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PATHOLOGY 2 > Nervous system > Flashcards

Nervous system Flashcards

1
Q
  1. Pathology of raised intracranial pressure:

CEREBRAL EDEMA general + morphology

A

= accumulation of excess fluid within the brain parenchyma

MORPHOLOGY:

  • flattened gyri
  • narrow sulk
  • compressed ventricular cavities
  • softer brain
  • herniation
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2
Q
  1. Pathology of raised intracranial pressure:

CEREBRAL EDEMA vasogenic edema

A
  • occurs when integrity of BBB is disrupted
  • increased vascular permeability ⇒ fluid to IC space
  • localized or generalized
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3
Q
  1. Pathology of raised intracranial pressure:

CEREBRAL EDEMA cytotoxic edema

A
  • neuronal, glial, endothelial cell membrane injury ⇒ increased IC fluid
  • due to generalized hypoxic/ischemic insult or exposure to toxins
  • ischemia ⇒ cells can’t supply sodium pump ⇒ loss of membrane potential ⇒ inflow of water
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4
Q
  1. Pathology of raised intracranial pressure:

SUBFALCINE HERNIATION

A
  • expansion of cerebral hemispheres displace the cingulate gyrus under the edge of falx cerebri
  • associated with compression of branches of ACA ⇒ ischemia of anterior cerebrum
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5
Q
  1. Pathology of raised intracranial pressure:

TRANSTENTORIAL HERNIATION

A
  • medial aspect of temporal lobe compressed against free margin of tentorium cerebelli
    ⇒ CN III compromised ⇒ pupillary dilation + blown pupil
  • PCA compressed ⇒ ischemia to visual cortex
    + Duret hemorrhage in pons and midbrain
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6
Q
  1. Pathology of raised intracranial pressure:

TONSILLAR HERNIATION

A
  • displacement of cerebellar tonsils through foramen magnum

⇒ life-treathening bc compromises vital respiratory and cardiac centers in medulla

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7
Q
  1. Pathology of raised intracranial pressure:

HYDROCEPHALUS pathophysiology

A

= increase in CSF volume within ventricular system

- occur as a consequence of impaired flow or impaired resorption of CSF, or overproduction of CSF

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8
Q
  1. Pathology of raised intracranial pressure:

HYDROCEPHALUS classification

A
  1. Communicating
    - no blockage
    - decreased CSF resorption
    - meningitis ⇒ fibrotic tissue in arachnoid mater
    - whole ventricular system dilates
  2. Non-communicating
    - obstruction of CSF flow
    - dilation of part of ventricular system
  3. Hydrocephalus ex vacuo
    - atrophy of brain due to infarct or degenerative disease
    - dilation of ventricular system ⇒ increase in CSF volume

Hydrocephalus internus or externus

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9
Q
  1. Pathology of raised intracranial pressure:

HYDROCEPHALUS clinical features

A

Adults:
- develop after fusion of sutures ⇒ associated with expansion of ventricles + increased ICP
Children:
- develops before closure of cranial sutures ⇒ enlargement of head

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10
Q
  1. Congenital malformations of central nervous system:

NEURAL TUBE DEFECTS

A
  • failure of neural tube to close or reopen after closure

- characterized by abnormalities involving neural tissue, meninges and overlying bone and soft tissues

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11
Q
  1. Congenital malformations of central nervous system:

SPINA BIFIDA OCCULTA

A
  • neural tube defect
  • asymptomatic bony defect
  • posterior end affected
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12
Q
  1. Congenital malformations of central nervous system:

MENINGOCELE

A
  • neural tube defect
  • flattened, disorganized segment of spinal cord + overlying meningeal outpuching
  • posterior end affected
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13
Q
  1. Congenital malformations of central nervous system:

MYELOMENINGOCELE

A
  • neural tube defect
  • extension of CNS tissues through defect in vertebral column ⇒ abnormal spinal cord
  • mostly in lumbosacral region
  • motor and sensory deficits in lower extremities and problems with bowel and bladder control
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14
Q
  1. Congenital malformations of central nervous system:

ANENCEPHALY

A
  • neural tube defect
  • malformation of the anterior end
  • absence of brain and top of skull
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15
Q
  1. Congenital malformations of central nervous system:

ENCEPHALOCELE

A
  • neural tube defect
  • diverticulum of malformed CNS tissue extending through defect in cranium
  • mostly occipital region and posterior fossa
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16
Q
  1. Congenital malformations of central nervous system:

