Pathology Flashcards by Maggie Berrigan

Immunologic destruction of normal myelin

Etiology unknown
Hereditary – HLA types A3, B7, Dw2, DRw2, DRw4, DRw6; common in Nordic Caucasians
Viruses – abnormal immune response to measles virus, retroviral (HTLV-1) demyelination

Epidemiology
Most common 20-40 years
Females > males

Gross pathology
Plaques at multiple CNS sites-Around lateral ventricles, optic nerves/chiasm/tracts, corpus callosum, cerebellar peduncles, cerebellum, spinal cord

Microscopic pathology
Loss of myelin (seen on LFB stain) with relative preservation of axons (silver or Bielschowsky stain)
Plaques centered around or extend along blood vessels (venules) with perivascular lymphocytes and plasma cells
Lipid laden macrophages filled with myelin fragments and breakdown products
Reactive astrocytosis

Clinical presentation
Multiple episodes of relapse and remission
Multiple CNS sites effected (visual, motor, sensory, cerebellar, brainstem related symptoms)
Stresses precipitate exacerbations

MRI is the most sensitive technique for lesion detection
Demyelinating foci are hyperintense on T2 weighted image

Natural history
Long course of alternating relapses and remission with increasing functional limitations
Eventual death from intercurrent infection, respiratory compromise, pulmonary embolus
Acute form with involvement of vital brainstem centers is fatal at first presentation

multiple sclerosis (MS)

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Acute fulminating immunologic destruction of myelin days/weeks after immune challenge

Often follows respiratory infection
Vaccination (rabies, smallpox)
Infection (measles, rubella, mumps, influenza, pertussis, strep) - precipitating infection is cleared before onset

Most common in children and adolescents
Monophasic but may relapse
Acute onset with hemiplegia, ataxia, optic neuritis and sometimes seizures

Demyelinating lesions centered around venules with perivascular chronic inflammation and macrophages

Multifocal (asymmetric) MRI hyperintense foci within white matter

Most cases are non-fatal with rapid recovery but a small subset can have residual neurologic deficit or die in acute phase

Acute Disseminated Encephalomyelitis (ADEM)

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Defective enzyme in metabolic pathway related to neurolipids, carbohydrates, amino acids, nucleic acids, pigments, or metals

Non-catabolized metabolite accumulates and destroys neurons and/or glia

Rare diseases of infancy and childhood

Motor disturbances, seizures, deafness, blindness, retardation

Insidious onset, relentlessly progressive

Primary Encephalopathies

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Primary leukodystrophy

Diffuse bilaterally symmetric white matter degeneration

Canavan Disease

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CNS metabolism perturbed by extra-CNS disease

Metabolic substrate deprivation (oxygen, glucose)
Metabolic cofactor deficiency (vitamins, hormones)
Major organ failure (heart, lungs, kidney, liver)
Chemical imbalances (fluid, electrolytes, acid-base, calcium, osmolality)
Intoxications (drugs, poisons, hormones)
Miscellaneous (sepsis, temperature extremes, trauma)

Seen in any age group
Acute/subacute onset
Amenable to treatment

Secondary Encephalopathies

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Clinical expression of cerebral thrombosis, embolism, or hemorrhage

Event lasts less than 24 hours

Transient Ischemic Attach (TIA)

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Vascular event in CNS with sudden onset and effects lasting more than 24 hours

Fifth most common cause of death in the US, incidence and prevalence is declining

Major risk factors: Hypertension, Cardiac disease, Cigarette smoking, Hyperlipidemia, Diabetes mellitus

Other risk factors: Oral contraceptives, Hematologic disease, Thrombotic coagulopathies, Vasculitis, Cerebral amyloid angiopathy, Dissecting aneurysm in extracranial blood vessel, Cocaine, heroin, amphetamines

