013015 adrenal insuff, cushing syndrome Flashcards
effects of cortisol
synchronizes circadian clock immune and inflam gluconeogenesis, lipolysis, proteolysis increase appetite depression, anxiety growth and reproduction cardiovascular tone
symptoms of adrenal insufficiency
fatigue
GI-nausea, vomiting, anorexia, weight loss
hypotension-dizziness, orthostasis
increased skin pigmentation (primary adrenal insuff)
salt craving (primary adrenal insuff)
lab abnormalities in adrenal insufficiency
hyponatremia
hyperkalemia (primary adr insuff)
lymphocytosis
imaging abnormalities for adrenal insuff
bilateral adrenal enlargement
pituitary mass
what drugs can cause adrenal insuff
ketoconzaole, etomidate, mitotane, metyrapone
mifepristone (glucocorticoid receptor antagonist)
how do you diagnose adrenal insuff?
plasma cortisol an hour after cosyntropin (ACTH analogue) stimulation
look at CBC, serum sodium, potassium, creatinine, urea, TSH
what is the value of the cosyntropin stimulation test?
it evaluates for maximum adrenocortical secretory capacity and tests for adrenal destruction (primary insufficiency) or adrenal atrophy (secondary adrenal insuff)
once we see that the cortisol levels are low and the cosyntropin stimulation test gives low cortisol, how do you determine the cause of adrenal insufficiency?
slide 15
most common cause of primary adrenal insuff
autoimmune adrenalitis
blood cortisol test looks at
free and bound cortisol
causes of secondary adrenal insuff
withdrawal from exogenous corticosteroid therapy
pituitary/hypothalamic disease (hypophysitis)
tx for primary adrenal insuff
hydrocortisone-authentic cortisol (important: plasma ACTH should remain elevated even with adquate hydrocortisone-low/normal levels may reflect overreplacement)
fludrocortisone-aldosterone equivalent
tx for secondary adrenal insuff
hydrocortisone (less needed than in primary adr insuff b/c there is usually still some cortisol secretion from adrenals)
cushing’s syndrome symptoms
weight gain proximal muscle weakness hirsutism/androgen excess in women violaceous striae cutaneous wasting easy bruising facial fullness diabetes osteoporosis increased BP myopathy neuropsych disorders edema hypogonadism growth retardation (in children)
physiologic hypercortisolism
due to stress, alcohol, neuropsych disorders, starvation
what diagnosis could raise your suspicion for Cushing syndrome
diabetes/hypertension/metabolic syndrome
osteoporosis
adrenal nodules
how do you diagnose Cushing’s syndrome
if Cushing syndrome is suspected, need exclude exogenous glucorticoid exposure first
then perform one of the following tests:
- -24 hour urine cortisol (not very sensitive)
- -overnight DST (dexamethasone)-many false positives
- -late night salivary cortisol
if the test result is abnormal, you need to exclude physiologic causes of hypercortisolism
what are possible causes of Cushing syndrome?
ACTH dependent:
- ACTH secreting pituitary tumor (Cushing’s dis)
- non-pituitary ACTH secreting tumor (ectopic ACTH)
ACTH independent:
- -exogenous glucocorticoid therapy-most common cause of Cushing syndrome
- -adrenal adenoma or carcinoma
- -nodular adrenal hyperplasia (bilateral)
how can you diagnose the cause of tCushing syndrome
measure plasma ACTH
see slide 38
tx for Cushing syndrome
surgery-remove tumor (pituitary, adrenal)
bilateraly adrenalectomy is indicated in pts who have failed other modalities of tx. definitive tx but then would depend on steroids for life
radiotherapy (for pituitary Cushing if surgery fails)
pituitary-directed: pasireotide (somatostatin receptor agonist) and cabergoline (dopamine receptor agonist) if surgery fails
adrenal steroidogenesis inhibitors:
- -ketoconazole
- -metyrapone
- -mitotane (used in adrenal cancer)
- -etomidate
glucocorticoid receptor antagonist:
–mifeprisone
in primary adrenal insuff, what can you see in the adrenal glands?
massive bilateral adrenal enlargement (due to trophic effects of ACTH)
