Term
| what characterizes the embryology of the adrenal gland? |
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Definition
| the adrenal cortex is of mesodermal origin while the medulla is of ectodermal origin. these different parts are combined in the 5th week of development. |
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Term
| what is the name of the fascia which the adrenals are within? what is the shape of the 2 adrenals? |
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Definition
| gerota's fascia. the R adrenal is triangular (between liver/diaphragm/IVC) and the L adrenal is cresenteric (between the pancreas/spleen/stomach/diaphragm/aorta) |
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Term
| where does the arterial supply to the adrenals come from? |
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Definition
| the *phrenic artery (off the diaphragm), the *renal artery (off the kidney), and the *aorta (directly) |
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Term
| what veins do the adrenals drain into? |
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Definition
| R side: IVC. L side: L renal vein (no IVC on L side) |
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Term
| what 3 zones is the adrenal cortex divided into? |
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Definition
| *zona glomerulosa (site of aldosterone production). *zona fasciculata (site of glucocorticoid production). *zona reticularis (site of sex steroid production. G-F-R. |
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Term
| what is primary aldosteronism? |
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Definition
| primary aldosteronism/conn syndrome pts have autonomous non-suppressible secretion of aldosterone. 75% of these pts have an adrenal adenoma and 25% have bilateral adrenal hyperplasia. |
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Term
| what is the pathogenesis of primary aldosteronism? |
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Definition
| aldosterone hypersecretion promotes excessive Na+ conservation and excretion of K+ and H+ (hypokalemic, metabolic alkalosis). Na+ retention expands the extracellular volume: HTN |
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Term
| what are the diagnostic hallmarks of primary aldosteronism? |
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Definition
| HTN, unprovoked hypokalemia (what you measure w/blood work), low plasma renin activity, and elevated urinary/plasma aldosterone levels. *despite excessive Na+ reabsorption, serum Na+ is not typically markedly elevated. |
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Term
| what are the 2 screening tests for primary aldosteronism? |
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Definition
| *pts are placed on Na+ restriction, which should raise renin levels - but pts w/primary aldosteronism still have high levels of aldosterone, so renin levels remain low. alternately, *pts can be loaded w/Na+ and their aldosterone should drop (b/c they are getting so much Na+), but primary aldosteronism pts' aldosterone levels should remain high. |
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Term
| how can primary aldosteronism be evaluated via procedure? |
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Definition
| adrenal venous sampling (putting a catheter into the femoral vein into the adrenal and measure the aldosterone level there), or a CT scan should show a thickened adrenal gland/mass |
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Term
| how is primary aldosteronism due to bilateral hyperplasia treated? |
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Definition
| since both adrenal glands cannot be removed, K sparing diuretics such as spironolactone are administered |
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Term
| how is primary aldosteronism due to unilateral adrenal adenoma treated? |
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Definition
| adrenalectomy w/pre-op spironolactone therapy |
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Term
| what is cushing's syndrome? |
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Definition
| excess glucocorticoid which has *escaped regulation - the normal diurnal variation in cortisol is lost. |
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Term
| what are the two types of cushing's syndrome? |
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Definition
| ACTH dependent and ACTH independent |
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Term
| what are the 2 subtypes of ACTH dependent cushing's syndrome? |
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Definition
| *cushing disease: excessive pituitary production of ACTH, ~75% of total cases, most result from a pituitary adenoma. *ectopic ACTH: from a variety of tumors (**oat cell CA**) |
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Term
| what is ACTH independent cushing's syndrome? |
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Definition
| the *zona fasciculata of adrenal gland itself is secreting too much cortisol, due to: benign adenoma, adrenocortical CA, or adenomatous hyperplasia. |
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Term
| how do pts present w/cushing's syndrome? |
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Definition
| proximal muscle weakness, truncal obesity, round face, buffalo hump, broad skin, mustache/beard (females too), and amenorrhea |
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Term
| what is the screening test or cushing's syndrome? |
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Definition
| 24 hr urinary cortisol (if positive, will be high), then the dexamethasone cortisol test. |
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Term
| what is the dexamethasone screening test? (*know this*) |
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Definition
| the normal response to dexamethasone (which looks like cortisol to the body) is cortisol secretion suppression. the *low dose dexamethasone test is then performed first, and those who suppress cortisol secretion in response to injected dexamethasone are determined to be normal. pts who did not suppress cortisol w/a low dose of dexamethasone are then given a high dose. pts whose pituitary gland is responsible for cushing's syndrome (cushing disease) will stop making cortisol at this higher dose of dexamethasone, while pts w/adrenal CA or ectopic ACTH will continue making cortisol. |