Stroke

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Normal blood flow but reduced O2 content
Low environmental partial pressure of oxygen
Acute respiratory failure
Carbon monoxide poisoning
Most hypoxic conditions depress cardiac output leading to cerebral ischemia

Hypoxia

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O2 content of blood is normal but blood flow is reduced
Cardiac arrest
Hypovolemic shock
More damaging than hypoxia, toxic metabolic wastes accumulate

Ischemia

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Characteristic of thrombotic infarcts

No reperfusion to necrotic area

Anemic cerebral infarct

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Characteristic of embolic infarcts

Reperfusion of necrotic area leads to extravasation of blood from necrotic vessels

Hemorrhagic cerebral infarct

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0-2 days after infarct
subtle tissue softening, dusky grey matter discoloration, blurring of grey/white matter demarcation
red neurons – neuronal cytoplasm shrinks and turns pink, nucleus collapses and breaks up
neutrophils migrate from vessels at infarct edge

Acute infarct

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2-4 days after infarct
findings of acute stage are more pronounced
swelling (edema) of tissue within mass effect
red neurons break up (liquefactive necrosis) and disappear
neutrophils are replaced by lymphocytes and macrophages

Subacute infarct

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4+ days after infarct
early liquefactive necrosis and late cystic cavitation (no fibrous scar formation)
cavity replaces liquefied dead tissue, spanned by reactive astrocytic processes and capillaries
reactive gliosis and partial tissue damage in surrounding non-necrotic parenchyma with neuronal encrustation (iron/calcium salt deposits on neurons in infarct rim)

Chronic infarct

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chronic hypertension results in hyaline arteriolosclerosis and lipohyalinosis in deep perforating central branches
vessel walls become thicker but less elastic, lumen narrows and microaneurysms may develop
thrombosis leads to lacunar infarcts, small cavities in the brain located in the basal ganglia, thalamus, pons, or deep cerebellum
vessel rupture leads to intracerebral hemorrhage

hypertensive hemorrhage

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thrombosis of dural venous sinus or cortical vein usually due to infection, tumor invasion, or thrombotic diathesis
blocked venous drainage leads to congestion, ischemia, hemorrhagic necrosis in drainage territory

cerebral venous thrombosis

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trauma
skull fracture lacerates underlying dural artery (most often the middle meningeal)
blood under arterial pressure accumulates in potential space between skull and dura
hematoma mass effect may cause herniation
patient may experience lucid interval between injury and neurologic deterioration
medical emergency requiring prompt evacuation

epidural hemorrhage

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trauma
tear in bridging vein between cortical surfaces and dural sinus
cortical vein attached to brain
bridging vein tethered in dura
inertial movement of brain relative to skull/dura shears bridging vein

venous blood accumulates between dura and arachnoid

organized by dural fibroblasts that form membranes around the hematoma

granulation tissue capillaries of organizing hematoma may rupture with minor trauma (re-bleed)

subdural hemorrhage

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trauma, saccular aneurysm, AVM rupture, spread of intraventricular or intracerebral hemorrhage
parenchymal contusion or lacerations bleeding through disrupted pia or ependyma
basilar blood vessels ruptured by basilar skull fracture
dissecting aneurysm of vertebral arteries

subarachnoid hemorrhage

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Associated with connective tissue disease, cerebral vascular malformations, aortic coarctation, AD PCKD, neurofibromatosis 1, smoking, HTN, turbulent blood flow

most common in the anterior circle of Willis

rupture occurs at the dome and extravasated blood collects in the subarachnoid space, brain parenchyma and ventricular system

rupture can result in severe headache, loss of consciousness and death

rupture might result in circle of Willis vasospasm resulting in infarct or arachnoid fibrosis which causes communicating hydrocephalus

saccular (berry) aneurysms

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trauma, chronic hypertension, hemorrhagic infarct, cerebral amyloid angiopathy
results from contusions and lacerations

intracerebral/parenchymal hemorrhage

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extension of intracerebral hemorrhage that ruptures ventricular lining

