Download The Nervous System

Pathology
Nervous System
Detailed outline
From:
Dr. Benjamin’s notes
And
Basic Pathology text
Tri 4
Dale Thompson
Spring 2000
1
The Nervous System
General Outline from Text
1.
Cells of the nervous system
a. Neurons
b. Astrocytes
c. Oligoendrocytes
d. Ependymal cells
e. Microglia
2.
Edema, herniation and hydrocephalus
a. Cerebral edema
b. Herniation
c. Hydrocephalus
3.
vascular diseases
a. global hypoxic-ischemic encephalopathy
b. infarcts
c. intracranial hemorrhages
i. primary brain parenchymal hemorrhage
ii. saccular aneurysms and subarachnoid hemorrhage
iii. vascular malformations
4.
central nervous system trauma
a. epidural hematoma
b. subdural hematoma
c. traumatic parenchymal injuries
5.
congenital malformations and perinatal brain injury
a. neural tube defects
b. malformations associated with hydrocephalus
c. disorders of forebrain development
d. neurocutaneous syndromes
e. perinatal injury
6.
infections of the nervous system
a. epidural and subdural infections
b. leptomeningitis
i. acute [purulent] leptomeningitis
ii. acute lymphocytic [viral] meningitis
iii. chronic meningitis
c. parenchymal infections [including encephalitis
i. brain abscess and other localized infections
ii. viral encephalitis
iii. spongiform encephalopathies
2
7.
neoplasms of the CNS
a. primary neuroglial tumors [gliomas]
i. astrocytomas
ii. oligodendrogliomas
iii. ependymomas
b. primitive neuroectoparencymal neoplasms
c. other primary intraparenchymal neoplasms
d. meningiomas and other meningeal neoplasm
e. metastatic neoplasms
8.
primary diseases of myelin
a. multiple sclerosis
b. other acquired demyelinating diseases
c. leukodystrophies
9.
acquired metabolic and toxic disturbances
a. nutritional diseases
b. acquired metabolic disorders
c. toxic disorders
10. degenerative diseases
a. Alzheimers disease
b. Parkinsonism
c. Huntingtons disease
d. Diseases of motor neurons
11. diseases of the peripheral nervous system
a. peripheral neuropathies
b. neoplasms of the peripheral nervous system
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Nervous system
Bold print is from Benjamin’s notes
Standard print is from text
1.
Cells of the nervous system
Glia cells: astrocytes, oligodendrocytes, microglia
Neurons often affected by anoxia
a. Neurons
b. Astrocytes
i. Similar to fibroblast
ii. Corpora amylacea
1. glycoproteins
a. astrocytic
b. foot processes
c. dorsal columns
iii. Alhezimer type II glial with liver failure
iv. Glial fibrillary acidic protein: major cytoskeletal protein
v. Rosenthal fibers: dense aggregates
c. Oligodendrocytes
i. Produce myelin in CNS
d. Ependymal cells
i. Line cerebral ventricles and related to cuboidal cells of choroids plexus
ii. Lead to ependymal granulations on ventricular surfaces
iii. Issue in CMV
e. Microglia
i. Similar to histiocytes
ii. From monocytes
iii. Accumulate lipids to become foamy macrophages called gitter cells
iv. Elongate to form rod cells
v. Aggregate to form microglial nodules
2.
Edema, herniation and hydrocephalus
Increased intracranial pressure causes headaches and vomiting, papilloedema
a. Cerebral edema [aka parenchymal edema]
i. Vasogenic: disruption of blood-brain barrier. Interstitial edema
ii. Cytotoxic edema: intracellular edema
b. Herniation
i. Due to increase intracranial pressure
1. temporal lobe herniation [aka transtentorial, uncinate]
a. medial temporal lobe against tentorium
b. compress CN III: dilation and impared movement
2. cerebellar tonsil herniation
a. cerebral tonsils thru foramen magnum
b. affect brainstem, respiration center
c. Duret’s hemorrhages
3. cingulated gyrus herniation [aka subfalcine]
a. cingulated gyrus under falx cerebri
b. assoc. with compression of branches of anterior cerebral artery
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3.
c.
