Cushings Flashcards
ACTH independent cushings is?
ppl who are taking exogenous steroids
ACTH dependent cushings is?
endogenous causes
90% of ACTH-dependent cushings is caused by?
pituitary issues
does ectopic ACTH or Cushings disease cause more elevated ACTH?
ectopic ACTH
first step to dx cushings
confirm hypercortisolemia
test for cushings should be done inpatient or outpatient
outpatient (less stress)
tests for hypercortisolemia (3)
- 24 hr urine collection - cortisol
- 11 pm salivary or serum cortisol
- low dose dexamethasone suppresion test
24 hr urinary free cortisol under 50, risk of cushings?
unlikely
24 hr urinary free cortisol 50-150, risk of cushings?
possible
24 hr urinary free cortisol >150, risk of cushings?
likely
does a normal 24 hr urinary free cortisol r/o cushings?
no
what is pseudo cushings
elevated cortisol levels from an underlying cause that stimulates HPA
best test to do for pseudo cushings?
overnight low dose DST
the midnight salivary test result of _______r/o cushings
under 5
the midnight salivary test result of _______indicates possibility of cushings
5-7.5
the midnight salivary test result of _______likely points to cushings
> 7.5
dexamethasone suppression test ____ is normal
under 2
dexamethasone suppression test ____ is suspicious of cushings
3-10
dexamethasone suppression test ____ is likely cushings
> 10
how to subtype a case of cushings
measure ACTH
how to image a pituitary lesion
MRI
to to image an adrenal lesion or ectopic lesion
CT
next step in w/u of high cortisol, low ACTH
CT to differentiate unilateral vs bialteral disease
tx of ACTH-independent cushings - adrenal adenoma
surgery + post-op tx of adrenal insufficiecy
ACTH dependent cushings - tests to differentiate b/w pituitary vs ectopic (2)
- inferior petrosal sinus sampling
2. high dose dexamethasone test
if patient shows no suppression with high dose dexamethasone test?
ectopic
if patient shows some suppresion of ACTH with high dose dexamethasone
pituitary cause
inferior petrosal sinus:peripheral concentration of ACTH >2:1 then?
pituitary source
most common type of pituitary irradiation
stereotactic radiosurgery/gamma knife
MOA: blocks conversion of cholesterol to pregnenolone
aminoglutethimide
MOA: blocks 11 beta hydroxylase
- ketoconazole
2. mitotane
a large adrenal adenoma would dictate what type of surgery
open laparatomy & right adrenalectomy