intraventricular hemorrhage

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amyloid deposited in small and medium-sized cortical and leptomeningeal vessels resulting in thickened but weakened vessels that are subject to rupture (see apple green birefringence on congo red stain)
cerebral hemorrhage is more superficial
reflects involvement of leptomeningeal and superficial cortical vessels, may see several hemorrhages of different ages in different brain areas
affected vessels have double-barrel appearance

cerebral amyloid angiopathy and intracerebral hemorrhage

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malformation of cerebral blood vessels
intracerebral +/- subarachnoid hemorrhage, seizure disorder
most often involves MCA
tortuous large caliber vascular tangle in parenchyma +/- subarachnoid space
rapid flow rates
direct AV shunt with no capillary bed, involves arterioles, veins and arteriolized veins
brain tissue is seen between abnormal vessels
reactive changes are seen in the surrounding brain (hemosiderin, Ca2+, gliosis)

arteriovenous malformation (AVM)

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malformation of cerebral blood vessels intracerebral with or without subarachnoid hemorrhage, seizure disorder occurs most often in the brainstem, cerebellum, and cerebral subcortical white matter grossly resembles hematoma sluggish flow rates abnormal vessels with thin fibrous wall, without intervening brain tissue no smooth muscle, elastic

cavernous hemangioma (cavernoma)

loss of memory and other cognitive abilities secondary to cerebrovascular disease multi-infarct dementia bilateral infarcts destroying threshold volume of grey matter or functionally critical grey matter (thalamus, hippocampus) diffuse white matter disease arteriolosclerosis leads to myelin damage, axonal loss, disconnection of association areas subcortical arteriolosclerosis leukoencephalopathy associated with chronic HTN, diabetes, cerebral atherosclerosis

vascular dementia

parenchymal bruise from impact of brain with skull head is struck, brain develops inertia relative to the skull resulting in impact between brain and skull, brain may rebound against inner skull opposite to the impact site

contusion

parenchymal contusion at impact site associated with blows to stationary head and falls tissue and vascular damage with hemorrhage impact greatest on crowns of gyri follows organization sequence of intracerebral hemorrhage

coup injury

parenchymal contusion opposite to the impact site due to rebound injury associated with falls tissue and vascular damage with hemorrhage impact greatest on crowns of gyri follows organization sequence of intracerebral hemorrhage

countercoup injury

stretching and shearing of axons in deep white matter (corpus callosum, periventricular white matter, brainstem) may be seen with open or closed head injury patients are unconscious from the moment of injury without a lucid interval (remain unconscious, vegetative, or disabled until death) axons severed at nodes of Ranvier, axoplasmic flow disrupted, rounded axonal swellings small hemorrhages in the corpus callosum, dorsal midbrain, dorsal pons with or without contusions or lacerations rounded swellings in white matter neuropil on microscopy, no axons on Bielschowsky stain

diffuse axonal injury (DAI)

Occurs in malnourished patients, especially alcoholics Wernicke’e encephalopathy/Korsakoff’s syndrome Bilateral hemorrhage and necrosis in mammillary bodies and periventricular grey matter Peripheral neuropathy Heart failure

Thiamine (B1) Deficiency

Occurs in malnourished and pernicious anemia patients Interferes with hematopoiesis and CNS myelin production leading to megaloblastic anemia and myelin destruction in posterior and lateral columns of spinal cord (subacute combined degeneration)

Cobalamin (B12) Deficiency

Elevated ammonia levels Toxic to CNS metabolism Neuronal membrane depolarization and neuronal hyperexcitability Perturbed neurotransmitter metabolism and imbalance among neurotransmitters Alzheimer type 2 astrocyte Grey matter astrocytes with swollen clear nuclei and no visible cytoplasm

