THE NERVOUS SYSTEMTHE NERVOUS SYSTEMByBy

DR IBRAHIM ALZAHRANI FRCPathDR IBRAHIM ALZAHRANI FRCPathDR IBRAHIM ALZAHRANI FRCPath DR IBRAHIM ALZAHRANI FRCPath

PATHOLOGY OF NS CONTENTSPATHOLOGY OF NS CONTENTSPATHOLOGY OF NS CONTENTSPATHOLOGY OF NS CONTENTS•• INTRODUCTIONINTRODUCTION•• CELLS OF NSCELLS OF NS•• RAISED INTRACRANIAL PRESSURERAISED INTRACRANIAL PRESSURE•• BRAIN SWELLINGBRAIN SWELLING•• BRAIN SWELLINGBRAIN SWELLING•• HYDROCEPHALUSHYDROCEPHALUS•• CEREBRAL OEDEMACEREBRAL OEDEMA•• CONGENITAL MALFORMATIONCONGENITAL MALFORMATION•• TRAUMATRAUMA•• CEREBROVASCULAR DISEASECEREBROVASCULAR DISEASE•• CEREBROVASCULAR DISEASECEREBROVASCULAR DISEASE•• INFECTIONS OF NSINFECTIONS OF NS•• NEOPLASMS OF NSNEOPLASMS OF NS•• PRIMARY / ACQUIRED DISEASES OF MYELINPRIMARY / ACQUIRED DISEASES OF MYELIN•• DEGENERATIVE DISEASESDEGENERATIVE DISEASES•• DISEASES OF PERIPHRAL NSDISEASES OF PERIPHRAL NS•• DISEASES OF PERIPHRAL NSDISEASES OF PERIPHRAL NS

PATHOLOGY OF NS PATHOLOGY OF NS CONTENTSCONTENTSاألسناناألسنانألأل

•• INTRODUCTIONINTRODUCTION•• CELLS OF NSCELLS OF NS•• RAISED INTRACRANIAL PRESSURERAISED INTRACRANIAL PRESSURE•• BRAIN SWELLINGBRAIN SWELLING•• BRAIN SWELLINGBRAIN SWELLING•• HYDROCEPHALUSHYDROCEPHALUS•• CEREBRAL OEDEMACEREBRAL OEDEMA•• x CONGENITAL MALFORMATIONx CONGENITAL MALFORMATION•• x TRAUMAx TRAUMA•• CEREBROVASCULAR DISEASECEREBROVASCULAR DISEASE•• CEREBROVASCULAR DISEASECEREBROVASCULAR DISEASE•• INFECTIONS OF NSINFECTIONS OF NS•• NEOPLASMS OF NSNEOPLASMS OF NS•• PRIMARY / ACQUIRED DISEASES OF MYELINPRIMARY / ACQUIRED DISEASES OF MYELIN•• DEGENERATIVE DISEASESDEGENERATIVE DISEASES•• DISEASES OF PERIPHRAL NSDISEASES OF PERIPHRAL NS•• x DISEASES OF PERIPHRAL NSx DISEASES OF PERIPHRAL NS

INTRODUCTIONINTRODUCTION•• The cells of NSThe cells of NS•• Unique physiological properties:Unique physiological properties:

BBB CSFBBB CSF Absence of lymphatic Absence of lymphatic limited space and immunological surveillance.limited space and immunological surveillance.M th d f i NSM th d f i NS•• Methods of assessing NS:Methods of assessing NS:

–– Clinical examination:Clinical examination:Lumbar puncture:Lumbar puncture:–– Lumbar puncture: Lumbar puncture:

(Chem. ,microbiology, microscopic)(Chem. ,microbiology, microscopic)–– Radiological examination:Radiological examination:Radiological examination: Radiological examination: Skull XSkull X--ray, CT, MRI, PET, myelography ray, CT, MRI, PET, myelography

carotid arterography, carotid arterography, ventriculography ventriculography g p y,g p y, g p yg p y–– Brain biopsy: Brain biopsy: --open biopsy open biopsy

-- stereotactic biopsystereotactic biopsyl h l h ( )l h l h ( )–– Electroencephalgraphy (EEG).Electroencephalgraphy (EEG).

THE CELL OF CNSTHE CELL OF CNSNEURONS:NEURONS:•• Vary in size Vary in size and appearance in and appearance in CNSCNSyy pppp•• Mainly seen in grey matter & gangliaMainly seen in grey matter & ganglia•• Carry impulses away from the cell bodyCarry impulses away from the cell body•• All have cell body, axons and All have cell body, axons and dendritesdendrites•• Represent the basic functional unit of NSRepresent the basic functional unit of NS•• Sensitive to damage (hypoxia) Sensitive to damage (hypoxia) red neuronsred neurons

Purkinje cells (cerebellum), pyramidal cells of sommer Purkinje cells (cerebellum), pyramidal cells of sommer sector ( hippocampus )sector ( hippocampus )sector ( hippocampus )sector ( hippocampus )

•• No regenerationNo regeneration•• ChromatolysisChromatolysis (degeneration)(degeneration) axonal injuryaxonal injury•• ChromatolysisChromatolysis (degeneration)(degeneration) axonal injuryaxonal injury•• AtrophyAtrophy•• IntraneuronalIntraneuronal inclusionsinclusionsIntraneuronalIntraneuronal inclusionsinclusions

THE CELL OF CNSTHE CELL OF CNSTHE CELL OF CNSTHE CELL OF CNS

GLIAL (neuroglial) CELLS:GLIAL (neuroglial) CELLS:GLIAL (neuroglial) CELLS: GLIAL (neuroglial) CELLS: Neuroectodermal Neuroectodermal -- derived cells derived cells havehave

