Acute disseminated encephalomyelitis

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Acute disseminated encephalomyelitis, abbreviated ADEM, is an uncommon neuropathology with some similarities with multiple sclerosis.

General

  • Thought to be autoimmune; often associated with/preceded by viral illness.[1]
  • May mimic multiple sclerosis.

Treatment:

  • Steroids.
  • Plasmapheresis.

Diagnosis:

  • Need to r/o infection (with lumbar puncture).
  • No old plaques on imaging (MRI).

An acute form exists known as acute hemorrhagic leukoencephalitis[2] (AKA acute necrotizing hemorrhagic encephalomyelitis).

Microscopic

Features:[3]

  • Myelin loss with sparing of axons.
  • Inflammation:
    • Early: neutrophils.
    • Late: mononuclear cells (lymphocytes, plasma cells).
  • Lipid-laden macrophages.

DDx:

  • Multiple sclerosis.
    • Tend to be larger, more lymphocytes,[4] age of the lesions differ.
  • Acute necrotizing hemorrhagic encephalomyelitis (ANHE) - if one considers this a separate entity.
  • Acute necrotizing encephalopathy.[5]

See also

References

  1. Tenembaum S, Chitnis T, Ness J, Hahn JS (April 2007). "Acute disseminated encephalomyelitis". Neurology 68 (16 Suppl 2): S23–36. doi:10.1212/01.wnl.0000259404.51352.7f. PMID 17438235.
  2. URL: http://path.upmc.edu/cases/case102/dx.html. Accessed on: 2 January 2012.
  3. Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1312. ISBN 978-1416031215.
  4. Lefkowitch, Jay H. (2006). Anatomic Pathology Board Review (1st ed.). Saunders. pp. 423. ISBN 978-1416025887.
  5. URL: http://path.upmc.edu/cases/case619/dx.html. Accessed on: 26 January 2012.