神经内科教学_motor neuron disease.ppt

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1、Motorneurondisease,MNDzhengdongming2021/10/42021/10/4BackgroundTheincidenceofthediseaseisonetotwoper100000.Thediseasepredominantlyaffectsmiddleagedandelderlypeople.youngerpeopleareoccasionallyaffected.Thediseaseissporadicin90%ofcases,butabout10%arefamilial,usuallywithanautosomaldominantmodeofinher

2、itance.2021/10/4Thediseasecausesprogressiveinjuryandcelldeathoflowermotorneuronegroupsinthespinalcordandbrainstemandusuallyalsoofuppermotorneuronesinthemotorcortex.Thoseaffectedtypicallydevelopacombinationofupperandlowermotorneuronesigns,withprogressivemuscleweaknessandwastingusuallyaccompaniedbyp

3、athologicallybriskreflexes,eventuallyinvolvingthelimbandbulbarmuscles2021/10/4EtiologyandpathogenesisGenetics:Morethan60differentmutations,mainlypointmutations,havebeendescribedthemostimportantfindingshasbeenthatmutationsinthegeneonchromosome21encodingtheenzymeCu/Znsuperoxidedismutase(SOD1)underli

4、e20%offamilialcasesofmotorneuronediseaseand2%ofallcases.2021/10/4EtiologyandpathogenesisExcitotoxicity:Glutamateisthemainexcitatoryneurotransmitterinthehumannervoussystem.Excessivestimulationofneuronalglutamatereceptorscandamageandkillthesecells.Immunefactorsviralinfection2021/10/41.Aamyotrophicla

5、teralsclerosisALSMotorneuronofAnteriorhorn,brainstem,pyramidaltract.>40yearsold,male>femalweaknessandwasting,Theinterosseiandthemusclesofthethenareminenceareaffectedearly.spreadproximallytoinvolvethemusclesoftheshouldergirdleandthetrunk.2021/10/41.AmyotrophiclateralsclerosisALSFasciculationisapr

6、ominentsign.Uppermotorneuronsignsinthelowerlimbs.Thereisusuallyaspasticweaknessofthelegswithincreasedtendonjerksandextensorplantarresponses.Uppermotorneuronsignsmayalsoextendtotheupperlimbssothatthereisaparadoxicalincreaseinthereflexesaccompanyingthewastingandfasciculation.2021/10/41.Amyotrophicla

7、teralsclerosisALSEventuallyemotornucleiofthemedullaareaffected,givingrisetoabulbarpalsy.Aspirationpneumoniaisthemostfrequentcauseofdeath.Thisoccurswithin4-5yearsoftheonsetofthediseaseinthemajorityofcases;somepat