Corticosteriods Flashcards
What is the HPA axis?
Hypthalmus
pituitary gland
adrenal cortex
What are the three layers of the adrenal cortex?
- Zona glomerulosa : mineralcorticoids
- Zona fasiculata - glucocorticoids
Zona reticularis - Glucocorticoids
Glucocorticoids play an important role in maintaining what body functions?
- Carbohydrate, gat, protein metabolism
- Gluid and electrolyte regulation
- inhibits inflammatory response
- Gluconeogenisis
What steroid mediates 95% of all glucocorticoids in the body?
Cortisol
What is the process of corticosteroidogenesis?
- Begins in the hypothalamus. Hypothalmus releases Corticotropin Releasing Hormone into the pituitary gland.
- The pituitary gland is stimulated to release ACTH into the adrenal cortex.
- The adrenal cortex is stimulated to release cortisol from the zona fascicularis and zona retiulosa
What hormone is produced in the adrenal cortex and released due to stress response by the HPA axis?
Cortisol
What metabolic effects are initiated by cortisol in order to releive stress on the body?
- Gluconeogenisis
- Carbs, protein, fat metabolism
- Control of fluid and electrolytes
- Inhibit inflammatory response
According to the normal circadian rhythm when are cortisol levels highest and lowest?
Cortisol levels are highest in the morning and lowest in the evening.
Will changes in sleep habits alter the cycle of cortisol production?
Yes, Changes in sleep habits will cause a change in cortisol production cycle
The main regulator of cortisol production is?
Negative feedback - high levels of cortisol in the blood signal the hypothalamus to stop producing CRH. It also signals the pituitary gland to stop producing ACTH.
Low cotisol levels will reverse the process
What is primary adrenocortical insufficiency?
Also known as Addison’s Deseases.
Adrenal do not secrete cortisol or aldosterone
Replacement therapy must include both glucocorticoids and mineral corticoids
What is secondary adrenocortical insufficiency?
Adrenals do not secret cortisol
Aldosterone secretion is maintained
Replacement of glucocorticoid (cortisol) only.
Due to chronic steroid use and HPA axis suppression.
What are the physiologic effects of glucocorticoids?
Increase cardiac output Increase Respiratory rate Increase gluconeogenesis Decrease inflammation Decrease immune response Inhibit digestion Enhanced analgesia Redistribution of CNS blood flow
What mineralcorticoid is also reeased from the adreanl cortex?
Aldosterone is also released for the adrenal cortex -specifically the zona glomerulosa
What is the function of aldosterone?
Increases Na+ and water aabsorbtion thus increasing blood volume, and promotes K+ excretion
What feedback is associated with the secretion of aldosterone?
Increased K+ levels
Decreased Na+ levels
Decreased blood volume/blood pressure
What is the path of secretion for aldosterone?
Increased renin levels converts angiotensenoigin to angiotensin I. Angiotensin I is converted in the lungs to Angiotensin II. Angiotensin II stimulates the adrenal cortex (zona glomerulosa) to secret adldosterone
Glucocorticoids are classified according to their?
Potency
What are the most potent aniinflammatory steroids?
Dexmethasone
Betamethasone
What is the least potent steroid?
Cortisone
Cortisol
Which steroid has the most sodium retaining potency
Fludrocortisone
Which steroid has the longest elimination half life?
Betamethasone - hours
Dexamethasone - 3.5 - 5 hours
Which steroid has the shortest eimination half-life?
Cortisone - 0.5 hours
Which steroid has the longest duration of action?
Dexmethasone and Betamethasone
Which steroid has the shortest duration of action
Cortisol 8-12 hours
Do steroids cross the placenta?
YES
What side effects to glucocorticoids have on the endocrine system?
Adrenal atrophy
HPA axis suppression
Cushing’s syndrom
Hyperglycemia/diabetes
What side effects do steroids have on the crdiovascular system?
Hypertension
Dyslipidemia
Thrombosis
What side effects do steroids have on the CNS?
Psychosis Manic depression Suicidal tendencies Cataracts/glucoma Mood changes
What side effects do steroids have on the immune system?
Immunosupression
Increase risk of infection
What side effects do steroids have on the renal system?
Increased Na+ and water retention (edema)
Increased K+ and H+ excretion
What electrolyte and metabolic changes are associated with steroid use?
Hypokalemic Metaboic Alkalosis - due to increased K+ and H+ secretion
Inhibits glucose use in the perphery and results in hyperglycemia
Redistribution of body fat - hump back or buffalo hump and moon face as seen with cushing’s synddrome
Long term use of steroidshas what effect on the blodd?
Hematocit and leukocytes are increased
70% reduction in lymphcytes
90% reduction in monocytes
These cells are sequestered and NOT Destroyed
What are some relative contraindications to the use of steroids?
Systemic infection immunosuppression Glaucoma Hypokelemia CHF Cushing's syndrome diabetes Hypertension Hyperthyroidism compounds Osteoporosis
When steroids are used for acute adrenal insufficiency when should higher doses be given?
In the morning
When considering steroid replacement as a stress does prior to surgery wheat factors must be considered?
Dose of previous steroid therapy
Duration of previous therapy
Time since previous therapy
When given as a antiemetic Dexamethsone should be administered early or late in the perioperative period?
