Hypercortisolism Flashcards
ACTH dependent cushings syndrome is due to what causes?
pituitary / hypothalamus / ectopic tumor
what are the levels of cortisol and ACTH in ACTH dependent cushings syndrome?
- high cortisol
- high ACTH
ACTH independent cushings syndrome is due to what cause?
adrenal gland pathology
what are the levels of cortisol and ACTH in ACTH independent cushings syndrome?
- high cortisol
- low ACTH
features of ectopic ACTH cushings syndrome
- rapid progression
- elevated ACTH (5-10x normal cushings)
- hirsutism
- hyperpigmentation
steps to diagnose cushings
- confirm hypercortisolemia
- determine subtype
- localize source of overproduction
confirmation of hypercortisolemia
- 24 hour urine collection for free cortisol excretion
- 11 pm salivary or serum cortisol
- low dose dexamethasone suppression test (DST)
does a normal 24 hour urine test result exclude cushings?
no
what is pseudo cushings syndrome?
elevated cortisol levels resulting from an underlying condition / illness which stimulates the HPA axis and thus mimics true cushings syndrome
what are the steps of treatment for pseudo cushings syndrome?
- delay testing until correction of underlying cause
- avoid 24 hour urine collection as means of diagnosis
- use overnight low dose DST
what is the rationale of the midnight salivary cortisol testing?
demonstrates disrupted circadian rhythm of cortisol secretion
for “soft” clinical findings of cushings syndrome, what tests should you use?
- midnight salivary cortisol
- low dose DST
high cortisol
low ACTH
which subtype of cushings?
adrenal
high cortisol
high ACTH
which subtype of cushings?
pituitary / hypothalamus / ectopic ACTH
what two tests are done to differentiate pituitary vs ectopic etiologies of cushings?
- inferior petrosal sinus sampling
- high dose dexamethasone suppression test (DST)