Supportive & nutritive functions:Supportive & nutritive functions:Supportive & nutritive functions:Supportive & nutritive functions:1.1. . Astrocytes: . Astrocytes: Gliosis, GFAP, BBB , Gliosis, GFAP, BBB ,

R th l fib lR th l fib lRosenthal fibers, corpra amylaceaRosenthal fibers, corpra amylacea2.2. OligodendrocytesOligodendrocytes:: NSNS myelinmyelin2.2. OligodendrocytesOligodendrocytes:: NS NS myelinmyelin3.3. EpendymalEpendymal cellscells:: CSFCSF, CMV, CMV444.4. ChoroidChoroid plexus plexus cellscells:: secretesecrete CSFCSF

THE CELL OF CNSTHE CELL OF CNS

MICROGLIAL CELLS:MICROGLIAL CELLS:Monocytes derived cells: Monocytes derived cells: antigenantigen--presenting cells, presenting cells, phagocytosisphagocytosis , , microglial nodules neuronophagiamicroglial nodules neuronophagiamicroglial nodules, neuronophagia microglial nodules, neuronophagia

MENINGIAL CELLS :MENINGIAL CELLS :MENINGIAL CELLS :MENINGIAL CELLS :ArachnoidalArachnoidal granulation (CSF granulation (CSF –– absorption)absorption)

BLOOD VESSELSBLOOD VESSELS ::BBBBBB(capillaries) non(capillaries) non--fenesterated, tight fenesterated, tight j i hi k l f i illij i hi k l f i illijunctions, thick cytoplasm, few microvilli, junctions, thick cytoplasm, few microvilli, network of astrocyte processesnetwork of astrocyte processes

RAISED INTRACRANIAL PRESSURERAISED INTRACRANIAL PRESSUREIt is defined as elevated CSF pressure It is defined as elevated CSF pressure >>1515mmHgmmHg>>1515mmHgmmHg

•• CAUSES:CAUSES:11 Ob t ti h d h lOb t ti h d h l1.1. Obstructing hydrocephalusObstructing hydrocephalus2.2. SpaceSpace--occuping lesions (hematoma, tumor, occuping lesions (hematoma, tumor,

infection & infarction)infection & infarction)infection & infarction)infection & infarction)3.3. Cerebral oedema (cytotoxic & vasogenic)Cerebral oedema (cytotoxic & vasogenic)

•• SYMPTOMES & SIGNS:SYMPTOMES & SIGNS:SYMPTOMES & SIGNS:SYMPTOMES & SIGNS:1.1. Severe HeadacheSevere Headache2.2. PapilloedemaPapilloedema2.2. PapilloedemaPapilloedema3.3. Nausea & VomitingNausea & Vomiting4.4. Drowsiness, coma & deathDrowsiness, coma & death,,

RAISED INTRACRANIAL PRESSURERAISED INTRACRANIAL PRESSURE•• EFFECTS:EFFECTS:

11 IIntracranial midline shiftntracranial midline shift1.1. IIntracranial midline shift ntracranial midline shift 2.2.Herniations:Herniations:

•• Transtentorial /Transtentorial / uncaluncal ((33rdrd Cr NerveCr Nerve•• Transtentorial / Transtentorial / uncal uncal ((33 dd Cr.Nerve , Cr.Nerve , midbrain, aqueduct & post.C.Art)midbrain, aqueduct & post.C.Art)

•• Tonsillar (Resp.Cent.& Duret hem.)Tonsillar (Resp.Cent.& Duret hem.) death.death.Tonsillar (Resp.Cent.& Duret hem.)Tonsillar (Resp.Cent.& Duret hem.) death.death.•• Subfalcine / Subfalcine / cingulate cingulate (ant.C.Art)(ant.C.Art)

infarctioninfarction•• TranscalvarialTranscalvarial

TThis depends on Age , Site of SOL ,Ratehis depends on Age , Site of SOL ,RateTThis depends on Age , Site of SOL ,Ratehis depends on Age , Site of SOL ,RateNOTE: LUMBAR PUNCTURE SHOULD NOT BE NOTE: LUMBAR PUNCTURE SHOULD NOT BE

PERFORMED.PERFORMED.

HERNIATIONSHERNIATIONSHERNIATIONSHERNIATIONS

Subfalcine

T t t i lTranstentorial

Tonsillar

HYDROCEPHALUSHYDROCEPHALUSHYDROCEPHALUSHYDROCEPHALUSIt is a term refers to the accumulation ofIt is a term refers to the accumulation ofIt is a term refers to the accumulation of It is a term refers to the accumulation of excessive CSF within the ventricular excessive CSF within the ventricular system of the brainsystem of the brainsystem of the brain.system of the brain.

•• Most cases caused by obstruction of Most cases caused by obstruction of CSF.CSF.

•• Rarely by decreased resorption of Rarely by decreased resorption of y y py y pCSF.CSF.

