Abstracts

Rationale: Infantile Spasms (IS) or West syndrome, is a rare epileptic encephalopathy of infancy, characterized by epileptic spasms, hypsarrhythmia on EEG and developmental regression. A 2012 American Academy of Neurology (AAN)/ Child Neurological Society (CNS) practice parameter on the medical treatment of IS concluded that adrenocorticotropic hormone (ACTH) or Vigabatrin (VGB) be offered for the short-term treatment of IS. Evidence suggests that ACTH be offered over VGB. The efficacy of VGB in the short-term treatment of IS (excluding Tuberous sclerosis) ranges from 40-74%. At the Hospital for Sick Children (Sickkids) in Toronto, VGB is the preferred first-line treatment for all patients with newly diagnosed IS. This is due to its relative ease of use and better short-term side effect profile compared to ACTH. Objective: To review the Sickkids experience of the first line, short-term effectiveness of VGB, in patients with IS. Hypothesis: VGB is effective in the short-term treatment of IS. Methods: This study was a single center, retrospective analysis of all cases of newly diagnosed IS from January 2010 to September 2013. All patients used the treatment regimen as per the Sickkids IS Treatment Guidelines. Duration of follow up was at least 6 months from treatment initiation. Results: 83 children who presented with IS between January 2010 and September 2013 were evaluated. There were 61 children included in the study. 18/61 (30%) children responded to VGB. Of the group who responded, 2/18 (11%) relapsed. There was seizure resolution at final follow up in 17/18 (94%) of the VGB responders.There were 43/61 children (70%) who failed VGB. Of these children 8/43 (19%) relapsed. There was seizure resolution at final follow up in 25/43 (58%) of the VGB failures. Normal development at diagnosis of IS was significantly associated with VGB response, with a p value of 0.001 and Odds Ratio of 8.58. A complicated birth history was significantly associated with VGB failure with a p value of 0.008. Seizure resolution at final follow up was significantly associated with VGB response with a p value of 0.005. There was no significant difference between gender, age at diagnosis, treatment lag time, etiology, family history of epilepsy or developmental delay and seizures prior to the onset of IS, between the two groups. Adverse events associated with VGB included dyskinesia in 3/61(5%) children, MRI changes in 10/61(16%) children and electro-retinogram changes in 1/61(2%) child. Conclusions: VGB is most effective in the first line treatment of infantile spasms when used in children with normal development at the time of diagnosis. Children with infantile spasms who respond to VGB first are more likely to undergo seizure resolution over time than those who failed VGB. Alternative effective, medications with acceptable and reversible side effects are needed to treat infantile spasms who present with developmental delay at diagnosis. This study has the potential to provide the evidence needed to change and improve the care of children with infantile spasms.