emg painful limb

7/28/2019 EMG Painful Limb

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EMG NerveEMG Nerve

Studies in PainStudies in Pain

AmmarAGilani,MD,DABPNAmmarAGilani,MD,DABPNAssociateProfessorandStaffNeurologistAssociateProfessorandStaffNeurologist

DepartmentofMedicine/NeurologyDepartmentofMedicine/NeurologyMcMasterUniversity/HamiltonHealthSciencesMcMasterUniversity/HamiltonHealthSciences

Hamilton,ONHamilton,ON


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PfizerPfizer

AstraZenecaAstraZeneca

AllerganAllergan

PurduePurdue

TevaNeurosciencesTevaNeurosciences

Lilly/BoehringerIngelheimLilly/BoehringerIngelheim

ayerayer

ValeantValeant


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BasicDescriptionofthelaboratoryproceduresBasicDescriptionofthelaboratoryprocedures

NerveconductionstudiesNerveconductionstudies

E ectromyograp yE ectromyograp y

ElectrodiagnosticabnormalitiesinpainfulperipheralnerveElectrodiagnosticabnormalitiesinpainfulperipheralnerve

diseasesdiseases

Pitfalls/limitationsoftechniquePitfalls/limitationsoftechnique


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SomatosensoryEvokedSomatosensoryEvoked

o en a so en a s

thePostthePostMRIera.MRIera.

A.SSEP

stimulation

to

the

left

A.

SSEP

stimulation

to

the

left

MediannerveMediannerve

B.SSEPstimulation totheleftB.SSEPstimulation totheleft

TibialnerveTibialnerve


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EMG and Nerve ConductionEMG and Nerve ConductionStudiesStudies

An

extension

o

the

Physical

ExaminationAn

extension

o

the

Physical

Examination Quantitatesnerveand/ormusclein urQuantitatesnerveand/ormusclein ur

ProvidesUsefulDataRegardingNerveInjuryProvidesUsefulDataRegardingNerveInjury SiteSite TypeType SeveritySeverity

ura onura on PrognosisPrognosis


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Goals of EDX Testing

Localization Severity

NerveNMJ Anterior HornMuscle


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erve on uct on tu es Studies

of

the

waveforms

generated

in

the

.

Motornerveconduction

fromamuscleinnervatedbythatnerve.

Sensorynerveconduction

Stimulationamixed

nerve

while

recording

from

a

mixedorcutaneousnerve


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LATENCY(DL)LATENCY(DL)IntervalbetweentheonsetofastimulusandtheonsetofaIntervalbetweentheonsetofastimulusandtheonsetofaresponseresponse

ThemaximumvoltagedifferencebetweentwopointsThemaximumvoltagedifferencebetweentwopointsItisproportionaltothenumberandsizeofnervefibersthatareItisproportionaltothenumberandsizeofnervefibersthatare

depolarized.depolarized.

electricallyactiveelectricallyactive

DURATIONDURATIONThetimefromonsettotermination.Thetimefromonsettotermination.

.

.MeasuresthedifferencesinconductionofthenervefibersMeasuresthedifferencesinconductionofthenervefibers

CONDUCTION VELOCITY(CV)CONDUCTION VELOCITY(CV)ThespeedatwhichthenervefibersarecarryingtheelectricalThespeedatwhichthenervefibersarecarryingtheelectrical

s mu us e ween wos es.s mu us e ween wos es.ComparisonofconductionbetweentwosegmentsofthesameComparisonofconductionbetweentwosegmentsofthesame

nervecanlocalizealesion.nervecanlocalizealesion.


