MEDICAL DISCLAIMER:The contents are under continuing development and improvements and despite all efforts may contain errors of omission or fact. This is not to be used for the assessment, diagnosis or management of patients. It should not be regarded as medical advice by healthcare workers or laypeople. It is for educational purposes only. Please adhere to your local protocols. Use the BNF for drug information. If you are unwell please seek urgent healthcare advice. If you do not accept this then please do not use the website.

Acute Disseminated Encephalomyelitis

Learning objectives

  • Learning
  • Understand
  • Integrate
  • Reflect

Many patients initially diagnosed with ADEM subsequently develop clinically definite MS upon long-term follow-up.

  • Relevant as a stroke mimic and so should be identifiable
  • Acute disseminated encephalomyelitis mainly affects children but can affect adults
  • Inflammatory condition of brain and spinal cord that damages myelin
  • May follow a viral illness or have another precipitant
  • Classically acute and monophasic but not always
  • Usually affects young adults and children
  • Pathological hallmark of ADEM is perivenular inflammation with limited "sleeves of demyelination"
  • CSF elevated IFN-gamma, IL-6, and IL-8
  • Bacterial infections: mycoplasma, Gram negative organisms, salmonella typhi
  • Vaccination for measles, mumps, or rubella.
  • Post viral: Measles, varicella, rubella, Herpes-zoster, Infectious mononucleosis
  • Cerebral malaria
  • Fever, meningism, seizures, coma, usually monophasic but not always
  • Weakness, hemianopia, neglect
  • CT: may show cerebral oedema
  • MRI scan: large symmetrical lesions with basal ganglia and thalamus involved.
  • LP: raised protein and slight increase in WCC in 80%.Protein > 100mg/dl. No oligoclonal bands
  • Brain biopsy: consistent with demyelination.
  • Multiple sclerosis
  • Susac syndrome
  • Progressive multifocal leukoencephalopathy
  • Mortality is up to 30%
  • Treat with high dose IV Methylprednisolone
  • Alternatives include Plasmapheresis, IVIG and Rituximab
References and further reading