Corticosteroids

Question 1

Actions of Cortisol

Answer 1

carbohydrate metabolism (gluconeogenesis)
increases protein catabolism
inhibits insulin from shuttling into cells
mobilized free fatty acids
suppression of pro inflammatory cytokines
suppress immune system

Question 2

normal mg cortisol production per day

Answer 2

15-30, highest at 0800.

Question 3

cortisol levels based on procedure

Answer 3

minor: up to 50mg/day. returns to baseline in 24h
moderate: up to 75-100mg/day. returns to baseline in 5d
major: up to 200mg/day. returns to baseline by day 5

Question 4

Addisons Disease

Answer 4

primary adrenocortical insufficiency. destruction of all cortical zones

Question 5

secondary adrenal insufficiency

Answer 5

after 2wks suppression of HPA axis, chronic glucocorticoid tx (3-4w), topical admin of aerosols for asthma, TBI.

Question 6

adrenal crisis sx and causes

Answer 6

hypotension (hallmark), acute abdominal sx, n/v, AMS, fatigue, fever, hyponatremia, hyperkalemia, hypocalcemia.
caused by interruption of glucocorticoid intake, infx, surgery, gastroenteritis stress

Question 7

adrenal crisis management

Answer 7

NS 1L over 6-12h, hydrocortisone 100mg. then 50mg q6h.

Question 8

Corticosteroids MOA

Answer 8

stimulate changes in transcription of 456 DNA. target cells contain enzyme 11 beta hydroxysteroid dehydrogenase

Question 9

PK of corticosteroids

Answer 9

antacids interfere with oral absorption
highly protein bound (90%) to corticosteroid binding globulin
readily crosses placenta
elimination half time of cortisol 1.5-3h
70% metabolized in liver to inactive or poorly active metabolites

Question 10

clinical uses of corticosteroids

Answer 10

antiemetic (preop), analgesia (postop), immunosuppression, laryngeal edema, regional blocks (prolongs them), asthma (not rescue), cerebral edema, adrenal insufficiency

Question 11

Prednisolone use

Answer 11

sole replacement therapy in adrenocortical insufficiency

Question 12

prednisone conversion

Answer 12

rapidly converted to prednisolone after absorption from GI tract

Question 13

methylprednisolone use

Answer 13

used to produce intense glucocorticoid effect

Question 14

dexamethasone use

Answer 14

multiple uses

Question 15

drug interactions: enzyme inhibition

Answer 15

antifungals (ketoconazole, fluconazole). 11b hydroxylation inhibitors (etomidate, metapyrone)

Question 16

drug interactions: metabolism acceleration

Answer 16

phenytoin (dilantin), rifampin, phenobarbital, ephedrine

Question 17

side effects of chronic usage of corticosteroids

Answer 17

HPA axis suppression, corticosteroid supplementation, electrolyte metabolic changes, CNS dysfx (20 prednisone x4y), peptic ulcer disease, skeletal muscle myopathy

Question 18

side effects: acute uses

Answer 18

hyperglycemia, inhibits T/NK cells but no real evidence of increased infection risk, cancer recurrence.

Question 19

you need to admin periop steroid replacement if

Answer 19

1. pharmacological doses of glucocorticoids greater than 5mg of prednisone equivalent per day is given (20mg of hydrocortisone or prednisone)
2. the period of tx with corticosteroids was for 2-3w or longer
3. the tx occurred during the immediate 12mo before surgery (for longer than 2-3w)

Question 20

do you dose for a superficial surgery

Answer 20

no ex) dental biopsy

Question 21

hydrocortisone dose for minor surgery

Answer 21

25mg IV ex) inguinal hernia repair, colonoscopy

Question 22

hydrocortisone dose for moderate surgery

Answer 22

50-75mg IV, taper over 1-2d. ex) colon resection, total joint replacement

Question 23

hydrocortisone dose for major surgery

Answer 23

100-150mg IV, taper over 1-2 days. ex) cardiovascular, thoracic