•• Rarely by increased CSF productionRarely by increased CSF production•• Rarely by increased CSF production Rarely by increased CSF production (choroid plexus papilloma)(choroid plexus papilloma)

HYDROCEPHALUSHYDROCEPHALUSHYDROCEPHALUSHYDROCEPHALUSClassificationClassification::

•• N i ti ( b t ti )N i ti ( b t ti )•• Noncommunicating (obstructive)Noncommunicating (obstructive)::–– Obstruction within the ventricular system (tumor , Obstruction within the ventricular system (tumor ,

inflammation) etinflammation) et•• Congenital hydrocephalusCongenital hydrocephalus : :

–– It is one of the main causes of obstructive hydrocephalus It is one of the main causes of obstructive hydrocephalus caused by:caused by:caused by:caused by:

1.1. Aqueduct stenosis / atresiaAqueduct stenosis / atresia2.2. ArnoldArnold--Chiary malformationChiary malformation3.3. DandyDandy--Walker syndromeWalker syndrome

•• Communicating hydrocephalusCommunicating hydrocephalus::Less common due to reduced CSF reabsorption (meningitisLess common due to reduced CSF reabsorption (meningitis–– Less common due to reduced CSF reabsorption (meningitis , Less common due to reduced CSF reabsorption (meningitis , subarachnoid hemorrhage)subarachnoid hemorrhage)

*Normal pressure hydrocephalus:*Normal pressure hydrocephalus:slow onset & presented with dementiaslow onset & presented with dementia

HYDROCEPHALUSHYDROCEPHALUSHYDROCEPHALUSHYDROCEPHALUS

Clinical Features:Clinical Features:•• InfantsInfants: sutures not fused; : sutures not fused;

Enlargement of the head ( circumference) with Enlargement of the head ( circumference) with g ( )g ( )NONO symptoms of raised intracranial pressure.symptoms of raised intracranial pressure.

•• AdultsAdults::AdultsAdults: : Symptoms of raised intracranial pressures. Symptoms of raised intracranial pressures. NONOchange in head circumference. change in head circumference. gg

* treatment * treatment ventricular shuntingventricular shunting

HYDROCEPHALUSHYDROCEPHALUSHYDROCEPHALUSHYDROCEPHALUSPathologyPathology::PathologyPathology::•• Dilated ventricular system with enlarged cerebral Dilated ventricular system with enlarged cerebral

hemispheres and reducedhemispheres and reduced white matterwhite matter ..hemispheres and reducedhemispheres and reduced white matterwhite matter ..•• Hydrocephalus ex vacuo:Hydrocephalus ex vacuo:

Refers to dilatation of the ventricular system andRefers to dilatation of the ventricular system andRefers to dilatation of the ventricular system and Refers to dilatation of the ventricular system and a compensatory increase in CSF volume a compensatory increase in CSF volume secondary to a loss of brain parenchymasecondary to a loss of brain parenchymasecondary to a loss of brain parenchyma secondary to a loss of brain parenchyma (atrophy).(atrophy).

HYDROCEPHALUSHYDROCEPHALUS

Arnold-Chiari malformation

DandyDandy--Walker malformationWalker malformationDandyDandy Walker malformation Walker malformation

BRAIN SWELLINGBRAIN SWELLINGBRAIN SWELLINGBRAIN SWELLING

1.1. Diffuse brain swelling:Diffuse brain swelling:–– Vasolidation ( head injury)Vasolidation ( head injury)–– Cerebral oedemaCerebral oedema

22 Focal brain swelling:Focal brain swelling:2.2. Focal brain swelling:Focal brain swelling:Areas around Areas around Abscess, haematoma, Abscess, haematoma, neoplasmneoplasm

CEREBRAL OEDEMACEREBRAL OEDEMACerebral oedema means abnormal accumulation Cerebral oedema means abnormal accumulation of fluid in the brain. of fluid in the brain. The brain is soft and swollen with flattened gyri The brain is soft and swollen with flattened gyri and compressed ventericles.and compressed ventericles.pp

1.1. Cytotoxic oedema (intracellular) :Cytotoxic oedema (intracellular) :–– ischaemia.ischaemia.22 Vasogenic oedema (extracellular):Vasogenic oedema (extracellular):–– all otherall other2.2. Vasogenic oedema (extracellular):Vasogenic oedema (extracellular):–– all other all other

causes (infections , trauma , neoplasms) due to causes (infections , trauma , neoplasms) due to increased vascular permeabilityincreased vascular permeabilityincreased vascular permeability.increased vascular permeability.

3.3. Interstitial oedema:Interstitial oedema:-- Due to transudation of Due to transudation of fluid from ventriclesfluid from ventriclesfluid from ventricles.fluid from ventricles.

b l d t th i ht hi hb l d t th i ht hi hcerebral edema seen at the right which cerebral edema seen at the right which obscures the normal structures. obscures the normal structures.

The surface of the brain in cerebral edemaThe surface of the brain in cerebral edemaFlattining of the gyri & narrowing sulci

MALFORMATIONS & DEVELOP. DISORDERSMALFORMATIONS & DEVELOP. DISORDERS

AA--Neural tube defects: Neural tube defects: 1.1. AnencephalyAnencephaly ( lack of cerebral ( lack of cerebral ((

hemispheres & calvaria ) , hemispheres & calvaria ) , incompatible with life , F > M , incompatible with life , F > M ,

mothers >mothers > 4040 high AFP Folic acidhigh AFP Folic acidmothers > mothers > 4040 , high AFP. Folic acid , high AFP. Folic acid 2.2. Encephalocele (herniation of brain tissue, Encephalocele (herniation of brain tissue,

mainly occipital)mainly occipital)mainly occipital)mainly occipital)3.3. Spinal neural tube defects (spina bifida):Spinal neural tube defects (spina bifida):Myelomeningocele,Meningocele, MyeloceleMyelomeningocele,Meningocele, MyeloceleMyelomeningocele,Meningocele, MyeloceleMyelomeningocele,Meningocele, MyeloceleSpina bifida occulta( common & mildest)Spina bifida occulta( common & mildest)

BB--Malformation associated with Hydrocephalus:Malformation associated with Hydrocephalus:11 A ldA ld Chi i lf ti ( ll tChi i lf ti ( ll t1.1. ArnoldArnold--Chiari malformation (small post. Chiari malformation (small post.

