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Flashcards in Steroids Deck (26)

what are adrenocortical steroids?

-produced and released by the adrenal cortex
-secretion controlled by the pituitary release of corticotropin (ACTH)
-two main classes: mineralocorticoids and glucocorticoids


where are mineralocorticoids secreted from?

the zona glomerulosa


where are glucocorticoids secreted from?

the zona fasciculata


describe mineralcorticoids and effects

-aldosterone responsible for 95% of activity
-maintains status quo regarding extracellular fluid volume
*maintains plasma concentrations of sodium and potassium
*conserves sodium to attract water into extracellular fluid
*maintains normal concentrations of potassium through excretion in urine


what stimulates secretion of mineralocorticoids?

-increased serum potassium
-Angiotensin II


describe glucocorticoids

-cortisol responsible for 95% of activity
*essential for life
*not stored anywhere in body


what are physiologic effects of cortisol?

-increase gluconeogenesis (amino acids to glucose) *^BG
-protein catabolism (less amino acids stored causes muscle weakness if cortisol excessive)
-fatty acid mobilization (movement and oxidation of fatty acids in the cells)
-anti-inflammatory effects (decrease capillary permeability; stabilize lysosomal membranes)
-decreased immune response (decreased movement of leukocytes into inflamed areas; decreased eosinophils and leukocytes; interfere with formation of leukotrienes)
-increased number and sensitivity of beta-adrenergic receptors (*increasing myocardial and vascular response to catecholamine)


what stimulates cortisol secretion? What stops cortisol secretion?

ACTH (adrenocorticotrophic hormone) released from anterior pituitary
-stimulation for the secretion of ACTH is from hypothalamic neurohormones (corticotropin-releasing hormone and AVP, arginine vasopressin)
-increased levels of cortisol cause negative feedback on the hypothalamus to decrease the production of corticotropin-releasing hormone and on the anterior pituitary to produce less ACTH


describe cortisol release in the body

-daily secretion: 20 mg with more secreted during the day
-stress response: output increased up to 150 mg/day
50 mg/day- minor surgery
75-150 mg/day-major surgery


how long does cortisol last in the body?

-elimination 1/2 life is 70 min
-there is NO storage in the body!
*if pt. cant produce cortisol themselves, we must provide steroid coverage


which drugs are synthetic corticosteroids?

-methylprednisolone acetate (Depo-Medrol)
-methylprednisolone sodium succinate (Solu-Medrol)


which drugs are endogenous corticosteroids?

-cortisol, hydrocortisone (Solu-Cortef)


what are the effects of synthetic corticosteroids?

-anti-inflammatory effect
-immune suppression
-suppression of hypothalamic-pituitary-adrenal (HPA) axis (when body needs to produce more cortisol d/t stress, it cant)
-weight gain
-skeletal muscle wasting


when is steroid coverage needed?

-the release of cortisol in response to the stress of surgery is decreased or eliminated
-HPA axis suppression (highly variable; occurs at different doses in different people)
*if taking steroids daily
*larger dose of steroids and longer the therapy, greater likelihood that suppression has occurred
-Critical illness-related corticosteroid insufficiency (CIRCI): adrenal response to stress is inadequate


what are signs and symptoms that steroid coverage is needed?

-unexplained vasopressor-dependent refractory hypotension (BP low for no explanation and only responds to vasopressor)
-hypovolemic shock with myocardial and vascular unresponsiveness to catecholamines


when should it be assumed that steroid coverage is needed?

-corticosteroid therapy has been used for more than two weeks within the previous year, assume some suppression has occurred
-anyone who has received corticosteroids equivalent to average daily adrenal output (hydrocortisone 20 mg/d) is considered depressed
-anyone who has received hydrocortisone equivalent of more than 20-30 mg daily for longer than two weeks during the previous year
*talk with surgeon and others on anesthesia care team
*keep some in room


what are the benefits of steroid coverage?

-prevention of life threatening secondary adrenal insufficiency: cardiovascular collapse, perioperative hypotension


what are the risks of steroid coverage?

-altered wound healing
-altered glucose metabolism (diabetics)
*limited effect if high dose steroid coverage is for a short time


what are the recommendation for steroid coverage for a minor surgery?

-usual morning dose OR
-preoperative corticosteroid dose (usual morning dose) + hydrocortisone 25 mg (or equivalent)


what are the recommendations for steroid coverage for a moderate surgery (colon resection, total joint)?

-hydrocortisone 50 mg IV, then 25 mg every 8 hrs for 24 hrs; then usual daily dose OR

-preoperative corticosteroid dose (usual morning dose) + hydrocortisone 50-75 mg or equivalent


what are the recommendations for steroid coverage for a major surgery (CV, thoracic)?

-hydrocortisone 100 mg IV at induction, 50 mg every 8 hrs for 3 doses; then taper rapidly down to daily dose (pediatric 2mg/kg IV)
-preoperative corticosteroid dose (usual morning dose) + hydrocortisone 100-150 mg or equivalent every 8 hrs for 48-72 hrs


what are pharmacologic effects on cortisol levels?

-etomidate suppresses the adrenal cortex synthesis of cortisol
-opioids in large doses may reduce the cortisol response to surgical stress
-volatile agents suppress the response to a lesser degree


what are equivalent doses of cortisol (hydrocortisone, Solu-Cortef) 20 mg?

-methylprednisolone (Solu-Medrol) 4 mg
-dexamethasone (Decadron) 0.75 mg
-prednisone (Deltasone) 5 mg


what are some clinical uses of corticosteroids?

-replacement therapy
-anti-inflammatory effect (prednisone)-palliative, not curative
-cerebral edema (dexamethasone)
-aspiration pneumonitis
-lumbar disc disease
-antiemetic effect
-collagen diseases
-ocular inflammation
-cutaneous disorders
-postintubation laryngeal edema (decadron)
-ulcerative colitis
-myasthenia gravis
-respiratory distress syndrome
-septic shock
-cardiac arrest


how are corticosteroids used as antiemetics?

-unknown mechanism for antiemetic effect
*dexamethasone (Decadron) 0.5 mg/kg
*enhances effectiveness of 5-HT3 antagonists (6-10 mg)


what are side effects of chronic corticosteroid therapy?

-suppression of HPA axis
-electrolyte, metabolic changes (distal renal tubules): absorption of Na+, loss of K+, hyperglycemia
-fat distribution: buffalo hump, supraclavicular, face, thin extremities (difficult airway?)
-osteoporosis: inhibit osteoblasts, activate osteoclasts, decreased calcium absorption
-peptic ulcer disease (don't give toradol)
-skeletal muscle myopathy
-CNS dysfunction: increased neuroses, psychoses, manic depression, suicidal
-cataracts (prednisone 20 mg/d x 4yrs)
-peripheral blood changes: decreased lymphocytes and monocytes
-inhibition of growth: in children, inhibition of DNA synthesis and cell division
**inhaled steroid for asthma in children do not suppress HPA axis or growth!!