CM: Adrenal Disorders Flashcards
What is the general evaluation of a pt with an incidentally discovered adrenal nodule?
look at the scan:
3 cm increases risk of hormone excess, CA
look at the other adrenal
look for HTN or other recent changes
Screen for cushings and pheo using 1 mg ON-DST and plasma metanephrines
screen for primary aldo if HTN and low K
most don’t need treatment
What is the follow-up/treatments recommended for incidentally discovered adrenal nodules?
nasty looking needs biopsy but only AFTER ruling out pheo (could precipitate crisis)
tumors >4cm or hyperfunction removed regardless
repeat imaging in 6-12 mos, sooner for larger
What are some additional diagnostic strategies for Cushings?
can use imaging, inf petrosal sinus sampling
What clinical features can distinguish primary from secondary adrenal insufficiency?
primary has eosinophilia
secondary has less hyperkalemia and hypotension, no hyperpigmentation
What tests can be used to diagnose adrenal insufficiency?
cortisol: 15 nL
ACTH: low (100)
cosyntropin stimulation test: 1 shot of ACTH then measure cortisol at 30min-1hr: >18-20 ug/dL is nL (better for primary)
DHEA-S: nL (>85) exclude acquired cortisol def but not CAH
What test findings can distinguish primary from secondary adrenal insufficiency?
Primary - high renin, low aldo
secondary - both normal or high
secondary - may pass standard cosyntropin test but fail low dose
Who should be screened for primary aldosteronism?
pts w HTN and spontaneous hypokalemia (<40
pts w HTN and known adrenal mass
What are the screening tests for primary aldosteronism?
discontinue aldo antagonists and antiHTN meds
24 h urine Na and K: high K excretion w low plasma K is evidence
plasma aldo/renin activity ratio (PAC/PRA): >15 diagnostic of aldosteronism
What are the confirmatory tests for primary aldosteronism?
prove that volume expansion doesn’t suppress aldo
24h urine aldo on high salt diet: high aldo excretion w high Na
saline infusion test: high levels of plasma aldo after test
fludrocortisone suppression test: high Na diet and take fludrocortisone - measure 24 h urine aldo and plasma aldo after 3 days of this
What are the localizing tests for aldosteronism?
goal is to distinguish APA from IHA
adrenal CT: but can’t tell what’s functional, lots of incidental, etc.
adrenal vein sampling: gold standard - infuse cosyntoprin, then sample both adrenal veins, IVC for aldo and cortisol - aldo/cortisol ratio for two sides compared, >4:1 discrepancy confirms unilateral aldo production - adrenal vein/IVC cortisol step ups >3:1 confirm good study
What clinical features of pheo/paraganglioma prompt testing for the disorders?
spells w high BP, tachycardia, headache, sweating, blanching of face that last 10-60 min
spontaneous or elicited by exercise, IV contrast or unusual stimuli
What are the pros and cons of measuring urine metanephrines and catecholamines in pheo?
any value >2x upper limit of normal is positive
BUT modest elevations common in conditions that mimic pheo - pts w symptomatic pheos have profound elevations (>5x normal) in proportion to symptoms
What are the differences b/w measure catecholamines and metanephrines in the plasma?
process of drawing blood itself will elevate catecholamines, but metanephrines are okay
What are the cons of measuring catecholamines and metanephrines in the plasma?
slightly elevated normetanephrine common, but must still be taken seriously
best reserved for pts w high probability of dz (MEN or VHL)
