ErinAkin,DVM,DACVIM(Neurology)BushVeterinaryNeurologyService

WoodstockGAApril9,2017

TheNeurologic ExamAnd

LesionLocalization

Whatisthegoaloftheneuroexam?

• Neuroanatomicallylocalizethelesion• Rememberthatitisthelocationofthediseasewithinthenervoussystem(notthedisease)thatdeterminestheclinicalsigns

Brain• Cerebrum(Hemispheres)• Diencephalon(Thalamus)• Mesencephalon(Midbrain)

§ CN– IIIandIV• Metencephalon(Pons)

§ CN– V• Myelencephalon(Medulla)

§ CN– VI-XII• Cerebellum

SpinalCordAnatomy

• SpinalSegments(NotVertebrae)§ C1-C5§ C6-T2§ T3-L3§ L4-S2(3)

• L4-L6(FemoralN.)• L6-S2(3)(SciaticN.)

NeurologicExamination• History/Signalment• MentalStatus• GaitandPosture• PosturalReactions• CranialNerves• SpinalReflexes• SpinalPain• Nociception• Syndrome/Localization• DifferentialDiagnoses

History/Signalment

• Establishtimeline• Reviewpertinentmedicalhistory

• Definechiefcomplaint

Observation

• Lookatthepatient§ LevelofConsciousness

• Alert• Depressed/Obtunded– drowsybutarousablewithmildstimulus

• Stuporous– patientina“sleepstate,”butarousablewithnoxiousstimulus

• Comatose– patientunconscious

GaitAnalysis

• Lameness• Ataxia

§ Spinal/proprioceptiveataxia§ Cerebellarataxia§ Vestibularataxia

• Paresis--weakness• Paralysis/plegia

Posture

• Positionofheadandbodywithrespecttogravity

• Examples:§ Wide-basestance§ Decerebraterigidity§ Decerebellaterigidity§ Opisthotonus§ Schiff-Sherrington

PosturalReactions

• Proprioceptivepositioning(knuckling)• Orthodiseasevs.neurodisease

• Hopping• Hemistandingandhemiwalking

• Wheelbarrow• Extensorposturalthrust

PosturalReactions

Hopping Hemiwalking/Hemistanding

PosturalReactions

Wheelbarrow

ExtensorPosturalThrust

CranialNerves

I. Olfactory*II. OpticIII. OculomotorIV. TrochlearV. TrigeminalVI. AbducentVII. FacialVIII.Vestibulocochlear

IX. GlossopharyngealX. VagusXI. AccessoryXII. Hypoglossal

CranialNerveII:Optic

• MenaceResponse• IItosee,VIItoblink

§ Maybeabsentinpuppiesandkittensyoungerthan12weeks

§ Ipsilateralcerebellarlesion

• Following(cottonball)• ObstacleCourse

CranialNervesIII,IV,andVI:Oculomotor,Trochlear,andAbducent

• Controleyemovements• Lookforstrabismus• Observeeyemovementsaspatientlooksaround

• MoveheadupanddownANDleftandrighttoinducenormalnystagmus

OcularMuscleAnatomy

Neuroanatomy and Clinical Neurology, pg. 142

CranialNerveIII:Oculomotor(PLR)

CranialNerveV:Trigeminal

• Motor§ Symmetryofmasseterandtemporalis

• Sensory§ Ophthalmic—medialcanthus

§ Maxillary—lateralcanthus

§ Mandibular—lowerlip

CranialNerveVII:Facial

• Observeforsymmetry(eyelids,ears,lips)

• Palpebralreflex• Muzzle/lipMovement

• EvaluatetearingwithSchirmerteartest

CranialNerveVIII:Vestibulocochlear

• Auditory§ BAER§ Makeanunexpectednoise

• VestibularSystem§ Centralvs.peripheral§ Headtilt,abnormalnystagmus,ataxia,broad-basedstance,falling,rolling

§ Elicitpositionalnystagmusorstrabismus

CranialNerveVIII:Vestibulocochlear

CranialNervesIXandX:GlossopharyngealandVagus• Consideredtogether• Askclientaboutdysphagia,regurgitation,voicechange,etc.