MEGAENCEPHALY AND MICROENCEPHALY

A
  • forebrain malformation
  • volume of brain abnormally large or small
  • occur with chromosome abnormalities, fetal alcohol syndrome and HIV-1 infection in utero
    ⇒ decreased number of neurons
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17
Q
  1. Congenital malformations of central nervous system:

LISSENCEPHALY AND PACHGYRIA

A
  • forebrain malformation
  • absence of normal gyration ⇒ smooth surface brain
  • cortex thickened and 4-layered
  • single gene defect
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18
Q
  1. Congenital malformations of central nervous system:

POLYMICROGYRIA

A
  • forebrain malformation
  • increased number of irregularly formed gyri ⇒ irregular bumpy or cobblestone-like surface
  • changes can be local or widespread
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19
Q
  1. Congenital malformations of central nervous system:

HOLOPROSENCEPHALY

A
  • forebrain malformation
  • disruption of normal midline patterning
  • mild form: absence of olfactory bulb
  • severe form: brain is not divided into hemispheres or lobes ⇒ cyclopia
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20
Q
  1. Congenital malformations of central nervous system:

CHIARI 1 MALFORMATION

A
  • posterior fossa malformation
  • cerebellar tonsils extend through foramen magnum
    ⇒ obstruction of CSF flow + compression of medulla
    ⇒ headache + cranial nerve deficits
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21
Q
  1. Congenital malformations of central nervous system:

ARNOLD-CHIARI MALFORMATION

A
  • posterior fossa malformation
  • small posterior fossa + misshapen midline cerebellum with downward extension of vermis through foramen magnum
    ⇒ hydrocephalus + lumbar myelomeningocele
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22
Q
  1. Congenital malformations of central nervous system:

DANDY-WALKER MALFORMATION

A
  • posterior fossa malformation

- enlarged posterior fossa

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23
Q
  1. Congenital malformations of central nervous system:

SPINAL CORD MALFORMATIONS

A

MORPHOLOGY:

  • discontinuous or confluent expansion of ependyma-lined central canal (hydromyelia)
  • formation of fluid-filled cleft-like cavity (syringomyelia)
  • may develop secondary to alteration in CSF flow by tumor or trauma
  • associated with destruction of grey and white matter + surrounded by reactive gliosis
  • cervical spinal cord mostly affected
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24
Q
  1. Cerebrovascular diseases:

GENERAL

A

= abnormality of the brain caused by:

  • thrombotic occlusion ⇒ infarct
  • embolic occlusion ⇒ infarct
  • vascular rupture ⇒ intracranial hemorrhage

3 causes of ischemia/hypoxia:
⇒ generalized cerebral hypoxia/ischemia
⇒ infarct
⇒ vasculitis

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25
Q
  1. Cerebrovascular diseases:

GLOBAL CEREBRAL ISCHEMIA etiology

A
  • when generalized reduction of cerebral perfusion ⇒ systolic pressure <55mmHg
  • decrease in O2 saturation/ increase in CO2 saturation
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26
Q
  1. Cerebrovascular diseases:

GLOBAL CEREBRAL ISCHEMIA clinical features

A

MILD:
- transient postischemic confusional state ⇒ complete recovery
- irreversible CNS changes ⇒ pyramidal cells of hippocampus, Purkinje cells, pyramidal neurons in neocortex most susceptible
SEVERE:
- widespread neuronal death ⇒ neurological impairment and comatose
- brain dead
BORDERZONE INFARCT:
- zone between major cerebral arteries suffers hypo perfusion ⇒ hemorrhagic infarct(encephalo malacia rubra)

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27
Q
  1. Cerebrovascular diseases:

GLOBAL CEREBRAL ISCHEMIA morphology

A
  • swollen brain ⇒ wide gyri, narrow sulci
  • poor demarcation between white and grey matter
  • herniation
    EARLY (12-24h):
    ⇒ red neurons, eosinophilia, neuronal pyknosis and karyorrhexis, neutrophilia
    SUBACUTE (24h-2w):
    ⇒ necrosis, macrophages, vascular proliferation, reactive gliosis
    REPAIR (>2w):
    ⇒ removal of necrotic tissue
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28
Q
  1. Cerebrovascular diseases:

GLOBAL CEREBRAL ISCHEMIA transient ischemic attack

A 
= episode of neurologic dysfunction caused by ischemia without infarction ("mini stroke")
- due to disrupted cerebral blood flow
- symptoms: paralysis, weakness
  ⇒ resolve after minutes-hours
- no morphological changes
- warning sign for infarct
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29
Q
  1. Cerebrovascular diseases:

