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adrenal gland clinical
R-GU
37
Medical
Graduate
10/04/2010

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Term
what characterizes the embryology of the adrenal gland?
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.
Term
what is the name of the fascia which the adrenals are within? what is the shape of the 2 adrenals?
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)
Term
where does the arterial supply to the adrenals come from?
Definition
the *phrenic artery (off the diaphragm), the *renal artery (off the kidney), and the *aorta (directly)
Term
what veins do the adrenals drain into?
Definition
R side: IVC. L side: L renal vein (no IVC on L side)
Term
what 3 zones is the adrenal cortex divided into?
Definition
*zona glomerulosa (site of aldosterone production). *zona fasciculata (site of glucocorticoid production). *zona reticularis (site of sex steroid production. G-F-R.
Term
what is primary aldosteronism?
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.
Term
what is the pathogenesis of primary aldosteronism?
Definition
aldosterone hypersecretion promotes excessive Na+ conservation and excretion of K+ and H+ (hypokalemic, metabolic alkalosis). Na+ retention expands the extracellular volume: HTN
Term
what are the diagnostic hallmarks of primary aldosteronism?
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.
Term
what are the 2 screening tests for primary aldosteronism?
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.
Term
how can primary aldosteronism be evaluated via procedure?
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
Term
how is primary aldosteronism due to bilateral hyperplasia treated?
Definition
since both adrenal glands cannot be removed, K sparing diuretics such as spironolactone are administered
Term
how is primary aldosteronism due to unilateral adrenal adenoma treated?
Definition
adrenalectomy w/pre-op spironolactone therapy
Term
what is cushing's syndrome?
Definition
excess glucocorticoid which has *escaped regulation - the normal diurnal variation in cortisol is lost.
Term
what are the two types of cushing's syndrome?
Definition
ACTH dependent and ACTH independent
Term
what are the 2 subtypes of ACTH dependent cushing's syndrome?
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**)
Term
what is ACTH independent cushing's syndrome?
Definition
the *zona fasciculata of adrenal gland itself is secreting too much cortisol, due to: benign adenoma, adrenocortical CA, or adenomatous hyperplasia.
Term
how do pts present w/cushing's syndrome?
Definition
proximal muscle weakness, truncal obesity, round face, buffalo hump, broad skin, mustache/beard (females too), and amenorrhea
Term
what is the screening test or cushing's syndrome?
Definition
24 hr urinary cortisol (if positive, will be high), then the dexamethasone cortisol test.
Term
what is the dexamethasone screening test? (*know this*)
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.
Term
how can cushing's syndrome be diagnosed via imaging?
Definition
CT, MRI, or adrenal scanning w/iodinated cholesterol
Term
what is the tx for cushing's syndrome?
Definition
cushing disease: XRT, transphenoidal sx. ectopic ACTH syndrome: remove source (lung CA, etc), if not possible - utilize steroid blocking agents (aminoglutethimide, metyrapone)
Term
what characterizes the incidence of adrenocortical CA?
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.
Term
what is the tx for adrenocortical CA?
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.
Term
what is the most common cause of ambiguous genitalia (intersex) in newborns?
Definition
congenital adrenal hyperplasia (80% of intersex cases), which is due to an autosomal recessive inborn error of adrenal steroid metabolism.
Term
what is the pathogenesis of congenital adrenal hyperplasia?
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.
Term
what is the tx for congenital adrenal hyperplasia?
Definition
cortisol administration and sometimes mineralcorticoid (aldosterone)
Term
what is the only disease of the adrenal medulla we will talk about?
Definition
pheochromocytoma
Term
what is pheochromocytoma?
Definition
non-innervated *chromaffin tumors produce, store, and secrete catecholamines
Term
what is the avg lag between the onset of symptoms of a pheochromocytoma and dx?
Definition
~4.5 yrs - problematic b/c complications such as CVA, MI, CHF, cariomyopathy, renal failure can all occur
Term
what is the presentation of pts w/pheochromocytoma?
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.
Term
how is pheochromocytoma diagnosed?
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.
Term
what is the rule of 10's w/pheochromocytoma?
Definition
10% are familial, 10% are bilateral, 10% are malignant, and 10% are extra-adrenal (paragangliomas)
Term
what is important to remember in surgical tx for pheochromocytomas?
Definition
do not squeeze - can bump up to lethal HTN, but do attempt early ligation of adrenal vein and beware of post-op hypoglycemia.
Term
what is an incidental adrenal mass? what are the 2 important accompanying questions?
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.
Term
what are the 2 common presentation of an incidental adrenal mass on CT?
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.
Term
what is the sizing rule of thumb for adrenal mass surgical removal?
Definition
remove anything more than 6 cm, watch anything less than 3 cm.
Term
what is *stouffer's syndrome*?
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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