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studies

Sensory:typically

antidromic

Commonly

examinednerves:

Sural,ulnar,median,

occas ona yra a

orsuperficial


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OnsetandpeakOnsetandpeaklatencieslatencies

ConductionvelocityConductionvelocity determinedbydeterminedby

velocityofaveryfewvelocityofaveryfewas ersas ers

AmplitudeAmplitude determinedb thedeterminedb the

numberoflargenumberoflargesensoryfiberssensoryfibersactivatedactivated


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Motor Nerve Conductions

Vital

part

of

EDX

as

this

importantforidentifyingdemyelination,compression

Needtodoproximalanddistal

studies

to

evaluate

for

conductionvelocit ,

conductionblock,temporaldispersion

, ,peroneal,

tibial

Lesscommon:radial,femoral,phrenic,spinalaccessory,facial


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F-waves and H-reflex

Usefulfor

identifying

proximalsegmental

demyelination

Canonly

be

done

w enmotoramplitudeis>1mV

epen en

onpatientsheight


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MotorFwavestudies roximalroots:

Antidromic motor

to

the

anterior

horn

of

the

spinal

cord;

orthodromically tothe

muscle.

. AprolongedasymmetricFwavessuggestaproximal

rootlesion.

Clinicalapplicationbestforplexopathy. Quiteprolongedindemyelination,AIDP,mild

rolon ationinaxonalin ur .

Lesssensitive

than

EMG

for

radiculopathy

since

only

shortsegmentofnerveisdemyelinatedin.


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Re lexloo : Orthodromicsensor andmotor Utilized

to

assess

for

radiculopathy

of

S1,

*C6/7

S1;Poplitealfossa,recordinMedialGastrocnemeus

C6/7;Mediannerveatwrist,recordatFlexorCarpiRadialis

,

,

,

sacralplexus,cord,S1motororsensoryroots. Onceabnormal,maynotnormalize;

O tenabsent

in

polyneuropathy

or

>60

years

o

age.


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Needle Electrom o ra h : Techni uesNeedle Electrom o ra h : Techni ues

NeedleelectrodeisinsertedintothemuscleNeedleelectrodeisinsertedintothemuscle Needleisdisposable,singleuseNeedleisdisposable,singleuse

MultiplemusclesareaccessibleforexaminationMultiplemusclesareaccessibleforexamination

CombinationofmusclestestedCombinationofmusclestested DependentuponclinicalquestionDependentuponclinicalquestion

LevelofdiscomfortismildLevelofdiscomfortismild


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NeedleElectromyography:DataNeedleElectromyography:Data

InsertionalActivityInsertionalActivity

SpontaneousActivitySpontaneousActivity

MotorUnitConfi urationMotorUnitConfi uration

MotorUnitRecruitmentMotorUnitRecruitment

Inter erencePatternInter erencePattern


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EMGFin ings


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InsertionactivityInsertionactivityincreaseswithinafewdaysofmuscleincreaseswithinafewdaysofmuscledenervation,whereasdenervation,whereasabnormalspontaneousactivityabnormalspontaneousactivityta es2ta es24 3 wee sto eve op, epen ngont e stance4 3 wee sto eve op, epen ngont e stance

betweenthenervelesionandthemusclebetweenthenervelesionandthemuscle

norma spontaneousact v tyan ncrease nsert onnorma spontaneousact v tyan ncrease nsert on

activityarenotpathognomonicofdenervation,mayoccuractivityarenotpathognomonicofdenervation,mayoccurincertaindisordersofmuscleortheneuromuscularincertaindisordersofmuscleortheneuromuscular

junctionjunction


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: ecru tment

Whenamuscleisvoluntarilycontractedasinglemotorunitmayfire.

Asthemuscleisfurthercontractedmoremotorunitsareaddedorrecruited.

Normall recruitmentofadditionalmotorunitsoccursatrelativelylowlevelsofeffort

IfthereisalossofMUAPswithanydiseaseprocessthen recruitmentisreduced.