FOCAL CEREBRAL ISCHEMIA classification

A
  1. Ischemic infarct - white infarct
    - artery occlusion
  2. Hemorrhagic infarct - red infarct
    - repercussion of ischemic infarct
    - vein obstruction
    - borderzone infarct
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30
Q
  1. Cerebrovascular diseases:

FOCAL CEREBRAL ISCHEMIA etiology + risk factors

A

Occlusion of cerebral artery due to:

  1. Atherosclerosis ⇒ in situ thrombosis (basilar a., MCA)
  2. Embolism
    • from bifurcation of carotids
    • from mural thrombi
    • paradoxial

RISK FACTORS:

  1. hypertension
  2. diabetes mellitus
  3. hypertriglyceremia
  4. atherosclerosis
  5. atrial fibrillation
  6. transient ischemic attack
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31
Q
  1. Cerebrovascular diseases:

VASCULITIS

A
  • may involve cerebral arteries ⇒ infarct
  • inflammatory disorder, involves medium-sized parenchymal and subarachnoidal vessels
  • chronic inflammation + destruction of vessel wall
  • symptoms: cognitive dysfunction
  • treatment: steroid and immunosuppression
  • infectious arteritis can be caused by toxoplasma, aspergillosis, CMV encephalitis
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32
Q
  1. Cerebrovascular diseases:

LACUNAR INFARCTS

A

= hypertensive cerebrovascular disease

  • HT ⇒ hyaline arteriolar sclerosis of deep arterioles of basal ganglia
  • walls become weaker + more vulnerable to rupture
  • small localized infarcts - few mm wide, mostly in deep grey matter + internal capsule
  • clinically silent or neurologic impairment
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33
Q
  1. Cerebrovascular diseases:

FOCAL CEREBRAL ISCHEMIA morphology

A

Non-hemorrhagic infarct;
0-6h: normal tissue
6-12h: red neurons
12-48h: tissue is pale, soft, swollen + neutrophilia
2-10d: brain is gelatinous + friable, edematous
10d-3w: tissue liquefies, macrophages
3w-months: astrocyte + cytoplasmic enlargement regresses

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34
Q
  1. Intracranial hemorrhage:

CAUSES

A

⇒ hypertension
⇒ vascular malformation
⇒ bleeding disorder
⇒ trauma

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35
Q
  1. Intracranial hemorrhage:

APOPLEXIA

A

= intracerebral hemorrhage

  • cause: HT
  • rupture by:
    • arteriolosclerosis ⇒ narrowing of lumen, fibrinoid material deposition in vessel wall
    • Charcot-Bouchard ⇒ small micro aneurysm
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36
Q
  1. Intracranial hemorrhage:

HEMORRHAGE FROM VASCULAR MALFORMATION

A

TYPES:

  1. arteriovenous malformation
    - abnormal connection of arteries to veins
    - loss of capillaries ⇒ increased pressure ⇒ prone to rupture
    • seizure disorder, intracerebral hemorrhage, subarachnoid hemorrhage
  2. cavernous angiomas
  3. capillary telangiectasias
  4. venous angiomas
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37
Q
  1. Intracranial hemorrhage:

PURPURA CEREBRI

A 
= small bleedings in brain
CAUSES:
 - thrombopathy
 - coagulopathy
 - vasculopathy
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38
Q
  1. Intracranial hemorrhage:

SUB-EPENDYMAL HEMORRHAGE

A

= bleeding under ependyma

  • in immature babies ⇒ vasculature not well developed ⇒ sensitive to changes in pH and PaO2
  • superimposed IRDS ⇒ low PaO2 ⇒ hypoxia ⇒ hemorrhage
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39
Q
  1. Intracranial hemorrhage:

SUBARACHNOID HEMORRHAGE

A

= bleeding between arachnoid mater and pia mater

  • cause: rupture of berry aneurysm (disorder of ECM, polycystic kidney disease cause berry aneurysm)
  • symptom: sudden, excrusiating headache + rapid unconsiousness
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40
Q
  1. Intracranial hemorrhage:

SUBDURAL HEMORRHAGE

A

= tear in bridging veins ⇒ hemorrhage between dura mater and arachnoid mater

  • cause: trauma
  • can be chronic in alcoholics (fall a lot)
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41
Q
  1. Intracranial hemorrhage:

