Ketogenic dietary therapy for Lennox Gastaut syndrome

Written by:
Elizabeth Neal MSc PhD RD
Research Dietitian, Matthew’s Friends Clinics
Honorary Research Associate, UCL – Institute of Child Health

First described in 1966 (1), Lennox-Gastaut syndrome (LGS) is an epileptic encephalopathy which typically presents before eight years of age and accounts for up to 10% of all childhood epilepsies (2). Seizures are severe and may range in type but LGS is characterised by tonic ‘drop attacks’ (3) which can cause frequent injuries. Anti-epileptic drug (AED) therapy is usually commenced as a treatment for epilepsy after presentation of two or more unprovoked seizures; however LGS is difficult to control with medication and failure of a first drug will significantly reduce the likelihood of subsequent seizure freedom (4). This will have considerable cost implications for NHS services due to a child’s need for regular clinical review, ongoing medications (both routine and emergency), support of other therapies and hospital admissions. LGS is usually accompanied by learning disability which will require educational assessment and support. The intractable seizures and associated cognitive and behavioural problems will have a major impact on the health-related quality of life of the affected children as well as their caregivers (5).

In view of these challenges it is important that all therapy options for the LGS child are explored. Non-pharmacologic treatments include vagal nerve stimulation and dietary therapy (6). The ketogenic diet is a high fat, restricted carbohydrate dietary regime that has been used as a treatment for epilepsy since the 1920s; efficacy has been demonstrated in many prospective studies and a randomised controlled trial (7). Modified variants include the modified Atkins diet (MAD). Retrospective reviews have shown the ketogenic diet (8, 9, 10) and MAD (11) to be efficacious for the treatment of LGS. In a prospective study of twenty LGS children on the ketogenic diet, seizures were reduced by over 50% in eight (40%) after 18 months (12). A literature review of 189 LGS children reported 88 (47%) with greater than 50% seizure reduction after 3-36 months on the ketogenic diet (8). One study has assessed long term outcomes of 68 LGS patients over a mean follow up period of 19 years: of the 19 who tried diet therapy, 5 maintained seizure freedom on the traditional ketogenic diet and one on MAD (13).

International consensus recommendations suggest that the ketogenic diet should be strongly considered in a child with epilepsy which has failed to respond to two or three AEDs (14). Guidelines (NICE) on management of the epilepsies in the UK also suggest that children and young people with epilepsy whose seizures have not responded to appropriate AEDs are referred to a tertiary paediatric epilepsy specialist for consideration of the use of a ketogenic diet (CG137, nice.org.uk). In view of these recommendations, we would propose that all children with LGS who have failed appropriate AED therapy are funded for an initial assessment of suitability for ketogenic dietary therapy. Children who start a diet will require a minimum of three months on treatment to allow adequate assessment of benefit and appropriate fine-tuning of the prescription to individual needs; it is recommended that successful treatment is continued for at least two years during which the potential for weaning AEDs will be regularly reviewed.

References

  1. Gastaut H, Roger J, Soulayrol R, et al (1966) Childhood epileptic encephalopathy with diffuse slow spike-waves (otherwise known as “Petit Mal Variant”) or Lennox syndrome. Epilepsia 7(2):139–79.
  2. Camfield PR (2011) Definition and natural history of Lennox–Gastaut syndrome. Epilepsia 52: 3–9.
  3. Archer JS, Warren AE, Jackson GD, Abbott DF (2014) Conceptualizing Lennox-Gastaut syndrome as a secondary network epilepsy. Front Neurol. 5:225.
  4. Kwan P, Brodie MJ (2000) Early identification of refractory epilepsy. N Engl J Med. 342 (5):314-9.
  5. Gibson PA (2014) Lennox-Gastaut syndrome: impact on the caregivers and families of patients. J Multidiscip Healthc. 7:441-8.
  6. Kossoff EH, Shields WD (2014) Nonpharmacologic care for patients with Lennox-Gastaut syndrome: ketogenic diets and vagus nerve stimulation. Epilepsia 55(4):29-33.
  7. Neal EG, Chaffe HM, Schwartz R, et al (2008) The ketogenic diet in the treatment of epilepsy: a randomised controlled trial. Lancet Neurol. 7:500-6.
  8. Lemmon ME, Terao NN, Ng YT, Reisig W, Rubenstein JE, Kossoff EH (2012) Efficacy of the ketogenic diet in Lennox-Gastaut syndrome: a retrospective review of one institution’s experience and summary of the literature. Dev Med Child Neurol. 54(5):464-8.
  9. Caraballo R, Vaccarezza M, Cersósimo R, et al (2011) Long-termfollow-up of the ketogenic diet for refractory epilepsy: multicenter Argentinean experience in 216 pediatric patients. Seizure 20(8):640-5.
  10. Dressler A, Stöcklin B, Reithofer E, et al (2010) Long-term outcome and tolerability of the ketogenic diet in drug- resistant childhood epilepsy–the Austrian experience. Seizure 19(7):404-8.
  11. Sharma S, Jain P, Gulati S, Sankhyan N, Agarwala A (2015) Use of the Modified Atkins Diet in Lennox Gastaut syndrome. J Child Neurol. 30 (5): 576-9.
  12. Caraballo RH, Fortini S, Fresler S, et al (2014) Ketogenic diet in patients with Lennox-Gastaut.Seizure 23(9):751-5.
  13. Kim HJ, Kim HD, Lee JS, Heo K, Kim DS, Kang HC (2015) Long-term prognosis of patients with Lennox-Gastaut syndrome in recent decades. Epilepsy Res. 110:10-9.
  14. Kossoff EH, Zupec-Kania BA, Amark PE, et al (2009) Optimal clinical management of children receiving the ketogenic diet: recommendations of the international ketogenic diet study group. Epilepsia 50:304-17.

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