Localization of neurological lesionApproach to neurological cases Localization: PNS, spinal cord, brainstem, cerebral cortex, cerebellar, subarachnoid space Pathology: congenital, trauma, tumor/paraneoplastic, infection, inflammatory/demyelinating, toxic/metabolic, vascular, degenerative

Localization of neurological lesion

1.Cerebral cortex:lesioncerebral cortexcortical dysfunctionRt hemiparesisaphasiaLt hemiparesisneglectapraxiacortical sensorygraphesthesia, stereognosia, 2 point discrimination basic sensationtouch, pain sensation Frontal lobe

motor map

oPrimary motor cortexhemiparesismotor mapanterior cerebral distributionweak> middle cerebral distributionweak> oPremotor cortex(motor program); lesion: apraxia (learning motor skill), deficitfine motor control (serial movement) oSupplementary motor area; lesion: mutism, akinesia oPrefrontal area ; lesion: frontal release signs (palmar grasp reflex, glabellar reflex), mental disorder oBrocas areawernickes area(dominant);(non-dominant); lesion: motor aphasia (-(broc)), monotone speech oFrontal eye field(succade); lesion:lesion(seizure) Parietal lobecortical sensationbasic sensationlesion 2 point discrimination, graphesthesia (),stereognosis (), double stimultaneous stimulation (pin prick2 ), abolition of optokinetic nystagmus, visual inattention; visual pathway: lower quadrant visual field defect oDominant parietal lobe:(anomia , aphasia , alexia, agraphia), Gerstmans syndrome (left-right confusion, finger agnosia, acalculia, agraphia), tactile agnosia, ideational apraxia oNon dominant parietal lobe:visuospatial disorder (), topographic memory loss, anosagnosia (/), hemi-neglect (), dressing apraxia, constructional apraxia ( ), confusion, blepharospasm** Apraxialearning motor skill Temporal lobe(Auditory cortex) oDominant lobe: receptive aphasia (Wernikes aprasia)-were nike oNondominant lobe: oMedial temporal lobe(hippocampal, amygdala): part of limbic system (aggressive behavior, unable to form memory)- oVisual pathway: superior quadrant field defect Occipital lobe: Homonymous hemianopia oVisual agnosia (), prosopagnosia (), Antons syndrome (), visual illusion, hallucination, alexia, impaired optokinetic nystagmus

**hemisphereCNfacial motor cortexcerebral cortex lesionCN lesion CNhemisphereCN 3,4,6,lower partfaceCNhemisphere2forehead, CN 5, 9-12lesionhemisphere( hemisphere transient weaknesspalatal, tongue, dysphagia)

2.Internal capsulepure motor cortical dysfunction

3.Thalamuspure sensory hemianesthesia

4.CerebellumoLateral part: ipsilateral upper extremities dysmetria (FTNTF), dysdiadocholinesia, ataxia, intention tremor, dysarthria with scanning speechoCentral (metabolic): truncal ataxia, lower extremities ataxia, wide bases gait, nystagmus

5.Brain stem

:lesionbrainstemcrossed sign

blood supplybrainstem paramedian brancheslong circumferential branches (SCA, AICA, PICA)medial brainstem syndromelateral brainstem syndromelesion4 rules of brainstemlesionmediallateralmidbrain, ponsmedulla Medial structure 44MMotor pathway(corticospinal tract: weak),Medial lemniscus(vibration, propioceptionlesion),Medial longitudinal fascculus(interinclear opthalmoplegiaadductionlesionnystagmuslateral),Motor nucleus/nerveCN12(CN 3, 4, 6, 12) Lateral structure 44SSpinocerebellar(ataxialesion),Spinothalamic tract(pain, templesion),Sympathetic tract(Horner syndromelesion),Sensory nucleus of CN 5(pain, templesion)* **Sympathetic system lesion thalamus, medulla, C8T1 root, sympathetic fiber carotid, carvernous sinus Cranial nerves oMidbrain lesionCN 3 (ptosis, dilated pupil, eye turn out + slightly down, ,adductionlesion), CN 4 (lesion) oPons lesion(CN 5-8)CN 5 (unilateral facial numbnesslesion), CN 6 (lateral gaze palsylesion), CN 7 (facial palsylesion), CN 8 (unilateral deafnesslesion) ***vestibular portionCN 8 (vertigo)lateral medulla oMedulla lesion(CN 9-12)CN 9 (pharyngeal sensationlesion), CN 10 (palatal weaknesslesion), CN 11 (weaknesstrapezius, sternocleidomastoidlesion), CN 12 (weaknesstonguelesion)IntraaxialextraaxiallesionCN involvementlong tract involvementintraaxialCN involvementlong tractextraaxial lesion

