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  • Updated 03.08.2024
  • Released 07.26.1994
  • Expires For CME 03.08.2027

Lennox-Gastaut syndrome



Lennox-Gastaut syndrome (LGS) is diagnosed in individuals with intractable epilepsy characterized by multiple seizure types, slow spike-wave pattern on EEG, and cognitive deterioration typically after first seizure onset. Seizure types include tonic seizures that mainly occur in sleep, atypical absences, and atonic and myoclonic seizures. The condition may follow West syndrome, but has also been associated with various genetic and neurocutaneous syndromes, metabolic diseases, and early infectious or ischemic insults, or may have an unknown etiology. Numerous interventions as well as medications have been studied in treating this condition. Clobazam and cannabidiol have been shown to be beneficial controlling drop attacks. Newer antiseizure medications being researched in Lennox-Gastaut syndrome include fenfluramine and felbamate. Other therapeutic approaches include the use of epilepsy surgery and ketogenic diet therapies. Deep brain stimulation is a promising new treatment modality for this debilitating epilepsy.

Key points

• Lennox-Gastaut syndrome is defined by severe seizures of multiple types in infancy and childhood, cognitive impairment, and by slow spike waves, as well as bursts of generalized fast activity on the EEG.

• Many associated conditions are identified as preceding Lennox-Gastaut syndrome, such as West syndrome, various genetic syndromes, and early CNS insults of various etiologies; however, many patients have unknown etiology.

• Treatment options include medications, ketogenic diet, surgery, and devices such as vagal nerve stimulation; however, seizures remain difficult to control even when all of these modalities are employed.

• Further studies are needed to better delineate the neurobiology and etiopathogenesis in an effort to improve therapeutic targets and outcomes.

Historical note and terminology

The history of Lennox-Gastaut syndrome begins in 1939 when a “slow” (2.5 Hz) spike-and-wave pattern was described by Gibbs, Gibbs, and Lennox (60). It was termed “petit mal variant,” as it was associated with a type of absence seizure characterized by incomplete loss of consciousness, in contrast to “petit mal absence,” which was associated with rhythmic generalized 3 Hz spike-and-wave.

Lennox and Davis first correlated the slow spike-and-wave EEG pattern with a distinctive group of clinical manifestations including specific seizure types (myoclonic jerks, atypical absences, and astatic seizures) and intellectual disability (94). Dravet first published a precise description of the syndrome in 1965 entitled “epileptic encephalopathy of infancy with slow spike-waves (petit mal variant)” (40). Later, Gastaut and his colleagues described the clinical manifestations and EEG patterns of 100 patients with slow spike-and-waves (56). They called this syndrome "Lennox syndrome" or "childhood epileptic encephalopathy with diffuse slow spike-and-waves."

The term "Lennox-Gastaut syndrome" first appeared in the literature in 1969 (110) after it was suggested by Margaret Buchtal-Lennox as a tribute to the work of Lennox and the Marseille School headed by Gastaut. The International Classification of Epilepsies, Epileptic Syndromes, and Related Seizure Disorders classifies the Lennox-Gastaut syndrome as a cryptogenic or symptomatic generalized epilepsy (03). In 2001, the ILAE Task Force on Classification and Terminology classified Lennox-Gastaut syndrome among the epileptic encephalopathies (45; 44). Berg and colleagues organized the etiologies of the syndrome as genetic, structural/metabolic, and unknown (16). Lennox-Gastaut syndrome was classified within the group of childhood onset developmental/epileptic encephalopathies in the recent ILAE position paper on epileptic syndromes (141).

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