EPIDURAL HEMORRHAGE

A

= tear in middle meningeal artery ⇒ separation of dura from skull

  • cause: fracture of skull
  • can compress brain surface
  • symptom: lucid for many hours, neurological signs
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42
Q
  1. Degenerative diseases and dementias:

DEFINITIONS

A

Degenerative disease=
- progressive cellular degeneration of neurons ⇒ deterioration of brain function
Dementia=
- memory impairment + cognitive deficits with normal level of consciousness

43
Q
  1. Degenerative diseases and dementias:

ALZHEIMER DISEASE general

A
  • slow loss of intellectual function + alteration of mood and behavior
    ⇒ progressive disorientation, memory loss, aphasia
    ⇒ disabled, mute, immobile
  • increasing incidence with age
44
Q
  1. Degenerative diseases and dementias:

ALZHEIMER DISEASE pathogenesis

A
  • sporadic or familial
    FAMILIAL:
  • accumulation of Beta amyloid (APP cleaved by beta-site of enzyme + gamma-seretase)
  • mutations in APP ⇒ earlier onset of disease
  • Down syndrome ⇒ APP located on chromosome 21
  • allele of apolipoprotein E4 ⇒ increase risk + earlier onset
  • SORL1 protein deficiency ⇒ late onset ⇒ alter intracellular trafficking of APP

⇒⇒ accumulations alter neurotransmission + are toxic to neurons and synapses + local inflammatory response to plaque
⇒ plaques, neurofibrillary tangles, neuronal loss

45
Q
  1. Degenerative diseases and dementias:

PARKINSONS DISEASE general

A
  • death of dopamine- containing cells in substansia nigra

- diagnosis: no etiology + response to L-DOPA treatment

46
Q
  1. Degenerative diseases and dementias:

PARKINSON DISEASE pathogenesis

A
  • sporadic or AD/AR
  • AD: alpha-synuclein mutation
  • Lewy body = intramural inclusion of alpha-synuclein ⇒ shows defective degradation of the protein in the proteasome
47
Q
  1. Degenerative diseases and dementias:

PARKINSONS DISEASE clinical features

A

Parkinsonism=

  • diminished facial expression
  • stooped posture
  • slowness of voluntary movement
  • festinating gait
  • rigidity and tremor
  • progresses over 10-15 years
  • develop dementia
48
Q
  1. Degenerative diseases and dementias:

HUNTINGTON DISEASE general

A
  • inherited AD neurodegenerative disease
  • age: 40-50s
  • progressive movement disorders and dementia caused by tandem repeats
  • death in about 15 years
49
Q
  1. Degenerative diseases and dementias:

HUNTINGTON DISEASE pathogenesis

A
  • tandem repeat CAG mutation in gene 4p16.3 ⇒ Huntingtin protein
  • the larger the number of repeats ⇒ the earlier onset of the disease
    • the mutated Huntingtin protein binds to and sequesters transcription factors ⇒ reduced synthesis of proteins
    • mutated Huntingtin protein causes functional abnormalities in mitochondria ⇒ neurodegeneration
50
Q
  1. Degenerative diseases and dementias:

HUNTINGTON DISEASE clinical features

A
  • Huntington chorea: involuntary jerky movement
  • may develop parkinsonism
  • forgetfulness + emotional disorders ⇒ dementia
51
Q
  1. Degenerative diseases and dementias:

AMYOTROPHIC LATERAL SCLEROSIS general

A
  • degeneration of motor neurons in ventral horn of spinal cord
  • sensory systems and cognitive functions unaffected
  • lateral sclerosis= degeneration of corticospinal tracts
  • age: 50s
52
Q
  1. Degenerative diseases and dementias:

AMYOTROPHIC LATERAL SCLEROSIS etiology

A
  • familial AD or sporadic
  • Mutation in gene superoxide dismutase SOD1 on chromosome 21
  • missense mutations ⇒ misfiling of protein ⇒ apoptosis
53
Q
  1. Degenerative diseases and dementias:

AMYOTROPHIC LATERAL SCLEROSIS clinical features

A 
Loss of upper motor neurons:
  ⇒ paresis
  ⇒ hyperreflexia
  ⇒ spasticity
  ⇒ positive Babinski sign
Loss of lower motor neurons:
  ⇒ denervation of muscular targets with symptoms of muscular atrophy
  ⇒ weakness
  ⇒ fasciculation