Lossof

nerve

axons

ConductionblockattheneuromuscularjunctionSufficientlossofmusclefibers


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The

electromyographic

findings

may

provide

a

guide

to

the

time

of

The

electromyographic

findings

may

provide

a

guide

to

the

time

of

onsetofthelesionandtoitschronicity,onsetofthelesionandtoitschronicity,

apa en repor s a awr s rop as eve ope mme a e yapa en repor s a awr s rop as eve ope mme a e yafteranoperativeprocedureandneedleelectromyographyafteranoperativeprocedureandneedleelectromyographyperformedshortlythereafterrevealsabnormalspontaneousperformedshortlythereafterrevealsabnormalspontaneousactivit fibrillation otentialsand ositiveshar waves intheactivit fibrillation otentialsand ositiveshar waves intheextensormuscleofthewrist,itislikelythatthelesionisatleastextensormuscleofthewrist,itislikelythatthelesionisatleast223weeksoldandtherefore itprecededthesurgery.3weeksoldandtherefore itprecededthesurgery.

,, ,, ,,polyphasicmotorunitpotentialsindicatesthatthedenervationpolyphasicmotorunitpotentialsindicatesthatthedenervationoccurredseveralweeksormorebeforesurgerybecausesomeoccurredseveralweeksormorebeforesurgerybecausesomereinnervationhasoccurred.reinnervationhasoccurred.


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MononeuropathyMononeuropathy

PolyneuropathiesPolyneuropathies

MultiplexMultiplex

Radiculo athRadiculo ath

TrigeminalMononeuropathyTrigeminalMononeuropathy

(BlinkReflex(BlinkReflex))

Plexopathy(BrachialPlexopathy(BrachialorLumbosacral)orLumbosacral)

MyopathyMyopathy


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AxonalAxonal Sensory+/Sensory+/ MotorMotor NormalCVNormalCV

DemyelinatingDemyelinating Motor+SensorychangeMotor+Sensorychange SlowNCVSlowNCV

NormalDLNormalDL

ReducedtoabsentAmp.ReducedtoabsentAmp.

NormalFNormalFWave(ifamp.>1Wave(ifamp.>1

ConductionBlockConductionBlock

DistalLatency:LongDistalLatency:Long

SlowFSlowFwaveswavesMV)MV)

NeedleEMGinmotororNeedleEMGinmotororsensorimotor;Denervationsensorimotor;Denervationandreinnervationchan esandreinnervationchan es

Amplitude:NormaltoAmplitude:Normaltoreduced(late)reduced(late)

NeedleEMG:Normal(lateNeedleEMG:Normal(late

(slowlyprogressivecan(slowlyprogressivecanshowonlyreinnervationshowonlyreinnervationchanges)changes)

Denervationand/orDenervationand/orreinnervation)reinnervation)


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PAINFULNEUROPATHIES:PAINFULNEUROPATHIES:

ToxicToxic AlcoholAlcohol

Metals:Thallium;ArsenicMetals:Thallium;Arsenic

HereditaryHereditary galactosidase(Fabry's)galactosidase(Fabry's) GM2gangliosidosis:LateGM2gangliosidosis:Lateonsetonset Sensor Neuro ath ILancinatin ainsSensor Neuro ath ILancinatin ains

ciscisplatinum;Disulfiram;Ifosfamide;platinum;Disulfiram;Ifosfamide;Nitrofurantoin;Dilantin;Perhexiline;Nitrofurantoin;Dilantin;Perhexiline;Taxol;Thalidomide;VincaalkaloidsTaxol;Thalidomide;Vincaalkaloids

ImmuneImmune

MotorMotorSensoryNeuropathyI&IIFootSensoryNeuropathyI&IIFootdeformitydeformity

BurningfeetsyndromeBurningfeetsyndrome

AmyloidosisAmyloidosis

AcuteonsetAcuteonset

GuillainBarrGuillainBarr

DiffusepainduringacutecourseDiffusepainduringacutecourse

DistalpainwithincompleteDistalpainwithincompleterecover recover

ParaesthesiasinlegsParaesthesiasinlegs

Carpaltunnelsyndrome:PaininCarpaltunnelsyndrome:Paininhandshands

PorphyriaPorphyria

ImmobilityImmobility

AcutepanautonomicAcutepanautonomic

AntiAntiSulfatideAntibodyassociatedSulfatideAntibodyassociatedpolyneuropathiespolyneuropathies

