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Flashcards in Adrenal III Deck (19):

clinical features of cushing's syndrome

incr. growth of fat deposits on face, trunk, and neck
catabolic effects on muscle cause wasting and myopathy
arrest of linear growth occurs in childhood Cushing's
catabolic effects on skin cause atrophy and easy bruising and striae


lab findings in Cushings

loss of diurnal rhythm of cortisol secretion, incr. urinary excretion of cortisol and metabolites, insulin resistance and hyperglycemia, potassium wasting causing hypokalemia


causes of Cushing's syndrome

iatrochenic, Cushing's disease (pituitary corticotroph neoplasms causing high ACTH), ectopic ACTH production by tumors, esp. small cell carcinoma of the lung, and adrenal corticol tumors (ACTH independent)


Dx of Cushing's syndrome

you need to show hypercortisolemia
meausre with salivary cortisols at midnight
then, establish ACTH dependence or independence. If it is dependent, look for a pituitary tumor.
look at regulatory system to distinguish ACTH excess from non-pituitary tumors


Tx of cushing's syndrome

pituitary surgery for cushing's disease
steroidogenic inhibitors as a temporary measure while you figure things out
adrenalectomy if you can't find a causative tumor
excision of non-pituitary ACTH-producing tumors


What are the state of mineralocorticod excess?

pirmary aldosteronism, like adrenal adenomas/hyperplasia
glucocorticoid suppressible hyperaldosterone
hypertensive forms of congential adrenal hyperplasia
syndrome of apparent mineralocorticoid excess


Tx of primary hyperaldosteronism

surgery to remove aldosterone producing tumors
medical management with mineralocorticoid receptor antagonists like spironolactone or eplerenone.
spironolactone is more effective but is unpopular with men because of its anti-androgen effects


What is glucocorticoid remediable aldosteronism?

a hypermineralocorticoid that aresponds to glucocorticoids
normally, glucocoritoid productio driven by ACTH
mineralocorticoid production driven my renin and K
in this case, you get a translocation of the glucocorticoid promoter (driven by ACTH) onto the mineralocorticoid (aldo) gene
now, aldo is sensitive to ACTH (which is senstive to cortisol levels). often cyclic
overall, this causes too much aldo and can cause HTN


tx fo glucocorticoid remediable aldosteronism?

glucocorticoids like dexamethasone to lower ACTH and reduce production of aldo


clincial manifestationsof remediable aldosteronism

salt and fluid retention with HTN
low renin and normal K (because the disease is not as severe)
autosomal dominant
incr. risk of hemorrhagic stroke in family


What is CYP11B1 hydroxylase deficiency? What are the clinical and lab symptoms

CYP11B1 is the last enzyme in cortisol synthesis.
these patients have partial adrenal insufficiency with low cortisol levels
ACTH promotes corticol hyperplasia
high ACTH leads to increased DOC producition in the zona fasciculata (DOC is the immediate precursor to cortisol_
DOC is a potent mineralocorticoid: SALT RETENTION, K LOSS, HTN
aldo is low
ACTH also drives androgen production- virulization and precocious puberty with high 17OH prgogesterone


Tx of CYP11B1 hydroxylase

low dose glucocorticoids- prevents adrenal crisis and lowers DOC production


Syndrome of apparent mineralocorticoid excess

condition where the inactivation of cortisol to cortisone by 11beta HS dehydrogenase enzyme is not working (either a genetic problem or a problem due to excess licorice consumption).
high cortisol cross-reacts with the mineralocorticoid receptors, causing salt retention, K wasting, and hypertension


Treatment of syndrome of apparent mineralocorticoid excess

dexamethasone. does not cross react with mineralocorticoid receptors but will suppress cortisol production


What are catecholamine secreting tumors of the adrenal medulla? location, causes, general types of symptoms

pheochromocytomas: catecholamine secreting tumors of chromaffin neuroendocrine cells
90% in adrenal medulla; 10% outside of adrenal medulla
may be hereditary or sporatic
symptoms are those of adrendergic stimulation


Clinical presentation of pheochromocytoma; pathophysiology of symptoms

triad of episodic HTN, sweating, and tachycardia is classic
most people with pheo actually have persistent HTN
some pheos are discovered incidentally in pts with "essential" HTN
vasoconstriction is d/t alpha receptor effects and contributes to HTN
cardioacceleration and inotropy are responsible for tachycardia and HTN


Dx of pheochromocytoma

elevated plasma levels of catecholamines or incr. excertion of their metabolites in urine
then, do a radiographic search to find the tumor


What inherited syndromes include pheochromocytoma?

Von Hippel Lindau
Neurofibromatosis-1 (NF-1 mutations)
multiple endocrine neoplasia type II (ret mutations)


Tx of pheochromocytoma

initate therapy with drugs that block alpha-adrenergic receptors to protect pt from catecholamine surges and allow vol expasnion as vasoconstriction reverses
once successful alpha blockade is in place, do surgical resection