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acute disseminated encephalomyelitis

Tuesday 10 June 2003

Acute disseminated encephalomyelitis (ADEM) is a rare acute inflammatory demyelinating disorder of central nervous system characterized by multifocal white matter involvement. Children and young adults are more commonly affected.

Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disorder of the central nervous system (CNS).

It is predominantly a pediatric disease with an incidence of 0.4/100,000. Also known as post-infectious encephalomyelitis, it typically follows a minor infection with a latency period of 2–30 days and is thought to be immune-mediated. The onset of ADEM usually follows a viral infection or immunization after a mean period of 7-14 days.

ADEM is clinically characterized by the acute onset of focal neurological signs and encephalopathy. Cerebrospinal fluid (CSF) analysis usually shows predominant lymphocytic pleocytosis but, unlike viral or bacterial encephalitis, no evidence of direct CNS infection is found.

Cerebral magnetic resonance imaging (MRI) is essential to ADEM diagnosis, detecting multifocal or diffuse lesions throughout the white matter.

The pathogenesis is not clear but several evidences support the autommune aetiology. ADEM is characterized by multifocal neurological signs and occasionally it rapidly progresses to coma.

Acute disseminated encephalomyelitis (ADEM) is a monophasic, demyelinating disease of the central nervous system that predominately affects prepubertal children. It is typically characterized by an abrupt onset of neurologic symptoms preceded by an infection or recent immunization.

ADEM is a diagnosis of exclusion in many cases, though the differential diagnosis is extensive.


- varicella infection (18029277)
- Mycoplasma pneumonia (17661054)
- classic dengue (17568897)
- mastoid surgery (17517165)
- multiple myeloma (17515558)

See also

- childhood inflammatory demyelinating CNS disorders

  • neuromyelitis optica (NMO)-IgG


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- Menge T, Hemmer B, Nessler S, Wiendl H, Neuhaus O, Hartung HP, Kieseier BC, Stuve O. Acute disseminated encephalomyelitis: an update. Arch Neurol. 2005 Nov;62(11):1673-80. PMID: 16286539

- Mihai C, Jubelt B. Post-infectious encephalomyelitis. Curr Neurol Neurosci Rep. 2005 Nov;5(6):440-5. PMID: 16263054


- Sawanyawisuth K, Phuttharak W, Tiamkao S, Boonpila A. MRI findings in acute disseminated encephalomyelitis following varicella infection in an adult. J Clin Neurosci. 2007 Dec;14(12):1230-3. PMID: 18029277

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