Pituitary Flashcards
pituitary adenomas are the main cause of pituitary ________
hyperfunction
T/F: pituitary adenoma has more correlation with MEN2a
F: more with MEN1
functional pituitary adenomas tend to be classed by…
cells involved
which pituitary tumour is the most common
prolactinoma
prolactinoma occurs due to…
-ve dopamine control (dopamine inhibits prolactin)
aetiology of inc prolactin
Physiology: breast feeding
Pathology: adenoma
Pharma: dopamine antagonist
s/s of prolactinoma
early in females: galactorrhea, menstrual irregularity, amenorrhea
males- late: impotence, bitemporal hemianopia
what is dx of prolactinoma
Sr prolactin >5000
mx of prolactinoma
dopamine antagonists, surgical removal
pituitary adenoma may be non-functional- why may this still be an issue
can compress optic chiasma, CN 3,4,6 etc
what is the main surgical technique for pituitary adenoma removal
transphenoidal surgery
acromegaly is a tumour of…
growth hormone secretion resulting in inc GH
s/s of acromegaly
thick soft tissue (large tongue, forehead), sweaty, HT, headaches, gigantism
ix for acromegaly
glucose tolerance test (as GH is insulin-like growth factor), suppression test of GH +ve if >0.4mg/l
tx for acromegaly
1st line: surgery
2nd line: somatostatin, dopamine antagonists
3rd line: Radiotherapy
Cushing’s is an inc in…
cortisol
difference between Cushing’s disease and Cushing’s syndrome
Cushing’s disease= ACTH dependent- pituitary adenoma
Cushing’s syndrome: ACTH independent- adrenal adenoma, pseudocushing’s etc
3 types of Cushing’s
cushion’s disease, cushion’s syndrome, paraneoplastic cushings(ACTH released from small cell lung cancer)
s/s of Cushing’s
round person, thin limbs
moon face, buffalo hump
myopathy (muscle wasting)
ix for Cushing’s
overnight dexamethasone suppression test (low dose)
then high dose given to identify origin
KNOW THE RESULTS
mx for Cushing’s
pituitary cause= surgery, radiotherapy
adrenal: surgery
pituitary hypofunction is due to…
no specific hormone- usually panhypopituitarism
aetiology of pituitary hypofunction
iatrogenic* (surgery), tumours, sudden haemorrhage, ishaemic necrosis, granulomatous inflammation, hypothalamic lesions
s/s of hypofunction
obesity, hair loss, dry skin, dull face, growth retardation, menstrual irregularities, infertility, gynecomastia
mx of hypofunction
hormone replacement therapy (hydrocortisone, ADH, thyroxine, GH etc)
which hormone do athletes use illegally
GH
craniopharyngeoma is a cause of hypo function, what is it?
bengin tumour of the hypothalamus (remnant from Rethke’s pouch). may present with headache, visual disturbance
posterior pituitary hyperfunction
SIADH- syndrome of inappropriate ADH
what is SIADH
ectopic production of ADH leading to large amounts of ADH= concentrated urine
why does SIADH cause a big Na dec in blood
large amounts being reabsorbed in kidney tubules > diluted blood so diluted Na [ ]
2 etiological features of SIADH
post pit secreting too much ADH: iatrogenic, head injury
non-osmotic stimuli: hypovolaemia, hypotension
ectopic: small cell lung cancer
what are the s/s of SIADH
usually only due to hyponatraemia- seizures, headache, fatigue, muscles aches, confusion
what are some findings for U&Es of SIADH
hyponatrameia, high Na in urine
mx of SIADH
fluid restriction, tolvaptan (ADH blocker)
main complication of SIADH Na resuc
central pontine myelinolysis: Na reintroduced too fast so brain cells don’t have time to adjust- H2O leaves brain cells too fast
posterior pituitary hypo function is….
Diabetes insipidus
what is DI
lack of ADH or lack of ADH response = dilute urine as ADH causes reabsorption of H2O from tubules to blood, high Sr Na
types of DI
cranial: hypothalamus doesn’t produce ADH
nephrogenic: collecting ducts don’t respond to ADH (resistant)
s/s of DI
polyuria, polydipsia, hypernatraemia
main sign of hypernatraemia
oedema
Ix for DI
low urine osmolarity, high serum osmolarity
water deprivation test: norm urine: SR osmolarity >2. desmopressin then given, if ratio normalises then it is cranial DI
mx of DI
cranial- desmopressin
nephrogenic: thiazide & NSAIDs
