Which clinical history is characteristic of acute disseminated encephalomyelitis (ADEM) arise?

Updated: Nov 08, 2018
  • Author: J Nicholas Brenton, MD; Chief Editor: Tarakad S Ramachandran, MBBS, MBA, MPH, FAAN, FACP, FAHA, FRCP, FRCPC, FRS, LRCP, MRCP, MRCS  more...
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ADEM is more common in the winter months, with most cases occurring between October and March. Typical cases of ADEM arise 1-2 days to several weeks after a childhood infectious illness.

  • There is usually a clearly defined phase of afebrile improvement lasting 2-21 days or more before onset of neurologic findings.

  • Generally, patients have shown partial or complete recovery from the prodromal illness at the time of onset of ADEM.

  • Whether latencies of longer than 21 days implicate a particular febrile illness as the prodrome of ADEM is unclear. Clinical experience suggests that this is possible.

  • Most of the large envelope-bearing viruses that figured prominently in older series of ADEM, of which measles was a particularly virulent example, no longer figure importantly in the etiology of ADEM because these diseases are prevented by vaccination.

  • Most cases encountered now occur in the wake of respiratory or gastrointestinal illness presumed to be of viral etiology, although a specific virus is seldom identified.

  • Documentation of at least 1 fever-free day is especially suggestive of ADEM, although such a hiatus is also found in post-infectious vasculitides.

  • Occasionally, ADEM may occur in the wake of several weeks of fever of unknown origin.

  • Some patients have premonitory pain in the back prior to the development of ADEM-related inflammatory myelitis.

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