***lesionbrain stemcerebellumcerebellum dysfunction

***facial palsyUMN lesioncerebral cortex lesion (UMN weakness of face)brain stem lesion(nucleusCN VIIponslesionpons (cerebral pedunclemidbrain)UMN weakness)Brain stem syndromeMedial syndrome

Lateral syndrome

lateral brainstem syndrome

Ventral midbrain syndrome(Webers syndrome) Contralateral hemiparesis Ipsilateral third nerve palsyDorsal midbrain syndrome(Benedicts syndrome) Ipsilateral oculomotor paresis Contralateral involuntary movement: rubral tremor, ataxia Contralateral hemiparesis6.Spinal cord

UMN weakness, increased muscle tone, hyperreflexia, upgoing plantar response, sensory level, autonomic disturbance

Intrinsic cordExtrinsic cord

WeaknessANSPainSensoryDescendingEarly autonomic involvementFunnicular painSacral sparingAscendingLate autonomic involvementBone pain, radicular painSensory level

Intrinsic cord lesion: acute transverse myelitis, spinal cord ischemia, intrinsic cord tumor (astrocytoma, ependymoma), syringomyelia Extrinsic cord lesion: metastatic tumor causing spinal cord compression, epidural abscess, extrinsic cord tumor (meningioma, schwannoma, lipoma), degenerative spine disease

7. Subarachinoid

LocalizationCNPathology

Superior orbital fissureIII, IV, V1, VI

Cavernous sinusIII, IV, V1, V2, VI

Retrosphenoid spaceII, III, IV, V, VITumor

Apex of petrous bone (Gradenigro)V, VItumor of petrous bone, infection, acoustic neuroma

Pontocerebellar angleV, VII, VIII, (IX)acoustic neuroma, menigioma

Jugular foramenIX, X, XItumor, aneurysm

Posterior laterocondylar spaceIX, X, XI, XIItumor of parotid gld

Posterior retroparotid spaceIX, X, XI, XII, Horners syndrome

Carvernous sinus lesion Infection: Carvernous sinus thrombosis, chronic granulomatous infection (TB, Fungal) Trauma: CC fistula Vascular: aneurysm of intracarvernous part of carotid a. Tumor:

oDirect extension from skull base: CA nasopharynxoMetastasis: breast, lungoHematologic: lymphoma, leukemiaoExtension from sella tumor Idiopathic inflammatory (Tolosa Hunt)

Cause of CN III lesion Diabetes Posterior communicating a. aneurysm Uncal herniation Carvernous sinus lesion Superior orbital fissure lesion Orbital apex lesion Inflammation in subarachnoid space

8.Peripheral neuvous system

Clinical LMN weakness: decreased muscle tone, muscle atrophy/ fasciculation, muscle weakness, hyporeflexia,down going plantar response

Approach Pure motor: anterior horn cell, NMJ, muscle oAnterior horn cell: atrophy, fasciculation, distal > proximal, DTR decrease (increase in ALS); eg. polio, ALS oNMJ: No atrophy, proximal > distal; Bulbar, ocular; Fluctuation, DTR-normal; eg. MG, Lambert Eaton, botulism oMuscle: No atrophy, proximal > distal or specific muscle group, muscle pain, DTR-normal; eg. muscular dystrophy (congenital, infection (viral, pyomyositis, trichinosis), inflammation (polymyositis, dermatomyositis, inclusion body myositis), toxic/metabolic (thyroid, DM, K, Ca, PO4, Mg), drug (statin, steroid, alcohol, ARV)) Mixed motor, sensory, autonomic: nerve root, plexus, peripheral nerve onerve root, plexus: distal = proximal; peripheral nerve: distal > proximal oPeripheral nerve: weakness & sensory loss in distribution, decrease DTR

Cause of peripheral neuropathy Hereditary: Charcot Marie Tooth (HMSN), HNPP, amyloidosis Tumor related (paraneoplastic): Lung, breast, ovarian cancer, hematologic malignancy, multiple myeloma Infection: HIV, hepatitis B, C, leprosy Autoimmune/ inflammation: GBS, chronic inflammatory demyelinating polyneuropathy (CIDP), vasculitis Metabolic/toxic: Diabetes, thyroid diseases, drugs/toxin related, alcohol related Nutritional deficiency: B1 deficiency, B12 deficiency

