Nerves and Muscles diseases - neurologiadziecieca.wum.edu.pl€¦ · Guillain–Barré syndrome...
Transcript of Nerves and Muscles diseases - neurologiadziecieca.wum.edu.pl€¦ · Guillain–Barré syndrome...
NervesandMusclesdiseasesDiagnosisandmanagement
NEUROPATHY• distalweakness• concomitantsensorysymptoms+signs• reflexeslostearly• +/-fascicula:ons• nocontractures• notassociatedwithmyocardialdysfunc:onnormuscletenderness
Mononeuropathy
Mononeuropathy
Neuropathy:• 1/mononeuropathy-traumaorcompression–deficitsreflecttheanatomicdistribu:onofthenerve(forexamplecarpaltunnelsyndrome)
• 2/polyneuropathy:symmetrical,featuringweakness,numbness,pins-and–needles,burningpain,itusuallybeginsinthehandsandfeet(“stockingandglove”paHern)andmayprogresstothearmsandlegs,lossordecreaseofreflexes,
• autonomicdisturbances(orthosta:chypotension,incon:nence,impotence,swea:ngabnormali:es)
• Causes:diabetesmellitus,uraemia,hypothyroidism,rheumatologicdisease,medica:ons(chemotherapy),toxins(alcohol)vitaminsdeficiencies(Bvitamin),hereditaryneuropathies(Charcot–Marie–Toothdisease)
FACIALNERVE(N.VII)PARALYSIS:• Thepathwayofthefacialnerveislongandrela:velyconvoluted,andsothereareanumberofcausesthatmayresultinfacialnerveparalysis.
• ThemostcommonisBell’spalsy,anidiopathicdiseasethatmayonlybediagnosedbyexclusion.
• Facialnerveparalysismaybedividedintosupranuclearandinfranuclearlesions.
SUPRANUCLEARandnuclearlesions-centralfacialpalsycanbecausedbyalacunarinfarctINFRANUCLEARLESIONS• characterisedbyunilateralfacialweakness,lossoftaste,hyperacusisanddecreasedsaliva:onandtearsecre:on.Symptomsmaydevelopoverseveralhours.
• Acutefacialpainradia:ngfromtheearmayprecedetheonsetofothersymptoms.
Causes:• Herpes,• O::smedia,• Lymedisease(causedbyBorreliaburgdorferiinfec:on-speciallyinendemicareas)
• Fracturesofthetemporalbone• Diabetesmellitus,sarcoidosis,• Moebiussyndrome(extremelyrare)-isabilateralfacialparalysisresul:ngfromtheunderdevelopmentoftheVIIcranialnerve(facialnerve),whichispresentatbirth.TheVIcranialnerveisalsoaffected,sopeoplewithMoebiussyndromecannotformfacialexpressionormovetheireyesfromsidetoside.
Investigationanddiagnosis:• Medicalhistory,neurologicalexamina:on,laryngologicalexamina:onwithaudiometryandtympanometry
• Bloodtests,Borrelia,CToftemporalbone,
• Treatment:steroids,vitB,rehabilita:on
Guillain–Barrésyndrome(GBS)
• Acutepolyneuropathy• rapid-onsetmuscleweaknessasaresultofdamagetotheperipheralnervoussystem,alsochangesinsensa:onorpainisreportedbythepa:ent-bothsidesequally,cranialnerveisinvolvedin50%
• thesymptomsdevelopoverhalfadaytotwoweekstoreachthemaximum,thenplateauphasethenimprovement
• duringtheacutephase,thedisordercanbelife-threateningwithaboutaquarterdevelopingweaknessofthebreathingmusclesandrequiringmechanicalven:la:on
• Someareaffectedbychangesinthefunc:onoftheautonomicnervoussystem,whichcanleadtodangerousabnormali:esinheartrateandbloodpressure
• Thisisautoimmunediseasecausedbythebody'simmunesystemmistakenlyaHackingtheperipheralnervesanddamagingtheirmyelininsula:on(veryo^enistriggeredbyaninfec:onofupperrespiratorysystemordiarrhoea3-6weeksbeforeorvaccina:on).