Hepatic Encephalopathy

Cerebral cortical necrosis (layers 3 and 5 or cortex) Neuronal necrosis in hippocampus (CA1 region), Purkinje cells of cerebellum Necrosis in watershed zones of major vascular territories

hypoxia/hypoglycemia

Patient with abnormal serum Na+ corrected too rapidly (alcoholics, chronically ill) Diamond-shaped area of myelin destruction in central pons

Central pontine myelinolysis

non-infectious inflammation due to chemical irritation in the subarachnoid space keratin from ruptured intracranial epidermoid cyst (misplaced squamous epithelium trapped inside developing skull during fetal development) can cause inflammation

chemical meningitis

spread of metastatic cancer/lymphoma in the subarachnoid space meningeal lymphomatosis

carcinomatous/lymphomatous meningitis

leptomeninges infected by bacteria that induce pus formation neonates: GBS, Gram negatives, L. monocytogenes, S. aureus children: S. pneumoniae, H. influenzae type B (if not immunized), N. meningitidis adults: S. pneumoniae (all ages, sporadic), N. menigitidis (young adults, crowded living conditions), Gram negative rods, L. monocytogenes, S. aureua fever, chills, anorexia, vomiting headache, photophobia, irritability, decreased level of consciousness, stiff neck septicemia Waterhouse-Friedrichsen syndrome (adrenal septic hemorrhagic necrosis, skin petechiae, systemic collapse) neurologic impairment at presentation ``` CSF findings Increased opening pressure Increase CSF cells (mostly PMNs) Increase CSF protein Decrease CSF glucose ``` Pus accumulates in the subarachnoid space (obscures view of underlying brain surface) Pus may collect at the base of the brain Subarachnoid space filled with PMNs May see inflammation +/- thrombosis of blood vessels passing through subarachnoid space

acute pyogenic meningitis

Meningitis caused by viral infection No organism found on Gram stain of culture of CSF Enteroviruses – poliovirus, echovirus, coxsackievirus; HIVl HSV, mumps, measles Less fulminant presentation than acute pyogenic meningitis Spontaneous remission ``` CSF findings Normal or increased opening pressure Increased cells (lymphocytes) Increased protein Normal glucose Negative microscopy ```

acute aseptic meningitis

Localized pus-forming infection of brain parenchyma Multiple sources of infection Hematogenous (cardiac, pulmonary) Local extension (oro-sino-naso-facial) Immunocompetent patient: staph and strep species Immunocompromised patient: Toxoplasma gondii, Nocardia asteroids, L. monocytogenes, gram negative bacteria, mycobacteria, fungi Clinical presentation Variable: indolent to fulminant Fever, headache, focal neurologic deficit, seizures ``` CSF findings – lumbar puncture rarely indicated and contraindicated with increased ICP Increased opening pressure Increased cells (PMNs and lymphocytes) Increased protein Normal glucose Negative cultures ``` Diagnosed by imaging and biopsy cultures Potentially fatal without treatment (surgery and antibiotics) Complications Rupture into ventricle or subarachnoid space Dural venous sinus thrombosis ``` Early cerebritis (1-3 weeks) – hyperemic softened focus Developed purulent abscess – suppurative cavity with fibrous capsule and surrounding edema; often at grey-white junction ``` Central core of suppurative liquefactive necrosis Intermediate zone of proliferating granulation tissue Outer ring of gliotic edematous brain

brain abscess

Pus-forming infection between inner dural surface and arachnoid Spread of skull or sinus infection Organized fibroblast from dura Thrombophlebitis of dural venous sinus or bridging veins with cerebral venous thrombosis

subdural emypema

Pus forming infection between bone and outer dural surface Spread from osteomyelitis or sinusitis Spinal infection may compress cord and require emergency decompression/drainage

epidural abscess

Chronic granulomatous meningitis = basilar infection resulting in adhesive arachnoiditis (fibrosis) that traps basilar vessels and cranial nerves Tuberculoma = brain abscess with caseous necrosis surrounded by granulomatous inflammation Tuberculous spondylitis/Pott’s disease = vertebral destruction, spinal deformity, epidural abscess Immunocompetent: M. tuberculosis Immunocompromised: M. avium-intracellulare ``` CSF findings Increased cells (lymphocytes) Increased protein Normal or slightly decreased glucose AFB positive ```

