We studied the long-term outcome of Acute disseminated encephalomyelitis (ADEM).

We performed a retrospective cohort study among children diagnosed with ADEM (fulfilling IPMSSG criteria). Major outcome variables were motor deficit, scholastic underperformance, and behavioral abnormality.

The inclusion criteria were fulfilled by 102 children. Three died in hospital. The follow-up ranged from one to 10 years (median 4 years). Motor deficit was seen in 17(17.2%), attention deficit in 25 (25.3%), behavioral abnormality in 13(13.1%), persistent seizures in seven (7%) invididuals and poor learning skills in 22 (22.2%). Recurrence of demyelination occurred in seven (7.1%). Two individuals had a recurrent demyelinating disorder (a chronic relapsing demyelinating disorder) that could not be classified as multiple sclerosis (MS), two had ADEM with sequential optic neuritis and three had multiphasic ADEM. At follow-up, the mean (SD) modified Rankin Scale (mRS) score was 0.556 (1.36) and Expanded Disability Status Scale score was 1.71(2.22). On multivariate analysis, the mRS score at discharge (p<0.01) and thalamic lesions on magnetic resonance imaging (MRI) (p<0.01) were associated with motor sequelae; poor learning skills with ADEM with concomitant polyneuropathy (p<0.02); and behavioral abnormality with tumefactive demyelination (p<0.02).

Children who had ADEM may have motor or cognitive sequelae, seizures or recurrent demyelinating events on follow-up. We identified a few risk factors for these sequelae. Factors that affected outcome on discharge from hospital did not affect chances of having long-term sequelae. On follow-up, none of the children fulfilled the diagnostic criteria for MS, suggesting that the chance of conversion of ADEM to MS is less likely.