Elsevier

Epilepsy & Behavior

Volume 21, Issue 2, June 2011, Pages 115-121
Epilepsy & Behavior

Review Article
Dietary treatments for epilepsy: Management guidelines for the general practitioner

https://doi.org/10.1016/j.yebeh.2011.03.008Get rights and content

Abstract

As ketogenic diets become more frequently used as a standard treatment for epilepsy in children and adults, hospital and community neurologists, pediatricians, intensivists, general practitioners, and house officers will readily encounter patients who are receiving these dietary treatments. A growing body of evidence demonstrates that dietary therapies for epilepsy (classic ketogenic diet, medium-chain triglyceride diet, modified Atkins diet, and low-glycemic-index treatment) are highly effective, with approximately 30–60% of children overall having at least a 50% reduction in seizures after 6 months of treatment. However, as would be true of any other medical anticonvulsant therapy, these treatments have known side effects and complications requiring recognition and timely action. In addition, the ketogenic diet is a significant intervention requiring rigorous daily adherence; not every family is willing or able to make the necessary commitment to this therapy. We provide herein a survey of the most common situations faced in both the inpatient and outpatient settings, including a discussion of triage and management based on our center's experience as well as the recent 2009 International Consensus Guideline.

Research highlights

► The diet is increasing in use for both children and adults. ► Pediatricians need to be aware of diet issues in their general practice. ► Neurologists should be cognizant of indications and contraindications. ► Emergency physicians have to be able to recognize common and rare problems.

Introduction

Despite continued advancements in anticonvulsant development, approximately 30% of patients with epilepsy have refractory seizures [1], and so there remains a significant demand for additional options. Carbohydrate-restricted diets have become increasingly used as a treatment of chronic and acute epilepsy [2], [3]. Evidence from randomized, controlled trials [2], [4] and meta-analyses [5] has demonstrated that overall approximately 50% of children will respond to these diets with at least a 50% reduction in seizures. Ketogenic diets may be also effective for adult status epilepticus [6] and adult epilepsy [6], [7], and as a first-line treatment of seizures associated with glucose transporter 1 deficiency [8]. These diets are being used worldwide in many new centers [9], and based on the approximately 200 centers today offering dietary treatment, an estimated 3000 children are likely actively receiving this treatment worldwide.

These children are also cared for by pediatricians, internists, emergency department physicians, intensivists, and house officers in academic and community hospitals when general pediatric illnesses arise. Similar to all children, they may become ill, require anesthesia for surgery, and receive oral medications. Therefore, there is a need for these general practitioners worldwide to recognize emergencies and common side effects and be aware of treatment aspects unique to carbohydrate-restrictive dietary therapies. This review highlights many of the common medical issues seen in children and adults receiving dietary treatment for epilepsy.

Section snippets

Composition of dietary treatments

All dietary therapies used to treat epilepsy share the common characteristic of restricting carbohydrate intake to shift the predominant caloric source of the diet to fat [10]. Body tissues are thereby forced to catabolize fats as their primary source of energy, and the catabolism of fats results in ketones, hence the origin of the common descriptor for these therapies, “the ketogenic diet.” The precise mechanisms by which the ketogenic diet yields its anticonvulsant effect are not known, but

Pre-ketogenic diet preparations

As groups have gained experience with ketogenic diets, it has become obvious that some patients with certain epilepsy syndromes particularly benefit from this therapy, some are less likely to benefit but may merit a trial, and there are some for whom the diet is contraindicated. Appropriate screening and selection of eligible patients are imperative for best chance of success and more importantly for safety.

Acute issues during initiation of the ketogenic diet

The practice at our institution and at the majority of institutions employing the ketogenic diet is that inpatient admission is helpful and important for close monitoring of children and the intense education of their parents. This short (3- to 4-day) admission is needed for patient safety should problems arise during diet initiation and as a means to ensure completion of parental education about the diet. In select circumstances, outpatient initiation has been reported as safe [26], but it

Chronic issues with the ketogenic diet

Beyond the admission period, there are other adverse effects that may arise in children on dietary treatment (Table 3). The vast majority of inquiries and on-call issues with the ketogenic diet can be triaged and solved without an emergency room evaluation or hospital admission. Although issues with the ketogenic diet may seem at first glance more complicated than those of anticonvulsant medications, fielding a phone call or outpatient query about a possible diet-related side effect requires

Gastrointestinal complaints

The most common reported chronic complications of the ketogenic diet typically include gastrointestinal issues. Constipation is frequently associated with the ketogenic diet and can be managed by increasing dietary fiber intake, ensuring adequate carbohydrate-free fluid intake, or, if other measures fail, by prescribing carbohydrate-free laxatives such as polyethylene glycol. These children can present with abdominal distention, hematochezia (as a result of straining and rectal mucosal

Long-term issues with the ketogenic diet

Several issues require particular attention from those caring for patients on long-term use of the ketogenic diet. Typically the issues regarding hypoglycemia, constipation, acidosis, and hunger become less problematic over time. Exceptions may occur during intercurrent illnesses. In general, the long-term (over years) issues that a general practitioner needs to be aware of are related to (1) inadequate supplementation to prevent systemic deficiencies and (2) increasing risk of poor growth,

Rare reported adverse effects

Rare side effects have been described in case reports that have not been mentioned so far in this review (Table 4). These include basal ganglia changes, increased illnesses, bleeding, and other electrolyte and mineral deficiencies. The correlation between these adverse effects and the ketogenic diet has not been definitively demonstrated. However, as no centralized adverse effect registry exists for dietary treatment, as often occurs during the initial introduction of a new anticonvulsant drug

Special issues for adults

As the number of adult patients trying ketogenic diets, especially the modified Atkins diet, for epilepsy has increased, issues unique to this population have become apparent. Caloric restriction in young women can cause loss of bone density and menstrual irregularities [48]. This has been described before in women treated with the ketogenic diet for epilepsy [49]. A reduction in ketogenic diet ratio to increase carbohydrate intake and increased calories to restore a normal body mass index

Discontinuing dietary therapy

Generally, for a patient whose response to the diet is a greater than 50% reduction in seizure frequency, the typical duration of ketogenic diet therapy is 2 years, though this time frame can be extended because of irreversibility of the underlying condition (i.e., GLUT-1 deficiency) or because of robust response without significant side effects. After 2 years, it is advisable to weigh the relative benefits with potential risks for any patients receiving dietary therapy, recognizing the adverse

Conclusions

Ketogenic diet therapy is a well-tolerated, safe treatment for many forms of epilepsy and can be used in adults and children following careful screening and education. Many complications of dietary therapy are easily prevented and, when present, can be managed on an outpatient basis. In acute illness, goals of care should focus on ameliorating the illness first; maintaining the diet is a secondary yet important consideration. Gastrointestinal complaints such as constipation and gastroesophageal

Acknowledgment

The authors gratefully appreciate the idea for this review by Dr. Jong Rho. This review is thus dedicated to his house officers at Alberta Children's Hospital in Calgary, Alberta, Canada.

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