Lennox Gastaut syndrome


Lennox-Gastaut syndrome (LGS) is a severe form of epilepsy that usually begins before 4 years, with most cases beginning at about 2 years. [NINDS: 2007]. Characteristics include:
  • The presence of multiple seizure types before age 11 years, with at least one seizure type resulting in falls (drop attacks) including:
    • Drop attacks (atonic seizures)
    • Tonic seizures
    • Atypical absence seizures
    • Myoclonic seizures
    • Generalized tonic-clonic seizures
    • Partial seizures
  • Atonic (drop) seizures seem to account for many of the injuries associated with LGS and many patients with intractable seizures must wear helmets for head protection
  • Children often have increased seizures during transitions to and from sleep
  • Slow spike-wave complexes are seen on EEG (<2.5 Hz)
  • 40% have a history of infantile spasms
  • Although not a diagnostic criterion, 91% of children with LGS have/will develop intellectual disability
  • One half to two-thirds have focal neurologic abnormalities, most commonly motor signs such as spastic diplegia, and hemiparesis
  • Tonic-clonic convulsions become more frequent in older children and adolescents
  • There are no pathognomonic findings for LGS and a presumptive cause cannot be determined in 30-35% of affected children.
[Trevathan: 1997].


Etiologies for LGS include perinatal asphyxia, hypoxic-ischemic brain injury, congenital brain malformations, CNS infections, tuberous sclerosis, and metabolic/degenerative disease though in approximately one third of cases no etiology can be found (cryptogenic cases). Approximately 1/3 of children will be normal intellectually and neurologically at presentation, but greater than 90% will eventually exhibit intellectual disability. See the module Intellectual Disability fr more information. This is particularly true if the onset of LGS is when the child is younger and if there is an obvious etiology. [Oguni: 1996]. There is speculation but no proof that control of the seizures would result in better cognitive outcome.


Prevalence is low (lifetime prevalence at 10 years is 0.26/1000 and 4% of all pediatric epilepsy [Trevathan: 1997]), but patients with LGS account for a large proportion of epilepsy clinic visits and phone calls.

Clinical Assessment

Diagnosis is based on the multiple seizure types and an EEG that shows slow spike wave complexes. The history and physical exam and further testing, such as MRI imaging, are aimed at identifying the cause of the LGS. Look for growth problems, including head circumference, skin abnormalities (signs of tuberous sclerosis; a Woods lamp exam should be performed), and neurological abnormalities.


Typically, children with LGS will be under the care of a pediatric neurologist with expertise in seizures. Generally, no single seizure medication will control seizures in these children and there is no cure. Multiple anti-epileptic medications are often used, but even then control is difficult. Valproic acid, lamotrigine and topiramate are considered initial drugs of choice. [Wheless: 2005] Felbamate has potentially serious side effects that include liver toxicity and life threatening bone marrow failure, and is only used when other treatment options are exhausted. Zonisamide and levetiracetam may be reasonable alternatives, but experience with these agents is limited. Benzodiazepines are sometimes effective, but tolerance is not uncommon, and escalating doses (with accompanying side effects) are required to achieve efficacy. Seizures tend to wax and wane, even when some degree of control has been achieved. The ketogenic diet, (see Ketogenic diet information (Stanford University), Ketogenic diet patient information (Epilepsy Foundation)) vagal nerve stimulation, (see Vagal nerve stimulator (Cyberonics)) and epilepsy surgery are also used after pharmacological treatment has failed. Most children with LGS will never be completely free of seizures.


Information & Support

Helpful Articles

PubMed search for articles on Lennox Gastaut Syndrome in children for the last 3 years.

Ferrie CD, Patel A.
Treatment of Lennox-Gastaut Syndrome (LGS).
Eur J Paediatr Neurol. 2009. PubMed abstract

Arzimanoglou A, French J, Blume WT, Cross JH, Ernst JP, Feucht M, Genton P, Guerrini R, Kluger G, Pellock JM, Perucca E, Wheless JW.
Lennox-Gastaut syndrome: a consensus approach on diagnosis, assessment, management, and trial methodology.
Lancet Neurol. 2009;8(1):82-93. PubMed abstract

Wheless JW, Clarke DF, Arzimanoglou A, Carpenter D.
Treatment of pediatric epilepsy: European expert opinion, 2007.
Epileptic Disord. 2007;9(4):353-412. PubMed abstract


Author: Lynne M. Kerr, MD, PhD - 6/2013
Content Last Updated: 4/2013

Page Bibliography

Lennox-Gastaut Syndrome Information Page.
Epilepsy Foundation; (2007)

Oguni H, Hayashi K, Osawa M.
Long-term prognosis of Lennox-Gastaut syndrome.
Epilepsia. 1996;37 Suppl 3:44-7. PubMed abstract

Trevathan E, Murphy CC, Yeargin-Allsopp M.
Prevalence and descriptive epidemiology of Lennox-Gastaut syndrome among Atlanta children.
Epilepsia. 1997;38(12):1283-8. PubMed abstract

Wheless JW, Clarke DF, Carpenter D.
Treatment of pediatric epilepsy: expert opinion, 2005.
J Child Neurol. 2005;20 Suppl 1:S1-56; quiz S59-60. PubMed abstract