Hydrocephalus
i. Distension of ventricle with increase in CSF due to over production of CSF
or usually due to decreased resorption of CSF
1. Infants: head enlargement due to sutures are not fused
2. Adults: no head enlargement
3. Acute hydrocephalus
a. Trauma
b. Infection [TB]
i. blood stream
ii. direct implantation due to trauma
iii. local extension from skull fracture
iv. peripheral nerves
1. rabies, herpes
c. Brain tumor
d. hemorrhage
4. communicating
a. obstruction outside ventricular system, subarachnoid space
5. noncommunicating
a. obstruction within ventricular system or too much
production
6. Hydrocephalus ex vacuo
a. dilation of ventricles
b. increase CSF volume
c. loss brain parenchyma
d.
Tumors
vascular diseases
a. hemorrhage
i. most associated with hypertension
ii. laminar cortical necrosis
1. from hypoxic-ischemic injury of cortical areas
iii. respirator brain
1. seen in “brain dead” cases, not caused by respirator
iv. Charcot-Bouchard microaneurysms
1. usually in basal ganglia
v. 7-17% of CVA [strokes]
vi. 80% in cerebrum
vii. 10% in midbrain and pons
viii. 10% in cerebellum
b. global hypoxic-ischemic encephalopathy
c. infarcts [aka encephalomalacia]
i. 80% of CVA
ii. first signs in 8-12 hours
iii. 36-48 hours: swollen and soft brain
iv. 1 month: phagocytic action results in increase softening and liquidfaction
v. 6 months: complete cavity
vi. transient ischemic attacks [TIA]
1. self-limited vascular obstruction
2. 1/3 in 5 years have significant infarcts
5
d.
vii. cause of infarcts
1. 44-75% thrombosis
2. 3-14% embolism
a. from heart, proximal carotids
b. affects mostly the middle cerebral artery
3. atherosclerosis: concerned areas
a. internal carotid
b. proximal middle cerebral
c. vertebral basilar
4. hypertension
viii. symptoms
1. hemiplegia aphasia
2. anoxic encephalopathy
3. lacunar infarcts
intracranial hemorrhages
i. middle cerebral artery
1. contralateral hemiparesis and spasticity
2. contralateral loss sensation
3. visual problems
4. possible speech problems
ii. internal carotid artery
1. possible monocular blindness
2. less severe due to anastomosis at circle of Willis
iii. vertebral basiliar artery
iv. primary brain parenchymal hemorrhage
1. Most common in basal ganglia
2. Headache due to intracranial pressure
3. Vomiting
4. Loss of consciousness
v. saccular aneurysms and subarachnoid hemorrhage
1. 5-15% CVA
2. most associated with berry aneurysm [aka saccular]
3. bloody CSF
4. headache
5. vomiting
6. loss of consciousness
7. 80% from bifurcations in carotid
8. 20% from vertebralbasiliar
9. congenital defect of media at branches of artery
10. 50% die within several days
vi. vascular malformations
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4.
central nervous system trauma
a. epidural hematoma
i. collection of blood between skull an dura matter
ii. 1-3% of head injuries [skull fractures]
iii. causes herniation
iv. due to tear in middle menigeal artery or vein
1. tear is at located between dura and squamous portion of temporal bone
b. subdural hematoma
i. acute: traumatic with laceration of brain: clotted blood
ii. chronic: mostly elderly and alcoholics
1. caused by brain atrophy
2. liquefied blood
3. may be confused with dementia
iii. collection of blood between dure and arachnoid
iv. from blunt trauma without skull fracture
v. whiplash type of injuries
vi. disruption of bridging veins
c. traumatic parenchymal injuries
i. complications: edema, herniation hydrocephalous, epilepsy
ii. concussion
1. transient loss of consciousness, most recover completely
2. widespread paralysis, sometimes seizures
3. loss of memory about incident
iii. contusion
1. hemorrhage in superficial parenchyma by trauma
2. coup contusion: immobile head, injury at site of impact
3. contrecoup contusion: moveable head against immoveable object
a. injury on opposite side of impact
iv. laceration
v. Diffuse axonal injury: from sudden angular deceleration/acceleration forces
vi. Traumatic intracranial hemorrhage
vii. Generalized brain swelling
5.