fossa, malformed midline cerebellum, fossa, malformed midline cerebellum, h i ti f i )h i ti f i )herniation of vermis) herniation of vermis)

2.2. DandyDandy--Walker malformation (enlarged Walker malformation (enlarged post.fossa ,absent vermis, cyst)post.fossa ,absent vermis, cyst)

Anencephaly is absence of the fetal cranial vault & lack of cerebral hemispheres

meningomyelocele

MALFORMATIONS &MALFORMATIONS &MALFORMATIONS & MALFORMATIONS & DEVELOPMENTAL DISORDERSDEVELOPMENTAL DISORDERS

CC--Inborn errors of metabolism:Inborn errors of metabolism:11 Lysosomal storage diseases (TayLysosomal storage diseases (Tay SachsSachs1.1. Lysosomal storage diseases (TayLysosomal storage diseases (Tay--Sachs, Sachs,

Mucopolysaccharidosis)Mucopolysaccharidosis)22 Leukodystrophies (Metacromatic&AdrenoLeukodystrophies (Metacromatic&Adreno2.2. Leukodystrophies (Metacromatic&AdrenoLeukodystrophies (Metacromatic&Adreno--

leukodystrophies ,Krabbe disease)leukodystrophies ,Krabbe disease)DD Phacomatoses ( neurocutaneous syndromes):Phacomatoses ( neurocutaneous syndromes):DD--Phacomatoses ( neurocutaneous syndromes): Phacomatoses ( neurocutaneous syndromes):

(table (table 2323--11,page ,page 821821))11 Neuorofibromatoses (Neuorofibromatoses (11&&22))1.1. Neuorofibromatoses (Neuorofibromatoses (11&&22))2.2. Tuberous sclerosisTuberous sclerosis33 V Hi lV Hi l Li d diLi d di3.3. Von HippleVon Hipple--Lindau diseaseLindau disease

TRAUMA (HEAD INJURY)TRAUMA (HEAD INJURY)( )( )A leadingA leading cause of death & longcause of death & long--term disability term disability Three groups caused by blunt trauma:Three groups caused by blunt trauma:Three groups caused by blunt trauma:Three groups caused by blunt trauma:1.1. Epidural Hematoma: Epidural Hematoma:

( t f i l t )( t f i l t )(rupture of meningeal artery)(rupture of meningeal artery)

2.2. Subdural Hematoma: Subdural Hematoma: (rupture of bridging veins)(rupture of bridging veins)(rupture of bridging veins)(rupture of bridging veins)

3.3. Parenchymal injuriesParenchymal injuries::C iC i–– ConcussionsConcussions

–– Contusions and lacerations (coup & contrecoup Contusions and lacerations (coup & contrecoup --contusions)contusions)contusions)contusions)

–– Diffuse axonal injuryDiffuse axonal injuryT a matic int ace eb al hemo hageT a matic int ace eb al hemo hage–– Traumatic intracerebral hemorrhageTraumatic intracerebral hemorrhage

–– Brain swelling (generalized or localized)Brain swelling (generalized or localized)

TRAUMA (HEAD INJURY)TRAUMA (HEAD INJURY)TRAUMA (HEAD INJURY)TRAUMA (HEAD INJURY)OUTCOME OF NONOUTCOME OF NON--MISSIL HEAD MISSIL HEAD

INJURY:INJURY:INJURY:INJURY:•• Most patient with minor head injury Most patient with minor head injury

k i fk i fmake a satisfactory recovery.make a satisfactory recovery.•• In severe head injuries:In severe head injuries:jj

–– 2020% Good recovery% Good recovery1010% Severely disabeld% Severely disabeld–– 1010% Severely disabeld% Severely disabeld

–– Others may develop:Others may develop:••EpilepsyEpilepsy••Vegetative stateVegetative state••Vegetative stateVegetative state••dementiadementia

TRAUMA OF SPINAL CORDTRAUMA OF SPINAL CORDTRAUMA OF SPINAL CORDTRAUMA OF SPINAL CORD

•• Spinal cord injuries:Spinal cord injuries:–– Thoracic and below =Thoracic and below = paraplegiaparaplegia–– Cervical below CCervical below C4 4 == quadriplegiaquadriplegiaq p gq p g–– Cervical above CCervical above C44 = quadriplegia + = quadriplegia +

respiratoryrespiratoryrespiratory respiratory difficultydifficulty

•• Meningeal tears:Meningeal tears:•• Meningeal tears:Meningeal tears:–– CSF rhinorrheaCSF rhinorrhea–– CSF otorrheaCSF otorrhea

CEREBROCEREBRO--VASCULAR DISEASE VASCULAR DISEASE ( t k )( t k )(strokes)(strokes)

The third leading cause of deathThe third leading cause of deathThe third leading cause of death The third leading cause of death after IHD after IHD and cancer.and cancer.