• Testwithgagreflex

CranialNerveXI:SpinalAccessory

• Deficitsmayresultinatrophyofthetrapeziusmuscle

CranialNerveXII:Hypoglossal

• Lookforasymmetry,atrophy,movementoftongue

• Innervationtostriatedmusclesofthetongue

Horner’sSyndrome• Miosis• Enophthalmos• Ptosis• Prolapsed3rd eyelid

Horner’sSyndrome• Midbrain• LateralTectotegmentalSpinalTract

• ExitsT1-T3• RamiCommunicans• VagosympatheticTrunk• CranialCervicalGanglion

• OphthalmicbranchofCNV

AnyQuestionsAboutCranialNerves?

SpinalReflexesReflex Nerve Spinal SegmentBiceps Musculocutaneous C6-T1

Triceps/Extensor CarpiRadialis

Radial C7-T2

Flexorwithdrawal(forelimb)

Ulnar,median,musculocutaneous

C6-T2

CranialTibial Peroneal (sciatic) L6-L7

Patellar Femoral L4-L6

Gastrocnemius Sciatic L7-S1

Flexorwithdrawal (pelviclimb)

Sciatic L6-S1

Perineal Pudendal S1-S3

Cutaneous Trunci Lateralthoracic C8-T1

ReflexArc

Veterinary Neuroanatomy, pg. 75

http://vetgrad.com/show10MinuteTopUp.php?type=&Entity=10MinuteTopUps&ID=21

ForelimbReflexes

Biceps Triceps ECR Withdrawal

HindlimbReflexes

CranialTibial Patellar Gastrocnemius Withdrawal

CutaneousTrunci• Afferent

§ Spinal

• Efferent§ LateralThoracic

OtherSpinalReflexes

PerinealS1-S3 Babinski

SpinalPain/Palpation• Palpateentirespine• Cervicalrangeofmotion

§ Dorsal,ventral,leftandrightlateral

• Rectalexam• Canperforminlateralrecumbency

§ Avoidsloadingjoints

NociceptionPROPRIOCEPTION

PARESIS

PARALYSIS

LOSSOFSENSATION

Nociception

• Superficialpain(skin)• Deeppain(bone)

MovingontoLesionLocalization

Remember,LocalizationistheGoal!

• Forebrain(includingdiencephalon)

• Brainstem(midbrain,pons,medulla)

• Cerebellum• Cervicalspinalcord• CTspinalcord• TLspinalcord• LSspinalcord• Neuromuscular

• Don’tforgetaboutmultifocaldisease

NeuroanatomicLocalization• Neurologicsignsarecaudaltolesion• TolocalizethelesionweinterrogatetheCNS

§ Cranialnerves§ Cervicalintumescence

• Tricepsreflex– RadialN.• Bicepsreflex– MusculocutaneousN.• Withdrawalreflex

§ Lumbarintumescence• Patellarreflex– FemoralN.• Cranialtibialreflex– CommonperonealN.• Withdrawalreflex

§ Cutaneoustrunci• DorsalspinalandLateralthoracic(C8-T1)

• Intercapitalligament§ LowincidenceofdiscextrusionsbetweenT2-T11

Forebrain(Hemisphere,Thalamus)Localization• ClinicalSigns

§ Contralateralposturaldeficits§ Contralateraldecreaseinnasalsensation§ Dullness,stupor,coma§ Lossoflearnedbehaviors§ Cognitive

• Thought,Thinking§ Pacing§ Staringoff§ Seizures§ Circling

ObtundedStray

BrainstemLocalization• Mesencephalon(Midbrain),Metencephalon(Pons),Myelencephalon(Medulla),Cerebellum

• Clinicalsigns§ IpsilateralDeficits§ AlteredlevelofConsciousness(ARAS)§ CNNIII-XII§ Ataxia,dysmetria§ Gaitabnormalities§ Vestibular

Handbook of Veterinary Neurology, 5th Ed., pg. 20

BrainstemMUE

VestibularLocalizationPeripheral Central

Headtilt Yes(ipsilateral) Yes(ipsilateral, maybecontralateralwithparadoxicaldisease)

