帕金森病英文

ExtrapyramidalDisorderIntroductionExtrapyramidaldisorderimpairstheregulationofvoluntarymotoractivitywithoutdirectlyaffectingstrength,sensationorcerebellarfunction.Manifestationsinclude:--hyperkineticdisordersassociatedwithabnormal,involuntarymovements--hypokineticdisorders.Tremor:asteadyrhythmicoscillatorymovementofthemusclesChorea:rapid,irregular,jerkymovementsDystonia:co-contractionofagonistsandantagonistmusclesinoneregiononattemptedvoluntarymovement.Myoclonus:Involuntaryshock-likecontractions,irregularinrhythmandamplitude,followedbyrelaxation.SuddenrapidtwitchlikemusclecontractionAbnormalmovementExtrapyramidalSystemTheextrapyramidalsystemconsistsofthosepartsofthecentralnervoussystemotherthanmotorcortexandcorticospinaltracts,whichareconcernedwithmovementsandposture.Theyinclude:

Basalganglia;Subthalamicnuclei;Substantianigra;Rednuclei.Parkinsonism

MajorcharactersTremorHypokinesiaRigidityAbnormalgaitandpostureOccursinallethnicgroups,intheUSAandWesternEuropeitsprevalenceis1-2/1000population,withanapproximatelyequalsexdistribution.Thedisorderbecomesincreasinglycommonwithadvancingage.Etiology

A.IdiopathicAverycommonvarietyofParkinsonismoccurswithoutobviouscause.ThisidiopathicformiscalledParkinson’sdiseaseB.EncephalitislethargicaInthefirsthalfofthetwentiethcentury,ParkinsonismoftendevelopedinpatientswithahistoryofVonEconomo’sencephalitis.Thistypeofinfectionisnotnowencountered,casesofpostencephaliticParkinsonismarebecomingincreasinglyrare.C.Drugortoxin-inducedParkinsonism1.Therapeuticdrugs—phenothiazines,butyrophenones,metoclopramide,reserpine,tetrabenazine,etccancauseareversibleParkinsoniansyndrome.2.Toxicsubstances—EnvironmentaltoxinssuchasmanganesedustcanleadtoParkinsonism.PesticideexposureisalsoassociatedwiththedevelopmentofParkinsonism.Pathogenesis

Dopamineandacetylcholinearepresentinthecorpusstriatum,wheretheyactasneurotransmitters.Inidiopathicparkinsonism,itisgenerallybelievedthatthenormalbalancebetweenthesetwoantagonisticneurotransmittersisdisturbedbecauseofdopaminedepletioninthedopaminergicneuron.ChangesinNeurotransmittersDopaminedecrease70-95%inputamenCholinergicactivityrelativelyincreasedReducedactivityofcholineacetyltransferaseinthenucleusbasalisandinthecortexClinicalFindingsCommonFeaturesOnsetisusuallyinmiddletolatelifeInsidiousonsetandprogressiveOnsetfromonesideProgresslikeas“N”ClinicalfindingsTremor4~6HztremorofParkinsonismischaracteristicallymostconspicuousatrest,itincreasesattimesofemotionalstressandoftenimprovesduringvoluntaryactivity.Itcommonlybeginsinthehandorfoot,whereittakestheformofrhythmic.Thefaceintheareaofthemouthmaybeinvolvedaswell.Itmayultimatelybepresentinallofthelimbs.Rigidity

RigidityisacharacteristicclinicalfeatureofParkinsonism.Thereisstiffnessofthelimbswhichcanbefeltthroughouttherangeofmovementandequallyintheflexorsandextesors.Thisistermed“lead-pip”rigidity.Whencombinedwithtremor,thereisajerkyelement,whichistermed“cog-wheel”rigidity.C.Hypokinesia

hypokinesia--aslownessofvoluntarymovementandareductioninautomaticmovement,suchasswingingthearmswhilewalking.Thepatient’sfaceisrelativelymasklikefacies.Thevoiceisoflowvolumeandtendstobepoorlymodulated.rapidlyalternatingmovementsareimpaired,butpowerisnotdiminished.Thehandwritingissmalltremulous,andhardtoread.D.Abnormalgaitandposture

Thepatientgenerallyfindsitdifficulttogetupfrombedandtendstoadoptaflexedpostureonstanding.It’softendifficulttostartwalking.Thegaititselfischaracterizedbysmall,shufflingsteps.Generallysomeunsteadinessonturning,andmaybedifficultyinstopping.Inadvancedcases,thepatienttendstowalkwithincreasingspeedtopreventafallbecauseofthealteredcenterofgravitythatresultsfromtheabnormalposture.TreatmentTheindicatedtreatmentisdirectedtowardrestoringthedopaminergic:cholinergicbalanceinthestriatum.BlockingtheeffectofacetylcholinewithanticholinergicdrugsorenhancingdopaminergictransmissionA.Anticholinergicdrugs

trihexyphenidyl(antan)commonsideeffects:drynessofthemouth,constipation,urinaryretention,confusion.startedwithasmalldose,thengraduallyincreaseduntilbenefitoccursorsideeffectslimitfurtherincrements.B.Amantadine

CanbegivenformildParkinsonismeitheraloneorincombinationwithananticholinergicagent.standarddose:100mgoraltwicedaily.ItcanimproveallclinicalfeaturesofParkinsonism,butmanypatientsfailtorespondforitsbenefitisshort-livedC.Levodopa

Levodopaisconvertedinthebodytodopamine,helpallthemajorclinicalfeaturesofParkinsonism,andisoftenparticularlyhelpfulagainsthypokinesia.

On-offphenomenon:whichabruptbuttransientfluctuationintheseverityofParkinsonismoccuratfrequentintervalsduringthedayapparentlywithoutanyrelationshiptothelastdoseoflevodopa.D.DopamineAgonists

BromocriptinestimulatesdopamineD2receptors,usuallyfolloweddopaminergictherapy,startingdose1.25mg/dfor1weekincrementsevery2weeks,dependingontheresponseanddevelopmentofsideeffects.E.Catechol-O-methyltransferaseinhibitorsTheseinhibitorsmaybeusedtoreducethedoserequirementsofandanyresponsefluctuationstoLevodopa.Tolcapone:100~200mgthreetimesdailyEnta