Steroids Flashcards
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
- hyponatremia
- ACTH
- 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?
- prednisolone
- prednisone
- methylprednisolone acetate (Depo-Medrol)
- methylprednisolone sodium succinate (Solu-Medrol)
- betamethasone
- dexamethasone
- triamcinolone
which drugs are endogenous corticosteroids?
- cortisol, hydrocortisone (Solu-Cortef)
- cortisone
- corticosterone
- desoxycorticosterone
- aldosterone
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)
OR
-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
- immunosuppression
- asthma
- antiemetic effect
- arthritis
- collagen diseases
- ocular inflammation
- cutaneous disorders
- postintubation laryngeal edema (decadron)
- ulcerative colitis
- myasthenia gravis
- respiratory distress syndrome
- leukemia
- 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!!
