Pituitary Disease Flashcards
how are pituitary tumours classified?
by their size
what is a pituitary adenoma <1cm called?
microadenoma
what is a pituitary adenoma >1cm called?
macroadenoma
why can a benign pituitary adenoma still be very damaging?
there is very little space available to them for growth before causing problems
what structures can a pituitary adenoma compress?
optic chiasma
cranial nerves
internal carotid arteries
how is a pituitary adenoma managed?
transsphenoidal surgery to remove
hormone replacement
what are three physiological causes of raised prolactin?
pregnancy
stress
lack of sleep
what drugs can cause a raised prolactin?
anything that reduces dopamine levels
dopamine antagonists, anti-psychotics
what are three pathological causes of raised prolactin?
hypothyroidism
lesions on the pituitary stalk
prolactinoma
how does hypothyroidism lead to a raised prolactin?
TRH stimulates prolactin - elevated in hypothyroidism due to loss of negative feedback
what value of prolactin suggests a prolactinoma?
over 5000
do men or women with prolactinoma present earlier?
women
how does a prolactinoma present in females?
galactorrhoea
menstrual irregularities
infertility
how does a prolactinoma present in males?
impotence
visual field abnormalities
anterior pituitary problems
what medication is used to treat a prolactinoma?
dopamine agonists
name a dopamine agonist
cabergoline
what causes acromegaly?
GH excess
what does GH excess in children cause?
gigantism
how is a diagnosis of acromegaly confirmed?
measure IGF-1
OGTT
what is the gold standard test for diagnosing acromegaly?
OGTT
how is an OGTT performed?
give 75g glucose orally and measure GH every 30 mins for two hours
what is a normal response to an OGTT?
GH suppresses to <0.4 after glucose
what is the response to an OGTT in acromegaly?
GH unchanged or raised
what is the main treatment for acromegaly?
pituitary surgery
what drugs can be used to manage acromegaly?
somatostatin analogues
dopamine agonists
GH antagonists
what management for acromegaly is done if drugs fail?
radiotherapy
what is cushing’s syndrome?
excess cortisol
what is the gold standard test for diagnosing cushing’s syndrome?
low dose dexamethasone suppression test
what is the main cause of cushing’s syndrome?
a pituitary adenoma - called cushing’s disease
what factors could create a false positive when doing tests for cushing’s disease?
alcohol
depression
steroid medication
how would a pituitary cause of cushing’s be diagnosed?
low dose dex test = abnormal
ACTH = slightly raised
how would a adrenal cause of cushing’s be diagnosed?
low dose dex test = abnormal
ACTH = low
how would a ectopic cause of cushing’s be diagnosed?
low dose dex test = abnormal
ACTH = very raised
name some of the main causes of hypopituitarism
pituitary tumours
brain tumours invading
side effect of surgery
name some signs and symptoms of anterior hypopituitarism
menstrual irregularities infertility impotence gynaecomastia obesity dry skin
what is given in hypopituitarism to replace TSH?
thyroxine 100-150mcg/day
what is given in hypopituitarism to replace ACTH?
hydrocortisone 10-15 split over the day - largest dose in the morning
what is given in hypopituitarism to replace ADH?
desmopressin tablets or desmospray
what is given in hypopituitarism to replace GH?
subcutaneous GH nightly
what is given in hypopituitarism to replace sex steroids?
HRT/COCP for females
testosterone for males
what is the test used to diagnose diabetes insipidus?
water deprivation test
what is involved in the water deprivation test?
nil by mouth for 8-12 hours
check serum and urine osmolalities for 8h and then 4h after giving IM DDAVP
what are the options for treating diabetes insipidus?
desmospray
desmopressin oral tablets