congenital malformations and perinatal brain injury
a. neural tube defects [aka dysraphic states]
i. abnormal closure of neural tube is most common CNS malformation
ii. environmental agents cause defects
1. maternal and fetal infections [rubella]
2. drugs [thalidomide: no longer used]
3. fetal anoxia
4. physical agents [radiation]
5. test for alpha protein
iii. encephaloceles and cranial meningoceles
1. encephaloceles: defect in skull bone
a. brain tissue protrudes thru cranial defect
b. usually in occipital area
2. myelocoele: vertebral defects.
a. only meninges and CSF protude
b. exposed plaque of flattened neuroectodermal tissue
iv. anencephaly
1. most common congenital brain malformation
2. frog-like look
3. incidence 0.5 – 2/1000 live births
4. associated with spina bifida in 15% of cases
5. no brain except disorganized brain stem
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b.
c.
d.
e.
v. spinal neural tube defects [spina bifida]
1. myelocele
2. spinal meningoceles
a. cystic masses filled with CSF, no spinal cord in cyst
3. meningomyeloceles
a. spinal meninges and spinal cord thru posterior vertebral defect
b. usually with hydrocephalus and Arnold-Chiari malformation
4. spina bifida occulta
a. defective closure of posterior vertebral arches
b. intact meninges and spinal cord
c. asymptomatic
d. 20% of population
e. dimple, tuft of hair
malformations associated with hydrocephalus
i. Arnold-Chiari malformation
1. downward displacement of vermis and tonsils of cerebellum into
foramen magnum
a. medulla oblongata and caudal portions
2. distortion of medulla
3. enlarged foramen magnum
4. hydrocephalous
a. seen if infant survives as a secondary condition
5. usually seen with menigomyelocele
ii. Dandy-Walker malformation
1. aplasia/hypoplasia of vermis
2. dilation of 4th ventricle
3. usually with hydrocephalus
4. agenesis of corpus callosum
5. occipital encephalocele
disorders of forebrain development
i. holoprosencephaly
1. abnormal division cerebral hemispheres
2. severe case is cyclopia
neurocutaneous syndromes [aka phakmatoses]
i. involves nervous system, skin, eyes and other organ systems
ii. autosomal dominant traits
iii. Table 23-1
1. neurofibromatosis type I
2. neurofibromatosis type II
3. tuberous sclerosis
4. von Hippel-Lindau disease
5. Sturge-Weber disease
perinatal injury
i. germinal matrix hemorrhage
1. premature infants
ii. periventricular leukomalacia
1. white matter necrosis
2. both term and premature
3. usually adjacent to lateral cerebral ventricles
iii. gray matter injury
1. some cases of cerebral palsy
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6.
infections of the nervous system
a. epidural and subdural infections
b. leptomeningitis: limited to leptomeninges and subarachnoid space
i. due to infection or chemicals
ii. pathology: exudates, pus in meninges
iii. clinical
1. do a lumbar puncture
2. fever
3. stiff neck
4. CSF has polymorphs, neutrophils
5. purvulent
6. increase protein in CSF
7. decrease sugar in CSF
iv. acute [purulent] leptomeningitis
1. newborns: E. Coli, S. pneumococcus
2. young adults: Nisseria meningitides
3. older adults: S. pneumoniae
4. elderly: S. pneumococcus and L. monocytogenes
v. acute lymphocytic [viral] meningitis [aka aseptic meningitis]
1. usually self-limiting
2. viral CSF
3. more lymphocytes
4. normal sugar in CSF
5. protein elevation is moderate
6. seen with
a. mumps
b. Epstein Barr virus
c. HSV II
d. Echovirus
e. coxsackievirus
vi. chronic meningitis
1. see increase in lymphocytes, plasma cells, epitheloid histiocytes
2. headache, stiff neck, increase protein, decrease glucose in CSF
3. Mycobacterium tuberculosis
a. exudates mostly seen in base of brain
4. complication factors
a. hydrocephalus
i. due to arachnoid adhesions
b. syphilis
c. Brucella and Treponema pallidum rarely
d. fungi
e. candida
f. cryptococcus neoformans
i. seen in AIDS
g. protozoa
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c.
