Adrenal Hormones Flashcards
Adrenal insufficiency
Most common cause is autoimmune
Clotting disorders- hemorrhage
Amyloidosis
Adrenoleukodystrophy- young boys have long chain fatty acids and demyelination, accumulate in adrenals
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Secondary AI
adrenal gland atrophy from ACTH
most often due to exogenous glucocorticoid use
Panhypopituitarism
isolated ACTH def
-low circulating ACTH levels because of hypothalamic or pituitary release as a consequence cortisol levels are low
no aldosterone deficiency
Primary adrenal insufficiency
-circulating ACTH is elevated because of negative feedback effects of low circulating cortisol
will have hyperpigmentation in palmar creases
Diagnosis of AI
morning cortisol value less than 4 mg/dl
cosyntropin (ACTH) stimulation test is gold standard- rise in cortisol to 18 and or change in 9 (after cosyntropin is given) is a normal response
tx of adrenal insufficiency
IV fluids, high dose IV glucocorticoids
chronic- mineralocorticoids (hydrocortisone or prednisone), dosage inc for stress
Hydrocortisone
short acting steroids
mimic diurnal rhythm and 100% bioavailable
once in morning and once in afternoon
Long actnig steroids
dexamethasone and prednisone
for non compliant pts
fludrocortisone
potent steroid mainly mineralocorticoid
for pts with primary adrenal insufficiency
-helps sodium retention
hypokalemia common side effect
steroid side effects
- at high doses
- immunosuppression, hypertension, weight gain, osteoporosis or bone loss, insomnia, mood swings, peptic ulcers, redistribution of body fat
- thinning of skin
- reduces growth in children
Cushing’s disease
excessive glucocorticoid exposure either from adrenals or exogenous
-obesity, htn, glucose intolerance, striae
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diagnosis of cushings
24 hr urine cortisol excretion 3 times the upper limit of normal (150 mg/dl)
-late evening salivary cortisol
tx for pituitary cushings
transphenoidal surgery to remove pituitary adenoma
ketoconazole
nonselective inhibitor of adrenal and gonadal steroids for adrenal cushing's -can cause headaches, sedation, nausea potential hepatotoxicity blocks 17 hydroxylase and 17,20 lyase
Mitotane
nonselective cytotoxic agent for adrenal cortex
-reserved for pts with adrenal carcinoma
severe toxicity
Mifepristone
glucocorticoid receptor antagonist
-rapidly effective for diabetes related to cushing’s
substantial side effects like hypokalemia and QT prolongation
Primary aldosteronism
asymptomatic htn and easily provoked hypokalemia
edema usually absent
aldosterone promotes reabsorpion of sodium by distal tubule with excretion of potassium
diagnosis of primary aldosteronism
urinary potassium >30 meq/l
-screen by plasma aldo/plasma renin ratio (>20 in primary aldosteronism, <10 in secondary aldosteronism)
24 hr urine for aldosterone and sodium or salt loading test
Secondary aldosteronism
htn, hypokalemia, inc aldosterone, inc plasma renin activity
due to renal artery stenosis
tx of aldosteronism
surgery- unilateral adrenalectomy unless poor surgical risk
dietary salt restriction and spironolactone to block aldosterone receptor
amiloride or triamterene
spironolactone and eplerenone
mineralocorticoid antagonist
limits potassium loss
may cause hyperkalemia
gynecomastia (not with eplerenone)
Congenital adrenal hyperplasia
90% due to 21 hydroxylase deficiency
full or partial block of glucocorticoid and mineralocorticoid production and spillover into androgen pw
low cortisol levels stimulate continued ACTH production and overproduction of precursors that are diverted to biosynthesis of sex hormones
females- ambiguous genitalia
males- no overt signs of disease
untreated congenital adrenal hyperplasia
rapid somaic growth, advanced bone age, premature epiphyseal fusion and short stature, acne
tx for CAH 21 OH def
Glucocorticoids in lowest dose
-long acting steroids such as dexamethasone is used to reduce ACTH levels, which suppresses androgen levels and maintains ormal growth
-mineralocorticoids in salt wasting form
No GC in asymptomatic children
100% glucocorticoids
dexamethasone
