Limited efficacy of the ketogenic diet in the treatment of highly refractory epileptic spasms

PURPOSE Numerous studies have suggested that the ketogenic diet is effective in the treatment of epileptic spasms, even in refractory cases. However, there has been very limited demonstration of prompt and complete (video-EEG confirmed) response. We set out to describe our center's experience with the ketogenic diet in the treatment of children with highly refractory epileptic spasms, with rigorous seizure outcome assessment. METHOD Children treated with the ketogenic diet for epileptic spasms between April, 2010 and June, 2014 were retrospectively identified. Seizure burden was tabulated at baseline and after 1, 3, 6, and 12-months of ketogenic diet exposure. Adverse events were similarly ascertained. RESULTS We identified a cohort of 22 consecutive patients who received ketogenic diet therapy, with median age of onset of epileptic spasms of 5.2 (IQR 2.0-9.0) months, with diet initiation beginning a median of 26.4 (12.5-38.7) months after onset, and following a median of 7 (IQR 5-7) treatment failures. Only 2 patients exhibited a complete response during ketogenic diet exposure, and response was more reasonably attributed to alternative therapies in both cases. A modest early reduction in seizure frequency was not sustained beyond 1 month of diet exposure. The diet was well tolerated, and continued in 6 patients with subjective and/or partial response. CONCLUSION In contrast to prior studies reporting substantial efficacy of the ketogenic diet, our findings suggest limited efficacy, albeit in a highly refractory cohort. Prospective studies in both refractory and new-onset populations, with both video-EEG confirmation of response and rigorous cognitive outcome assessment, would be of great value to more clearly define the utility of the ketogenic diet in the treatment of epileptic spasms.