Abstracts

Rationale: Purpose: Parents often expect immediate seizure improvement after starting the ketogenic diet (KD) for their children. However, they are often counseled by physicians that the ketogenic diet may in fact take several months to be effective. The purpose of this study was to determine the typical time to first note seizure reduction as well as the time after which it was unlikely to be helpful in those children started on the KD.Methods: Methods: Records of all children started on the KD at Johns Hopkins Hospital (JHH), Baltimore (n=83) and Children’s Memorial Hospital (CMH), Chicago (n=35) from 11/03-12/06 were evaluated retrospectively. There were more children with partial seizure disorders treated with the KD at JHH, but no other significant differences in baseline patient demographics between the two centers. At Johns Hopkins Hospital the KD was started after 1-2 days of fasting with a predominantly 4:1 ratio (grams of fat: carbohydrate and protein), whereas no fast after 1/05, and a majority receiving a 3:1 ratio occurred at Children’s Memorial Hospital. Seizure calendars were examined to determine the first day in which seizures were reduced.Results: Results: Of the 118 children started on the KD, 99 (84%) had documented seizure reduction. The overall median time to first improvement was 5 days (range, 1-90 days). Seventy-five percent of children improved within 14 days and 92% within 30 days. In those children who were fasted at KD onset, the time to improvement was quicker (median 5 vs. 14 days, p=0.004) with a higher percentage improving within 5 days (60% vs. 31%, p=0.006). No difference was identified between fasting and non-fasting in outcomes after 3 months, however. There was no difference in times to improvement between KD ratios or baseline seizure types. Conclusions: Conclusions: The KD works quickly when effective, typically within the first 1-2 weeks. Starting the KD after a fasting period may lead to a more rapid, but equivalent long-term seizure reduction, as has been published previously. In children in whom seizures are not improved after 2 months, the KD can probably be discontinued.