parenchymal infections [including encephalitis]
i. encephalitis from bacteria
1. tuberculosis
a. tuberculoma: focal lesion with caseous necrosis
b. granulomatous inflammation reaction
c. to CNS from pulmonary infection
2. neurosyphilis
a. seen in tertiary stage
b. meningeal [chronic meningitis]
c. paretic: cerebral atrophy [dementia]
d. tabes dorsalis
i. aka general paresis of insane
1. in brain parenchyma
2. cortical atrophy
3. neuronal loss
4. rod cells
ii. damage to dorsal roots
1. in posterior column
2. sensory and gait abnormalities
iii. spinal cord
iv. charcot joints: knee
ii. cerebral abscess from staphylococcus and streptococci
1. hematogenous spread: migrate to brain from body
2. contigous spread: from adjacent foci infection, usually to temporal or
frontal lobes
3. direct implantation: from trauma to head
4. fever, intracranial pressure, focal neurological deficits, increase protein
iii. brain abscess and other localized infections
iv. fungal infections: chronic meningitis, granuloma, abscess
1. candida
2. aspergillus
3. toxoplasmosis
v. viral encephalitis
1. Perivascular mononuclear inflammation infiltrates [PMII]
2. microglial nodules [MN]: phagocytosis of neuron [neuronophagia]
3. perhaps inclusion bodies [IB] in nuclei or cytoplasm
a. Negri bodies in rabies
b. Intranuclear inclusions in CMV
4. arbovirus
a. via arthropod-borne viruses
b. most common epidemic encephalitis in US
c. examples: eastern and western equine, Venezuelon, St. Louis,
California
d. late summer due to mosquitoes
e. nonspecific perivascular inflammation
f. microglial nodules
5. enterovirus
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6.
HIV I
a.
b.
c.
Aseptic meningitis
Subacute encephalitis
Vacuolar myelopathy
i. Dorsal and lateral horns
ii. Looks like Vitamin B12 deficiency
Peripheral neuropathy
Atrophic brain
Scanty PMII
MN
Multinucleated cells with virions
d.
e.
f.
g.
h.
7. mumps
8. Progressive multifocal leukoencephalopathy [PML]
a. Slow virus
b. Papovavirus group: JC virus
c. Seen in AIDS
d. Infects oligodendroglia leading to demyelination
9. Viral infection of oligodendrocyte [Papova virus]
a. Deymelination
b. Slow virus
10. measles virus
a. slow virus
b. SSPE
c. Subacute silesosing panencephatis
i. Personal changes and dementia
11. chicken pox
12. rubella
13. CMV
a. Encephalitis: microcephaly and perventricular
calcification
b. Herpes virus group
c. Neonates and immune depressed
d. AIDS
e. Affects ependyma
f. PMII, MN, IB
14. herpes simplex
a. in temporal lobe and orbital frontal
b. HSV I most common form of sporadic viral encephalitis in US
c. PMII, MN, IB
d. Type II is less common: to neonate from infected mother
15. herpes zoster
16. EMV
17. poliomyelitis: anterior horn cells of spinal cord leads to paralysis
18. rabies: fatal encephalitis, spread through nerves and negri bodies
19. Toxoplasmosis
a. Seen in AIDS
b. Multiple focal lesions usually in gray matter
vi. spongiform encephalopathies
1. slow virus
2. Creutzfeldt Jacob disease
a. Dementia
b. Spongy brain
c. Slow atrophy of brain
d. Spongiform change: vacuoles within neurophil and cell bodies
e. Startle myoclonus
f. Gait abnormalities
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7.
