hyperadrenals Flashcards
features of cushings
excess cortisol centripetal obesity, proximal (trunk) myopathy, moon face and buffalo hump, hypertension and hypokalaemia, striae, thin skin= bruising (immunosupression), and osteoporosis and diabetes
causes of cushings syndrome (from any cause)
most common taking too many steroids (mainly corticosteroids) endogenous causes are mainly pituitary dependent cushings disease (disease caused by pituitary fault), but also ectopic ACTH from lung cancer, and adrenal adenoma= excess cortisol
investigating cushings syndrome with dose and why DIAGRAM
24hr urine collection for cortisol OR blood diurnal (different times of day) cortisol levels as cortisol highest in morning, and lowest during midnight (as asleep) also low dose (0.5mg every 6 hrs for 48 hrs) dexamethasone supression test (artifical steroid that stops cortisol production to 0 if normal- )
problem with dexamethasone
doesn’t tell you cause of cushings, as any cause will fail to surpress cortisol
example of diagnosis using dexamethsone test
basal cortisol (9am) 800nM, cortisol after test 680
main treatment of cushings syndrome, and problem with solution
main treatment is surgery, but patients are immunosurpressed (risk of infection during surgery), so must ensure they recover well after surgery- thus drugs are used to reduce cortisol
adrenal cortex+ synthesis of cortisol
derived from cholesterol glomerulosa= aldosterone, fasciculata= cortisol, reticularis= SOME sex steroids
metyrapone mechanism
inhibits 11beta-hydroxylase, which converts 11-deoxycortisol to cortisol (ie deoxycortisol rises- has no negative feedback) enzyme also converts 11-deoxycorticosterone to corticosterone, so this is also inhibited
uses of metyrapone
controls cushings before surgery, adjusting dose according to cortisol controlling cushing after radiotherapy (slow to take effect- used for pituitary tumour)
problem with metyrapone
deoxycorticosterone accumulates, and it has aldosterone-like properties= salt retention+ hypertension many of precursors accumulate, which are also used to produce sex hormones, thus more androgen production in women= HIRSUTISM
ketoconazole- uses- who used for and mechanism
also reduces cortisol production in cushings prior to surgery- is antifungal agent as a tablet that is not usually used as potential toxic to liver, but used for a select group of patients inhibits 17alpha hydroxylase
treating cushings after drugs
depending on cause, pituitary surgery can be used (transphenoidal surgery- removing tumour through nasal cavity) bilateral/unilateral adrenalectomy (no ACTH production)
what is conns syndrome+ main effects
benign adrenal cortical tumour of zona glomerulosa= excess aldosterone= hypertension+ hypokalemia (retain sodium and lose potassium)
diagnosis of conns (primary hyperaldosteronism)
measure aldosterone- should be high measure renin- should be low ie primary hyperaldosteronism, not secondary
overview of treatment of conns
rather than blocking production of hormone, the receptor is blocked
spironolactone mechanism+ pharmacokinetics
converted to canrenone, a competitive antagonist of mineralocorticoid receptor (MR), blocking Na+ in and K+ out ie potassium sparing tablet+ metabolised in liver
problem with spironolactone
not very specific to MR receptor- binds to progesterone receptor (menstrual problems) and inhibits androgen receptor (gynaecomastia)
epleronone advantage
also MR antagonist with similar affinity, but less binding to other receptors= less side effects
what are phaeochromocytomas
tumour of adrenal medulla= XS adrenaline+ NA
clinical features of phaeo
INTERMITTENT severe episodes of hypertension- often in young pp= MI/stroke: can also cause ventricular fibrillation and death sweating sick/headache/dizziness anxiety more common in certain inherited conditions
treatment of phaeo
surgery, although patient needs careful preparation of anesthetic, as it can cause a hypertensive attack alpha blockade is needed (possibly IV fluid before to prevent large decrease in BP), and THEN beta blockade to prevent tachycardia- once this is done, surgery can occur
facts about phaeochromocytone
10% extra-adrenal (not from adrenal gland), 10% malignant, 10% bilateral extremely rare