Basic Neurological localizing signs1.Lobar localization1.1 Frontal lobe lesion : 1.1.1 Motor dysfunctions = homunculus at motor area , pyramidal signs (UMN lesion) Ex : 1.1.2Conjugate diviayion of eyes = Area 8 irritative lesion --> conjugate eye movement lesiondestructive lesion -->conjugate eye movement lesion 1.1.3 Grasping reflex = lesion diffuse cerebral lesion or hydrocephalus 1.1.4 Apathy or Personality change 1.1.5 Motor aphasia (Dysphasia) = lesion at Broca area1.2 Parietal lobe lesions :1.2.1 Sensory dysfunction = homunculus atpostcentral gyrus Ex : 1.2.2Failure to detect simultaneous stimuli = ( parietal lobe ) visual inattention 1.2.3 Finger agnosia = 1.2.4Right / Left disorientation = 1.2.5Astereognosia = ( lesion) 1.2.6 Agraphesthesia = ( lesion) 1.2.7 Acalculia = 1.2.8Alexia = 1.2.9 Unaware of affected part = lesion 1.2.10Visual field defect = homonymous lower quadrantanopia ( lesion) 1.2.11 Sensory aphasia = Wernicke's aphasia1.3 Temporal lobe lesions : 1.3.1 Visual field defect = homonymousupper quadrantanopia ( lesion) 1.3.2 Memory impairment1.4 Occipital lobe lesions :1.4.1 Visual field defect = homonymoushemianopia with macular sparing ( lesion) 1.4.2 Cortical blindness =bilateraloccipital lesion --> blindness with normal pupil reflex2.Cerebellar lesion: lesion 2.1 Nystagmus = rapidphase swing lesion 2.2Dysarthria (Slurred speech) 2.3 Over shooting = 2.4 Intention tremor(terminal tremor) = 2.5 Dysdiadokokinesia 2.6 Heel to knee test 2.7 Ataxic gait = Tandem walking--> swaying 2.8 Wide base gait 2.9 Truncal ataxia = vermis lesion3.Cranial nerves lesion: 3.1 Olfactory nervelesion : 3.2Optic nerve lesion : VA , , visual field defect , papilledema 3.3 Occulomotor nervelesion : medial rectus palsy , ptosis, pupil dilate 3.4 Troclear nervelesion : diplopia , 3.5Trigeminal nervelesion : facial pain (trigeminal neuralgia) , sensation dysturbance (dermatome) 3.6 Abducens nerve lesion : lateral rectus palsy 3.7 Facial nerve lesion : facial palsy , 3.8Acoustic nerve lesion : coclear division --> hearing loss vestibular lesion --> vertigo 3.9 Glossopharyngeal nerve lesion : loss of gag reflex , dysphagia , aspiration 3.10 Vagus nerve lesion : 3.11Accessory nerve lesion : weakness of stenocleidomastoid , trapezius 3.12 Hypoglossal nerve lesion : tongue deviated to lesion side, fasciculation , atrophy4.Brainstem lesion : 4.1 polycranialnerves involvement 4.2 loss of Doll's eye phenomenon ( good conscious) 4.3 Coma 4.4 Respiration point --> to lesion4.4.1 Cheyne stoke breathing ----- upper brainstem lesion 4.4.2 Central neurogenic hyperventilation ----- midbrain and upper pons 4.4.3 Apneustic breathing ----- lower pons 4.4.4 Ataxic breathing ----- medulla 4.5 cranial nerves piont ---> to lesion 4.5.1 midbrain --- CN 3 4 4.5.2 pons --- CN 5 6 7 8 4.5.3 medulla --- CN 9 10 11 125. Spinal cord lesion : Tract spinal cord 5.1 Dorsal column (fasciculus gracilis , cuneatus ) --- vibration, proprioception 5.2 Corticospinal tract (Pyramidal tract) ---motor5.3 Lateral spinothalamic tract ---sensory 5.4 Intermediolateral (ANS)