CVA divided into THREE groupsCVA divided into THREE groupsCVA divided into THREE groupsCVA divided into THREE groups::

1.1. Infarctions (Infarctions (local vascular obstructionlocal vascular obstruction):):11 EmbolismEmbolism1.1. EmbolismEmbolism2.2. ThrombosisThrombosis3.3. Vasculitis / traumaVasculitis / trauma

22 S t (S t ( t ti )t ti )2.2. Spontaneous ( nonSpontaneous ( non--traumatic) traumatic) Hemorrhages :Hemorrhages :

11 IntraparenchemalIntraparenchemal1.1. IntraparenchemalIntraparenchemal2.2. Subarachnoid Subarachnoid

3.3. Generalized reduction in blood Generalized reduction in blood flowflow

CEREBROCEREBRO--VASCULAR DISEASE VASCULAR DISEASE (strokes)(strokes)(strokes)(strokes)

•• Stroke: Stroke: Stroke is a clinical term defined as a sudden Stroke is a clinical term defined as a sudden development of neurologic deficit due to development of neurologic deficit due to p gp gvascular disease, which last for more than vascular disease, which last for more than 2424hours.hours.–– cerebral infarctions (cerebral infarctions (7070--8080%)%)–– spontaneous hemorrhages (spontaneous hemorrhages (1515%%--2020%):%):–– spontaneous hemorrhages (spontaneous hemorrhages (1515%%--2020%): %):

))intracerebral and subarachnoidintracerebral and subarachnoid((•• Transient Ischaemic Attacks (TIA):Transient Ischaemic Attacks (TIA):•• Transient Ischaemic Attacks (TIA):Transient Ischaemic Attacks (TIA):

–– Similar to stroke but recovery of neurologic Similar to stroke but recovery of neurologic d f hd f h hhdeficit within deficit within 2424 hours.hours.

CEREBRAL INFARCTIONCEREBRAL INFARCTIONTh t f CVATh t f CVA 7070 8080%%•• The most common cause of CVA The most common cause of CVA 7070--8080%%

•• Occures commonly in Occures commonly in 77thth decadedecadeM l f lM l f l•• Males > femalesMales > females

•• Atherosclerosis is the main causeAtherosclerosis is the main causeh l d b l (h )h l d b l (h ) dd•• Other causes include emboli (heart)Other causes include emboli (heart) mid C. Amid C. A

•• Effect Depends on:Effect Depends on:–– Site and size of blood vessels affectedSite and size of blood vessels affected–– Adequacy of collateral circulationAdequacy of collateral circulation

•• Causes:Causes:•• Causes:Causes:–– Thrombosis Thrombosis –– pale infarctspale infarcts–– EmbolismEmbolism –– red infarctsred infarctsEmbolism Embolism red infarctsred infarcts–– Rare causes (Vasculitis, trauma, cardiac arrest)Rare causes (Vasculitis, trauma, cardiac arrest)

CEREBRAL INFARCTIONCEREBRAL INFARCTION

Morphology & grossMorphology & gross::–– First First 44--1212hrs = normal grossly.hrs = normal grossly.–– 11--2 2 days = soft, swollen, indistinct days = soft, swollen, indistinct

junctionjunction–– 22--10 10 days = gelatinous, more sharper days = gelatinous, more sharper

extreme softening ,more distinct extreme softening ,more distinct boundary with rim of hemorrhage.boundary with rim of hemorrhage.

–– 22--33 weeks = tissue liquefies = cystic weeks = tissue liquefies = cystic cavitycavity

–– Few months = cavity with thin rim of Few months = cavity with thin rim of subpial parenchyma.subpial parenchyma.

CEREBRAL INFARCTIONCEREBRAL INFARCTIONCEREBRAL INFARCTIONCEREBRAL INFARCTION

••••

This is an intermediate to remoteThis is an intermediate to remoteThis is an intermediate to remote This is an intermediate to remote infarctinfarctinfarct infarct

CEREBRAL INFARCTIONCEREBRAL INFARCTION

Microscopically:Microscopically:

Neuronal necrosis, oedema, demyelination, gliosis, neutrophils and phagocytic cells.gliosis, neutrophils and phagocytic cells.

SPONTANEOUS INTRACRANIAL SPONTANEOUS INTRACRANIAL HAEMORRHAGEHAEMORRHAGEHAEMORRHAGEHAEMORRHAGE

•• Intracerebral haemorrhage:Intracerebral haemorrhage:•• Intracerebral haemorrhage:Intracerebral haemorrhage:•• Majority Hypertensive vascular disease.Majority Hypertensive vascular disease.•• 8080% in the basal ganglia (putamen)% in the basal ganglia (putamen)•• 8080% in the basal ganglia (putamen)% in the basal ganglia (putamen)•• Rupture of small microaneurysms of the cerebral Rupture of small microaneurysms of the cerebral

arterioles called Charcotarterioles called Charcot--Bouchard aneurysmsBouchard aneurysmsarterioles called Charcotarterioles called Charcot Bouchard aneurysmsBouchard aneurysms•• Middle to late adults.(Middle to late adults.(6060Y)Y)•• Other causes (coagulation disorders amyloidOther causes (coagulation disorders amyloid•• Other causes (coagulation disorders, amyloid, Other causes (coagulation disorders, amyloid,

neoplasms, cardiac surgery, vasculitis, vascular neoplasms, cardiac surgery, vasculitis, vascular malformation) malformation) ))

•• Abrupt onsetAbrupt onset•• Increase ICPIncrease ICP•• Coma & deathComa & death

The intraventricular and intracerebral The intraventricular and intracerebral hemorrhagehemorrhagehemorrhage hemorrhage

SPONTANEOUS INTRACRANIAL HAEMORRHAGESPONTANEOUS INTRACRANIAL HAEMORRHAGESubarachnoid hemorrhageSubarachnoid hemorrhageSubarachnoid hemorrhageSubarachnoid hemorrhage

The common cause is rupture ofThe common cause is rupture of berryberry aneurysmsaneurysmsThe common cause is rupture of The common cause is rupture of berry berry aneurysmsaneurysms

–– Congenital defects ! of smooth muscle of tunica Congenital defects ! of smooth muscle of tunica di h i f bif idi h i f bif imedia at the sites of bifurcation.media at the sites of bifurcation.

