How is acute disseminated encephalomyelitis (ADEM) defined by the International Pediatric Multiple Sclerosis Study Group (IPMSSG)?

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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In 2007, the International Pediatric Multiple Sclerosis Study Group (IPMSSG) proposed operational definitions for the pediatric acquired demyelinating diseases (including ADEM) in attempts to improve consistency in terminology for clinical and research purposes. These guidelines were revised in 2013 and are outlined below. [59]

  • The criteria requires that a child must meet all of the following to be accurately classified as pediatric ADEM:

    • A first, polyfocal clinical CNS event with presumed inflammatory demyelinating cause

    • Encephalopathy that cannot be explained by fever

    • No new clinical and MRI findings emerge 3 months or more after onset

    • Brain MRI is abnormal during the acute phase

    • Typical findings on brain MRI (discussed below) that include diffuse, poorly demarcated large lesions involving the cerebral white matter; T1 hypointense lesions of the white matter are rare; deep gray matter lesions may be present.

Recurrent ADEM was previously defined as a new event of ADEM with a recurrence of the initial symptoms and signs 3 or more months after the first ADEM event. Based upon the 2013 consensus criteria from IPMSSG, [59] this entity is now included under the entity known as multiphasic ADEM.

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