early in the emergency department through pulmonary function testing (in cooperative children) and close clinical monitoring for fatigue and other clinical signs of impending failure Most children will recover with immunomodulatory therapy (intravenous [IV] immunoglobin, or plasma exchange [PLEX] in more severe cases), however, recovery times vary and can take months to a year in some patients Definitive treatment will require collaboration with critical care and neurology Randomized trials for the treatment of ADEM are lacking, but general consensus indicates that high-dose IV methylprednisolone (30 mg per kg per day, maximum 1,000 mg per day) should be initiated early and given for days, usually followed by an oral taper over to weeks IV Ig (2 g per kg over to days) is often considered as a second-line agent in cases poorly responsive to steroids PLEX is reserved for refractory and particularly severe cases Prompt initiation of treatment usually results in excellent outcome, with full recovery in the majority of cases within days or weeks Suggested Readings and Key References Caffarelli M, Kimia AA, Torres AR Acute ataxia in children: a review of the differential diagnosis and evaluation in the emergency department Pediatr Neurol 2016;65:14–30 Thakkar K, Maricich SM, Alper G Acute ataxia in childhood: 11-year experience at a major pediatric neurology referral center J Child Neurol 2016;31(9):1156– 1160