Lennox-Gastaut syndrome 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, atonic seizures, atypical absences, 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 has been studied in controlling drop attacks and cannabidiol is being researched as an adjunctive antiepileptic agent in patients with Lennox-Gastaut syndrome and other intractable epilepsy syndromes.
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• Lennox-Gastaut syndrome is defined by severe seizures of multiple types in infancy and childhood, cognitive impairment and on the EEG by slow spike wave, as well as bursts of generalized fast activity in sleep.
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• 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.
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• 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.
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• Further study is needed to identify etiology 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 (48). 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 (76). Dravet first published a precise description of the syndrome in 1965 entitled “epileptic encephalopathy of infancy with slow spike-waves (petit mal variant)” (29). Later, Gastaut and his colleagues described the clinical manifestations and EEG patterns of 100 patients with slow spikes-and-waves (44). 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 (87) 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 (Engel and International League Against Epilepsy 2001; 33). Berg and colleagues organized the etiologies of the syndrome as genetic, structural/metabolic, and unknown (12).