PNSinvolvementPNSinvolvement Hereditary(Acromelalgia):12qHereditary(Acromelalgia):12q HSN1HSN1

HMSN5HMSN5

onnect vet ssue seaseonnect vet ssue sease

HIV(DILS)HIV(DILS)

MMproteinprotein

Ganglionopathies:Sjgren's;ParaneoplasticGanglionopathies:Sjgren's;Paraneoplastic(Hu)(Hu)

HuntingtondiseaseHuntingtondiseaselike1like1 Also:RenalfailureAlso:Renalfailure


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PAINFULNEUROPATHIES:PAINFULNEUROPATHIES:

D erent a D agnos sD erent a D agnos s

MetabolicMetabolic DiabeticDiabetic

Acute:LumbarorThoracicAcute:LumbarorThoracic

Motor

disorders

with

pain

Motor

disorders

with

pain

DiabeticamyotrophyDiabeticamyotrophy PolioPolio

InfectionsInfections

Chronic:"Smallfiber"Chronic:"Smallfiber"neuropathyneuropathy

Alcoholic:AcuteAlcoholic:Acute Pella ra niacin Pella ra niacin

PolioPolio HIVHIV

LocalizeddisordersLocalizeddisorders Nervelesions:Nervelesions:

TrigeminalTrigeminal BrachialplexusBrachialplexus

Beriberi(thiamine)Beriberi(thiamine) Strachansyndrome(CubanStrachansyndrome(Cuban

neuropathy)neuropathy) PostgastroplastyPostgastroplasty

LumbosacralplexopathyLumbosacralplexopathy ThoracicoutletsyndromeThoracicoutletsyndrome MedianMedian Posteriortibial(Tarsaltunnelsyndrome)Posteriortibial(Tarsaltunnelsyndrome) Radiculopathies:Upper&LowerExtremitiesRadiculopathies:Upper&LowerExtremities

Burnin mouths ndromeBurnin mouths ndrome

HypertriglyceridemiaHypertriglyceridemia ChronicmountainsicknessChronicmountainsickness IdiopathicIdiopathic

DistalsensorypolyneuropathyDistalsensorypolyneuropathy

Diabetic

Amyotrophy

Diabetic

Amyotrophy

ReflexSympatheticDystrophy (ComplexregionalReflexSympatheticDystrophy (Complexregionalpainsyndrome)painsyndrome)

Infections:HerpeszosterInfections:Herpeszoster Neoplasticinfiltration:BurningpainwithNeoplasticinfiltration:Burningpainwith

dysesthesiainareaofsensorylossdysesthesiainareaofsensorylosssyn romessyn romes

ErythromelalgiaErythromelalgia

MononeuritismultiplexMononeuritismultiplex

PostsurgicallocalizedpainsyndromesPostsurgicallocalizedpainsyndromes

Acuteonsetofpain&paresthesiasAcuteonsetofpain&paresthesias AcuteporphyriaAcuteporphyria

Toxic:Thallium;Arsenic;Perhexiline;VincaToxic:Thallium;Arsenic;Perhexiline;Vincaalkaloidsalkaloids

GuillainGuillainBarrBarr


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Diabetes

and

PNS

DiseasesS mmetric Pol neuro athies

Chronic Distal sensory +/- AutonomicAutonomic

-

Acute PainfulReversible

As mmetric neuro athies

Lumbosacral plexopathy

Mononeuropathies i.e., CTS

Mononeuritis multiplex

Predisposition to immune PNCIDP

Diabetic amyotrophy

Muscle infarction


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MedianattheWrist(CTS)MedianattheWrist(CTS)

