Steroids, NSAIDS, Prostaglandins

Question 1

Arachidonic acid

Answer 1

20 carbon polyunsaturated fatty acid
Target specific, released where they’re synthesized, then rapidly degraded
Released from phospholipids as phospholipase (activated by trauma, injury, etc)
Bind to G protein coupled receptors

Question 2

Pathways of arachidonic acid metabolism

Answer 2

Cyclooxygenase: converts AA to..
-Prostaglandins
-Prostacyclin
-THromboxanes
Lipoxygenase: converts AA to..
-Leukotrienes
-Lipoxins
Epoxygenase

Question 3

Prostacyclin (naturally produced, effect, drug, interaction)

Answer 3

Produced by vascular endothelium
Vasodilator, inhibits platelet aggregation
Epoprostenol: For pulmonary hypertension
Interactions: Vasodilators, antiplatelet/anticoag

Question 4

Thromboxane A2

Answer 4

From platelets

Vasoconstrictor, platelet adhesion/aggregation

Question 5

HPA axis

Answer 5

Hypothalamic pituitary adrenal axis: How cortisol is created/released
Stimulation
-Corticotropin releasing hormore
-Decreased cortisol
-Sleep to awake
-Hypoglycemia, trauma/sepsis, alpha/beta agonists
Inhibition
-Adrenocorticotropic hormone (ACTH)
-Increased cortisol
-General anesthesia
-Etomidate

Question 6

HPA axis suppression

Answer 6

Patients who have received 20mg/day of prednisone for >3 weeks in a 1 year period have HPA axis impairment during acute stress

Question 7

Which zone of the adrenal cortex is cortisol produced

Answer 7

Middle layer: zona fasciculata

Question 8

Synthetic equivalent of cortisol

Answer 8

Hydrocortisone

Question 9

Hydrocortisone vs prednisone vs dexamethasone potency/NA retention/duration

Answer 9

Potency
-Hydrocortisone: 1
-Prednisone: 4
-Dexamethasone: 25
NA retention
-Hydrocortisone: 1
-Prednisone: 0.8
-Dexamethasone: 0
Duration
-Hydrocortisone: 8-12 hours
-Prednisone: 18-36 hours
-Dexamethasone: 36-54 hours

Question 10

IV steroid mechanism of action

Answer 10

Acute: Rapidly increased cortisol production because of increased supply of cholesterol substrate
Chronic: Hours-days, genetic changes, increases steroidogenic enzymes

Question 11

Normal vs maximum daily output of cortisol

Answer 11

Normal: 20 mg
Maximum: 200 mg

Question 12

Acute adrenal crisis s/sx

Answer 12

Hypoglycemia
Hypovolemia
Hyponatremia
Hyperkalemia
Metabolic acidosis
*Hypotension that doesn't respond to pressors

Question 13

Treatment of acute adrenal crisis

Answer 13

Hydrocortisone 100mg then 200mg over 24 hours
IVF, vasopressors
*Decadron won’t work (only has glucocorticoid effects, no mineralocorticoid (aldosterone) effect)

Question 14

Etomidate -> cortisol inhibition

Answer 14

11 beta hydroxylase inhibited by Etomidate

• Enzyme that converts one of steps of cholesterol to cortisol
• > Higher mortality in sepsis patients given etomidate

Question 15

Physiologic effects of synthetic steroids

Answer 15

Blood flow redistributed to CNS
Increased CO, RR, gluconeogenesis
Decreased inflammatory/immune response
Enhanced analgesia

Question 16

Epidural steroid injection safety concern

Answer 16

FDA: Serious neurologic events after epidural glucocorticoid injection

• Vision loss, CVA, paralysis, death
• Associated with particulate steroid prep
• Use a steroid that comes prepared as a liquid (decadron vs hydrocortisone that comes as a powder)