| Identifier system | Code/term | Notes/definition snippet | Primary supporting source (with URL and year) |
|---|---|---|---|
| ICD-10 | G04.0 | Used as the core discharge/registry code for ADEM ascertainment in nationwide studies; one study identified ADEM-related hospitalizations using ICD-10 code “G04.0” and defined ADEM as “an immune-mediated demyelinating disorder characterized by a widespread attack of inflammation in the brain and spinal cord that damages myelin” (pqac-00000017) | Xiu Y et al. *Incidence and Mortality of Acute Disseminated Encephalomyelitis in China: A Nationwide Population-Based Study*. 2021. https://doi.org/10.1007/s12264-021-00642-7 |
| ICD-10 | G04.0, G04.8, G04.9 | Danish pediatric registry validation study used ADEM-related ICD-10 codes “G04.0, G04.8, G04.9” for case finding; unspecified encephalitis codes G04.0/G04.8/G04.9 were included in capture before record-level validation against clinical/IPMSSG criteria (pqac-00000016, pqac-00000018) | Boesen MS et al. *Implications of the International Paediatric Multiple Sclerosis Study Group consensus criteria for paediatric acute disseminated encephalomyelitis: a nationwide validation study*. 2018. https://doi.org/10.1111/dmcn.13798 |
| IPMSSG 2013 pediatric criteria | Pediatric ADEM | IPMSSG operational definition requires “A first polyfocal, clinical CNS event with presumed inflammatory demyelinating cause” plus “Encephalopathy that cannot be explained by fever,” no new clinical/MRI findings for at least 3 months, and acute-phase abnormal brain MRI (pqac-00000009) | Krupp LB et al. *International Pediatric Multiple Sclerosis Study Group criteria for pediatric multiple sclerosis and immune-mediated central nervous system demyelinating disorders: revisions to the 2007 definitions*. 2013. https://doi.org/10.1177/1352458513484547 |
| IPMSSG 2013 MRI characterization | Typical pediatric ADEM MRI | Typical MRI lesions are described as “diffuse, poorly demarcated, large (>1–2 cm) lesions involving predominantly the cerebral white matter”; “T1 hypointense lesions in the white matter are rare,” and deep gray matter lesions may occur (pqac-00000009, pqac-00000008) | Krupp LB et al. *International Pediatric Multiple Sclerosis Study Group criteria for pediatric multiple sclerosis and immune-mediated central nervous system demyelinating disorders: revisions to the 2007 definitions*. 2013. https://doi.org/10.1177/1352458513484547 |
| Registry/clinical classification label | Clinical ADEM vs IPMSSG ADEM | Registry validation work distinguishes physician-diagnosed “Clinical ADEM” from stricter “IPMSSG ADEM,” highlighting that many coded/clinical ADEM cases do not fulfill mandatory encephalopathy/polyfocal-deficit criteria (pqac-00000021, pqac-00000022, pqac-00000023) | Boesen MS et al. *Implications of the International Paediatric Multiple Sclerosis Study Group consensus criteria for paediatric acute disseminated encephalomyelitis: a nationwide validation study*. 2018. https://doi.org/10.1111/dmcn.13798 |
| Abbreviation / disease term | ADEM = acute disseminated encephalomyelitis | Standard expansion used in registry and clinical studies; defined as an immune-mediated inflammatory/demyelinating CNS disorder, often characterized by encephalopathy, multifocal deficits, and large poorly demarcated white-matter MRI lesions (pqac-00000022, pqac-00000017) | Boesen MS et al. 2018. https://doi.org/10.1111/dmcn.13798 ; Xiu Y et al. 2021. https://doi.org/10.1007/s12264-021-00642-7 |


*Table: This table summarizes the key coding and classification systems used for ADEM in the available evidence, highlighting ICD-10 codes used in registry studies and the defining IPMSSG 2013 pediatric criteria. It is useful for mapping disease terminology across clinical, epidemiologic, and knowledge-base contexts.*