[Endo] Cushing's syndrome Flashcards
what does Cushing’s syndrome cause?
hypercortisolism
what can the causes of Cushing’s syndrome be divided into?
- ACTH dependent
- ACTH independent
- exogenous
what does ACTH dependent mean?
increased/inappropriately normal ACTH
what are some ACTH dependent causes of Cushing’s syndrome?
- pituitary adenoma (Cushing’s disease)
- ectopic ACTH secretion
what does ACTH independent mean?
excessive cortisol despite suppressed ACTH
what are some ACTH independent causes of Cushing’s syndrome?
- adrenal adenoma
- bilateral adrenal hyperplasia
what are exogenous causes of Cushing’s syndrome?
exogenous corticosteroids use
what are the differentials for hypercortisolism?
- metabolic syndrome
- physical stress
- malnutrition
- alcoholism
- depression
- pregnancy
you suspect a pt has Cushing’s syndrome. what do you do first?
exclude exogenous glucocorticoid exposure
once you have excluded exogenous glucocorticoid exposure, what test would you perform?
one of:
- 24 h urinary cortisol
- overnight (low-dose) 1mg dexamethasone suppression test
- salivary cortisol
the test you performed for Cushing’s syndrome came back with an abnormal result. what do you do next?
- exclude physiological causes
- perform other tests that have not been initially completed. if abnormal result → Cushing’s syndrome diagnosed
you have confirmed a dx of Cushing’s syndrome. what test do you order now?
serum midnight ACTH measurement
serum midnight ACTH measurement showed an inappropriately normal/raised ACTH. what does this mean?
ACTH dependent cause
how do you further investigate an ACTH dependent cause of Cushing’s syndrome?
high-dose dexamethasone suppression test
high-dose dexamethasone suppression test shows cortisol being suppressed. what is the cause of Cushing’s syndrome?
Cushing’s disease (pituitary adenoma)
how do you confirm a dx of Cushing’s disease?
pituitary MRI
high-dose dexamethasone suppression test does not suppress cortisol. what is the cause of Cushing’s syndrome?
ectopic ACTH
how do you confirm a dx of Cushing’s syndrome 2˚ to ectopic ACTH?
CT TAP
serum midnight ACTH measurement showed a low ACTH. what does this mean?
ACTH independent cause
how do you further investigate an ACTH independent cause of Cushing’s syndrome?
CT TAP for ? adrenal adenoma
what may be needed to differentiate between pituitary and ectopic ACTH secretion?
petrosal sinus sampling of ACTH
what is the medical mx for Cushing’s disease?
one of:
- somatostatin analogues
- steroidogenesis inhibitors
- glucocorticoid receptor antagonists
what is the surgical mx for Cushing’s disease?
transsphenoidal resection of pituitary adenoma
what is the mx for ACTH independent Cushing’s syndrome?
surgical: laparoscopic adrenalectomy