• Molecularmimicry-theproduc:onofan:bodiesa^eraninfec:on-theimmunesystemisreac:ngtomicrobialsubstancesbuttheresultantan:bodiesalsoreactwithsubstancesoccurringnaturallyinthebody.
• Causes:Campylobacterjejuni,CMV,Varicellazoster,Mycoplasmapneumoniae,influenzavirus,Zika-virus
DifferenttypesofGuillain–Barrésyndromefeaturedifferenttypesofimmuneattack:• 1/thedemyelina:ngvariant(AIDP)featuresdamagetothemyelinsheathbywhitebloodcells(Tlymphocytesandmacrophages)thisprocessisprecededbyac:va:onofagroupofbloodproteinsknownascomplement
• 2/theaxonalvariantismediatedbyIgGan:bodiesandcomplementagainstthecellmembranecoveringtheaxonwithoutdirectlymphocyteinvolvement
DIAGNOSIS:
• 1/Thesignsandsymptoms(rapiddevelopmentofmuscleparalysis,absentreflexes,neurologicalexamina:on:reducedpowerandreducedorabsenttendonreflexes(hypoorareflexia)
• 2/examina:onofcerebrospinalfluid:“albuminocytologicaldissocia:on”-increasedofspinalfluidproteinconcentra:onbutanormalcellcount
• Despitethis,theCSFisunremarkablein50%ofpeoplewithGuillain–Barrésyndromeinthefirstfewdaysofsymptoms,and80%a^erthefirstweek;therefore,normalresultsdonotexcludethecondi:on
• 3/nerveconduc:onstudiesandelectromyography–demieliniza:onor/andaxonalabnormali:esButinthefirsttwoweeks,theseinves:ga:onsmaynotshowanyabnormalitysoneurophysiologystudiesarenotrequiredforthediagnosis
• 4/MRIofthespinalcord-enhancementofthenerveroots
Type Symptoms PopulaConaffected NerveconducConstudies
AnCgangliosideanCbodies
AcuteinflammatorydemyelinaCng
polyneuropathy(AIDP)
Sensorysymptomsandmuscle
weakness,o^enwithcranialnerveweaknessandautonomicinvolvement
MostcommoninEuropeandNorth
America
Demyelina:ngpolyneuropathy
(âCV)
Noclearassocia:on
Acutemotoraxonalneuropathy(AMAN)
Isolatedmuscleweaknesswithout
sensorysymptomsinlessthan10%;cranialnerveinvolvement
uncommon
RareinEuropeandNorthAmerica,substan:al
propor:on(30–65%)inAsiaandCentralandSouthAmerica;some:mescalled"Chineseparaly:c
syndrome"
Axonalpolyneuropathy(âamplitude),normal
sensoryac:onpoten:al
GM1a/b,GD1a&GalNac–GD1a
Acutemotorandsensoryaxonalneuropathy
(AMSAN)
SeveremuscleweaknesssimilartoAMANbutwithsensoryloss
MillerFishersyndrome
Ataxia,eyemuscleweakness
(ophtalmoplegia),areflexiabutusuallynolimb
weakness
Thisvariantoccursmorecommonlyinmenthaninwomen(2:1ra:o).Cases
typicallyoccurinthespringandtheaverageageof
occurrenceis43yearsold
Generallynormal,some:mesdiscretechangesinsensoryconduc:onor
H-reflexdetected
GQ1b,GT1a
Treatment:• 1/Immunotherapy:plasmapheresisandintravenousimmunoglobulins(IVIg)bothareequallyeffec:ve,butIVIgisusuallyusedfirstinprac:ce
• IVIgtotaltherapy2g/kg-0,4g/kg/x5doses• 2/Painmedica:on• 3/Rehabilita:on• 4/Mechanicalven:la:on/Intensivecare-incaseofRespiratoryfailure
• usuallyproximalweakness• usuallynosensorydeficit• reflexespreservedun:llate• fascicula:onabsent• contracturesusuallypresent• maybeassociatedwithmyocardialdysfunc:onormuscletenderness
MYOPATHY
• Musculardystrophies• Myotonia• Congenitalmyopathieswithmicroscopicchanges(nemalinemyopathy-withnemalinerods,minicoremyopathy,centronuclearmyopathy)
• Mitochondrialmyopathy-defectsinmitochondria,whichprovideacri:calsourceofenergyformuscle
• Metabolicmyopathies(glycogenosis,lipidoses)
Inheritedformsofmyopathy:
• ThepaHernofBMDsymptomdevelopmentresemblesthatofDMDbutwithalater,andmuchslowerrateofprogression.