Early symptoms:
- weakness of hands, cramping of arms and legs
Late symptoms:
- muscle mass + strength decreases, involuntary contractions

54
Q
  1. Infections of the nervous system:

BRAIN INFECTIONS ROUTES

A
  1. Hematogenous spread
  2. Direct implantation (post-traumatic, iatrogenic)
  3. Local extension
  4. Peripheral nerves
55
Q
  1. Infections of the nervous system:

MENINGITIS classification

A
  1. Infectious meningitis
    - acute pyogenic meningitis
    - aseptic meningitis
    - chronic meningitis
  2. Non-infectious meningitis
    - spread of cancer
    - drugs
    - inflammatory lesions
56
Q
  1. Infections of the nervous system:

ACUTE PYOGENIC MENINGITIS

A 
BACTERIA:
 - neonates: E.coli, S.agalactiae
 - adolescents: N.meningitides
 - elderly: S.pneumoniae, L.monocytogenes
SYMPTOMS:
 - headache
 - photophobia
 - irritability
 - clouding of consciousness
 - neck stiffness
- Lumbar puncture ⇒ increased pressure, neutrophilic, elevated protein, reduced glucose
- untreated ⇒ fatal
57
Q
  1. Infections of the nervous system:

ASEPTIC MENINGITIS

A 
VIRUS:
 - enterovirus
 - HSV-2
CLINICAL FEATURES:
 - less severe + self-limited
 - increased lymphocytes
 - protein elevation moderate
 - glucose normal
 - brain swelling
58
Q
  1. Infections of the nervous system:

CHRONIC MENINGITIS

A

TUBERCULOUS MENINGITIS:
- generalized symptoms: malaise, headache, mental confusion, vomiting
- high protein, normal glucose
- tuberculoma
- leads to arachnoid fibrosis, hydrocephalus
NEUROSYPHLIS:
- tertiary stage of syphilis
- invasion of brain by T.pallidum
NEUROBORRELIOSIS:
- Borrelia burgdorferi
- symptoms: aseptic meningitis, facial nerve palsies, encephalopathy, polyneuropathies

59
Q
  1. Infections of the nervous system:

ENCEPHALITIS general

A

= acute inflammation of the brain

- causative agents: bacterial, viral, fungal

60
Q
  1. Infections of the nervous system:

BACTERIAL ENCEPHALITIS

A
  • can spread directly to brain

- syphilis ⇒ neurosyphilis ⇒ encephalitis

61
Q
  1. Infections of the nervous system:

ARBOVIRUS

A
  • cause epidemic encephalitis

- generalized neurologic symptoms ⇒ seizures, confusion, delirium, stupor, coma, reflex assymetry, ocular palsies

62
Q
  1. Infections of the nervous system:

HSV-1

A
  • causes encephalitis
  • any age group, mostly children + young adults
    Symptoms:
    ⇒ alterations in mood
    ⇒ memory
    ⇒ behavior
63
Q
  1. Infections of the nervous system:

VZV

A
  • chickenpox ⇒ latent in sensory ganglia ⇒ shingles

- immunosuppressed patients ⇒ encephalitis

64
Q
  1. Infections of the nervous system:

CYTOMEGALOVIRUS

A
  • fetuses + immunocompromised

- in-utero infection ⇒ periventricular necrosis, microcephaly

65
Q
  1. Infections of the nervous system:

POLIOVIRUS

A
  • enterovirus ⇒ paralytic poliomyelitis
  • symptoms:
    • gastroenteritis
    • damages motor neurons
    • flaccid paralysis
    • death from paralysis of respiratory muscles
    • post-polio syndrome ⇒ decreased muscle bulk and pain
66
Q
  1. Infections of the nervous system:

RABIES

A
  • causes encephalitis
  • virus enters CNS by ascending along peripheral nerves
  • symptoms:
    • flu-like (malaise, headache, fever)
    • extraordinary CNS excitability
    • periods of alternating mania and stupor
    • coma + death
67
Q
  1. Infections of the nervous system:

HUMAN IMMUNODEFICIENCY VIRUS HIV

A
  • Aseptic HIV-1 meningitis
  • HIV-1 meningoencephalitis
    ⇒ AIDS-dementia complex
    ⇒ chronic inflammation with microglial nodules
  • Vacuolar myelopathy
    ⇒ spinal cord tracts
68
Q
  1. Infections of the nervous system:

