Pituitary Tumours Flashcards
what is the most common functioning pituitary tumour
prolactinoma
what is a micro vs macroadenoma
micro - <1cm
macro - >1cm
what are all the classifications of pituitary tumours?
size sellar/suprasellar compressing optic chiasm or not invading cavernous sinus or not benign or malignant functioning or non-functioning
how do you measure how aggressive a pituitary tumour is
ki67 index - benign <3%
carcinomas are very rare
how do prolactinomas affect fertility?
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
how do prolactinomas present?
menstrual disturbance erectile dysfunction reduced libido galactorrhoea (less common in men) subfertility
what is normal serum [prolactin]
> 5000mU/L
men usually 300
women usually 600
what may be physiological causes of falsely elevated prolactin?
pregnancy/breastfeeding
stress: exercise, seizure, venepuncture
nipple/chest wall stimulation
what may be some pathological causes for elevated prolactin besides prolactinoma?
primary hypothyroidism
polycystic ovarian syndrome
chronic renal failure (excretion issue)
what may be some lactogenic causes of elevated prolactin besides prolactinoma
antipsychotics SSRIs anti-emetics high dose oestrogen opiates
what must you think of if you see mild serum prolactin elevation with no clinical features?
review the patients’ medication list
consider the stress of venepuncture
consider macroprolactin - sticky prolactin
what is macroprolactin?
polymeric form of prolactin - antibody-antigen complex of monomeric prolactin and IgG (natural variation in some people)
how do you resolve the stress of venepuncture?
measure sequential serum prolactin 20 mins apart with an indwelling cannula to reduce venepuncture stress
how do you treat prolactinomas?
first line: medical
dopamine receptor agonists Cabergoline
dose depends upon size of tumour
what is acromegaly?
excess growth hormone
what are the symptoms of acromegaly?
sweatiness
headaches
macroglossia, prominent nose, prognathism, increased hand&feet size
snoring and obstructive sleep apnoea
hypertension
impaired glucose tolerance/diabetes mellitus
how do you diagnose acromegaly?
elevated serum IGF-1
oral glucose tolerance test - failed suppression of GH
treatment for acromegaly?
trans-sphenoidal pituitary surgery
medical treatment prior to surgery or in unsuccessful resection - somatostain analogues (octreotide) or dopamine agonists (cabergoline)
potential radiotherapy
what is cushings syndrome?
excess of cortisol or other glucocorticoid
what are the symptoms of cushings syndrome
red cheeks fat pads moon face easy bruising, purple stridae, poor wound healing impaired glucose tolerance hypertension proximal myopathy depression
what are the ACTH dependent causes of cushings syndrome?
cushings disease - corticotroph adenoma (pituitary)
ectopic ACTH lung cancer
what are the ACTH independent causes of cushings syndrome?
steroids by mouth
adrenal adenoma/carcinoma
diagnosis of cushings syndrome
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
what are non-functional pituitary adenomas?
tumours don’t secrete specific hormones
often present with visual disturbances
how do non-functional pituitary adenomas present?
visual disturbances (bitemporal hemianopias) hypopituitarism sometimes elevated prolactin (dopamine can't travel down pit. stalk)