Lesion of posterior column : joint position sense (JPS) ,position sense , vibratory sense lesion lesion Lesion of corticospinal tract: weakness lesion lesion Lesion of spinothalamic tract: pinprick sensation ,temperature sensation lesion lesion nerve fibers --> tract fiber Posterior column--> S-L-Th-C (sacrum-lumbar-thoracic-cervical)Lateral column --> C_Th_L_S (cervical-thoracic-lumbar-sacrum) spinal cord sacral segment cervical segment --> (lateral column)6. Reflexes :

LOCALIZING LESIONS IN NEUROLOGY lesion investigation 1.lesion ?2.nature ?localizedlesiondiagnosiswork up conceptlesion1.Intracranial compartment : supretentorial & infratentorial2.Spinal cord : CTLS level3.Peripheral nerves : plexus, cranial nerves, spinal nerves4.Neuromuscular junction : NMJ5.MusclesLOCALIZINGINDICATORS indicatorsA.Intracranial lesion1. higher cortical functions2.cranial nerves deficit3. Neurological deficithemiplegia / hemianesthesia4.signs of cortical lesiongrasping reflexB.Spinal level lesion1.2.paraplegia, suspended sensory loss,sensory loss below level ,3.spinal cord syndrome ;central cord syndrome, Brown-Sequard syndrome, anterior cord syndrome, posterior cordsyndrome, conus medullaris syndrome4.involve bowel bladder functionC.Peripheral nerve lesion1.anatomy2.motor & sensory3. hyporeflexia4.diatal weakness5. marked atrophy6. fibrillationMotor Weakness predominantly distalHypotoniaGlove and stocking sensory lossDiminished reflexes-HyporeflexiaPan-sensory modalities affectedGuillain- Barre syndrome, Diabetic neuropathy

D.Muscles & Neuromuscular junction disease:1. Myastiniagravis2.motor(sensory intact)3. absent / hyporeflexia4. marked atrophy5. pain & tendernessProximal greater than distal muscle weaknessNeck muscles often affectedSensations are intactMuscle stretch reflexes are normalDuchenne muscular dystrophy, polymyositisA1.supratentorial or Infratentorial lesionSupratentorial lesion1.higher cortical functionsaphasia2. Deficit of CN I, II3. conjugate eye deviation4. Neurological deficitfacial palsyUMNs5.reflexeslobar lesionInfratentorial lesion1. Infratentorial compartmentcross paralysis ()2. cerebellum cerebellar signs3.Brainstem (brainstemlongtract (corticospinal, spinothalamic tract, etc)nucleicranialnerves 7-8-9-10-11-12cranial nerveslong tract signs & symptoms4.cranial nerves deficit ; CN 5,6,7,8,9,10,11infratentorial lesionmidbrain : CN 3,4 deficitPons:CN 5,6,7,8deficitMedulla:CN 9,10,11,12 deficit5.pinpoint pupils, abnormal respirationpatternbrainstemCHARACTERISTICS OF NEURAXIS LESIONSINTRACRANIAL COMPARTMENTI.SUPRATENTORIAL LESION SIGNS & SYMPTOMSSupratentorial compartment :cortex, subcortical, deep nucleiCORTEX :frontal, temporal, parietal, occipital lobeFrontal lobe lesion :Symptoms :frontal lobe lesion aphasia,homanculusSigns : hemiparesis / hemiplegia, conjugate eye deviation,Grasping reflex, Brocas aphasiaParietal lobe lesion:Symptoms : Signs : sensory disfunction(lesion)finger agnosia()Right/Left disorientation()Astereognosia( )Agraphestesia()Acalculia()Alexia()VF defect (homonymus lower quadrantanopiaWernickes aphasiaTemporal lobe lesion: Signs : VF defect (homonymus upper quadrantanipia)Occipital lobe lesion:Signs : VF defect (Homonymus hemianopia with macular sparing)Cortical blindness(fundi & pupil reflex)Parasagittal lesion:Homunculusparasagittal lesionparaparesis / paraplegiaspinal cordlesionparasagittal meningioma spinal cord lesionwork upMRI spinelesionAnterior skull base lesion: (anosmia)optic nerve atrophypapilledemaolfactory groove meningiomaFoster-Kenedy syndromeSUBCORTICAL LESIONInternal capsule : lesionIClesionICparaplegia gr 0Thalamic lesion / Basal ganglia lesion :structuresnerve fiberinternal capsule- contralateral loos of dorsal column sensations, contralateralspastic paresis, contralateral facial weakness UMNs, dysarthria,thalamic syndromeBasal nuclei : lesiondeep nucleiinvoluntarymovement (Chorea, athetoid, ballistic), ParkinsonismII.INFRATENTORIAL LESIONSBrainstem lesions: neurological deficit1.polycranial nerves involvement :CN 5,7,8,9,10,11,122.loss of Dolls eye phenomenon :Dolls eyegood conscious,unconscious Dolls eye phenomenonbrainstem Dolls eyebrainstemlesion3.coma4.pinpoint pupils5.abnormal respiratory pattern eg: central neurogenic hyperventilation, ataxic of breathing6.Nystagmus, Hornors syndrome, vertigo7.internuclear ophthalmoplegia (INO)8.Cross paralysis()