FUNGAL ENCEPHALITIS

A
  1. Candida albicans ⇒ multiple microabscesses
  2. Mucor ⇒ mostly in diabetics with ketoacidosis
  3. Aspergillus fumigatus ⇒ widespread septic hemorrhagic infarctions
  4. Cryptococcus neoformans ⇒ often associated with AIDS
69
Q
  1. Infections of the nervous system:

PROTOZOAL ENCEPHALITIS

A

TOXOPLASMOSIS:

  • connatal:
    • multifocal nectosis
    • calcification
    • hydrocephalus
  • immunocompromised:
    • necrotizing endephalitis
70
Q
  1. Infections of the nervous system:

HELMINTH ENCEPHALITIS

A

ECHINOCOCCUS:
⇒ granulosus + multilocularis
T.SOLIUM :
⇒ cysticerosis

71
Q
  1. Prions:

PRION DISEASES pathogenesis

A

= misfolded abnormal forms of a normal cellular protein, PrPc
⇒ acts as infectious agent ⇒ propagates + injures cells near by
- PrPc ⇒ PrPsc ⇒ resistant to protease digestion ⇒ initiate similar transformation to other PrPc molecules
⇒ accumulation of PrPsc in neural tissue ⇒ cell injury

PrPc: alpha-helix, soluble, non-infectious
PrPsc: beta-sheat, insoluble, infectious

72
Q
  1. Prions:

CREUTZFELDT-JAKOB DISEASE

A
  • manifests as rapidly progressive dementia
  • sporadic / familial
  • peak incidence age: 70s
  • symptoms:
    • memory and behavior changes
    • dementia
  • uniformly fatal, duration 7months
73
Q
  1. Prions:

VARIANT CREUTZFELDT-JAKOB DISEASE

A
  • affects young adults
  • symptoms:
    • behavior changes
    • progresses more slowly
  • consequence of exposure to prion disease of cattle, bovine spongiform encephalopathy
  • similar pathologic appearance than other CJDs - spongiform change + absence of inflammation
74
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    CNS AND PNS MYELIN
A 
CNS MYELIN:
 - multiple layers of oligodendrocytes
 - 1 oligodendrocyte ⇒ processes to many different axons
 - internodes + nodes of Ranvier
 - dominant in white matter
PNS MYELIN:
 - made by Schwann cells
 - each cell contract to only 1 internode
 - specialized proteins + lipids
75
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    DEMYELINATING DISORDERS
A
  • acquired diseases
  • characterized by damage to previously normal myelin
  • Diseases:
    • multiple sclerosis (immune-mediated injury)
    • progressive multifocal leukoencephalopahty (viral infection of oligodendrocytes)
76
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    DYSMYELINATION
A
  • characterized by defective structure and function of myelin sheaths
  • associated with mutations affecting proteins required for formation of normal myelin or in mutation affecting synthesis/degradation of lipids
  • leukodystrophies
77
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    MULTIPLE SCLEROSIS general + etiology
A
  • autoimmune inflammatory disease with demyelination
  • age: 15-45 years old
  • more in women 2:1
  • relapsing and remitting episodes
    ETIOLOGY:
  • combination of environmental + genetic factors ⇒ loss of tolerance to self proteins
78
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    MULTIPLE SCLEROSIS clinical features
A
  • pattern of relapsing-remitting disease ⇒ gradual accumulation of increasing neurologic deficits
  • Visual impairment ⇒ unilateral
  • Brain stem symptoms ⇒ cranial nerve signs, ataxia
  • Spinal cord symptoms ⇒ motor and sensory impairment of trunk + limbs, spasticity, difficulty with bladder control
  • Cognitive function
79
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    MULTIPLE SCLEROSIS morphology
A

MACROSCOPIC:
- grayish plaques in white matter
- mostly periventricular
MICROSCOPIC:
- active: macrophages
- inactive: no macrophages
- active plaque: fragmentation of myelin, preserve axon, luxol in macrophages
- subacute plaque: myelin loss, PAS positive, astrocytosis, perivascular lymphocytic infiltrate
- inactive plaque: no inflammation, no myelin
- on periphery ⇒ iron deposits
- shadow plaque: between normal and affected are ⇒ thin myelin

