17.6 Demyelinating disorders Flashcards
Demyelinating disorders
-list them (5 categories)
- leukodystrophies
- Multiple sclerosis
- Subacute sclerosing panecephalitis
- progressive multifocal leukoencephalopathy
- central pontine myelinolysis
Multiple sclerosis
- how are MS symptoms explained by these?
1. optic n
2. brainstem
3. medial longitundinal fasciculus (MLF)
4. cerebral white matter
5. spinal cord
6. ANS
-relapsing neurologic deficits, with periods of remission
- optic n–blurred vision in 1 eye
- brainstem–vertigo, drunk-like speech
- medial longitundinal fasciculus (MLF)–internuclear ophthalmoplegia (when gazing to left, the R eye does not move)
- cerebral white matter–hemiparesis/unilateral loss of sensation
- spinal cord–lower extremity loss of sensation or paresis
- ANS–dysfunction with bowel, bladder, sexual activity
Multiple sclerosis
-mech
destruction of CNS oligodendrocytes and myelin. not PNS
Subacute sclerosing panencephalitis
- mech
- presentation
- what population
“Dawson’s disease”
- Measle infection–persistent, progressive infection that leads to death
- affects both gray and white matter (“pan”)
- infection occurs in infancy, neurologic signs arise year later during childhood
Subacute sclerosing panencephalitis
-characterized by whay histologically
measles virus, so viral inclusion within neurons (gray matter) and oligodendrocytes (white matter)
Multiple Sclerosis
- how does the pt present when the brainstem is affected?
- what not to confuse with?
- Vertigo, along with impaired speech
- mimics drunkeness
Central Pontine myelinolysis
- mech
- presentation
- population affected
- focal demyelination of the pons
- caused by rapid IV correction of hyponatremia
- affects severely malnourished patients (eg alcoholics, pts with liver disease)
- classically presents as “Locked In syndrome”
Multiple Sclerosis
- how to diagnose (2)
- what to look for in each test?
- MRI
- shows plaques (white matter demyelination) - LP
1) increased lymphocytes
2) increased immunoglobulins with oligoclonal IgG bands
3) myelin basic protein (b/c myelin is destroyed)
Leukodystrophies
-general mechanism
-inherited mutations in enzymes necessary for production or maintenance of myelin
Progressive multifocal leukoencephalopathy
- mech
- presentation
- population affected
JC virus infection of oligodendrocytes
- immunosuppression (AIDS, leukemia) leads to reactivation of latent virus
- rapidly progressive neurologic signs leading to death (visual loss, weakness, dementia,)
Leukodystrophies
-list them (3) and describe them
- metachromatic leukodystrophy
- lysosomal storage disease–myelin cannot be degraded, sulfatides accumulate in lysosomes of oligodendrocytes - Krabbe disease
- galactocerebroside accumulates in macrophages - Adrenoleukodystrophy
- LCFA accumulate, damagin adrenal and white matter
Infant exposed to measles from unvaccinated children, gets infected
-What can happen to infant?
Chronic measles infection of neurons and oligodendrocytes (gray and white matter) leads to slow, progressive encephalitis that leads to death
(Subacute Sclerosing Panecephalitis, aka Dawson’s disease)
-infection occurs in infancy but neurologic signs arise years later in childhood
Name the CNS disorder:
- rapid IV correction of hyponatremia
- JC virus
- Measles
- Central pontine myelinolysis
- Progressive Multifocal Leukoencephalopathy
- Subacute sclerosing panencephalitis (Dawson’s disease)
Internuclear ophthalmoplegia
- what is this
- when is it seen
- possible presentation of MS
- paralysis of certain eye muscles…
When gazing left, CN6 from L eye ‘pulls’ CN3 from right eye via MLF. However, if MLF is demyelinated, R eye is unable to gaze left
Multiple sclerosis
- what population affected
- what HLA
autoimmune
- young adults 20-30, more women
- regions far from equator
- HLA-DR2
