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acute disseminated encephalomyelitis (ADEM)
also see encephalomyelitis
Etiology:
- generally occurs post infection
- no specific link to infection has been identified
- typically occurs days to weeks after an infection or vaccination
Epidemiology:
- children & young adults
Pathology:
- simultaneous multifocal CNS demyelination
Clinical manifestations:
- subacute presentation
- monophasic
- moderate to severe symptoms
- headache
- fever*
- seizures, encephalopathy*
- focal neurologic signs* [1]
* differentiating features from multiple sclerosis [1]
Special laboratory:
- lumbar puncture (after neuroimaging)
- CSF analysis
- lymphocytic pleocytosis (
- CSF protein and CSF glucose may be normal
Radiology:
- neuroimaging
- magnetic resonance imaging (MRI)
- multiple areas of demyelination (fluffy appearance)
Differential diagnosis:
- multiple sclerosis
- posterior reversible encephalopathy syndrome
- risk factors: hypertension, preeclampsia, kidney or liver disease, exposure to cytotoxic medications or immunosuppressants, or sepsis
- recent infection or vaccination are not typical risk factors
- primary CNS lymphoma
- typically presents with an avidly enhancing brain mass
- usually occurs in patients > 50 years
Management:
- prognosis:
- generally self-limited, without recurrence
General
encephalomyelitis
References
- Medical Knowledge Self Assessment Program (MKSAP) 15, 16, 17, 18.
American College of Physicians, Philadelphia 2009, 2012, 2015, 2018.
- Medical Knowledge Self Assessment Program (MKSAP) 20
American College of Physicians, Philadelphia 2025
- Dale RC, de Sousa C, Chong WK,
Acute disseminated encephalomyelitis, multiphasic disseminated
encephalomyelitis and multiple sclerosis in children.
Brain. 2000 Dec;123 Pt 12:2407-22.
PMID: 11099444
- Pohl D, Alper G, Van Haren K, et al.
Acute disseminated encephalomyelitis: updates on an inflammatory CNS syndrome.
Neurology. 2016;87:S38-45.
PMID: 27572859