Abstracts

RATIONALE: The ketogenic diet has been used as a therapy for epilepsy since the 1920s. Recently, it has been used more frequently as an alternative therapy for children with medically refractory epilepsy. As with other epilepsy therapies, the ketogenic diet has been associated with treatment side effects, including a secondary carnitine deficiency. Potential reasons for this deficiency may include an inadequate intake of carnitine, a greater demand on carnitine usage, or an increase in the renal excretion of carnitine conjugates (1). At the end of this presentation, the participants will better under stand the incidence of carnitine deficiency in children on the ketogenic diet and the response to carnitine supplementation in those children who are identified as being carnitine deficient.
METHODS: A retrospective chart review was done for 20 children between 6 months and 15 years who were started on the ketogenic diet. There were 9 children who received their nutrition enterally and 11 children who were orally fed.
RESULTS: Three (43%) of the enterally fed children and 8 (73%) of the orally fed children developed a carnitine deficiency (free carnitine [lt] 20[mu]M/dl). The decreases in free carnitine levels were manifested one to six months after starting the diet. The carnitine deficient children were on a ketogenic diet ratio of 3:1 to 4:1. Two of the enterally fed children who were on valproate therapy had a carnitine deficiency at the onset of the diet. Of the children with carnitine deficiency, 10 were started on carnitine supplementation (30-63 mg/kg/day) and 2 had the diet discontinued due to lack of efficacy. Seven of the children who received supplementation had normalization of free carnitine levels after initiation of carnitine; one child had normalization of free carnitine after supplementation was increased from 30 mg/kg/day to 43 mg/kg/day. Two of the children did not receive follow-up carnitine levels due to discontinuation of the diet. Additionally, after one month on the diet, one (8%) of the oral feeders developed a symptomatic carnitine insufficiency (acyl/free ratio [gt] 0.4) characterized by an increase in seizures and lack of energy. One of the children with carnitine deficiency and the child with carnitine insufficiency (on 5 mg/kg/day) described improved energy and alertness after supplementation.
CONCLUSIONS: Of the children on the ketogenic diet, 61% developed a carnitine deficiency with the greater portion (73%) of these children receiving their nutrition orally as opposed to enterally (43%). The discrepancy between orally fed and enterally fed children could be related to the fortification of carnitine in the enteral formula. All of the children that had follow-up carnitine levels after supplementation had improved free carnitine levels. Children on the ketogenic diet should have a baseline carnitine level and regular monitoring of their carnitine levels so that supplementation can be initiated when appropriate. Additional research is needed to determine if there is a clinical response related to symptoms of carnitine deficiency after supplementation in children who are carnitine deficient secondary to the ketogenic diet.
1. De Vivo DC, Bohan, TP, Coulter DL, Dreifuss FE, Greenwood RS, Nordli DR Jr, Shields WD, Stafstron CE, Tein I. L-carnitine supplementation in childhood epilepsy: current perspectives. Epilepsia 1998;39:1216-25.