–– 11--22% population & higher in polycystic kidney % population & higher in polycystic kidney disease , AV Malformation, coar. of aortadisease , AV Malformation, coar. of aortadisease , AV Malformation, coar. of aortadisease , AV Malformation, coar. of aorta

–– Branches of middle cerebral arteryBranches of middle cerebral artery3434%, junction %, junction of A.C.artery and A.communicating arteryof A.C.artery and A.communicating artery4040%.%.W ff t d thW ff t d th–– Women are affected more than men.Women are affected more than men.

–– 5050% risk of rupture at % risk of rupture at 66--1010mmmm–– 2525--5050 die withdie with 11stst rupturerupture2525 5050 die with die with 11stst rupturerupture–– Rebleeding/spasm is common Rebleeding/spasm is common infarctioninfarction–– Thin giant saccular aneurysm Thin giant saccular aneurysm 22--3 3 cm (less likely to cm (less likely to

))rupture)rupture)–– Hydrocephalus / herniation may occur, pain.Hydrocephalus / herniation may occur, pain.

GLOBAL ISCHAEMIA (iscaemicGLOBAL ISCHAEMIA (iscaemicGLOBAL ISCHAEMIA (iscaemic GLOBAL ISCHAEMIA (iscaemic enchephalopathy)enchephalopathy)

•• Watershed areas( border zone) infarctsWatershed areas( border zone) infarcts•• Laminar cortical necrosis (cerebral midLaminar cortical necrosis (cerebral mid--

cortex)cortex)co te )co te )•• Severe global ischaemia (vegetative Severe global ischaemia (vegetative

state)state)state).state).•• Respirator brain (brain death).Respirator brain (brain death).p ( )p ( )

Hypertensive cerebrovascularHypertensive cerebrovascularHypertensive cerebrovascular Hypertensive cerebrovascular diseasedisease

•• Effect of Hypertension on the brainEffect of Hypertension on the brain::–– Hypertensive haemorrhagesHypertensive haemorrhages..Hypertensive haemorrhagesHypertensive haemorrhages..–– Lacunar infarctsLacunar infarcts (tiny infarcts deep at basal (tiny infarcts deep at basal

ganglia)ganglia)ganglia).ganglia).–– Binswanger subcortical leukoencephalopathyBinswanger subcortical leukoencephalopathy..–– Acute hypertensive encephalopathyAcute hypertensive encephalopathy: :

it is a clinicopathological syndrome characterised it is a clinicopathological syndrome characterised by evidence of diffuse cerebral dysfunction by evidence of diffuse cerebral dysfunction (headaches, confusions, convulsions and coma). (headaches, confusions, convulsions and coma).

ffDue to sudden rises of blood pressure.Due to sudden rises of blood pressure.

INFECTION OF CNSINFECTION OF CNSINFECTION OF CNSINFECTION OF CNS•• Acute Meningitis (bacterial / viral)Acute Meningitis (bacterial / viral)•• Viral EncephalitisViral Encephalitis•• Brain abscess / cerebritisBrain abscess / cerebritis//•• Chronic MeningoencephalitisChronic Meningoencephalitis

ROUTES:ROUTES:–– Hematogenous Hematogenous –– Direct implantation (trauma , congenital Direct implantation (trauma , congenital

lf ti )lf ti )malformation)malformation)–– local extention (sinuses, middle ear)local extention (sinuses, middle ear)

P i h l ( bi )P i h l ( bi )–– Periphral nerves (rabies)Periphral nerves (rabies)

MENINGITISMENINGITISMENINGITISMENINGITIS““infectious leptomeningitis”infectious leptomeningitis”

11 A t l t i itiA t l t i iti1.1. -- Acute purulent meningitis Acute purulent meningitis bacterialbacterial

2.2. Acute (aseptic) Lymphocytic Acute (aseptic) Lymphocytic meningitismeningitis viralviralgg

3.3. Chronic and granulomatous Chronic and granulomatous meningitismeningitis T B fungi brucellaT B fungi brucellameningitismeningitis T.B. , fungi , brucellaT.B. , fungi , brucella , , syphylis (late)syphylis (late)

BACTERIAL MENINGITISBACTERIAL MENINGITISBACTERIAL MENINGITISBACTERIAL MENINGITISCauses vary with the age:Causes vary with the age:Causes vary with the age:Causes vary with the age:

•• NeonatesNeonates: : E.coli, group B streptococcal , E.coli, group B streptococcal , Listeria monocytogenesListeria monocytogenesListeria monocytogenesListeria monocytogenes

•• InfantsInfants (>(>66mon.) and childrenmon.) and children::H. influenzae, St.pneumonaeH. influenzae, St.pneumonaeH. influenzae, St.pneumonaeH. influenzae, St.pneumonae

•• AdultAdult :: N.meningitidis, epidemics/ hajN.meningitidis, epidemics/ haj•• ElderlyElderly:: St. pneumonae , gramSt. pneumonae , gram--N and N and de yde y St p eu o ae , g aSt p eu o ae , g a a da d

listeria monocytogeneslisteria monocytogenes•• Staph.aureus & gramStaph.aureus & gram--N bacilli : after N bacilli : after

i l hi l h f CSFf CSFsurgical shuntssurgical shunts of CSFof CSF•• Immunosuppressed: any thingImmunosuppressed: any thing

The yellowThe yellow--tan exudate of acute bacterial tan exudate of acute bacterial meningitis seen here obscures the sulci. meningitis seen here obscures the sulci.

