortisolism confirmed, measure ACTH

24
Q

what are non-functional pituitary adenomas?

A

tumours don’t secrete specific hormones

often present with visual disturbances

25
Q

how do non-functional pituitary adenomas present?

A
visual disturbances (bitemporal hemianopias)
hypopituitarism
sometimes elevated prolactin (dopamine can't travel down pit. stalk)

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