The NeurologicExam And Lesion...
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Erin Akin, DVM, DACVIM (Neurology) Bush Veterinary Neurology Service Woodstock GA April 9, 2017 The Neurologic Exam And Lesion Localization
Transcript of The NeurologicExam And Lesion...
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?