This is another case of acute purulent This is another case of acute purulent i itii itimeningitis meningitis

neutrophils

BACTERIAL MENINGITISBACTERIAL MENINGITISBACTERIAL MENINGITISBACTERIAL MENINGITIS

•• Clinical features:Clinical features:ll–– Fever, malaiseFever, malaise

–– HeadacheHeadache–– Stiff neck, irritability, photophopiaStiff neck, irritability, photophopia–– CSF changes:CSF changes:gg

•• Turbid , neutrophils ,high protein, low glucose , Turbid , neutrophils ,high protein, low glucose , bacteria (culture &Grambacteria (culture &Gram--stained)stained)

Notes:Notes:The prognosis depends on rapid diagnosis & The prognosis depends on rapid diagnosis &

appropriate antibioticsappropriate antibiotics

CHRONIC MENINGITISCHRONIC MENINGITISCHRONIC MENINGITISCHRONIC MENINGITIS•• Caused mainly byCaused mainly by bacteria & fungibacteria & fungiCaused mainly by Caused mainly by bacteria & fungibacteria & fungi•• Mycobacterium tuberculosis Mycobacterium tuberculosis Granuloma & Granuloma &

caseous necrosis (tubrculoma)caseous necrosis (tubrculoma)caseous necrosis (tubrculoma).caseous necrosis (tubrculoma).May cause hydrocephalus , always May cause hydrocephalus , always

li t i l t b l ili t i l t b l icomplicate primary pulmonary tuberculosis.complicate primary pulmonary tuberculosis.Often associated with encephalitis.Often associated with encephalitis.

•• Other causes include ( Cryptococcus Other causes include ( Cryptococcus neoformans , Brucella , Treponema pallidum)neoformans , Brucella , Treponema pallidum), , p p ), , p p )

PARENCHYMAL INFECTIONSPARENCHYMAL INFECTIONS ((ENCEPHALITIS)ENCEPHALITIS)((ENCEPHALITIS)ENCEPHALITIS)

•• Generalized (encephalitis)Generalized (encephalitis)Generalized (encephalitis)Generalized (encephalitis)•• Localized cerebritis (brain abscess)Localized cerebritis (brain abscess)•• Causes :Causes :

–– ViralViral–– BacterialBacterial

ParasiticsParasitics–– ParasiticsParasitics–– PrionsPrions

BRAIN ABSCESSBRAIN ABSCESSBRAIN ABSCESSBRAIN ABSCESSBrain abscess is a localized area of Brain abscess is a localized area of

suppurative inflammation in the brainsuppurative inflammation in the brainsuppurative inflammation in the brain suppurative inflammation in the brain caused by variety of bacteria caused by variety of bacteria ((staph.staph.,,strept…) strept…)

Occurs as complication of other diseases:Occurs as complication of other diseases:•• Direct spreadDirect spread::

MiddlMiddl–– Middle earMiddle ear–– Mastoid air spaceMastoid air space–– Paranasal sinusesParanasal sinusesParanasal sinusesParanasal sinuses–– Trauma Trauma

•• HaematogenousHaematogenous::gg–– infective endocarditisinfective endocarditis–– Congenital cyanotic heart diseasesCongenital cyanotic heart diseases

S ti l diS ti l di–– Suppurative lung diseasesSuppurative lung diseasesTreatment:Treatment: Surgical evacuation and antibiotic.Surgical evacuation and antibiotic.

FUNGAL INFECTIONFUNGAL INFECTIONFUNGAL INFECTIONFUNGAL INFECTION

•• In Immunosuppressed patients:In Immunosuppressed patients:•• Candida, mucorCandida, mucor ،،aspergillusaspergillus ،،cryptococcicryptococci•• Chronic meningitisChronic meningitis•• Chronic meningitisChronic meningitis•• VasculitisVasculitis•• Cerebral abscessesCerebral abscesses

This resulted from a disseminated This resulted from a disseminated Aspergillus infectionAspergillus infectionAspergillus infection Aspergillus infection

P iti i f tiP iti i f tiParasitic infectionParasitic infection•• Toxoplasma (congenital and acquiredToxoplasma (congenital and acquired•• Toxoplasma (congenital and acquired Toxoplasma (congenital and acquired

with AIDS)with AIDS)•• Cerebral malaria Cerebral malaria -- P. falciparumP. falciparum•• AmebiasisAmebiasis solitary abscesssolitary abscess•• AmebiasisAmebiasis -- solitary abscesssolitary abscess•• TrypanosomiasisTrypanosomiasis -- chronic chronic

meningoencephalitismeningoencephalitis•• Echinococcus granulosusEchinococcus granulosus•• Echinococcus granulosusEchinococcus granulosus

-- hydatid cysthydatid cyst•• Taenia solium Taenia solium cystcyst

toxoplasmosistoxoplasmosistoxoplasmosis

toxoplasmosis

Thi i i li l d l ithThi i i li l d l ith•• This is a microglial nodule with This is a microglial nodule with toxoplasmatoxoplasma pseudocystspseudocysts

Here is a cysticercus cyst of the brain. Here is a cysticercus cyst of the brain. CysticercosisCysticercosisCysticercosis Cysticercosis

VIRAL MENINGITISVIRAL MENINGITISVIRAL MENINGITISVIRAL MENINGITIS•• M t f t l h ti i itiM t f t l h ti i iti•• Most cases of acute lymphocytic meningitis are Most cases of acute lymphocytic meningitis are

caused by viruses.caused by viruses.•• Ro tine c lt e is negati e (aseptic)Ro tine c lt e is negati e (aseptic)•• Routine culture is negative (aseptic)Routine culture is negative (aseptic)•• SelfSelf--limeted & better prognosislimeted & better prognosis•• Can be associated with encephalitisCan be associated with encephalitis•• Causative agents include (echovirus , Causative agents include (echovirus ,

coxsackieviruse , mumps , HIV)coxsackieviruse , mumps , HIV)•• CLINICAL FEATURES are similar to bacterial CLINICAL FEATURES are similar to bacterial

b ll lb ll lmeningitis but usually less severe.meningitis but usually less severe.•• CSF changes ( clear , lymphocytes, normal CSF changes ( clear , lymphocytes, normal

l )l )glucose )glucose )

