Adrenal Insufficiency Flashcards
What is the major glucocorticoid released by the adrenal glands?
Hydrocortisone
How much cortisol is actually active in the body?
10%
What is the mechanism of CIRCI in septic shock?
Suppression of the hypothalamic-pituitary level by inflammatory cytokines
Why are total cortisol levels often misleading?
Because the total cortisol levels include the bound cortisol which is 90%, but this could be diminished while the active cortisol level is normal or high.
What are the drugs that increase the metabolism of cortisol?
Phenytoin
Rifampin
What are the drugs that decrease the synthesis of cortisol?
Ketoconazole
Etomidate
What is the principal manifestation of adrenal insufficiency in the ICU.
Hypotension refractory to volume resuscitation
How do you diagnose adrenal insufficiency
ACTH stimulation test
Total cortisol level
Random cortisol level
What is the best test for diagnosing adrenal insufficiency
Random cortisol level
What is a normal ACTH stimulation test?
Less than 9 ug/dl increment after ACTH
What is the dose of ACTH to give for the stimulation test?
250 ug/dl
What is a normal random plasma cortisol?
Above 35 ug/dl
How much cortisol do we produce daily?
15-25 mg/day
What level or random cortisol level would suggest adrenal insufficiency?
Less than 10 ug/dl
What is the shortcoming of an ACTH stimulation test in diagnosing adrenal insufficiency?
It would not tell you if the hypothalamus was being suppressed
What is suggested for patients with septic shock?
A trial of IV hydrocortisone when hypotension is refractory to volume resuscitation
What is the treatment of critical illness related adrenal insufficiency
200-300 mg daily of hydrocortisone
(50 mg IV q6h or 100 mg q8h
What is the mechanism of adrenal insufficiency in the ICU?
ACTH from the anterior pituitary is blocked from hitting the adrenal gland by inflammatory cytokines
Drugs decrease the production of cortisol (ketoconazole, etomidate)
Infection causing hemorrhage of the adrenal glands
CRF from the hypothalamus is blocked by inflammatory cytokines
What is an equivalent prednisone dose to hydrocortisone?
20 mg of hydrocortisone to 5 mg of prednisone
What is the hydrocortisone equivalent of methylprednisone
20 mg of hydrocortisone to 4 mg methylprednisone
What is the hydrocortisone equivalent to dexamethasone?
20 mg to 0.75mg
How does ACTH do?
Stimulates zone glomerulosa of the adrenal cortex to release aldosterone
Stimulates cortisol production in the zona fasciculata
What do glucocorticoids do?
Produce more aldosterone
Inhibit phospholipase A2
What does phospholipase A2 do?
Creates arachidonic acid from phosphatidylcholine which is the precursor to prostaglandins, leulotrienes and other inflammatory cytokines
What is the dosing of stress dose steroids?
200-300 mg/day
50 mg IV q6h
100 mg IV q8h
What is the initial IV bolts dose?
100 mg