neoplasms of the CNS
a. primary neuroglial tumors [aka gliomas]
i. brain tumors
1. local effects
2. hemiparesis
3. seizures
4. weakness
5. increased intracranial pressure
6. 9.2% of all primary neoplasms
7. most common group of neoplasms in infants and children
8. usually after 70 y/o
9. in children 70% infratentorial
ii. astrocytoma [aka fibrillary astrocytic neoplasms, diffuse astrocytoma]
1. most common
2. 20-30% of all glial tumors in adults
3. anatomic location influences prognosis
4. treatment
a. surgical resection and radiotherapy
b. 70% survive one year
c. 25-35% survive 5 years
5. well differentiated lesions grade I-II
6. anaplastic grade III- IV
a. greater cellularity
b. nuclear pleomorphism
c. mitotic activity
d. vascular endothelial proliferation
7. microcysts: small accumulations intercellular fluid
8. pilocystic astrocytoma
a. in children
b. Rosenthal fibers
9. grading in book
a. astrocytoma: grade 1
b. anaplastic astrocytomia: grade 2
c. glioblastoma multiforme: grade 3
iii. glioblastoma multiforme
1. most aggressive
2. edema in parenchyma
3. necrosis with dense cluster tumor cells with prominent nuclei
4. anaplastic tumor
5. 50% of all gliomas
6. 45-55 y/o
7. increased number of males
8. mostly arise in cerebrum
9. 90% die within 2 years
iv. oligodendrogliomas
1. 5% of all gliomas
2. 40-50 y/o
3. mostly in cerebrum
4. calcification, satellitosis of neoplastic cells
v. ependymomas
1. mostly in children and adolescence
2. 5-6% of gliomas
3. hydrocephalous possible
4. ventricular cavities
5. perivascular “pseudorosettes”
6. ependymal rosettes
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b.
c.
d.
e.
vi. juvenile astrocytoma
1. mostly in cerebellum
2. nonanaplastic
3. excellent prognosis
primitive neuroectodermal tumors
i. neuroblastoma
1. common in children
2. do not produce catecholamines
ii. medulloblastoma
1. most in children
2. 25% of all brain tumors
3. increase in males
4. cerebellum vermis in children
5. cerebellum hemisphere in adults
6. Homer Wright rosettes
7. increased intracranial pressure
8. abnormal gait
9. CSF obstruction
10. cerebellar obstruction
iii. pineoblastomas
iv. ependymoblastomas
other primary intraparenchymal neoplasms
i. primary intraparenchymal neoplasms
1. tumor of B lymphocytes
2. angiocentric growth
ii. germ cell neoplasms: suprasellar and pineal area
iii. ganglion cell tumor
1. mature dystplastic ganglion cells
2. temporal lobes
3. seizures
iv. hemangioblastomas
1. cerebellum or meninges
2. may be part of von Hippel-Lindau syndrome
meningiomas and other meningeal neoplasm
i. meningioma: tumor of the meninges
ii. usually lesions attached to the dura
iii. arise from arachnoid cells, fibroblast or blood vessels
iv. mostly benign
v. frequent in middle aged adults, esp women
vi. headaches, seizures
vii. prognosis depends on location and accessibility to excision
viii. rarely malignant: a sarcoma produces metastases
ix. transitional varient has both syncytial and fibroblastic variants
x. psammoma bodies: calcified granules
metastatic neoplasms
i. 20-25% of all intracranial tumors
ii. mostly from lung, breast, kidney, GI tract, melanoma
iii. may have edema
iv. increased intracranial pressure
v. herniation
vi. focal neurological deficiets
vii. dura matter
1. when primary is prostate, breast or lungs
viii. leptomeningeal carcinomatosis
1. opacification of leptomeninges
2. cranial nerve palsies
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f.
