therapeutic use of adrenal steroids

Question 1

what are the zones of the adrenal glands?

Answer 1

• zona fasciculata: cortisol
• zona glomerulosa: aldosterone
• zona reticualris: sex steroids

Question 2

describe glucocorticoid receptors?

Answer 2

• widely distributed
• selective for glucocorticoids
• low affinity for cortisol

Question 3

describe mineralocorticoid receptors

Answer 3

• discrete distribution
• non selective b/ aldosterone and cortisol
• high affinity for cortisol

Question 4

what happens in Cushing’s, regarding these receptors, when you produce too much cortisol?

Answer 4

• 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

Question 5

what are some drugs used to mimic human hormones?

Answer 5

• hydrocortisone: glucocorticoid with mineralcorticoid at high doses
• prednisolone: glucocorticoid with weak mineralcorticoid activity
• dexamethasone: glucocorticoid with no mineralocorticoid activity
• fludrocortisone: aldosterone analogue

Question 6

what are the DoAs of hydrocortisone, prednisolone, dexamethasone?

Answer 6

• hydrocortisone (8 hrs)
• prednisolone (12 hours)
• dexamethasone (40 hours)

Question 7

what is the CRT in primary adrenocortical failure?

Answer 7

• Addson’s disease
• pt lack cortisol and aldosterone
• treated w/ hydrocortisone (for cortisol) and fludrocortisone (for aldosterone)

Question 8

what is the CRT in secondary adrenocortical failure?

Answer 8

ACTH def
Pt lack cortisol but aldosterone is normal
treat w/ hydrocortisone

Question 9

how do you treat an Addisonian Crisis?

Answer 9

1. IV saline - rehydrate
2. High dose hydrocortisone (ensures mineralcorticoid effect as 11beta HSD2 is overwhelmed)
3. 5% dextrose - if hypoglycaemic

Question 10

what is the most common CAH? what happens?

Answer 10

21 hydroxyalse def

• causes 17a-hydroxyprogesterone to accumulate
• no cortisol production so ACTH rises
• high ACTH drives further androgen production

Question 11

what is the therapy for this?

Answer 11

• replace cortisol (hydrocortisone)
• suppress ACTH
• replace aldosterone (fludrocortisone)

Question 12

how do you monitor/optimise this therapy?

Answer 12

by measuring:

• 17 hydroxyprogesterone levels
• clinical assessments (if GC dose too high - cushingoids, GC dose too low, hirsutism)

Question 13

when is it important to change the glucocorticoid dosage?

Answer 13

• should be inc. when patients are vulnerable to stress
• in minor illness
• surgery