Lennox-Gastaut syndrome (LGS)

Key-words Disease name and synonymes Excluded diseases Diagnostic criteria / definition Differential diagnosis Frequency Clinical description Management including treatment Etiology Diagnostic methods Genetic counselling Unresolved questions References Abstract Lennox-Gastaut syndrome (LGS) belongs to the group of severe childhood epileptic encephalopathies. This disorder is defined as a cryptogenic or symptomatic generalized epilepsy, which is characterized by the following symptomatic triad: several epileptic seizures (atypical absences, axial tonic seizures and sudden atonic or myoclonic falls); diffuse slow interictal spike wave in the waking electroencephalogram (EEG) (< 3 Hz) and fast rhythmic bursts (10 Hz) during sleep; slow mental development associated with personality disturbances. Incidence is estimated to 1:1,000,000 inhabitants per year, and the prevalence to 5-10% of epileptic patients, representing 1-2% of all childhood epilepsies. The onset occurs between 2 and 7 years. The most characteristic clinical manifestations in LGS consist of tonic seizures (17-92%), atonic seizures (26-56%) and atypical absences (20-65%). Diagnosis is based on the presence of specific EEG recordings. Treatment is difficult as LGS is usually refractory to conventional therapy. Some of the new antiepileptic drugs (AED) (Felbamate, Lamotrigine, Topiramate) have proven efficient in the control of seizures in LGS. The symptoms in cryptogenic LGS forms (20-30%) appear without antecedent history or evidence of brain pathology, whereas symptomatic LGS cases (30-75%) are associated with pre-existent brain damage.Lennox-Gastaut syndrome (LGS) belongs to the group of severe childhood epileptic encephalopathies. This disorder is defined as a cryptogenic or symptomatic generalized epilepsy, which is characterized by the following symptomatic triad: several epileptic seizures (atypical absences, axial tonic seizures and sudden atonic or myoclonic falls); diffuse slow interictal spike wave in the waking electroencephalogram (EEG) (< 3 Hz) and fast rhythmic bursts (10 Hz) during sleep; slow mental development associated with personality disturbances. Incidence is estimated to 1:1,000,000 inhabitants per year, and the prevalence to 5-10% of epileptic patients, representing 1-2% of all childhood epilepsies. The onset occurs between 2 and 7 years. The most characteristic clinical manifestations in LGS consist of tonic seizures (17-92%), atonic seizures (26-56%) and atypical absences (20-65%). Diagnosis is based on the presence of specific EEG recordings. Treatment is difficult as LGS is usually refractory to conventional therapy. Some of the new antiepileptic drugs (AED) (Felbamate, Lamotrigine, Topiramate) have proven efficient in the control of seizures in LGS. The symptoms in cryptogenic LGS forms (20-30%) appear without antecedent history or evidence of brain pathology, whereas symptomatic LGS cases (30-75%) are associated with pre-existent brain damage.