8.
lymphomas
i. secondary
ii. more common
iii. primary: 0-4% of brain tumors
iv. mostly adults 50-60 y/o
primary diseases of myelin
a. multiple sclerosis
i. normal myelin is damaged
ii. most common demyelinating disease of CNS
iii. 20-40 y/o [rare over 50]
iv. increased in women
v. in more temperate climates
vi. viral
1. papovavirus
2. canine distemper virus: increased antibody to virus in patients
vii. immunological factors: autoimmune T cells
viii. enviromental
ix. hereditary: HLA A3 B7 DW2
x. chronic course with relapse and remissions
xi. mild sensory or motor disorders or incoordination, ataxia, paraplegia,
diplopia incoordination, incontinence
xii. gait abnormalities, speech disturbances, paresthesias, spasms, Ig’s in CSF
xiii. basic process is dymelination [loss of olgiodendrites]
xiv. plaques in brain and spinal cord: multiple areas of demyelination
xv. starts in periventricular areas
xvi. ACTH has some benefit in the disease
xvii. Autoimmune disease: immuno-suppression can arrest the progress of
disease
xviii. Schilder’s disease is similar only in younger children
b. other acquired demyelinating diseases
i. Acute disseminated encephalomyelitis
1. demyelination following vaccination or infection
a. small pox, chicken pox, measles
b. autoimmune mechanism
c. fever, seizures, coma
d. spinal cord dysfunction
ii. Central pontine myelinolysis
1. demyelination within basis pontis
2. alcoholism
c. leukodystrophies
i. inborn metabolic error in myelin production
ii. manifest early childhood
iii. autosomal recessive disorder of sphingomyelin metabolism
iv. due to deficiency of arylsulfatase
v. progressive motor impairment, mental retardation and peripheral
neuropathy
vi. From table 23-2
1. Metachromatic leukodystrophy
2. Krabbe’s disease
3. Adrenoleukodystrophy
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9.
acquired metabolic and toxic disturbances
a. nutritional diseases
i. Niacin
1. pellagra
a. diarrhea
b. dermatitis
c. dementia
ii. thiamine
1. Beri Beri
2. wet: heart right side
3. dry: brain
4. Wernicke-Korsakoff syndrome
a. Chronic alcoholics: atrophy cerebrum of cerebellum
5. Wernicke’s encephalopathy
a. Affects mammillary bodies of hypothalamus, dorsal medial
areas of thalamus, gray matter around cerebral aqueduct
b. Confusion, paralysis of extraocular muscles, ataxia
c. Untreated
i. Korsakoff’s psychosis
1. no new memories or retrieve old memories
ii. Coma and death
d. Treat with thiamine in early stages
6. alcoholic cerebellar degeneration
a. atrophy of superior vermis
iii. vitamin 12
1. pernicious anemia
2. subacute combined degeneration of spinal cord
3. spasticity, weakness, loss of proprioception, megaloblastic madness
b. acquired metabolic disorders
i. hepatic failure
1. Alzheimer type II glia
a. Large, naked astrocytic nuclei in gray matter
c. toxic disorders
i. metals: arsenic, mercury, lead
ii. industrial chemicals: organophosphates, methyl alcohol
iii. environmental pollutants: carbon monoxide
iv. therapeutic agents: cause: peripheral neuropathies, convulsions
1. methotrexate
a. necrotic white matter, demyelination, gliosis, calcification
2. Ionizing radiation
a. Vasculopathy leading to ischemia and infarction
15
10. degenerative diseases
a. all cause degeneration of neurons
b. selective degeneration of neurons
c. some hereditary, others sporadic
d. some have inclusions in neurons
e. Alzheimers disease
i. Most common dementia in elderly
ii. Affects cortex
iii. Death from intercurrent bronchopneumonia, other infections
iv. 50-60 y/o or earlier
1. genetic factors: chromosome 14
2. depositon of amyloid
3. expression of specific alleles of apoprotein E
4. theory: aluminum toxicity, familial
