The Ketogenic Diet: A Nonpharmacological Option for Refractory Epilepsy
Research has shown that 0.5–1% of the population suffers from epilepsy.1 The onset of seizures typically occurs early in life, with approximately 60% of cases beginning during childhood. Unfortunately, 20–30% of patients with epilepsy become refractory to treatment. Epilepsy is considered “refractory” when seizures are not managed by at least two first-line therapies at adequate doses. Fortunately, the ketogenic diet (KD) has proven to be an effective, valuable, non-pharmacological treatment option for refractory epilepsy, especially in the pediatric population.2,3 This high-fat, low-carbohydrate, and adequate-protein diet aims to achieve a metabolic state of ketosis which causes the body to burn fat cells, instead of glucose, for energy. 3,4
Various studies over several years have demonstrated the effectiveness of the KD.1,2 Research has shown that of patients receiving the KD, about half will see a 50% reduction in seizures while one-third will see a 90% reduction in seizures.1 In pediatric patients with refractory epilepsy, the KD has been the most commonly used therapy in the past decade. The effectiveness of the diet may vary depending on the type of epileptic syndrome, therefore appropriate patient selection is important. Table 1 lists the indications of use for the KD.
Two recent studies also proved the effectiveness of the KD in various patient populations. A study by Appavu et al found the KD to be effective in pediatric patients with super-refractory status epilepticus (SRSE).4 SRSE is defined as the continuation of status epilepticus at least 24 hours after beginning general anesthesia medications and is associated with high morbidity and mortality. This retrospective case review found that 9 of 10 patients receiving the KD achieved resolution of SRSE within 1–19 days after initiation of the diet. A second recent report published by Louw et al describes standardized procedures and management recommendations for the KD in infants.2 In the past, the KD was not used in children <2 years old as it was perceived to be high risk in this population. However, recent research found the KD to be highly effective and well tolerated in these patients. These standardized protocols provide recommendations on patient selection, counseling, nutritional requirements, as well as initiation, monitoring, and discontinuation of the KD.
There are several factors to consider prior to initiating the KD.1 First, it is important to calculate the appropriate fluid, calorie, and protein intake for the patient. Intakes are estimated based on the age, nutritional status, and activity level of the patient. The type of diet and the ketogenic ratio must also be established. Generally, a 4:1 ratio is initially used. This ratio indicates the proportion of fat to combined protein plus carbohydrate in the diet. The typical range for the KD is 2.5-4:1, and is highly dependent on the patient's response and tolerance to treatment.2,5 Performing baseline laboratory monitoring prior to the initiation of the KD is also strongly recommended. It is important to determine a patient's metabolic status and to ensure that no pre-existing deficiencies exist prior to initiating therapy.1,2 Table 2 lists the suggested initial monitoring parameters. Lastly, because the KD contains insufficient micronutrients, addition of a multivitamin and calcium, vitamin D, and iron supplements to a patient's diet is recommended.1
Initiation of the KD can occur in an inpatient or outpatient setting.1 Research has shown that there are no significant differences in seizure control when a patient initiates the KD outpatient versus inpatient. Advantages of implementation of the KD in an outpatient setting include avoiding hospitalization, decreased stress to the patient, reduced risk of hypoglycemia and dehydration, and minimization of cost. If an outpatient setting is chosen, appropriate laboratory testing is still necessary and adequate training for the preparation and management of the KD is required. Inpatient initiation of the KD allows for trained individuals to closely monitor a patient and is recommended for all patients <12 months old.2