Lennox-Gastaut syndrome (LGS), also known as Lennox syndrome, is a difficult to treat form of childhood-onset epilepsy, that most often appears between the second and sixth year of life and is characterized by frequent seizures and different seizure types and is often accompanied by mental retardation and behavior problems. more...
As a rule, the age of seizure onset in LGS is between two and six years old. However, some patients get their first seizure within the first two years of life or after the first eight. The syndrome shows clear parallels to West syndrome, enough to suggest a connection.
Daily multiple seizures are typical in LGS. Also typical is the broad range of seizures that can occur, larger than that of any other epileptic syndrome. The most frequently occurring seizure types are: tonic, which are often nocturnal (90%); the second most frequent are myoclonic seizures, which often occur when the patient is over-tired.
Atonic, atypical absence, complex partial, focalized and tonic-clonic seizures are also common. Additionally, about half of patients will suffer from status epilepticus, usually the nonconvulsive type, which is characterized by dizziness, apathy, and unresponsiveness. The seizures can cause sudden falling (or spasms in tonic, atonic and myoclonic episodes) and/or loss of balance, which is why patients often wear a helmet to prevent head injury.
In addition to daily multiple seizures of various types, children with LGS frequently have have arrested/slowed psychomotor development and behavior disorders. The most common type
The syndrome is also characterized by an interictal (between-seizures) EEG featuring slow spike-wave complexes.
Incidence and Prevalence
Approximately 5% of children with epilepsy have LGS, and is more common in males than females. Whereas some children seem perfectly normal prior to the development of seizures, others already had some form of epilepsy, such as West syndrome, which is seen in 20% of patients before (symptomatic) LGS. West syndrome is characterized by Blitz Nick Salaam seizures, and typically evolves into LGS in the second year of life.
According to a 1997 community-based retrospective study in the Helsinki metropolitan area and the province of Uusimaa, the annual incidence of both Lennox-Gastaut was 2 in 100,000 (0.002%) from 1975-1985.
0.026% of all children in the Atlanta, Georgia metropolitan area were estimated to have LGS in 1997, which was defined as, "onset of multiple seizure types before age 11 years, with at least one seizure type resulting in falls, and an EEG demonstrating slow spike-wave complexes (<2.5 Hz)." The study concluded that LGS accounts for 4% of childhood epilepsies.
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