Abstracts

Rationale: Infantile spasms (IS) are a component of West syndrome, the most frequent epilepsy syndrome in children with Trisomy 21 (T21), but little data is available regarding IS in this population. The T21 population afflicted with IS is thought to be particularly responsive to treatment. We set out to evaluate the features of the presentation, response to treatment, and outcomes of IS in the T21 population. In addition we attempted to determine if there were factors of their clinical course that could account for better outcomes such as earlier diagnosis or more rapid response to treatment. Methods: We retrospectively reviewed the records of children with a diagnosis of IS seen in Neurology clinic between 2003 and 2013. Thirteen children with Trisomy and IS without other evidence of neurologic injury were identified and compared to a control group of 32 children with IS without a known etiology. Children were diagnosed with IS if they had a history consistent with IS and an electroencephalogram (EEG) demonstrating hypsarrhythmia or electroclinical spasms. Results: There was not a significant difference between age at onset, age at diagnosis, age at clinical resolution, age at EEG resolution, duration between clinical onset and diagnosis, or duration between initiation of treatment and clinical or EEG resolution between the two groups. There were no relapses of IS amongst the Trisomy 21 population in comparison to a 19% relapse rate in the control group (though not reaching significance, p = 0.09). Adrenocorticotropic hormone was the most common treatment in both groups and did not account for differences in the groups. With a median follow-up time for all children of 16.4 months, none of the children with Trisomy 21 went on to develop epilepsy versus 40% of the control group (p = 0.01). Conclusions: The onset, diagnosis and response to treatment of IS is similar between the T21 population and those children without a known etiology for their IS. Even with a similar time course, the Trisomy 21 population is less likely to develop epilepsy following IS, suggesting there is something unique about IS in this population.