Dexamethasone should be administered early in the intraoperative period just after induction.
Which steroids have no Na+ retention qualities?
Betamethasone
Dexamethasone
Triamcinalone
When used for asthma relief what is the most common side effet of inhaled steroids??
Oral candidiasis (Thrush)
Are corticosteroids good for acute asthma attacks
No, it usually take steroid 4-6 hours to reach an anti inflamatory afffec
No, it usually take steroid 4-6 hours to reach an anti inflammatory affect
When topical steroids are administered does heat increase or decrease the rate of absorption?
Heat increases the rate of absorption for topical steroids
When are patient more at risk for post intubation laryngeal edema?
When intubated for more then 6 days
When is the use of steroids NOT recommended?
Septic shock
Cardia arrest
Aspiration pneumonitis
What factors infuence the degree of HPA axis suppression associated with steroid use?
Dose and duration of gluocorticoid therapy
Cause a reduction in the stress response of HP axis
What therapies are unlikely to produce a suppression of the HPA axis?
Prednisone 5 mg/day or less
Long term every other day does
Dose therapy <3 weeks
True of False: Steroids such as prednisone or dexamethasone administered at any does on a dailty basis is associated with suppression of HPA axis.
TRUE
After cessation of steroid therapy recovery of the HPA axis may take how many months to recover?
12 months
HP funcction returns to normal before adrenal function in the HPA axis
What is a good rule of thumb to assum HPA axis suppression
If steroid dose is greater than 10 mg/day and given for more than 3 weeks
Any sign of Cushing’ssyndrome moon face, buffalo hump, weight gain (edema)
For patients receiving chronic steroid therapy how should plasma cortisol levels be maintained for major surgery
Cortisol levels should be above normal during major surgeries and stress doeses should be administered.
No additional ceverage should be needed for minor operations
When considering stress doses prior to surgery what doeses should be administered according the level of surgery to be performed
Minor - 25 mg cortisol IV
Moderate 50 - 75 mg cortisol
Major 100 - 150 mg cortisol
What are some signs of acute adrenal crisis?
Hypotension unresponsive to vasopressors Hyperdynamic circulation hypoglycemia hyperkalemia hypoatremia hypovolemia metabolic alkalosis Decreased level of consciousness
Where are thyroid hormone levels controlled
Hypothalamus
How is T4 and ultimately T3 secreted?
Hypothalamus releases thyroid releasing hormone into the anterior pituitary gland. The anterior pituitary gland releases thyroid stimulating hormone into the thyroid gland. The thyroid gland releases T4 which is changed to T3 which is the active hormone
Level are controlled by feedback from the thyroid gland inhibiting the release of TRH from the hypotalamus
Describe the presentation of Hashimoto Desease
Hypothyroid Cold Intolerance Dry skin Gatigue Weight gain Bradycardia Slow reflexes Coarse skin and hair Periobital swelling Painful menstration Myxedema coma
Describe the presentation of Graves Desease
Hyperthyroid Weight loss with increased appetite Heat intolerance Goiter Gine hair Tachycardia Nervous, anxiety insomnia Lighter menstration Sweating warm moist skin Exophthalmus Thyroid storm
What are the two hypothyroid medication and what hormone do they replace?
Levothyroxine T4 Later converted to T3 by deiodination
Liothyronine T3 stronger than levothyroxine
What is the perferred route of administration for levothyroxine
Oral is preferred but IV is available
A euthyroid state is maintained with hypothyroid with what does of levothyroxine
100 - 200 mcg/day
What is the half life of leveothyroxine and will replacement of missed dose be required on the day of surgery?
Half life is 7 days
A missed dose on the day of surgery is not required
after 7 days administer half the required dose for euthyroid (50 - 100 mcg)
Which is the stronger medication for hypothyroid - levothyroxine or liothyronine?
Liothyronine - T3 is stronger
Which replacement medication is better for long term use for hypothyroid?
Levothyroxine is better than liotyronine for long term use
Which hypothyroid medication has greater cardiac side effects?
Liothyronine
What are the anesthetic implication for hypthyroidism?
Hyponatremia hypthermia hypoglycemia delayed gastric emptying slowed metabolis of drugs decreased CO, HR, SV More sensitive to inhaled gases Unresponsive baroreceptor reflex
What drug is given as an antithyroid drug and inhibits the formation of thyroid hormone by blocking T4 and T3?
Propylthiouracil(PTU)
What drug treates hyperthyroidism and thyroid storm
Propylthiouracil (PTU)
How is propylthyiouriacil administered?
Only in the PO form. Takes several days for effect
What is the oldest medication used for the treatment of hypothyroidism
Lugols solution inhibits the release of the thyroid hormone
Excessive release of thyroid hormone by the pituitary gland can cause what disorder?
Thyroid storm
What conditions are seen with a thyroid storm
Hyperthermia Tachycardia CHG Dehydration Shock Symptoms resemble MS
When is a thyroid storm most likely to develop?
6 - 19 hours post op
How is thyroid storm treated?
IV crystalloids IV sodium iodide Cortisol Propranolol - alleviates cardio side effects Propylthiouracil PO
During a thyroid storm hyperthermia occurs and may result in a fever. Should ASA be given for the fever?
NO. ASA should be avoided as thyroxin levels may increase and worsen the effects of thyroid storm