CNS Mycobacterium infection

Treponema pallidum may spread to meninges Early CNS infection is limited to meninges Asymptomatic: normal to increased cells (lymphocytes), protein, normal glucose, + CSF VLDR Symptomatic: presents as acute aseptic meningitis Late CNS infection: Involvement may be limited to meninges and arteries (mesoderm) - Meningeal gummas, Fibrosing vascular infection occluding lumens (obliterative endarteritis) with plasma cells resulting in parenchymal infarcts Involvement may include meninges, arteries, and parenchyma - Neuronal loss, microglial activation (rod cells), gliosis, Progressive mental deterioration resulting in dementia, Tabes dorsalis = degeneration of spinal dorsal columns (ataxia, loss of pain sensation) Gumma Granulomatous tissue reaction Necrosis with preservation of tissue reticulin Prominent plasma cells Occurs in meninges and may extend into the brain cortex May occur in brain parenchyma in late disease

Neurosyphilis

CNS infection by spirochete Borrelia burgdorferi transmitted by Ixodes ticks Part of a multisystem disorder involving skin, cardiovascular, joint, PNS, and CNS systems Aseptic meningitis, CN VII palsy, peripheral neuropathy, encephalopathy Microglial activation (rod cells), granulomas, vasculitis

Neuroborreliosis

Viral infection of meninges and brain parenchyma Perivascular and parenchymal mononuclear cell infiltrates Perivascular lymphocytic cuffing ``` Microglial nodules (lymphocytes, plasma cells, macrophages, rod cells) Microglial cell activation Microglia nuclei enlarge, long, and thin (rod cells) ``` Neuronal death and phagocytosis, often in a microglial nodule (neuronophagia) Gliosis Viral inclusions may be present May be followed by demyelinating syndrome (ADEM)

viral meningoencephalitis

Sporadic viral encephalitis Primary infection (lips, face) or reactivation from trigeminal ganglion Targets medial temporal lobe, limbic regions Causes necrotizing, hemorrhagic infection Intranuclear viral inclusions in neurons and glia

CNS HSV1 infection

Adults Retrograde spread to CNS from sacral dorsal root ganglia, latency established after genital infection Aseptic meningitis in healthy adults Necrotizing encephalitis in the immunocompromised Neonates Acquired during birth or transplacentally Necrotizing encephalitis

CNS HSV2 infection

Childhood viral exanthema Varicella latency established in DRG and trigeminal ganglia, reactivation with anterograde axonal transport to skin in dermatomal distribution Herpes zoster by primary infection or reactivation may travel retrograde to spinal cord/brain especially in the immunosuppressed Myeloradiculitis, encephalitis, CNS vascular infection Intranuclear inclusions in neurons and glia

CNS Varicella Zoster Virus infection

Intrauterine infection Targets periventricular regions with severe necrosis leading to periventricular calcification, microcephaly, and CNS malformations Infection in immunosuppressed leads to encephalitis, retinitis, myeloradiculitis Cellular enlargement with prominent intranuclear inclusions in neurons, glia, endothelial cells

CNS Cytomeglovirus infection

Epidemic viral encephalitis Viruses endemic in birds and small mammals, transmitted by arthropods (mosquitoes, ticks) Mostly seen in summer and early fall Eastern Equine Encephalitis, West Nile Virus

CNS Arbovirus infection

Enterovirus that infects gut and spreads to blood Some strains can invade CNS from blood and produce aseptic meningitis +/- acute myelitis In myelitis, virus targets motor neurons in anterior horn of spinal cord and brainstem resulting in flaccid areflexic paralysis and respiratory muscle involvement which may be fatal Vaccination has reduced worldwide incidence