UlnarattheElbow (TardyUlnarPalsy)UlnarattheElbow (TardyUlnarPalsy)

PeronealPalsyattheFibularHeadPeronealPalsyattheFibularHead


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Plexopathy: SelectedPlexopathy: Selected

EtiologiesEtiologies

CompressionCompression (CABG)(CABG)

InflammatoryInflammatory (Parsonage(ParsonageTurnerTurnerSyndrome)Syndrome)

RadiationInjuryRadiationInjury (Radiotherapy)(Radiotherapy)

, ,, ,

missile)missile)

sc em asc em a a et camyotrop ya et camyotrop y


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prolongationofthemediannervemotor/sensorylatencyuponprolongationofthemediannervemotor/sensorylatencyuponstimulationatthewrist("terminal"or"distal"latency),stimulationatthewrist("terminal"or"distal"latency),

normalmedianmotorconductionvelocityintheforearm,normalmedianmotorconductionvelocityintheforearm,

slowmediansensor conductionvelocit acrossthewrist slowmediansensor conductionvelocit acrossthewrist

normalmotorandsensoryNCSoftheulnarnerve(notinvolvednormalmotorandsensoryNCSoftheulnarnerve(notinvolvedinCTS).NCSarepositivein91inCTS).NCSarepositivein9198%ofpatientswithclinicalCTS98%ofpatientswithclinicalCTS

DiagnosedbycomparingMediantoUlnarsensoryandmotorDiagnosedbycomparingMediantoUlnarsensoryandmotorDLsDLs


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58YearoldpatientwithLowBack58YearoldpatientwithLowBack

pa nan e t oot roppa nan e t oot rop

RetiredsteelworkerwithlongstandinghistoryoflowbackfromworkRetiredsteelworkerwithlongstandinghistoryoflowbackfromworkrelatedinjuryandS/Pbacksurgery10yrs.Ago. Presentedwith2relatedinjuryandS/Pbacksurgery10yrs.Ago. Presentedwith2monthhistoryofnumbnesstinglingandpainofdorsalaspectofleftmonthhistoryofnumbnesstinglingandpainofdorsalaspectofleft

. .

NerveConductionStudiesNerveConductionStudies

MotorNerveConductionstudies: CMAPsonLeftMotorNerveConductionstudies: CMAPsonLeft TibialTibial NormalNormal Amp.,DL&CVAmp.,DL&CV

DeepPeronealDeepPeroneal ReducedAmp,NormalDLandCVbelowfibularReducedAmp,NormalDLandCVbelowfibularheadand12m/sslowingacrossfibularhead,Dispersionan55%dropinheadand12m/sslowingacrossfibularhead,Dispersionan55%dropinampl.ampl.

SensoryNerveConductionStudies:SNAPsonLeftSensoryNerveConductionStudies:SNAPsonLeft Sural:Sural: NormalAmp.,DL&CVNormalAmp.,DL&CV

Sup.Peroneal:Sup.Peroneal: Slightlyreducedamp.,NormalDLandCVSlightlyreducedamp.,NormalDLandCV


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58YearoldpatientwithLowBack

NeedleEMGLeftLowerExtremitNeedleEMGLeftLowerExtremit

Muscle Insertional Spontaneous Configuration Recruitment Interfennce

Vastus

Lateralis

N N N N N

Anterrior Lar e/

Tibialis Poly

Peroneus

MedialGast. N N Large/poly

. .

Large/Poly

Glut.Med. N N Large/Poly


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Guideline:NeedleEMGexaminationofatleast1muscleinnervatedb theC C6 Guideline:NeedleEMGexaminationofatleast1muscleinnervatedb theC C6 C7,C8,andT1spinalrootsinasymptomaticupperlimb,andL3,L4,L5,andS1C7,C8,andT1spinalrootsinasymptomaticupperlimb,andL3,L4,L5,andS1

spinal

roots

in

the

symptomatic

lower

limb.

spinal

roots

in

the

symptomatic

lower

limb.

