Demyelinating Diseases

on 30.1.09 with 0 comments

  • Multiple Sclerosis – most common

    • Mostly in whites in northern latitudes, 20-40 YOA, female > male

    • Autoimmune or postviral

    • Formation of plaques in white matter that exhibit demyelination, inflammation, and gliosis

      • Gitter cells will be present

      • Plaques are separated from one another and come and go with time (get better during periods of remission)

      • Axons seem to be spared

    • Intermittent but progressive disease

      • Early C/S: paresthesias, incoordination, and mild sensory and motor symptoms of extremities

      • Late C/S: ataxia, paraplegia, and mental dysfunction

    • Variants

      • Neuromyelitis optica (Devic’s disease)

        • Demyelinating disease of spinal cord and optic tract

        • Permanent damage to axons

      • Acute MS – more accelerated form in younger patients

      • Balo concentric sclerosis – fuhgedaboudit

  • Progressive multifocal leukoencephalopathy

    • Caused by JC virus (a papovirus); may rarely come from SV40

    • Opportunistic – seen in AIDS and other immunocompromised patients

    • Oligodendrocytes are affected and show intranuclear inclusions

    • Causes focal demyelinating plaques that mimic those seen in MS (plaques tend to be larger and more separated, giving a “moth-eaten” appearance)

    • See also a bizarre reactive gliosis (very atypical-looking astrocytes that aren’t infected with the virus)

    • Progressive neurologic signs and symptoms, no effective treatment

  • Perivenous encephalomyelitis

    • Severe disease centered around blood vessels

    • Probably from immune-mediated reactions

    • Acute disseminated encephalomyelitis

      • Perivenous demyelination

      • Rapidly progressive and can be fatal (most patients do recover and may have neurological sequellae)

      • Usually follows a viral infection and may be an immune reaction against myelin

    • Acute necrotizing hemorrhagic encephalomyelitis

      • Similar to ADE with acute vasculitis

      • May be related to immune complex deposition; poorly understood

Category: Pathology Notes



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