Pituitary Tumours

Question 1

what is the most common functioning pituitary tumour

Answer 1

prolactinoma

Question 2

what is a micro vs macroadenoma

Answer 2

micro - <1cm

macro - >1cm

Question 3

what are all the classifications of pituitary tumours?

Answer 3

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

Question 4

how do you measure how aggressive a pituitary tumour is

Answer 4

ki67 index - benign <3%

carcinomas are very rare

Question 5

how do prolactinomas affect fertility?

Answer 5

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

Question 6

how do prolactinomas present?

Answer 6

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

Question 7

what is normal serum [prolactin]

Answer 7

> 5000mU/L
men usually 300
women usually 600

Question 8

what may be physiological causes of falsely elevated prolactin?

Answer 8

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

Question 9

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

Answer 9

primary hypothyroidism
polycystic ovarian syndrome
chronic renal failure (excretion issue)

Question 10

what may be some lactogenic causes of elevated prolactin besides prolactinoma

Answer 10

antipsychotics
SSRIs
anti-emetics
high dose oestrogen
opiates

Question 11

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

Answer 11

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

Question 12

what is macroprolactin?

Answer 12

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

Question 13

how do you resolve the stress of venepuncture?

Answer 13

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

Question 14

how do you treat prolactinomas?

Answer 14

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

Question 15

what is acromegaly?

Answer 15

excess growth hormone

Question 16

what are the symptoms of acromegaly?

Answer 16

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

Question 17

how do you diagnose acromegaly?

Answer 17

elevated serum IGF-1

oral glucose tolerance test - failed suppression of GH

Question 18

treatment for acromegaly?

Answer 18

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

Question 19

what is cushings syndrome?

Answer 19

excess of cortisol or other glucocorticoid

Question 20

what are the symptoms of cushings syndrome

Answer 20

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

Question 21

what are the ACTH dependent causes of cushings syndrome?

Answer 21

cushings disease - corticotroph adenoma (pituitary)

ectopic ACTH lung cancer

Question 22

what are the ACTH independent causes of cushings syndrome?

Answer 22

steroids by mouth

adrenal adenoma/carcinoma

Question 23

diagnosis of cushings syndrome

Answer 23

24hr urine free cortisol showing increased cortisol secretion
should show elevated late night cortisol
oral dexamethasone suppression test
should show elevated cortisol

once hypercortisolism confirmed, measure ACTH

Question 24

what are non-functional pituitary adenomas?

Answer 24

tumours don’t secrete specific hormones

often present with visual disturbances

Question 25

how do non-functional pituitary adenomas present?

Answer 25

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