32. Diseases of Myelin Flashcards Preview

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Flashcards in 32. Diseases of Myelin Deck (58)
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Central Pontine Myelinolytis: a few characteristics?

only in CENTRAL PONS. no inflammation. edema from vascular leakage. oligo cells die, axons are transected.
found in individuals who are ill from another cause (may be alcs with liver failure)
rapid onset of motor and sensory sx, freq coma and death


Central Pontine Myelinolitis: etiology?

iatrogenic. from rapid correction of electrolyte imbalance.


Central Pontine Myelinolitis: appearance on imaging?

very distinct: a hole in the central pons. symmetrical. starts in center of pons and moves outward.


Central Pontine Myelinolitis: how to diagnose?

brain imaging.


3 types of Leukodistrophy?

-Globoid Cell (Krabbe's Disease)


if leukodyst is an error of metabolism or enzyme deficiency, why does it appear in the CNS mainly?

because the CNS uses specific pathways/materials that are affected by these problems.


another list of features of leukodystrophies?

-all body tissues are affected
-material that accum is heterogenous
-a single enzyme is defective/absent
-material accumulates in membrane-bound intracellular compartments
-tissues that most use the enzyme are most affected


Clinical features of Globoid Cell Leukodystrophy?

dev delay, retardation, blindness.
coma/death in 1-2 y.
usually late infantile


Globoid Cell: enzyme that is defective?



Globoid Cell Leukodystrophy? what happens at the cellular level?

Galactocerebroside accum in cells of CNS.
large macrophages called GLOBOID CELLS develop.
Oligo cells are vulnerable, the die, hence demyelination


Globoid Cell Leukodystrophy: appearance on gross brain?

widespread demyelination, bilateral
looks a lot like Schilder's type of MS.


Globoid Cell Leukodystrophy: appearance on histo?

accumulation of large macrophages
globoid cells with foamy cytoplasm


Metachromatic Leukodystrophy: clinical profile?

loss of abilities, motor/gait problems, behavior probs, blindness and decr abilities
ultimately coma/death


Metachromatic Leukodystrophy: what is accumulating? is there inflammation?

a sulfated liquid accumulates in CNS and kidney. oligo's die, hence myelin is lost.
no inflammation despite macrophages in CNS to remove debris


Metachromatic Leukodystrophy: how did it get its name?

appearance with a specific stain. stain is purple but pathological area (macrophages) -> brown.


Pelizaeus-Merzbacher: clinical profile?

neurodegeneration with blindness and seizures, spacticity, leading to death.


Pelizaeus-Merzbacher: is PNS involved? is there inflammation in the CNS?

PNS not involved becuase it uses a diff gene.
CNS: no inflammation


Pelizaeus-Merzbacher: feature of knockout mouse?

PLP knockout mouse basically normal. meaning: better to not have any PLP at all than to have mutated PLP


MS: cause?

but seen in some families.
higher risk for people who are farther away from equator in first 15 yrs of life


what do we call a single episode of demyelination?

clinically isolated syndrome


a single episode of demyelination is a risk for what?

50% risk of going on to have recurrent episodes (ie, MS)


can we dx MS if a patient only has one single location of damage?

no. look for local cause before assuming this is demyelinating.


MS: symptoms focal or diffuse?

scattered throughout nervous system


what is L'Hermitte's sign?

finding in MS. aka Barber Chair phenomenon.
electrical sensation down back or legs when neck is flexed (chin to chest). due to irritation of cervical spinal cord sensory tracts.


does MS damage neuron cell bodies?

NO. does not result in LMN damage, damage to cranial nerve nuclei, damage to peripheral nerves


MS and aphasia, memory, cognition: what is seen?

MS does not produce aphasia or effect memory/cognition until late


MS: what will be seen in CSF?

oligoclonal bands, elevated IgG.


Devic's MS: what is being attacked? what are the antibodies against?

spinal cord and optic nerves. (neuromyelitis optica)
ABs against aquaporin channels