Cerebellar lesion: neurological deficitlesion1.Nystagmus :2.Dysarthria (slurred speech)3.over shooting (Rebound phenomenon)4.intention tremor (terminal tremor) : ()5.Dysdiadokokinesia (impaired rapid alternate movement of hands)6.Impaired HTK test7.Ataxic gait (wide base gait, Tandem walking)8.Truncal ataxia (vermis lesion)9.Scanning speech (Staccato)10.Dysmetria, hypotonia

No 1 :Cortical lesion=lobar, seizure,homunculuslesionRt. frontal lobehomunculusarm focal seizurehyperreflexialesionfiberarealoss ofconsciousherniationNo 2 :Corona radiate / Internal capsule=lesion fiber3 (internal capsule)lesion dense fibergrade 0-IconsciouslesionRt.internal capsuleUMN lesionNo 4 :Brainstem lesion=Crossed paralysisLMN lesion lowercranial nerves (CN 5,6,7,8,9,10,11,12) No 5 :Spinal cord lesion= level patternspinal cord syndromeNo 6,7,8 :Peripheral nerves, NMJ, muscular lesions= CASE STUDY142 6 PE : vital signs are normalGA : normal allNS : hyperreflexia of right arm, other WNLCase discussion:focal seizurehyperreflexia lesionmotor cortexhomunculusleft cerebral cortexMRI brainConfirm diagnosis

256 PE : BP210/120HR 64RR16BT 36.8 CGA : obesity womanNS : good conscious, pupil R3L3 RTLBELeft hemiplegia grade I,Lt. BBK dorsiflexionLeft facial palsy (UMNs type)Case discussion = UMNsBBK +velesionRightinternal capsulefibervascular causeHT and poorcompliancehypertensive putamen hemorrhageCT brain

3326 PE : normal vital signsGA : looked sick young man , not coorperationNS : E3M5V3,pupil R1.5L1.5 mm SRTLBE, nystagmusmotor, sensory can not evaluationReflexes : hyperreflexia both arms & legsBBK : dorsiflexion bilaterallyStiff neck veCase discussion=localization lesionbrainstemlower cranial nerves deficitlong tractsignsMRI

436 carpal tunnel syndromePE: normal vital signsGA : looked normal womanNS : good conscious, normal all CNs, Downbeat nystagmusSuspended sensory loss both arms, muscle atrophy of boththenas, hyporeflexia both biceps, tricepsmotor power both arm Gr III, both legs Gr VCase Analysis:(problem lists)1. ()2.suspended sensory loss3.downbeat nystagmusCN lesioncordinvolvelesioncordcentral canaldownbeat nystagmus() Chiari malformation(tonsilcerebellumupper cervical)casetypical.. ?MRI cervical spine()

532 PE : normal vital signsGA : alert, coorperativeNS : good conscious, Rt. facial palsy LMN type, poor gag reflex,Motor :DeltoidR4L4BicepsR4L4TricepsR4L4Wrist extensorR3L3Hand gripR2L2Hip flexorR4L4QuadricepsR4L4HamstringR3L3DTR absent, PPS decrease both hand & feetCase discussion :progressive fromdistal to proximalinvolvebrainstem andspinal cordnucleifacial palsy LMN type, absent DTR, distalmuscle weakness,motor & sensorylesionnerve rootsbrainstem spinal nerve rootspolyradiculoneuritis or Guillain Barre syndromeconfirm diagnosis by CSF profile.624 PE : normal vital signsGA : alert, coorperative womanNS : good conscious, bilateral ptosis, diplopia R>LWeakness of all extraoccular musclesptosisOther WNLCase discussion:NMJ myastinia gravis