Studydroid is shutting down on January 1st, 2019

by gnomey

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Manifestations of myxedema coma?
R/t hypothyroidism
1. hypothermia
3. Hyponatremia
4. Hypoventilation
5. Coma or stupor
What is the risk of treating a hypothyroid patient with thyroid hormones?
May precipatate myocardial ischemia
Treatment for myxedema coma?
1. IV thyroid hormones 200-300mcg iV over 5-10min
2. Hydrocortisone 100mg IV
3. Fluid and electrolyte replacement
4. cover to conserve body heat, no warming blankets (peripheral dilation augments HOTN)
What is the relationship to albumin and calcium levels?
Calcium is highly bound to albumin

Inc or dec in albumin 1gm/dL=0.8 serum Ca change in same direction
How does acidosis and alkalosis influence iCa?
pH and temp influence Ca and albumin bonding
1. acidosis decreases bonding, therefore increases iCa
2. alkalosis increases bonding, therefore decreases iCa
What regulates PTH secretion by the parathyroid glands?
serum iCa concentrations
Function of PTH?
1. causes release of Ca from bones (resorption) (most rapid change of Ca levels)
2.Direct resportion of Ca at distal tubules of kidneys
What is the purpose of hydrooxylation of Vitamin D in the kidneys?
Hypocalcemia and hypophosphotemia cause the kidneys to metabolize 1,25 OH2D and decrease of 24,25 OH2D. This causes increased intestinal absorption of calcium and phosphate
At what serum Ca levels is treatment required before surgery can continue? treatment?
Serum Ca >15mg/dL
1. Intravascular volume expansion with NS, dilutes serum and dec by 2mg/dL or greater.
2. Diuresis, IV Furosemide to promote Ca excretion with Na excretion
What must be avoided during surgery if a rapid PTH assay is going to be used?
No propofol within 15 minutes of assay
What is the daily amount of endogenous cortisol production?
What 3 factors primarly influence the production of ACTH and CRF?
1. sleep-wake cycle
2. stress
3. glucocorticoid plasma concentrations (primarily cortisol levels)
How do glucocorticoids (cortisol) influence the immune system?
1. Anti-inflammatory effects (stabilize leukocytes and maintain capillary wall integrity)
2. Antagonize leukocyte migration inhibition factor->decrease response to local inflammation
3. Reduce killing potential of macrophages and monoctyes, not their activity though
How does the renin-angiotensin system regulate the release of aldosterone?
1. Juxtaglomeular apparatus surrounds the renal afferent arterioles
2. in response to hypoperfusion or SNS stimulation of the Juxta apparatus  renin is released
3. Renin splits angiotensinogen to form angiotensin I
4. Angiotensin I is converted to Angiotensin II by an enzymes in the lungs
5. Angiontensin II stimulates the adrenal cortex to produce aldosterone
What is angiotensin II?
Result of renin-angiotensin system
1. most potent endogenous vasopressor
2. Stimulates adrenal cortex to produce aldosterone
What are the S & S of Cushing syndrome?
1. Tuncal obesity and thin extremities that reflect muscle wasting and redistribution of fat
2. Osteopenia r/t impaired Ca absorption
3. Hyperglycemia, with DM in 20%
4. HTN and fluid retention
5. Risk of infection d/t immunosupressive effects of corticosteroids
Is Hypokalemia seen with an endocrine tumor?
no see with nonendocrine tumor
What is the difference between primary pituitary disease and adrenal tumors?
1. Exogenous glucorticoid administration causes decrease levels of cortisol and 17-hydroxycorticosteroid levels in PRIMARY PITUITARY because some negative feedback control exists
What diuretic is helpful in diuresing patient with Cushing's and normalizing intravascular volume?
Spironolactone, aldosterone antagonist
- helps normalize K+ concentrations
What adrenal cortex response does supraphysiologic hydrocortisone doses mimic?
Exerts significant mineralocorticoid activity
What percentage of patients with essential HTN have suppressed renin acitivity?
25% have depressed renin activity
What is the difference between primary and secondary hyperaldosteronism?
Primary- Increased aldosterone levels are not caused by increase renin. hyposecretion of renin that fails to increase in presence of hypovolemia. usually do not have edema
Secondary- there is an elevation in renin production
What is the differnce between primary and secondary adrenal insufficiency?
Primary- the adrenal gland cannot produce sufficient amounts of hormones

Secondary- There is a deficiency in ACTH production
What is the clinical significance of HPA suppression?
Chronic corticosteroid therapy causes a suppression of the hypothalmic-pituitary-adrenal response to stress, resulting in HOTN and possible cardiac collapse
What is the cause of hyperkalemia found in Addison's disease?
The adrenal glands are not able to produce aldosterone, which is a hormone responsible for the hemostasis of K+ concentrations.

