Abstracts

Rationale: Early and effective treatment of infantile spasm (IS) may be necessary to improve the prognosis for developmental outcomes. However, 25-50% of patients with IS do not respond to initial therapies with corticotrophin (ACTH) or vigabatrin. Furthermore, over 50% of patients with IS go on to develop additional seizure types, for which ACTH and vigabatrin have little benefit. In the present investigation we examined the role of the ketogenic diet (KGD) in treating IS, as well as its efficacy in treating additional and concurrent seizure types in these patients. Methods: We conducted a retrospective chart review to identify patients who received the KGD as treatment for IS. All included children were evaluated and treated at our tertiary-care institution and had evidence of classic or modified hypsarrhythmia on EEG (n=18). Clinical history, epilepsy severity, and treatment outcomes were obtained, as well as anthropormorphic and neuropsychological profiles. Results: Eighteen patients with cryptogenic, idiopathic or symptomatic IS met inclusion criteria. IS were diagnosed in patients at 7.1 ± 1.1 months of age. At the time of KGD initiation patients were 18.0 ± 2.4 months of age, and all but 2 (11%) had been on ACTH and/or vigabatrin therapy without effective reduction in IS. 12 of 18 (67%) patients had additional seizure types. At 2-months after the start of the KGD treatment, 7 of 18 (39%) patients had a 50-90% reduction in IS and 8 of 18 (44%) had a greater than 90% decrease in IS. At this time point, there was no increases or additions of anti-epileptic medications in all but 1 patient with a reduction in IS frequency greater than 50%. Furthermore, the observed decreases in IS frequency persisted at 6- and 12-months after start of KGD. Significant side-effects of KGD were encountered in just 3 of 18 (17%) patients. In those patients with additional seizure types at KGD initiation, 9 of 12 (75%) had a greater than 50% decrease in IS, and 7 of these 9 (78%) responders had concomitant greater than 50% reductions in the severity of their other seizure types. In this cohort, there was no significant relationship between reduction in IS and prior use of vigabatrin, ACTH, or both medications. Furthermore, there were no significant correlations between reduction in IS and age at onset of spasms, time to treatment of spasms with medication, or time to treatment of spasms with the KGD. Conclusions: In corroborating with previous work, we show the ketogenic diet is a well-tolerated and efficacious treatment of IS. Furthermore, we demonstrate that the KGD is can cause significant reductions in IS and concomitant seizure types, irrespective of prior ACTH or vigabatrin use, or total duration of spasms. These results suggest that in those patients with IS and additional seizure types, the KGD may be offered as a first-line therapeutic treatment.