Background: Acute demyelinating syndromes (ADS) of the central nervous system (CNS) in children may occur as an isolated illness with rapid resolution, may result in permanent neurological disability, or may represent the first clinical manifestation of chronic diseases such as multiple sclerosis (MS).In a national prospective cohort study we delineate the clinical features, acuity, medical management, and clinical outcome of children with incident ADS.

Results: 299 eligible children were followed prospectively from ADS presentation: 71 (24%) with monofocal optic neuritis, 61 (21%) with  clinically monofocal transverse myelitis, 36 (12%) with  monofocal deficits extrinsic to the optic nerve and spinal cord, 75 (25%) with acute disseminated encephalomyelitis (ADEM), and 54 (18%) with polyfocal deficits without encephalopathy.Hospitalization at the time of first attack was required for 258 participants (87%) with a median length of stay of 6 (range 1-99) days. At onset, 75 children were profoundly encephalopathic with polyfocal deficits, 69 were unable to ambulate independently, and 48 had severely impaired vision. Twelve patients with monoADS and one patient with MS experienced severe sequelae following their incident attacks of demyelination.

Conclusions: ADS is a serious illness in Canadian children, with 87% of children requiring hospitalization due to severe neurological deficits during acute illness. Over 95% of children recovered physically from their ADS event. However, permanent visual and spinal cord impairment occur in a small proportion of children, and 17% were diagnosed with MS within the first few years post ADS.