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42 Cards in this Set
- Front
- Back
What is the cause of NMS? |
chronic administration of psychoactive drugs |
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What are symptoms of NMS? |
1. rhabdo, |
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What is the difference between NMS and MH? |
-MH is defect in skeletal muscle metabolism, has a genetic basis, |
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Is MH susceptibility present in patients with NMS? |
probably not, can use SCh |
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What is the therapy for NMS? |
no completely effective therapy, |
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What is the basic underlying problem in MH? |
SR loses it's ability to bind or reuptake calcium |
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How does dantrolene work in MH? |
decreases the release of Ca from the SR |
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How does MH work on the SR? |
leads to disruption of the ATPase in the SR, resulting in consumption of available energy resources and acidemia which is the hallmark of the condition |
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What drugs are unsafe in MH susceptable pts? |
decamethonium, SCh, volatiles (not nitrous) |
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Why should you not give verapamil to a patient being treated for MH? |
has been shown to depress cardiac function when given with dantrolene |
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How should you give dantrolene for treatment of MH? |
-bolus 2.5mg/kg IV |
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What is troponin and what is tropomyosin? |
-troponin - inhibitory protein that binds to actin (thin filaments) in the resting state (calcium binds to troponin and inhibits the inhibition); |
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how do nondepolarizers affect the muscle rigidity of MH? |
they don't |
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When in relation to the trigger does MH occur? |
either acute or delayed |
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When giving SCh what should raise your suspicion to the possibility of MH? |
trismus signals the onset of MH about 50% of the time, |
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CPK levels of what postop signal MH? |
>20,000 |
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If a patient develops masseter spasm during or after a MH triggering anesthetic what should you do? |
Should mandate conversion to a non-triggering anesthetic |
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What are the earliest signs of MH? |
hypercarbia > tachycardia |
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What are signs of MH? |
1. tachycardia, |
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What are complications from MH? |
1. death from cardiac arrest, |
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What is the differential diagnosis of MH? |
1. sepsis, |
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How is dantrolene prepared? |
must be dissolved in sterile water (20mg vial with 60cc sterile water) |
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What is the half life of dantrolene and what are the routes through which it can be given? |
T1/2 = 12 hrs, |
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What is the treatment for MH? |
1. stop anesthesia and surgery, |
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What is the gold standard for evaluating patients possibly susceptible to MH? |
halothane contracture test, |
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What conditions were once thought to be more prevalent in MH pts, but were found to be no more than the general population? |
1. strabismus, |
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What is the best indicator of MH risk? |
hx of MH episode in patient or relative |
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How does pretreatment with dantrolene affect the occurence of MH? |
masks the early signs but doesn't prevent the actual event |
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When should you do a muscle biopsy? |
history of masseter spasm or questionable MH (if for sure MH no reason to do the biopsy) |
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When do you do a MH test in a child with a distant relative with MH? |
test the child's parent then only if the childs parent is positive do you test the child |
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What size should a child be to test for MH? |
20kg minimum is recommended to avoid injury to the muscle group |
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When is an optimal CPK test done? |
patient fasting and resting (no exercise for 1-2 days) |
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Why should you not do the halothane contracture test in patients with NMS? |
patients with NMS can have an abnormal response to halothane |
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Other than drugs, what are other possible triggers of MH? |
1. stress |
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What may be useful for arrhythmias in MH? |
BBs or Lidocaine, but verapamil should be avoided |
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What is the best tx for rhabdo that occurs with MH? |
Aggressive hydration with forced diuresis and urine alkanization |
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What is the sarcotubular system? |
It is made of the T system and the sarcoplasmic reticulum and surrounds each muscle fiber |
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Explain the physiology of MH. |
- During contraction there is "sliding" between actin and mysosin as they break and reform cross linkages |
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If symptoms of MH appear, what must you immediately do? |
Obtain an ABG and switch to a nontriggering anesthetic |
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What is Dantrolene? How does it work? |
It is a hydantoin developed as a muscle relaxant |
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Management of MH susceptible or high risk pts. |
1. heightened awareness and readiness |
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What neurotransmitter system does NMS involve? |
The dopaminergic system and has been associated with the withdrawal of L-Dopa |