Ataxia Yes Yes

Nystagmus--Horizontal--Rotary--Vertical--Positional

YesYesNo (?)Rarely

YesYesYesYes

PosturalReactionDeficits No Yes(ipsilateral)

Circling Yes(ipsilateral) Yes(eitherdirection)

FacialParalysis Yes(ipsilateral) Nottypically

Horner’sSyndrome Yes(ipsilateral) Nottypically

VestibularDisease

• Fastphaseofnystagmusrunsawayfromthelesion(usually)

• Bilateral—wideheadexcursions• Paradoxical

§ SideofCPdeficits§ Headtiltopposite

VestibularDisease

CerebellarLocalization

• Intentiontremor• Dysmetria(Hypermetria)• Ipsilateralmenacedeficit• NoCPdeficits• Decerebellatepostureifsevere

C1-C5Localization• Cranialnerves

§ +/- IpsilateralHorner’s• Posture

§ Scoliosis§ Torticollis

• Gait§ Tetra/Hemiparesis§ Tetra/Hemiplegia

• Posturalreactions§ Posturaldeficits(normaltodecreased

toabsentx4)• Reflexes

§ Normaltohyper-reflexivex4limbs§ Normaltoincreasedmuscletonex4

limbs• Bladder

§ +/- Normalorlargeandfirm• RespiratoryFailure

§ PhrenicN(C5-C7)

C1-C5Localization

C6-T2(CervicalIntumescence)Localization• Cranialnerves

§ +/- IpsilateralHorner’s• Thoraciclimb

§ Brachialplexusavulsion§ Monoparesis/plegia

• Posture§ Torticollis,nerverootsignature

• Gait§ Tera/Hemiparesis§ Tetra/Hemiplegia

• Posturalreactions§ Posturaldeficits(normaltodecreased

toabsentx4)• Reflexes

§ Normaltohyper-reflexivehindlimbs§ Decreasedtoabsentreflexesforelimbs§ Reducedtoabsentcutaneoustrunci

• Bladder§ +/- NormalorLargeandfirm

C6-T2(CervicalIntumescence)Localization

T3-L3Localization• Thoraciclimbs

§ Normal• Gait(Pelviclimbs)

§ Spastic§ Mono/Paraparesis§ Mono/Paraplegia

• Posturalreactions§ Posturaldeficits(oneorboth

limbs)• Reflexes

§ Normaltohyper-reflexive§ Reducedtoabsentcutaneous

trunci• Bladder

§ +/- NormalorLargeandfirm§ Overflowincontinence§ Increasedurethralsphinctertone

T3-L3Localization

Schiff-Sherrington• Clinicalsigns

§ Severeextensorrigidityofthoraciclimbswithflaccidparalysisofpelviclimbs• Normalmovementofthoraciclimbs• Disinhibitionofextensormotorneurons• InjurytoBorderCells

– GraymatterfromspinalsegmentsL1-L5– SynapseonthoraciclimbextensorLMNsinthecervicalintumescence

• Possibleareflexiainpelviclimbs• Takeaway

§ Schiff-Sherringtonindicatesaseverelesion§ ItisNOTaprognosticindicator!

Neuroanatomy and Clinical Neurology pg. 249

Myelomalacia

L4-S3Localization• Thoraciclimbs

§ Normal• Gait(Pelviclimbs)

§ Shortstrided§ Mono/Paraparesis§ Mono/Paraplegia§ Plantigrade

• Posturalreactions§ Posturaldeficits(oneorbothlimbs)

• Reflexes§ Decreasedtoabsentreflexes

• Tail§ Normal,Paresis,Plegia§ Lossofperinealreflexandsensation

• Bladder§ Flaccidbladder§ Lossofurethralsphinctertone§ Incontinence§ Internalurethralsphincterintact

AnatomyoftheBladder• Hypogastric

§ SympatheticL1-L4• α-adrenergictotheurethra(increasetone)• β-adrenergictothebladder(relaxdetrusor)