80
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    MULTIPLE SCELROSIS 4 patterns
A
  1. Classic ⇒ Charcot
  2. Acute ⇒ Marburg, aggressive
  3. Neuromyelitic optica ⇒ Devic syndrome, affects optic nerve + spinal cord
  4. Concentric sclerosis ⇒ Balo, demyelinated tissues form concentric layers
81
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    POST INFECTIOUS DEMYELINATION
A
  • not related to direct spread of infectious agent but immune response to pathogen antigen ⇒ cross react with myelin antigens
    1. Acute disseminated encephalomyelitis
    • symptoms after week or two after infection
    • diffuse brain involvement ⇒ headache, lethargy, coma
    • progresses rapidly ⇒ fatal
      2. Acute necrotizing hemorrhagic encephalomyelitis
    • affects young adults + children
82
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    CENTRAL PONTINE MYELINOLYSIS
A
  • nonimmune process
  • loss of myelin in center of pons after rapid correction of hyponatremia
  • causes: alcoholism + severe electrolyte imbalance
  • symptoms:
    • rapidly evolving quadriplegia
83
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    LEUKODYSTROPHIES
A
  • inherited dysmyelinating diseases
  • caused by abnormal myelin synthesis or turnover
  • some involve lysosomal enzymes or peroxisomal enzymes
  • some involve mutations in myelin proteins (AR)
    CLINICAL FEATURES:
  • diffuse involvement of white matter ⇒ deterioration in motor skills, spasticity, hypotonia and ataxia
84
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    HYPOGLYCEMIA
A
  • resemble global hypoxia (mostly evident in hippocampus)

- Purkinje cells spared

85
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    HYPERGLYCEMIA
A
  • found in inadequately controlled DM + ketoacidosis or hyperosmolar coma
  • symptom:
    • confusion
    • stupor
    • coma
  • must be corrected gradually (otherwise severe central edema)
86
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    HEPATIC ENCEPHALOPATHY
A
  • decreased hepatic function ⇒ depressed level of consciousness ⇒ coma
  • early: flapping tremor
  • liver fails to clear ammonia ⇒ alteration of synaptic transmission + metabolic alteration in astrocytes
87
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    NUTRITIONAL DISEASES
A

VITAMIN B12 DEFICIENCY:

  • ascending + descending fibers of spinal cord
  • numbness in legs ⇒ spastic weakness ⇒ paraplegia
88
Q
  1. Primary diseases of myelin. Acquired metabolic and toxic disturbances of the brain:
    TOXIC DISORDERS
A
  1. Metals (lead)
  2. Arsenic and mercury
  3. Industrial chemicals (organophosphates)
  4. Methanol ⇒ blindness
  5. Environmental pollutants (CO)
  6. Ethanol
    ⇒ excessive intake: brain swelling + death
    ⇒ chronic: cerebellar dysfunction (trunkal ataxia, unsteady gait, nystagmus)
  7. Chemotherapeutic agents
  8. Ionizing radiation
    ⇒ headache, nausea, vomiting, papilledema
    ⇒ coagulative necrosis in white matter
89
Q
  1. Tumors of central and peripheral nervous system:

CHARACTERISTICS OF CNS TUMORS

A 
HISTOLOGY:
 - distinction between benign and malignant more subtle
PATTERN OF GROWTH:
 - of low grade lesions may still infiltrate ⇒ serious clinical defects
CLINICAL COURSE DEPENDENT ON SITE:
 - benign tumor can compress medulla
METASTATIC PROPERTIES:
 - rarely metastasize outside CNS
 - subarachnoid space provide pathway
90
Q
  1. Tumors of central and peripheral nervous system:

CLASSIFICATION OF CNS TUMORS

A
  1. GLIOMAS
    - astrocytoma
    - oligodendroglioma
    - ependyoma
  2. NEURONAL TUMORS
    - central neurocytoma
    - ganglioglioma
    - dysembryoplastic neuroepithelial tumor
  3. POORLY DIFFERENTIATED TUMORS:
    - medulloblastoma
  4. MENINGIOMA
  5. METASTATIC TUMORS
91
Q
  1. Tumors of central and peripheral nervous system:

FIBRILLARY ASTROCYTOMA

A
  • location: cerebral hemispheres
  • symptoms:
    • seizures
    • headaches
    • focal neurologic deficits
  • spectrum of histologic differentiation
  • types depending on differentiation
    • type 1-3: diffuse astrocytoma and anaplastic astrocytoma
    • type 4: glioblastoma multiforme
  • poor prognosis
  • treatment: resection, radiotherapy + chemotherapy (survival of 8-10 months)
92
Q
  1. Tumors of central and peripheral nervous system:

PILOCYTIC ASTROCYTOMA

A
  • benign tumors
  • affects children + young adults
  • location: cerebellum, 3rd ventricle, optic nerve, cerebral hemispheres
  • morphology: cystic appearance, bipolar cells, GFAP positive hairlike projections
93
Q
  1. Tumors of central and peripheral nervous system:

OLIGODENDROGLIOMA

A
  • arise from oligodendrocytes
  • loss of heterozygosity for chromosomes 1p and 19q
  • age: 40-50s
  • symptoms: neurologic complaints, seizures
  • location: cerebral hemispheres- white matter
  • better prognosis
  • treatment: surgery, chemotherapy, radiotherapy
  • survival 5-10years
94
Q
  1. Tumors of central and peripheral nervous system:

EPENDYMOMA

A
  • arise next to ependyma-lined ventricular system
  • location: 4th ventricle in childhood, spinal cord in adults
  • CSF dissemination is common
    MORPHOLOGY:
  • solid/papillary masses outputting into ventricle
  • pseudo-rosettes
95
Q
  1. Tumors of central and peripheral nervous system:

CENTRAL NEUROCYTOMA

A
  • arise from neural tissue
  • low-grade tumor
  • location: within or adjacent to ventricular system
  • characterized by evenly spaced, round and uniform nuclei
96
Q
  1. Tumors of central and peripheral nervous system:

GANGLIOGLIOMA

A
  • arise from neural tissue
  • tumors with mixture of glial elements and mature-appearing neurons
  • slow growing
  • glial component becomes anaplastic ⇒ progress rapidly
  • symptoms: seizures
97
Q
  1. Tumors of central and peripheral nervous system:

DYSEMBRYOPLASTIC NEUROEPITHELIAL TUMOR

A
  • low-grade tumor
  • age: childhood
  • slow growth + good prognosis after resection
  • symptom: seizures
  • location: superficial temporal lobe
  • morphology: small round cells with features of neurons arranged in columns and around central cores of processes
98
Q
  1. Tumors of central and peripheral nervous system:

MEDULLOBLASTOMA

A
  • age: childhood
  • location: cerebellum
  • neuronal + glial markers, but undifferentiated
  • highly malignant
  • poor prognosis without treatment
  • radiosensitive
  • with total excision 5 years survival - 75%
99
Q
  1. Tumors of central and peripheral nervous system:

MENINGIOMA

A
  • benign tumor in adults
  • location: attached to dura or arise from meningothelial cells of arachnoid
  • may be found along any external surface of the brain+ in ventricular system ⇒ stromal arachnoid cells of choroid plexus
100
Q
  1. Tumors of central and peripheral nervous system:

SCHWANNOMA

A
  • benign tumors
  • arise from Schwann cells
  • symptoms due to compression of involved nerve or adjacent structures
  • location: cranial vault, cerebellopontine angle, within dura or extradural
  • easily surgically removed
101
Q
  1. Tumors of central and peripheral nervous system:

NEUROFIBROMA

A
  1. Cutaneous + solitary neurofibroma
    - location: skin, peripheral nerves
    - skin tumors: nodules, hyper pigmentation, grow large + pedunculated
  2. Plexiform neurofibroma
    - involve major nerve trunks
    - potential for malignant transformation
102
Q
  1. Tumors of central and peripheral nervous system:

MALIGNANT PERIPHERAL NERVE SHEATH TUMOR

A
  • highly malignant sarcomas
  • locally invasive
  • multiple recurrence
  • metastatic spread
  • arise de novo or from transformation of plexiform neurofibroma
  • can occur after radiation therapy
103
Q
  1. Tumors of central and peripheral nervous system:

METASTATIC TUMORS

A

PRIMARY SITES:

  • lung
  • breast
  • skin (melanoma)
  • kidney
  • GI tract
  • form sharply demarcated masses, at grey-white matter junction, surrounded by edema
104
Q
  1. Tumors of central and peripheral nervous system:

METASTATIC TUMORS/ PARANEOPLASTIC SYNDROMES

A
  1. Subacute cerebellar degeneration ⇒ ataxia with destruction of Purkinje cells, gliosis, mild inflammatory infiltrate
  2. Limbic enceohalitis ⇒ subacute dementia with perivascular inflammatory cuffs, microglial nodules, neuronal loss, gliosis
  3. Subacute sensory neuropathy ⇒ altered pain sensation with loss of sensory neurons of dorsal root ganglia + inflammation

PATHOLOGY 2 (11 decks)

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