Found in primary adrenal insufficency
what is the initial therapy for acute adrenal insufficiency?
1. isotonic crystalloid replacement
2. Hydocortisone 100mg then q 8 hours
What anesthesia suppresses the elevation of stress hormones?
1. Regional
2. Deep GA

-both block the sympathetic nervous system response
What patient populations require preop steroid supplementation?
5 daily doses of prednisone greater or equal to 20mg within the las 12 months
How much steroid supplementation is needed in preop for patient with history of taking steroids within last 12 months?
1. Not currently on: 200-300mg divided thourghout day, 25mg IVP at induction
2. Currently on: daily dose morning of sx and supplementation with daily dose at induciton
what exogenous glucocorticoids go through liver metabolism?
Prednisone and methylprednisolone
What exogenous glucocorticoids have the most mineralocorticoid effect?
Hydrocortisone and cortisone
What glucocorticoid has the strongest anti-inflammatory response?
Dexamethasone- 0.75mg is same as 30x the strength of cortisol

Prednisone- 5mg has 4x the strength as cortisol
What is the only important disease process associated with the adrenal medulla?
Pheochromocytoma- tumor that produce, stores, and secretes catecholamines

-usually localized tumor in right adrenal gland
What class of drugs is given initially to patients diagnosed with a pheochromocytoma, and must be started prior to surgery? names?
alpha-adrenergic blockers at least 10-14 days before surgery
What can labetalol do if given alone when treating pheochromocytoma?
can increase blood pressure
what drug can be used if emergent surgery is needed in untreated pheochromocytoma pt?
Nipride gtt @ induction
-start @ 0.5mcg/kg/min
What drugs must definetly need to be avoided periop in a pt with pheochromocytoma?
1. Histamine releasing drugs- morphine,
2. Catecholamine releasing drugs- pancuronium, ketamine, ephedrine
During removal of pheochromocytoma removal, what causes an abrupt decrease in BP? treatment?
Ligaion of the tumors venous supply. IV fluid replacement offsets HOTN caused by this. Phenylephrine maybe given if needed after fluid resuscitation
Diagnostic criteria for DI?
plasma osmolarity>295 mOsmol
hypotonic urine tonicity 2ml/kg/hr
What is the goal for treatment of hypovolemia r/t DI periop?
1. ADH infusion (100-200mU/hr)
2. isotonic crystalloid until osmolarity
What is secreted from a carcinoid tumor during carcinoid syndrome?
1. Histamine
2. Bradykinin
3. Serotonin
4. Prostaglandins
5. Kallikrein
What type of drugs could induce a response from a carcinoid tumor?
1. Histamine releasing (morphine)
2. Catecholamine releasing (ketamine)
What organ requires involvement with carcanoid tumor to  postentially develop into carcinoid syndrome?
Metasis of the carcanoid tumor to the liver. Carcanoid tumor metasis to the liver allows for direct release of secretions into the blood and bypassing of metabolism by the liver
What cardiac changes occur due to carcinoid tumors?
Pulmonic valve stenosis and tricuspid valve insufficiency
-primarly tricuspid valve insufficiency
What are common drugs used in anesthesia that cause histamine release?
Treatment of HOTN and HTN in carcinoid tumor?
HOTN: Avoid catecholamine releasing and B-agonists. Use: IV fluid administration, phenylephrine, octerotide, angiotensin

HTN: often associated w/ bronchospasm. Use: Nitroglycerin or Nipride
What drug is given prophylactically preoperative to patients with Carcinoid tumors?
Octreotide- synthetic analog of somatostatin
Dose:50-150mcg q 8 hour subq
-inhibits release of serotonin from tumor
What is the difference between epi and norepi secreting pheochromocytomas?
1. Epi secreting: Inc SBP, Dec DBP, tachycardia
2. Norepi secreting: HTN, narrow pulse pressure, bradycardia
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