Acquired demyelinating diseases

This is a brief video on non-hereditary demyleinating disorders. I created this presentation with Google Slides. Image were created or taken from Wikimedia Commons I created this video with the YouTube Video Editor. ADDITIONAL TAGS: Acquired demyelinating diseases Non-hereditary diseases in which normally-formed myelin degenerates as a result of insult on myelin or oligodendrocytes with preservation of the axons Multiple sclerosis Acute disseminated encephalo- myelitis Progressive multifocal leukoenceph- alopathy Leukoenceph- alopathy associated with AIDS Central pontine myelinolysis By BruceBlaus - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=44926477 Multiple sclerosis (MS) Most common chronic CNS disorder in young adults (up to 1/1000) Perivascular inflammation Shows both acute and chronic lesions (polyphasic) Acute: loss of oligodendrocytes; reactive astrocytes/macrophages Chronic: fibrous astrocyte gliosis Diagnosed with MRI and oligoclonal IgG bands in CSF (but not in serum) RIGHT: abundant neutrophils and macrophages infiltrate where myelin is missing (top-left of image) Distinct lesion edge Multiple sclerosis Acute disseminated encephalo- myelitis Progressive multifocal leukoenceph- alopathy Leukoenceph- alopathy associated with AIDS Central pontine myelinolysis By Marvin 101 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2846763 Acute disseminated encephalomyelitis (ADEM) Resembles MS (sometimes called borderline form of MS) Thought to follow viral infection (flu, MMR, herpes) Perivenous inflammation Loss of white matter to the vessels, histo shows macrophages Monophasic lesions in white matter Multiple sclerosis Acute disseminated encephalo- myelitis Progressive multifocal leukoenceph- alopathy Leukoenceph- alopathy associated with AIDS Central pontine myelinolysis Progressive multifocal leukoencephalopathy (PML) Caused by the papovavirus JC virus Most people have positive serology for JC (infected), with virus kept under control Complication for immunocompromised patients (AIDS) Early stage: multiple demyelination foci in white matter Late stage: growing necrotic lesion involves cortex Histo: Macrophages engulfing myelin debris; not many other WBCs bc immunocompromised Large, bizarre, transformed astrocytes Enlarged oligodendroglial nuclei Multiple sclerosis Acute disseminated encephalo- myelitis Progressive multifocal leukoenceph- alopathy Leukoenceph- alopathy associated with AIDS Central pontine myelinolysis Leukoencephalopathy associated with AIDS Perivascular giant cells (multinucleated, with HIV antigens) Release toxic cytokines that play role in pathogenesis Causes AIDS dementia Pallor of cerebral white matter (myelin degeneration not seen on histo) Normal CT on left, AIDS brain on right Multiple sclerosis Acute disseminated encephalo- myelitis Progressive multifocal leukoenceph- alopathy Leukoenceph- alopathy associated with AIDS Central pontine myelinolysis LEFT: By Afiller (talk) (Uploads) - Own work, CC BY-SA 3.0, https://en.wikipedia.org/w/index.php?curid=23542660 RIGHT: Public domain (government work) Central pontine myelinolysis Pathogenesis Patients have chronic, severe hyponatremia (low Na) Intracellular adaptations (cells pump out other osmoles) to compensate Patients treated with saline to increase serum tonicity Cells can’t decompensate fast enough, causes shearing of the myelin cells Predominantly iatrogenic Demyelination is worse at base of pons (sometimes lateral geniculate bodies and internal/external capsules → osmotic myelinolysis) Multiple sclerosis Acute disseminated encephalo- myelitis Progressive multifocal leukoenceph- alopathy Leukoenceph- alopathy associated with AIDS Central pontine myelinolysis Pontine perivascular fibers hypointense to the rest of the pons By Jto410 - clinical work as a radiologist, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=25606029