We conducted a review of hospital records of infants with acute encephalitis syndrome with bilateral symmetrical basal ganglia infarcts, between 2011-2015, at a single center in Assam. Thiamine (as part of multivitamin injection) was used in the treatment of 23 infants and not used in 27; Only 1 (3.7%) infant died in the former group and 20 infants (86.9%) died in the latter [RR (95% CI) 0.04 (0.006,0.29); P<0.001). Two infants on follow-up had normal development, both in the thiamine group. The study suggests the possibility of subclinical thiamine deficiency, mitochondrial diseases, or SLC19A3 gene mutation in this population.