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Term
| how can cushing's syndrome be diagnosed via imaging? |
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Definition
| CT, MRI, or adrenal scanning w/iodinated cholesterol |
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Term
| what is the tx for cushing's syndrome? |
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Definition
| cushing disease: XRT, transphenoidal sx. ectopic ACTH syndrome: remove source (lung CA, etc), if not possible - utilize steroid blocking agents (aminoglutethimide, metyrapone) |
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Term
| what characterizes the incidence of adrenocortical CA? |
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Definition
| rare, but poor prognosis. *50% of pts w/this are diagnosed at stage 1 and have a 50% 5 yr survival rate. *50% of pts will have a functional CA and present w/some kind of endocrine syndrome, conn etc - and are more likely to be diagnosed earlier, and thus fare better. |
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Term
| what is the tx for adrenocortical CA? |
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Definition
| sx - wide operative exposure is necessary and all regional lymph nodes should be removed, sometimes even even the kidneys. pts with inoperable/recurrent/metastatic disease are given mitotane (chemo), which can cause adrenal insufficiency. |
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Term
| what is the most common cause of ambiguous genitalia (intersex) in newborns? |
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Definition
| congenital adrenal hyperplasia (80% of intersex cases), which is due to an autosomal recessive inborn error of adrenal steroid metabolism. |
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Term
| what is the pathogenesis of congenital adrenal hyperplasia? |
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Definition
| an enzyme (21 hydroxylase 95% of cases) necessary to cortisol production is missing, which the body attempts to compensate for w/ACTH overproduction - which then leads to hyperplasia of the adrenal cortex and overproduction of cortisol precursors. sex steroid over-production will also occur and female genitalia will become masculinized. |
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Term
| what is the tx for congenital adrenal hyperplasia? |
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Definition
| cortisol administration and sometimes mineralcorticoid (aldosterone) |
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Term
| what is the only disease of the adrenal medulla we will talk about? |
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Definition
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Term
| what is pheochromocytoma? |
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Definition
| non-innervated *chromaffin tumors produce, store, and secrete catecholamines |
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Term
| what is the avg lag between the onset of symptoms of a pheochromocytoma and dx? |
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Definition
| ~4.5 yrs - problematic b/c complications such as CVA, MI, CHF, cariomyopathy, renal failure can all occur |
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Term
| what is the presentation of pts w/pheochromocytoma? |
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Definition
| paroxysmal or sustained HTN. paroxysmal attacks may be precipitated by stress, anesthesia, manipulation (during operation) or foods rich in tyramine (rubarb) and cause headaches, diaphoresis, apprehension, high anxiety, constipation, visual complaints, weakness, and wt loss. |
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Term
| how is pheochromocytoma diagnosed? |
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Definition
| 24 hr urine and measure VMA/*metanephrines* (stable breakdown product of epinephrine). CT/MRI, but MRI is better (superior soft tissue differentiation) b/c it will give you the **light bulb sign**. an MIBG scan is also available which images the whole body (extra-adrenal/metastatic) for excessive epinephrine if MRI is inconclusive. |
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Term
| what is the rule of 10's w/pheochromocytoma? |
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Definition
| 10% are familial, 10% are bilateral, 10% are malignant, and 10% are extra-adrenal (paragangliomas) |
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Term
| what is important to remember in surgical tx for pheochromocytomas? |
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Definition
| do not squeeze - can bump up to lethal HTN, but do attempt early ligation of adrenal vein and beware of post-op hypoglycemia. |
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Term
| what is an incidental adrenal mass? what are the 2 important accompanying questions? |
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Definition
| the discovery of an adrenal mass during evaluation of an unrelated disease. once discovered, whether it is *hormonally active and whether it is *malignant need to be determined. |
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Term
| what are the 2 common presentation of an incidental adrenal mass on CT? |
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Definition
| *a smooth homogenous mass of low density w/little contrast enhancement is consistent w/an adenoma. *a large heterogenous mass that enhances (hypervascular - takes up more contrast) is more likely to be malignant. |
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Term
| what is the sizing rule of thumb for adrenal mass surgical removal? |
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Definition
| remove anything more than 6 cm, watch anything less than 3 cm. |
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Term
| what is *stouffer's syndrome*? |
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Definition
| kidney CA can sometimes *raise LFTs* even if the liver is unaffected. this is important b/c pts may be denied kidney sx due to increased LFTs. |
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