Paraspinalmusclesat1ormorelevels,asappropriatetotheclinicalpresentation,Paraspinalmusclesat1ormorelevels,asappropriatetotheclinicalpresentation,s ou eexam ne excep npa en sw pr orcerv ca am nec omyus ngas ou eexam ne excep npa en sw pr orcerv ca am nec omyus ngaposteriorapproach).posteriorapproach).

If

a

specific

root

is

suspected

clinically,

or

if

an

abnormality

is

seen

on

the

initial

If

a

specific

root

is

suspected

clinically,

or

if

an

abnormality

is

seen

on

the

initial

needleEMGexamination additionalstudiesasfollows:needleEMGexamination additionalstudiesasfollows:

Examinationof1or2additionalmusclesinnervatedbythesuspectedrootandadifferentExaminationof1or2additionalmusclesinnervatedbythesuspectedrootandadifferentperipheralnerve.peripheralnerve.

Demonstrationofnormalmusclesaboveandbelowtheinvolvedroot.Demonstrationofnormalmusclesaboveandbelowtheinvolvedroot.

OptionaOptional:

Perform

Fl:

Perform

F

Wave

and

HWave

and

H

Reflex

(C6,C7

and

S1).

Compare

with

the

Reflex

(C6,C7

and

S1).

Compare

with

the

contralateralsideifnecessary.contralateralsideifnecessary.

Abnormalonlywithaxonalinvolvement.Abnormalonlywithaxonalinvolvement.

Dennervationin2Dennervationin23weeks,reinnervation43weeks,reinnervation46weeksafteronsetofsymptoms.6weeksafteronsetofsymptoms.


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What to Expect From anWhat to Expect From an

EMG ReportEMG Report

AclinicallyandphysiologicallyrelevantAclinicallyandphysiologicallyrelevant

Anoutlineofthelocalization,severity,andacuityofAnoutlineofthelocalization,severity,andacuityof

NotationofotherdiagnosesthatareNotationofotherdiagnosesthataredetected excludeddetected excluded

ExplanationofanytechnicalproblemsExplanationofanytechnicalproblems


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NerveConductionStudies:limitationsNerveConductionStudies:limitations NCSassessdistalsegmentsofnervesNCSassessdistalsegmentsofnerves PainfulstimulationsPainfulstimulations

empera uresens ve > empera uresens ve > AssessmainlylargefibersAssessmainlylargefibers MostusefulfornerveconditionsMostusefulfornerveconditions

SkillsoftheelectromyographerSkillsoftheelectromyographer Timing(Walleriandegeneration) fewweeksuntilfullpictureTiming(Walleriandegeneration) fewweeksuntilfullpicture

emergesemerges

MultiplemusclesneedtobeexaminedMultiplemusclesneedtobeexamined SamplingerrorscanleadtoerroneousconclusionsSamplingerrorscanleadtoerroneousconclusions


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DetectsdynamicandfunctionalinjurymissedbyMRIDetectsdynamicandfunctionalinjurymissedbyMRI

rov es n orma onregar ngc ron c yo nerve n uryrov es n orma onregar ngc ron c yo nerve n ury

ProvidesprognosticdataProvidesprognosticdata

g y oca z ngg y oca z ng

ClarifiesclinicalscenarioswhenonedisordermimicsanotherClarifiesclinicalscenarioswhenonedisordermimicsanother

en escom ne muen escom ne mu s e n ury,avo ngm sse agnosess e n ury,avo ngm sse agnoses

IdentifiesmoreglobalneuromuscularinjurywithfocalonsetIdentifiesmoreglobalneuromuscularinjurywithfocalonset

Prov es ong tu na ata orc art ngcourse,responsetot erapyProv es ong tu na ata orc art ngcourse,responsetot erapy


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ThankyouThankyou

emg painful limb

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