SDL: Diseases of White Matter

Question 1

myelin damage with relative preservation of axons; what causes this?

Answer 1

myelin loss; autoimmune attack, infection, hypoxic-ischemic injury, trauma

Question 2

loss of previously-formed and intact myelin due to a specific problem destroying it, such as MS and related conditions

Answer 2

demyelination

Question 3

demyelination includes preservation of…

Answer 3

axons, although eventually without their myelin sheaths they degenerate (secondary damage to axons)

Question 4

diseases where myelin is defective from the start and either cannot be produced or maintained appropriately

Answer 4

dysmyelinating diseases (leukodystrophies)

Question 5

diseases with indirect damage to myelin

Answer 5

HIV leukoencephalopathy, progressive multifocal leukoencephalopathy, carbon monoxide poisoning

Question 6

most common demyelinating disorder; gender ratio of affected

Answer 6

multiple sclerosis; M:F=1:2

Question 7

Clinical findings of MS

Answer 7

random “attacks” of blurred vision, paresthesia, weakness; findings do not fit into a definitive anatomical distribution

Question 8

MS is usually common in what areas of the world?

Answer 8

N. Europe and the US (rare in orientals)

Question 9

autoimmune aspect of MS

Answer 9

mainly CD4 and CD8 T-cells and macrophages

Question 10

the pathology behind the acute phase of MS

Answer 10

inflammatory cells emigrate from the blood vessels, attack myelin sheaths, resulting in demyelination. axons are initially intact.

Question 11

pathology of chronic MS lesion

Answer 11

inflammation subsides, reactive astrocytosis, some axons degenerated, new myelin is forming on others

Question 12

most common locations for MS manifestation and their clinical signs

Answer 12

optic nerve (unilateral vision impairment), spinal cord (motor/sensory impairment, bladder control problems), brain stem (cranial nerve defects, ataxia)

Question 13

diagnostic tool for MS lesions

Answer 13

MRI, CSF electrophoresis to look for increased Ig’s and oligoclonal bands

Question 14

MS plaques on cross section of the rain are characterized as..

Answer 14

irregular tan-grey lesions randomly distributed in the white matter, typically deep and in some connection to the ventricular surface.

Question 15

pathology of acute MS vs chronic MS

Answer 15

acute has many inflammatory cells and myelin breakdown, but not much astrocytosis, so it appears soft and shiny. chronic has a dull appearance, is firm, because the inflammation has subsided and astrocytosis took place

Question 16

vairants of MS

Answer 16

Marburg type (death in 1-6 mons), balo type (death in 2 yrs), shilder type (predom in children)

Question 17

another name for devic disease

Answer 17

neuromyelitis optica (involved the optic nerve and spinal cord)

Question 18

symptoms/signs of devic disease

Answer 18

synchronous blindness and paraplegia; autoantibodies to aquaporin-4 receptors

Question 19

acute disseminated encephalomyelitis seen post..//this suggests what?

Answer 19

post infection, perivenous, post vaccine (suggesting a cross reaction with and autoimmunity against myelin)

Question 20

gross pathology of ANHE

Answer 20

numerous petechiae in white matter

Question 21

other primary demyelinating diseases

Answer 21

central pontine and extrapontine myelinosis (osmotic demyelination syndrome); marchiafava-bignami; demyelinating pseudotumor

Question 22

typical lesion of osmotic demylination/central pontine myelinosis

Answer 22

demyelinating lesion in the center of base of pons

Question 23

main culprit of osmotic demyelination/central pontine myelinosis

Answer 23

rapid CORRECTION of hyponatremia (electrolyte imbalance)

Question 24

neuroimaging aspect of demyelinating pseudotumor

Answer 24

an incomplete, C-shaped ring enhancement pattern which may look like a neoplasm. the opening of the incomplete ring opens toward the ventricle side.

Question 25

a viral infection of oligodendrocytes, interfering with their myelin-forming function

Answer 25

progressive multifocal leukoencephalopathy (usually in HIV pos patients