• anX-linkedrecessiveinheriteddisorder(carrierfemales,affectedboys)
• amuta:onofthedystrophingeneatlocusXp21,locatedontheshortarmoftheXchromosome
• whichcodesfortheproteindystrophin• Dystrophinisanimportantcomponentwithinmuscle:ssuethatprovidesstructuralstabilitytothedystroglycancomplexofthecellmembrane.
Duchennemusculardystrophy(DMD)Becker’smusculardystrophy(BMD)
Muscular Dystrophy
In affected muscle (right) the tissue becomes disorganized and the concentration of dystrophin (green) is
greatly reduced, compared to normal muscle (left)
• Boysareaffected,firstsignsabout3-4yearsofold• Frequentfalls• Fa:gue• Difficultywithmotorskills(running,hopping,jumping)• Troublegerngupfromlyingorsirngposi:on• Aposi:veGower’ssignreflectsthemoresevereimpairmentofthelowerextremi:esmuscles.Thechildhelpshimselftogetupwithupperextremi:es:firstbyrisingtostandonhisarmsandknees,andthen"walking"hishandsuphislegstostandupright.
Signs:
Gowers' sign
• Lumbarhyperlordosis• MusclecontracturesofAchillestendon• Progressivedifficultywalking• Musclefibredeformi:es• Pseudohypertrophy(enlarging)oftongueandcalfmuscles.Themuscle:ssueiseventuallyreplacedbyfatandconnec:ve:ssue,hencethetermpseudohypertrophy.
• Higherriskofneurobehavioraldisorders(e.g.,ADHD),learningdisorders(dyslexia),andnon-progressiveweaknessesinspecificcogni:veskills(inpar:cularshort-termverbalmemory),whicharebelievedtobetheresultofabsentordysfunc:onaldystrophininthebrain.
• Eventuallossofabilitytowalk(usuallybytheageof12)
• Skeletaldeformi:es(scoliosis)• Abnormalheartmuscle(dilatedcardiomyopathy)• Conges:veheartfailureorirregularheartrhythm(arrhythmia)–EchocardiographyandECGisrequired
• Respiratorydisorders,includingpneumoniaandswallowingwithfoodorfluidpassingintothelungs(inlatestagesofthedisease)
• DNAtest:Themuscle-specificisoformofthedystrophingeneiscomposedof79exons,andDNAtes:ngandanalysiscanusuallyiden:fythespecifictypeofmuta:onoftheexonorexonsthatareaffected.DNAtes:ngconfirmsthediagnosisinmostcases.