CNS poliovirus infection

Virus endemic in small mammals Virus transmitted to humans via bite of infected animal, travels retrograde via PNS axons to CNS (time to onset of disease reflects bite distance from CNS) Fulminant encephalitis: neuronal cytoplasmic inclusions that are round and pink and are seen best in Purkinje cells and hippocampal pyramidal neurons

CNS Rabies infection

Rare complication of early age measles infection Non-productive (no viral replication) CNS latency of altered measles virus after primary infection Onset of progressive behavior, cognitive, and motor disturbances months to years after infection Encephalitis with widespread neuronal and white matter destruction Intranuclear inclusion in neurons and oligodendrocytes

Subacute sclerosing panencephalitis (SSPE)

Reactivation during a period of immunocompromised of latent JC polyomavirus infection acquired earlier in life Primary JC virus infection is asymptomatic, latency in lymphocytes and kidney JC virus infects glia on reactivation Oligodendrocyte involvement leads to myelin loss Astrocyte involvement leads to enlarged bizarre astrocyte nuclei Progressive neurologic syndrome due to CNS white matter destruction Multiple foci of secondary demyelination in cerebral, cerebellar, brainstem white matter Viral intranuclear inclusion in oligodendrocyte nuclei

progressive multifocal leukoencephalopathy (PML)

Early/with seroconversion: aseptic meningitis Late: subacute meningoencephalitis Direct HIV infection of cerebral microglia and macrophages Neurons destroyed by cytokines, BBB failure Clinical dementia, motor disturbances, seizures More common in pediatric patients Secondary infectious and malignant CNS complications

CNS HIV infection

Target host endothelium, reproduce in host cells Spread by insect vectors (ticks, lice, mites) Infect CNS vascular endothelium resulting in vasculitis, hemorrhage, thrombosis, infarction

CNS Rickettsial infection

Infection of meninges +/- parenchyma associated with immunocompromised Causative agents: candida albicans, aspergillus fumigatus, mucor, Cryptococcus neoformans Inflammatory response may be granulomatous or minimal depending on host status and infecting agent

fungal meningoencephalitis

Meningocerebral infection by Toxoplasma gondii Cat is the definitive host, humans infected via contaminated oocyst containing cat feces Cysts ingested, tachyzoites infect GI macrophages and are disseminated via blood and lymph Intrauterine/neonatal Transplacental passage of tachyzoites during primary maternal infection Fetal meningoencephalitis targets subpial and subventricular regions widespread grey and white matter destruction diffuse brain calcification, hydrocephalus, CNS malformations primary/reactivation in immunocompromised ring enhancing cerebral abscess(es) at grey/white cortical function or deep grey matter meningitis, vasculitis, retinitis free tachyzoites and encysted bradyzoites on microscopy

CNS Toxoplasmosis

Larvae of Tenia solium encyst in human CNS following ingestion of eggs in undercooked pork Humans are dead end intermediate hosts

Neurocysticercosis

Neuronal protein PrPc converted from alpha helix to beta pleated sheet PrPsc PrPsc is resistant to cellular degradation mechanisms and normal techniques of sterilization and tissue fixation Aberrant PrPsc may arise spontaneously, be inherited, or introduced via surgery, ingestion, or organ transplantation Sporadic prion disease Creutzfeldt-Jacob disease Rapidly progressive dementia with myoclonic jerks Fatal in less than 1 year Widespread neuronal loss, gliosis, spongiform change in grey matter (no inflammatory reponse) Heritable prion disease Gerstmann-Straussler-Scheinker syndrome Fatal familial insomnia Infectious prion disease Kuru – transmission via cannibalism

Transmissible Spongiform Encephalopathies

Autosomal dominant disorder resulting from CAG repeat on chromosome 4 huntintin gene Loss of neurons in caudate, putamen, thalamus, and cerebral cortex Extrapyramidal movement disorder +/- dementia

