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63 Cards in this Set
- Front
- Back
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What are some myelin forming cells?
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Oligodendrocytes (CNS)
Schwann Cells (PNS) |
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What is the major component of the white matter?
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myelin
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T or F: Oligodendrocytes myelinate one segment of many axons
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TRUE
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T or F: Schwann Cells myelinate multiple segments of multiple axons
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False! Schwann cells myelinate one segment of one axon
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What are the components of the white matter?
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Myelin
Oligodendrocytes Astrocytes Microglia Axons Blood vessels |
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What do oligos look like with H&E stain?
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fried eggs
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What is silver stain used for?
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visualize axons
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What characterizes dz of myelin formation or maintenance by intrnsic (genetic) causes? (metabolic disease)
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leukodystrophy
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What is dz of normally formed myelin caused by extrinsic (exogenous) cause? (acquired disease)
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demyelinating disease
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T or F: in demyelinating diseases, axons are well preserved
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TRUE
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What are some immune-mediated demyelinating diseases?
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Multiple Sclerosis
Acute disseminated encephalomyelitis Acute hemorrhagic leukocephalitis |
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What are some viral causes of demyelinating diseases?
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Progressive multifocal leukoencephalopy (PML) from JC virus
AIDS |
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What are some toxic causes of demyelinating diseases?
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osmotic myelinolysis
solvent vapor abuse |
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What are some vascular causes of demyelinating diseases?
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Subcortical arteriosclerotic leukoencephalopathy (Binswanger disease)
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What are some histo characteristics of MS?
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1. myelin degeneration w/ preservation of axons
2. MS plaques 3. perivascular of inflammatory cells |
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How do you dx MS?
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MRI and detection of oligoclonal IgG bands isoelectric focusing in the CSF (80%)
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What are Dawson's fingers?
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perpindicular excursion of perivenous inflammation seen on MR of MS.
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What are some favorite sites for MS plaques?
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Optic nerves, radiations, periventricular white matter
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What does the luxol fast blue stain of the white matter show?
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myelin
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What are the main causes of acute disseminated encephalomyelitis (ADEM)?
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measles, varicella, rubella
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When does acute disseminated encephalomyelitis show up?
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several days to weeks after exanthematous viral infections
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What does an MR of ADEM look like?
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multiple asymmetric foci in white matter.
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Perivenous inflammatory infiltrates w/ monophasic demyelination --> __
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ADEM
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What causes PML?
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Papova virus (JC) infection
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Who gets PML?
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immuno-compromised pts (sarcoid, TB, AIDS, Cancer, Transplant)
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What is the hallmark of PML
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Multiple foci of demyelination in subcortical white matter in early lesion
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What is the hallmark gross inspection of PML look like?
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rat bitten, moth eaten, chewed up corpus callosum
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T or F: Viral cytopathic effect is seen in PML
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TRUE
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T or F: multinucleated astorcytes are common in PML
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TRUE
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T or F: There is very little inflammation in PML and AIDS leukoencephalopathy?
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TRUE
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What is the cine qua non of AIDS leukoencephalopathy?
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multinucleated giant cells expressing HIV viral antigens
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T or F: AIDS leukoencephalopathy shows lots of histo evidence of myelin degeneration
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false! Very little
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What causes central pontine myelinolysis?
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rapid correction of serum electrolyte imbalance
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What is the hallmark of central pontine myelinolysis?
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Demyelination in the central pontine base
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T or F: leukodystrophies affect both the CNS and the PNS
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TRUE
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What is contained in macrophages in ALD?
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long chain fatty acid
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What is contained in macrophages in MLD?
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sulfatides
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What is contained in macrophages in GLD?
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galactocerebroside
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What do the leukodystrophies preserve despite the white matter demyelination?
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subcortical U-fibers
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What is the inheritance of ALD and AMN?
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X-linked recessive
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What is a useful diagnostic marker of ALD and AMN?
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elevated long chain fatty acid in tissue
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Demyelination of predominatly occipital white matter --> __
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ALD
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What is the hallmark feature (gross) of leukodystrophies?
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preservation of the subcortical U fibers (thin rim near cortex)
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What is the most common leukodystrophy?
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MLD
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MLD --> __
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arylsulfatase A deficiency
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what is the inheritance of MLD?
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AR
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What is the deficiency in Krabbe Disease (GLD)?
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galactosylceramidase (galactocerebrosidase) deficiency
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what is the inheritance of Krabbe (GLD)?
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AR
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Contrast enhancing lesion of the brain -->
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metastatic tumor or radiation induced demyelination
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Define demyelinating disease
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d/o relayed to the selective loss of myelin in the CNS
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Define Multiple Sclerosis
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A chronic demyelinating dz w/ sx referable to multiple locations in the CNS over time
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What is transverse myelitis?
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demyelinating dz of the spinal cord
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What is optic neuritis??
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demyelinating dz of the optic nerve
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What is the mean age of MS dx?
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30
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What are some signs of MS?
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tremor/ataxia
weakness/spasticity/hyperreflexia sensory deficits relative afferent pupillary defect intranuclear opthalmoplegia |
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What is Lermitte's sign?
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an electric-shock like sensation felt down the spine when the head is flexed forwards.
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Intranuclear opthalmoplegia is a lesion of what?
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MLF
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What does MRI of MS look like?
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periventricular white matter lesions
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What does LP of MS show?
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oligoclonal bands in the CSF
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What is the treatment of MS?
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immune modulating therapies (steroids, interferons, monoclonal Abs)
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The mainstay of MS is __
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symptomatic (treat whatever problems they have)
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T or F: Physical measures (like bracing) are not useful in MS
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FALSE
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What is the clinical course of MS?
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normal life expectancy
need a wheelchair 20 yrs after dx highly variable course |