• Prenataltestpossible• Musclebiopsy• Crea:ninekinase(CPK-MM)levelsinthebloodstreamareextremelyhigh
• EMG–myogenicchangesbutnotspecificforDMD
DIAGNOSIS:
• Treatmentisgenerallyaimedatcontrollingtheonsetofsymptomstomaximizethequalityoflife,andincludethefollowing:
• cor:costeroidsincreaseenergyandstrengthanddeferseverityofsomesymptoms
• Mildphysicalac:vitysuchasswimmingisencouraged;inac:vitycanworsenthemuscledisease
• Physicaltherapyishelpfultomaintainmusclestrength,flexibility,andfunc:on
• Orthopedicappliances(suchasbracesandwheelchairs)mayimprovemobilityandtheabilityforself-care.Form-firngremovablelegbracesthatholdtheankleinplaceduringsleepcandefertheonsetofcontractures
• Appropriaterespiratorysupportasthediseaseprogressesisimportant
• Cardiologiccare(echo,ECG,HolterECG)
Treatment:
• externalsubstanceinducedmyopathy:druginduced(sta:ns,glucocor:coid),alcoholic,othertoxicagents
• dermatomyosi:s• polymyosi:s
Acguiredformsofmyopathy:
Feature Neuropathic Myopathic
DistribuConof
weakness
Distal Proximal
Reflexes Absent UsuallyPresent
Sensoryloss Usuallypresent Absent
Atrophy Present Absentun:llate
CPK Normal Elevated
NerveconducCon
Velocity
Usuallydecreased Normal
EMG Fibrilla:onsand
fascicula:ons
Smallmotorunits
Musclebiopsy Groupatrophy Irregular,necro:cfibers
MYASTENIAGRAVIS:
• fluctua:ngmuscleweaknessandfa:gue• Inthemostcommoncases,muscleweaknessiscausedbycircula:ngan:bodiesthatblockacetylcholinereceptorsatthepostsynap:cneuromuscularjunc:on,inhibi:ngtheexcitatoryeffectsoftheneurotransmiHeracetylcholineonnico:nicreceptorsatneuromuscularjunc:ons.
Myastheniagravissigns:• Apokamnosis-Themuscleweaknessbecomesprogressivelyworseduringperiodsofphysicalac:vity,andimprovesa^erperiodsofrest.
• Inabouttwo-thirdsofindividuals,theini:alsymptomofMGisrelatedtothemusclesaroundtheeye.Theremaybeeyeliddrooping(ptosis-weaknessoflevatorpalperbaesuperioris)anddoublevision(diplopiaduetoweaknessoftheextraocularmuscles)
• Dysphagia,dysarthria,hypophonia• Facialweakness-manifes:ngasinabilitytoholdthemouthclosed(the"hangingjawsign")
• Inamyastheniccrisis-aparalysisoftherespiratorymuscles
Myastheniagravisdiagnosis:• Serology-testforan:bodiesagainsttheacetylcholinereceptor,oran:bodiesagainsttheMuSKprotein
• CTMRofmedias:num-Myastheniaassociatedwiththymoma
• EMG-singlefibretest
Myastheniagravismanagement:• acetylcholinesteraseinhibitorstodirectlyimprovemusclefunc:onandimmunosuppressantdrugstoreducetheautoimmuneprocess.
• ThymectomyisasurgicalmethodtotreatMG.
• Myastheniacrisis-plasmapheresis,IVIg
Weaknessduetomotorneurondisease:• SMA(spinalmuscularatrophy)
• Autosomalrecessivediseasecausedbyagene:cdefectintheSMN1gene,whichencodesSMNSMNisapparentlyselec:velynecessaryforsurvivalofmotorneurons,asdiminishedabundanceoftheproteinresultsinlossoffunc:onofneuronalcellsintheanteriorhornofthespinalcordandsubsequentsystem-widemusclewas:ng
• Areflexia• Muscleweakness,poormuscletone-“Floppybabysyndrome”• Difficultyachievingdevelopmentalmilestones,difficultysirng/standing/walking
• Lossofstrengthoftherespiratorymuscles:weakcough,weakcry(infants)
• Fascicula:on• serumcrea:nekinase(CK)maybenormalorincreased• gene:ctes:ngwillshowbi-allelicdele:onofexon7oftheSMN1gene
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