Huntington's Chorea

Autosomal recessive disorder resulting from GAA repeat on chromosome 9 frataxin gene Loss of axons/neurons in spinal cord, cerebellum (spinocerebellar degeneration) Gait ataxia, cerebellar/posterior column/pyramidal tract signs and symptoms

Friedreich's ataxia

Autosomal dominant, segmental repeat in PMP 22 gene for myelin structural protein, chromosome 17 Myelin damage and axonal loss in peripheral nerves Distal leg weakness and muscle atrophy +/- sensory loss

Peroneal muscular atrophy/hereditary and sensory neuropathy type 1/Charcot-Marie-Tooth disease

X-linked recessive deletion in dystrophin gene Slowly progressive wasting of skeletal and cardiac muscle Progressive loss of muscle function, immobility, respiratory paralysis

Duchenne's Muscular Dystrophy

Most common dementia Widespread neuronal loss and gliosis Cerebral cortex, brainstem, basal ganglia Decrease in brain weight and volume Increase in ventricular volume (hydrocephalus ex vacuo) Senile/neuritic plaques Extracellular, amyloid core, neurites with abnormal cytoskeletal filaments (tau protein) Neurofibrillary tangles Intraneuronal, altered cytoskeletal elements (tau protein) Granulovacuolar degeneration Lysosomes with altered cytoskeletal proteins (tau) Hirano bodies Abnormal cytoskeletal microfilaments (actin) Amyloid angiopathy Deposition of amyloid in blood vessels of leptomeninges, cerebral cortex Neuronal loss leads to decreased neurotransmitters Decreased ACh in cerebral cortex and nucleus basalic of Maynert NE, DA, somatostatin, 5-hydroxytriptamine, substance P may decrease Genetic predisposition Chromosomes 21, 14, 1, 19 implicated Early onset in Down’s syndrome (trisomy 21)

Alzheimer's Disease

Dementing illness clinically similar to Alzheimer’s but involving mostly frontal lobe related symptoms Marked atrophy of the frontal lobe and anterior portion of the superior temporal gyrus Microscopic round silver-positive neuronal inclusions (pick bodies)

Pick's disease

Cumulative consequence of many small strokes (multi-infarct dementia) Diffuse damage to CNS white matter from arteriolar disease (hypertension) – Binswanger encephalopathy

Vascular Dementia

Intermittent increases in CSF pressure enlarge ventricles Dementia, gait ataxia, urinary incontinence

Normal Pressure Hydrocephalus

Extrapyramidal movement disorder due to loss of pigmented neurons in substantia nigra Bradykinesia, cogwheel rigidity, resting tremor Pallor of substantia nigra and locus ceruleus Round pink target-like inclusions (Lewy bodies) in surviving neurons of the substantia nigra and locus ceruleus

Idiopathic Parkinson's Disease

Primary motor neuron disease Idiopathic fetal and infantile degeneration of lower motor neurons (spinal cord, cranial nerve nuclei) without corticospinal tract signs SMA type 1 (Werdig-Hoffman disease) – fatal cause of neonatal hypotonia, autosomal recessive disease (chromosome 5) Loss of motor neurons in anterior horn of spinal cord Atrophy of anterior spinal nerve roots and skeletal muscle

Spinal Muscular Atrophy

Primary motor neuron disease Loss of motor neurons and astrocytes in spinal cord, brainstem, and motor cortex Upper and lower motor neuron signs Degeneration of corticospinal tract

Amyotrophic Lateral Sclerosis

Secondary motor neuron disease Lytic infection of the motor neurons caused by enterovirus Can be confined to spinal cord but may also affect the brain In chronic case, asymmetric loss of anterior horn motor neurons and muscle atrophy Lower extremities are involved more often than trunk or upper extremities

Poliomyelitis motor neuron disease

Pathology Flashcards

(73 cards)