Vi l M i E h litiVi l M i E h litiViral MeningoEncephalitisViral MeningoEncephalitis

•• Arbovirus Arbovirus epidemicepidemic encephalitisencephalitis•• HSVHSV II Hemorrhagic NecrotizingHemorrhagic Necrotizing temporaltemporal•• HSVHSV--I I Hemorrhagic Necrotizing Hemorrhagic Necrotizing temporal temporal

encephalitisencephalitis•• HSVHSV--IIII Generalized encephalitis (neonates ofGeneralized encephalitis (neonates of•• HSVHSV II II Generalized encephalitis (neonates of Generalized encephalitis (neonates of

+ve mother)+ve mother)•• CMVCMV hemorrhagic ependymahemorrhagic ependyma•• CMVCMV hemorrhagic ependymahemorrhagic ependyma

–– in utero in utero –– periventriculardystrophic calcificationperiventriculardystrophic calcification–– ImmunosuppressionImmunosuppression –– encephalitisencephalitisImmunosuppression Immunosuppression encephalitisencephalitis

•• Herpes ZosterHerpes Zoster AIDS CNS VasculitisAIDS CNS Vasculitis

The hemorrhages seen here in the temporal lobe The hemorrhages seen here in the temporal lobe are due to Herpes simplex virus infection are due to Herpes simplex virus infection

CMVC

Vi l M i E h litiVi l M i E h litiViral MeningoEncephalitisViral MeningoEncephalitis•• PoliovirusPoliovirus Lymphocytic meningitisLymphocytic meningitis•• PoliovirusPoliovirus Lymphocytic meningitis Lymphocytic meningitis

& poliomyelitis& poliomyelitis•• Rabies virusRabies virus MeningoencephalitisMeningoencephalitis•• Measles virusMeasles virus Subacute sclerosingSubacute sclerosing•• Measles virus Measles virus Subacute sclerosing Subacute sclerosing

panencephalitispanencephalitis•• JC PapovavirusJC Papovavirus Progressive Progressive

Multifocal leukoencephalopathy (PML)Multifocal leukoencephalopathy (PML)Multifocal leukoencephalopathy (PML)Multifocal leukoencephalopathy (PML)

HIVHIV--CNSCNSHIVHIV--CNSCNSNeurological disease of HIVNeurological disease of HIV::gg1.1. HIVHIV--I aseptic lymphocytic meningitisI aseptic lymphocytic meningitis2.2. HIVHIV--I meningoencephalitisI meningoencephalitis33 P i h l thP i h l th3.3. Progressive encephalopathyProgressive encephalopathy

–– AIDS dementia complexAIDS dementia complexGait disturbancesGait disturbances–– Gait disturbancesGait disturbances

–– Bladder & bowel incontinenceBladder & bowel incontinence4.4. Vacuolar myelopathyVacuolar myelopathy4.4. Vacuolar myelopathyVacuolar myelopathy5.5. Cerebral vasculitisCerebral vasculitis6.6. Opportunistic infectionsOpportunistic infections7.7. Primary cerebral lymphomaPrimary cerebral lymphoma8.8. Peripheral neuropathyPeripheral neuropathy

SPONGIFORM ENCEPHALOPATHY SPONGIFORM ENCEPHALOPATHY (PRION DISEASES)(PRION DISEASES)(PRION DISEASES)(PRION DISEASES)

This represent a group of transmissible disorders This represent a group of transmissible disorders caused by PRIONS (proteinaceous infectious caused by PRIONS (proteinaceous infectious y (py (pmaterial )material )

•• HUMANHUMAN::C t f ldtC t f ldt J k b di (CJD) l i &J k b di (CJD) l i &–– CreutzfeldtCreutzfeldt--Jakob disease (CJD) ,classic & Jakob disease (CJD) ,classic & newnew--variantvariant

–– KuruKuruKuruKuru–– GerstmannGerstmann--Straussler syndromeStraussler syndrome–– Fatal familial insomniaFatal familial insomnia

ANIMALSANIMALS•• ANIMALSANIMALS::–– Mad cow disease (BSE)Mad cow disease (BSE)–– Scrapie (sheep)Scrapie (sheep)–– Scrapie (sheep)Scrapie (sheep)–– Transmissible mink encephalopathyTransmissible mink encephalopathy–– OthersOthersOthers Others

SPONGIFORM ENCEPHALOPATHY SPONGIFORM ENCEPHALOPATHY (PRION DISEASES)(PRION DISEASES)(PRION DISEASES)(PRION DISEASES)

Clinically:Clinically:yyRapidly progressive dementia often Rapidly progressive dementia often

associated with gait abnormalities.associated with gait abnormalities.associated with gait abnormalities.associated with gait abnormalities.Fatal disease (death within Fatal disease (death within 1 1 year)year)NewNew--variant CJD linked to BSEvariant CJD linked to BSENewNew--variant CJD linked to BSE variant CJD linked to BSE Histology:Histology:

V l ti i th b i ( t )V l ti i th b i ( t )Vacuolation in the brain (cortex)Vacuolation in the brain (cortex)spongiform changespongiform changeN l l & li iN l l & li iNeuronal loss & gliosisNeuronal loss & gliosis