therapeutic use of adrenal steroids Flashcards
what are the zones of the adrenal glands?
- zona fasciculata: cortisol
- zona glomerulosa: aldosterone
- zona reticualris: sex steroids
describe glucocorticoid receptors?
- widely distributed
- selective for glucocorticoids
- low affinity for cortisol
describe mineralocorticoid receptors
- discrete distribution
- non selective b/ aldosterone and cortisol
- high affinity for cortisol
what happens in Cushing’s, regarding these receptors, when you produce too much cortisol?
- producing too much cortisol
- 11 beta HSD2 overwhelmed
- cortisol binds too much to MR causing hypertensive episodes
- cortisol has higher affinity for MR than aldosterone
what are some drugs used to mimic human hormones?
- hydrocortisone: glucocorticoid with mineralcorticoid at high doses
- prednisolone: glucocorticoid with weak mineralcorticoid activity
- dexamethasone: glucocorticoid with no mineralocorticoid activity
- fludrocortisone: aldosterone analogue
what are the DoAs of hydrocortisone, prednisolone, dexamethasone?
- hydrocortisone (8 hrs)
- prednisolone (12 hours)
- dexamethasone (40 hours)
what is the CRT in primary adrenocortical failure?
- Addson’s disease
- pt lack cortisol and aldosterone
- treated w/ hydrocortisone (for cortisol) and fludrocortisone (for aldosterone)
what is the CRT in secondary adrenocortical failure?
ACTH def
Pt lack cortisol but aldosterone is normal
treat w/ hydrocortisone
how do you treat an Addisonian Crisis?
- IV saline - rehydrate
- High dose hydrocortisone (ensures mineralcorticoid effect as 11beta HSD2 is overwhelmed)
- 5% dextrose - if hypoglycaemic
what is the most common CAH? what happens?
21 hydroxyalse def
- causes 17a-hydroxyprogesterone to accumulate
- no cortisol production so ACTH rises
- high ACTH drives further androgen production
what is the therapy for this?
- replace cortisol (hydrocortisone)
- suppress ACTH
- replace aldosterone (fludrocortisone)
how do you monitor/optimise this therapy?
by measuring:
- 17 hydroxyprogesterone levels
- clinical assessments (if GC dose too high - cushingoids, GC dose too low, hirsutism)
when is it important to change the glucocorticoid dosage?
- should be inc. when patients are vulnerable to stress
- in minor illness
- surgery