Ketogenic Diet - Indications and Contra-indications

Indications and Contra-indications

The ketogenic diet is indicated as an adjunctive (additional) treatment in children with drug-resistant epilepsy. It is approved by national clinical guidelines in Scotland, England and Wales and reimbursed by nearly all US insurance companies. Children with a focal lesion (a single point of brain abnormality causing the epilepsy) who would make suitable candidates for surgery are more likely to become seizure-free with surgery than with the ketogenic diet. In the UK, the National Institute for Health and Clinical Excellence advises that the diet should not be recommended for adults with epilepsy. About a third of epilepsy centres that offer the ketogenic diet also offer a dietary therapy to adults. Some clinicians consider the two less restrictive dietary variants—the low glycemic index treatment and the modified Atkins diet—to be more appropriate for adolescents and adults. A liquid form of the ketogenic diet is particularly easy to prepare for, and well tolerated by, infants on formula and children who are tube-fed.

Advocates for the diet recommend that it be seriously considered after two medications have failed, as the chance of other drugs succeeding is only 10%. The diet can be considered earlier for some epilepsy and genetic syndromes where it has shown particular usefulness. These include Dravet syndrome, infantile spasms, myoclonic-astatic epilepsy and tuberous sclerosis complex.

A survey in 2005 of 88 paediatric neurologists in the US found that 36% regularly prescribed the diet after three or more drugs had failed; 24% occasionally prescribed the diet as a last resort; 24% had only prescribed the diet in a few rare cases; and 16% had never prescribed the diet. There are several possible explanations for this gap between evidence and clinical practice. One major factor may be the lack of adequately trained dietitians, who are needed to administer a ketogenic diet programme.

Because the ketogenic diet alters the body's metabolism, it is a first-line therapy in children with certain congenital metabolic diseases. However, it is absolutely contraindicated in others. The diseases pyruvate dehydrogenase (E1) deficiency and glucose transporter 1 deficiency syndrome prevent the body from using carbohydrates as fuel, which leads to a dependency on ketone bodies. The ketogenic diet is beneficial in treating the seizures and some other symptoms in these diseases and is an absolute indication. In contrast, the diseases pyruvate carboxylase deficiency, porphyria and other rare genetic disorders of fat metabolism prevent any use of the diet. A person with a disorder of fatty acid oxidation is unable to metabolise fatty acids, which replace carbohydrates as the major energy source on the diet. On the ketogenic diet, their body would consume its own protein stores for fuel, leading to ketoacidosis, and eventually coma and death.