v. progressive dementia and death
vi. increase in neurofibrillay tangles in cytoplasm and senile plaques in neuritis
[amyloid core with amyloid angiopathy] due to deficiency in acetylcholine
and acetylcholinesterase in cortex hippocampus
vii. atrophy of brain [mostly frontal, parietal and temporal]
viii. ventricles enlarged: hydrocephalus ex vacuo
ix. senile plaques
1. central amyloid surrounded by neurons with neurofibrillay tangles
and granulovascoular degeneration
x. senile dementia
1. similar to Alzheimers except it occurs after 65 y/o
2. neurofibrillary tangles, senile plaques, granulovacuolar
degeneration of neurons
f. Parkinsonism
i. Rigidity
ii. Expressionless facies
iii. Stooped posture
iv. Gait disturbance
v. Slow voluntary movements
vi. Pill-rolling tremor
vii. Increase in women 50 or older
viii. Possible causes
1. trauma
2. some toxins
3. vascular diseases
4. encephalitis [influenza epidemic: rare]
ix. Parkinsons disease [aka paralysis agitans]
1. tremors and rigidity
2. 50-80 y/o
3. disturbance of motor function
4. depigmentation of substantia nigra and locus ceruleus
a. loss of neuromelanin containing neurons
i. also seen in dorsal motor nucleus of vagus nerve
5. Lewy bodies seen in some neurons
a. Concentrically laminated
b. eosinophilic
c. intracytoplasmic inclusion
6. deficiency of dopamine
7. neurophils
a. gliotic
b. scattered accumulations neuromelanin pigment
8. death due to intercurrent infections or falls
16
g.
h.
i.
j.
k.
Spinocerebellar degeneration
i. Dominant or recessive
Freidreich ataxia
i. Autosomal recessive
ii. Small spinal cord
iii. Loss of nerve fibers in posterior column
Pick’s disease
i. Affects women more often, middle to late life
ii. Atrophy of frontal and temporal lobes
iii. Rare to see plaques
iv. Neuronal loss of pick bodies in some neurons: inclusions
Huntington disease
i. Starts in basal ganglia
ii. Gain of function mutations
iii. Death due to suicide or intercurrent infections
iv. Atrophy of caudate nucleus, putamen, globus pallidus
v. 20-50 y/o
vi. lateral ventricle and 3rd ventricle dilated
vii. small brain: loss of neurons
viii. autosomal dominant disorder
1. chromosome 4
ix. dementia
x. abnormal movements [aka choreiform movements]
xi. deficiency of GABA
xii. increase N-Methyl – D aspartic receptor
xiii. progressive disease
Diseases of motor neurons
i. Amyotrophic lateral sclerosis [aka Lou Gehrigs disease]
1. upper and lower motor neurons of pyramidal system
2. possible causes: viral, immunologic, metabolic
3. perhaps superoxide dismutase gene
4. loss of corticospinal fibers
5. fasciculations: small involuntary contractions
6. death from respiratory insufficiency and infections
ii. infantile spinal muscle atrophy [aka Werdnig-Hoffman disease]
1. autosomal recessive
2. floppy infant: muscular weakness, loss of motor neurons
3. hypotonia
4. loss of anterior horns of spinal cord
17
11. diseases of the peripheral nervous system
a. peripheral neuropathies
i. primary axonal degeneration
1. less myelin ovoids
2. nutritional deficiencies and intoxications
ii. segmental demyelination
1. injury to sheath but not to axon
iii. Guillain-Barre syndrome
1. probably immunological
b. neoplasms of the peripheral nervous system
i. seen in von Recklinghausens’ disease
ii. schwannomas
1. masses attached to nerve, esp. CN VIII: acoustic neuroma
2. Antoni A tissue: dense spindles which may form Verocay bodies
3. Antoni B tissue: loose myxoid region
iii. neurofibromas
1. fusiform enlargement of nerve
2. more prone to be malignant
12. Lipid storage disorders
a. Tay Sachs: gangliocytes [pg 186]
b. Gaucher disease [pg 187]
c. Nieman Pick: syringomylinase deficiency
18