Long-term outcome of the ketogenic diet for intractable childhood epilepsy with focal malformation of cortical development

OBJECTIVE. We evaluated the efficacy and long-term outcome of the ketogenic diet in patients with intractable childhood epilepsy as a result of focal malformation of cortical development. METHODS. A retrospective analysis evaluated seizure outcomes of 47 patients who had intractable epilepsy from (and) surgically remediable focal malformation of cortical development and were first treated with the classic ketogenic diet, involving the 4:1 lipid/nonlipid ratio. The long-term prognosis of 21 patients, who became seizure-free 3 months after the ketogenic diet, was followed up with that of 22 patients who eventually underwent epilepsy surgery. RESULTS. Three months after diet initiation, 29 (61.7%) patients showed a reduction in seizure frequency of >50%, including 21 (44.7%) who became seizure-free. Of the 21 patients with complete seizure control at 3 months, 16 (76.2%) successfully completed the diet for 2 years without relapse, and 10 (47.6%) have remained seizure-free after cessation of the diet (mean follow-up for 3 years and 10 months), including 1 patient who remained seizure-free with additional medication after a relapse. Of the 22 patients who underwent epilepsy surgery, a seizure-free outcome was obtained for 13 (59.1%). CONCLUSIONS. The ketogenic diet should be considered to be an additional option even in patients with focal malformation of cortical development, and long-term seizure-free outcome can be expected for patients who become seizure-free 3 months after the diet.