• Pelvic§ ParasympatheticS1-S3

• Contractionofdetrusor§ Afferenttosympathetic

• Pudendal§ S1-S3§ Somatic

BSAVA Neurologia, pg. 312

Neuroanatomy and Clinical Neurology, pg. 184

TreatmentsforMicturitionDisorders• Stimulatedetrusorcontraction

§ Bethanechol• Viacholinergic• 1.25-25mgperdayTID

• Decreaseurethraltone§ Diazepam

• Skeletalmusclerelaxant• 2-10mgTID

§ Phenoxybenzamine• α-adrenergicantagonist• 0.25-0.5mg/kgSID-BID

§ Prazosin• α1-adrenergicantagonist• 1mg/15kgSID-BID

NeuromuscularLocalization• Shortchoppygaitx4limbs,

fatiguesandthencollapse• Weak(crouched,trembling)• Normalproprioceptionx4limbs• Notataxic• Non-painfulonspinalpalpation• Diminishedtoabsentreflexes• Denervationatrophy• Perceivespain,unableto

withdraw• Fatiguingpalpebral• Regurgitation

NeuromuscularLocalization

DifferentialDiagnoses• D—degenerative• A—anomalous

(congenital)• M—metabolic• N—neoplastic,

nutritional• I—infectious,

inflammatory,idiopathic

• T—trauma,toxin• V—vascular

World’sSmallestTakeHomePoints• Takingathoroughhistoryisalwaysimportant,butitiscriticalwhendealingwitha

neurologicpatient.• Knowwhatisnormal!• Thethreegoalsoftheneurologicexaminationareto1)determineifthepatient

hasaneurologicproblem,2)localizethelesion,and3)generateashortlistofdifferentialdiagnoses.

• Usefultoolsfortheneuroexaminclude:aquietroom,anexperiencedassistant,non-slipsurface(i.e.yogamatorother),reflexhammer,hemostats,cottonballs,penlight,lens,etc.

• Thereareeightbasicareastowhichalesionmaybelocalized:forebrain(includingdiencephalon),brainstem(midbrain,pons,medulla),cerebellum,cervicalspinalcord,cervicothoracicspinalcord,thoracolumbarspinalcord,lumbosacralspinalcord,andneuromuscular.Rememberthatitisthelocationofthediseasewithinthenervoussystem(notthedisease)thatdeterminestheclinicalsigns.

• PleasecallDr.AkinorDr.Nearyaboutanyquestionsorcasesyoumayhave.Weareeagertohelp!

References• Chrisman,C.,C.Mariani,S.Platt,andR.Clemmons.2003.Neurologicalexaminationtechniquesand

lesionlocalization.InNeurologyforthesmallanimalpractitioner,15–40.Jackson:TentonNewsMedia.

• deLahuntaA,GlassE.VeterinaryNeurologyandClinicalNeurology.Elsevier:Philadelphia,3rd ed.pgs248-250,2009.

• Glass,E.N.,andM.Kent.2002.Theclinicalexaminationofneuromusculardisease.VeterinaryClinicsofNorthAmerica:SmallAnimalPractice32(1):1–29.

• LorenzeMD,KornegayJN.Handbookofveterinaryneurology.Elsevier:Philadelphia,5th ed,pgs49-89,2009.

• Oliver,J.E.,M.D.Lorenz,andJ.N.Kornegay.1997.Neurologichistoryandexamination.InHandbookofveterinaryneurology,3rded.,3–46.Philadelphia:W.B.Saunders.

• Platt,S.R.,andN.J.Olby,eds.2004.BSAVAmanualofcanineandfelineneurology,3rded.Gloucester,UK:BSAVA,1–23.

• SharpNJH,WheelerSJ.Smallanimalspinaldisorders:Diagnosisandsurgery.Elsevier:Philadelphia,2nd ed,pgs11-17.2004.

• http://www.vetmed.wsu.edu/cliented/anatomy/nervous.aspx• http://www.aisti.info/en/neurology/neurological_examination.html• http://www.neuroanatomy.wisc.edu/SClinic/Weakness/Weakness.htm• http://www.vetmed.wsu.edu/cliented/anatomy/nervous.aspx

Anyquestions?