Abstracts

Rationale: Infantile Spasms (IS), is a rare epileptic encephalopathy of infancy. A 2012 AAN/ CNS practice parameter on the treatment of IS concluded that ACTH or vigabatrin (VGB) may be offered for short-term treatment of infantile spasms. The variation in approval of regulatory bodies, side effects of VGB and prohibitive cost of ACTH have led to other forms of corticosteroids being considered. Objective: To review the Hospital for Sick Children experience of the short-term effectiveness of prednisolone vs ACTH in patients with IS who have failed VGB.Methods: A Single center, non-randomized, retrospective health record analysis of all cases of newly diagnosed IS at the Hospital for Sick children (HSC) Toronto, between January 2009 and December 2011 was performed. Inclusion criteria: Clear diagnosis of IS: Clinical spasms and EEG demonstrating hypsarrhythmia or modified hypsarrhythmia, Age 1- 36 months and no clinical and EEG response after 2 weeks of maximum VGB dose. Exclusion criteria: Lennox Gastaut syndrome, Age < 1 month or > 36 months, EEG not initially performed to confirm hypsarrhythmia or modified hypsarrhythmia and no follow-up EEG after treatment with either hormonal agents. Results: There were 20 children eligible for enrollment in this study. Fifteen (75%) children received high dose Synacthen ACTH as 2nd line therapy and 5 (25%) received prednisolone (dose 4-6 mg/kg/day) as 2nd line therapy. The 2nd line treatment lag time in the ACTH group was a mean of 2.2 months and in the prednisolone group 1.6 months. In the ACTH 2nd line treatment cohort 9/15 (60%) responded to treatment. Of those who responded 4/9 (44%) relapsed. The overall seizure resolution for the cohort was 5/15 (33%). In the prednisolone 2nd line treatment cohort 1/5 (20%) responded to treatment and 1 child (100%) relapsed. The overall seizure resolution was 3/5 (60%). In the cohort who had failed or relapsed on ACTH 2/10 (20%) received prednisolone as a 3rd line therapy and neither responded to treatment. Neither patient had resolution of seizures. Of the children who failed to respond to prednisolone 4/5 (80%) received ACTH as 3rd line treatment. One of four (25%) responded and this child did not relapse post ACTH therapy. The overall seizure resolution rate was 2/4 (50%).Conclusions: This study discusses the short-term outcome of 2nd and 3rd line treatment of infantile spasms post Vigabatrin failure. The results show that high dose ACTH appears to be more effective than prednisolone. Those patients who failed Prednisolone as 2nd line therapy were able to show a response to 3rd line ACTH whereas those who had not responded to high dose ACTH were unlikely to respond to prednisolone as a 3rd line agent. These results may relate to the difference in mechanism of action between ACTH and prednisolone, the doses of each treatment used and the underlying etiology of IS which lead to VGB failure in the first place. These findings may assist clinicians in the choices of 2nd and 3rd line treatment of IS post VGB failure.