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33 Cards in this Set
- Front
- Back
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What is the cause of NMS?
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chronic administration of psychoactive drugs(butyrophenones, phenothiazines, MAOi, lithium)
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What are symptoms of NMS?
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rhabdo, ARF, impaired motor fxn(generalized rigidity), mental status deterioration, coma, delirium, hyperpyrexia, autonomic instability, respiratory failure, mortality of 15%
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What is the difference between NMS and MH?
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MH is defect in skeletal muscle metabolism, MH has a genetic basis, NMBDs are able to produce flaccid paralysis in NMS but not MH
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Is MH susceptibility present in patients with NMS?
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probably not, can use SCh
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What is the therapy for NMS?
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no completely effective therapy, bromocriptine(dopamine agonist) can be used, dantrolene has also been effective
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What is the basic underlying problem in MH?
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SR loses it's ability to bind or reuptake calcium
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How does dantrolene work in MH?
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decreases the release of Ca from the SR
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How does MH work on the SR?
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leads to disruption of the ATPase in the SR, resulting in consumption of available energy resources and acidemia
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What drugs are unsafe in MH susceptable pts?
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decamethonium, SCh, volatiles
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Why should you not give verapamil to a patient being treated for MH?
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has been shown to depress cardiac function when given with dantrolene
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How should you give dantrolene for treatment of MH?
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bolus 2.5mg/kg repeat every 5min until symptoms abate or a max of 10-20mg/kg is reached then 24 hours of 10mg/kg/day should be given
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What is troponin and what is tropomyosin?
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troponin: inhibitory protein that binds to actin(thin filaments) in the resting state(calcium binds to troponin and inhibits the inhibition); tropomyosin: inhibitory protein that binds to myosin(thick filaments) in the resting state
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how do nondepolarizers affect the muscle rigidity of MH?
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they don't
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When in relation to the trigger does MH occur?
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either acute or delayed(if delayed may not occur until the patient is in recovery)
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When giving SCh what should raise your suspicion to the possibility of MH?
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trismus signals the onset of MH about 50% of the time, also failure to achieve muscle relaxation
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CPK levels of what postop signal MH?
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>20,000
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If a patient develops masseter spasm during or after a MH triggering anesthetic what should you do?
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assume that the spasm is due to MH and postpone surgery, follow serum creatinine levels for 24 hours
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What are the earliest signs of MH?
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hypercarbia>tachycardia
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What are signs of MH?
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tachycardia, tachypnea, rigidity, hypercarbia/hypoxemia/acidosis/cyanosis, hyperthermia, arrhythmias, hyperkalemia
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What are complications from MH?
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death from cardiac arrest, death from cerebral or pulmonary edema, renal failure, DIC
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What is the differential diagnosis of MH?
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sepsis, pheochromocytoma, thyroid storm, NMS
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How is dantrolene prepared?
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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?
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T1/2=12 hrs, highly lipid solube and comes in PO and IV forms
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What is the treatment for MH?
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stop anesthesia and surgery, hyperventilate with 100% O2, dantrolene, treat hyperthermia, treat hyperkalemia(insulin/glucose), treat acidosis, treat arrhythmias(procainamide), place foley, arterial, and central lines
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What is the gold standard for evaluating patients possibly susceptible to MH?
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halothane contracture test, varying doses of halothane and caffeine and measuring muscle tension(caffeine causes a muscle sample to contract when halothane is added muscle contraction is greater); perform on a fresh sample of muscle
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how does strabismus, hernia, kyphoscoliosis, muscle cramps and muscle weakness affect your anesthetic as pertains to MH?
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it shouldn't these are just as prevelant in MH patients and the general population
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What is the best indicator of MH risk?
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hx of MH episode in patient or relative
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How does pretreatment with dantrolene affect the occurence of MH?
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masks the early signs but doesn't prevent the actual event
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When should you do a muscle biopsy?
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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?
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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?
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20kg
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When is an optimal CPK test done?
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patient fasting and resting(no exercise for 1 day)
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Why should you not do the halothane contracture test in patients with NMS?
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patients with NMS can have an abnormal response to halothane
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