cushing

Question 1

cushing syndrome/ disease causes?

Answer 1

syndrome = primarily high cortisol
disease = high ACTH with high cortisol

1. iatrogenic from prescribed steroids
2. adrenal adenoma
3. ACTH-producing pituitary adenoma
4. ectopic ACTH production from small cell carcinoma

Question 2

clinical features?

Answer 2

labs: hypernatremia, hypokalemia, hyperglycemia, metabolic alkalosis, hyperlipidemia
explanation: excess cortisol is free to bind to mineralocorticoid receptors, causing Na and water retention and K and H secretion

skin: purple abdominal striae, acne, hirsutism, acne, facial flushing
fat: central obesity, moon face, buffalo hump
insulin resistance and hyperglycemia
MSK: muscle weakness/ atrophy, osteoporosis
others: HTN
cushing disease: high ACTH and skin pigmentation

Question 3

diagnosis?

Answer 3

screening: 24 urine cortisol, late night salivary cortisol, low dose dexamethasone suppression test (all have high cortisol)

confirmatory is by checking ACTH level to also know the type
high ACTH: from pituitary or ectopic
low ACTH: from adrenal

then do high dose dexamethasone suppression: if suppressed then pituitary source if not then ectopic

Question 4

treatment?

Answer 4

cushing syndrome: taper doses or surgical adrenalectomy

cushing disease: transphenoid hypophysectomy

ectopic: surgical removal with node dissection as appropriate