Background: Infantile spasms are a rare, catastrophic, age-specific seizure disorder of infancy. Adrenocorticotropic hormone or vigabatrin have been recommended for the short-term treatment of infantile spasms by the Child Neurology Society/American Academy of Neurology practice parameter.

Objective: This retrospective study reviewed the Hospital for Sick Children's experience with the short-term efficacy of vigabatrin as first-line treatment for infantile spasms not related to tuberous sclerosis complex.

Method: We performed a single-center, retrospective analysis of all cases of newly diagnosed infantile spasms between January 2010 and September 2013. Duration of follow-up was at least 6 months from treatment initiation.

Results: Eighteen of the 61 infants (30%) had a clinical and electrographic response to vigabatrin therapy within 4 weeks of treatment. Of the vigabatrin responders, 2/18 (11%) relapsed. At final follow-up after initiation of vigabatrin therapy, 17/61 (27%) of the vigabatrin responders were free of all clinical seizure types. Normal development at the time of infantile spasms diagnosis was statistically associated with vigabatrin response.

Conclusion: These findings do not support our hypothesis that vigabatrin is effective as first-line, short-term treatment of infantile spasms in non-tuberous sclerosis complex patients. However, when used in this setting, vigabatrin is most effective in children with normal development at the time of diagnosis. These findings may assist clinicians in the optimal treatment choice for children at the first presentation of infantile spasms not related to tuberous sclerosis complex.