Lennox-Gastaut syndrome (LGS) is the most severe type of childhood epilepsy and is a common clinical epileptic encephalopathy with an age of onset of 1-8 years. it is named after two investigators, Lennox and Gastaut. the clinical and EEG characteristics of seizures in this group of patients were first studied by Lennox in 1945 and further studied by Gastaut in 1966. The Lennox-Gastaut syndrome accounts for 5-10% of epilepsy in children and is classified as symptomatic or idiopathic. LGS is characterized by a variety of seizure types, intellectual impairment and widespread slow (1.5-2.5 Hz) spike-and-slow wave discharges on the EEG. The most common seizure types are tonic, atypical akathisia and atonic seizures, but also myoclonic, generalized tonic-clonic and focal seizures are often present. There are multiple etiologies and the pathogenesis is unclear. Seizures are usually frequent, difficult to control, and have a poor overall prognosis. The etiology is widely varied. Idiopathic LGS has no clear etiology. The main causes of symptomatic LGS include: perinatal brain injury, intracranial infection, cerebral dysplasia, tuberous sclerosis and metabolic diseases. Mechanism: LGS is generally considered to be a severe abnormal response of the immature brain in children to extensive and localized brain injury. The main features of LGS include: (1) early age of onset, mostly before the age of 4 years, most common at the age of 1.2 years; (2) various forms of seizures, including tonic seizures, myoclonic seizures, atypical akathisia seizures and atonic seizures; (3) very frequent seizures; (4) often accompanied by intellectual developmental disorders; (5) difficult to treat; (6) the EEG during the interictal period is slow spiking slow about 20% of children in this disease About 20% of children have infantile spasms before the onset of the disease. The child may have one or more forms of seizures at the same time, and may change from one form of seizure to another during the course of the disease. Among these seizure types, tonic seizures are the basic seizure type. LGS is often associated with varying degrees of mental retardation, with 20% to 60% of children having mental retardation at the onset of the disease, and the incidence of mental retardation rising to 75% to 93% as the disease progresses, and children may lose skills they have learned. 2. Diagnosis: LGS manifests itself in multiple seizure forms and can be transformed into each other, which makes diagnosis difficult. The possibility of this syndrome should be considered for refractory epilepsy with multiple seizure types in childhood. 3. Treatment: Lennox-Gastant syndrome is one of the most difficult childhood epilepsy syndromes to treat. Antiepileptic drugs are ineffective in many children, and some children may require a combination of more than one antiepileptic drug. In some children, the frequency of seizures can be reduced with oral antiepileptic drugs, but their effectiveness is short-lived and rarely lasts for 1 year. Commonly used medications are sodium valproate, clonazepam, lamotrigine, and topiramate. Ketogenic diet therapy may be effective in some children. Surgical removal of the lesion may be considered in those with focal damage. Corpus callosotomy has some effect. 4. Prognosis: The short-term mortality rate is 4%-7%, and the long-term prognosis for seizure control and mental development are poor. The majority of children cannot live independently due to neurodevelopmental delay, neurological defects, and frequent seizures. 80% of the children have persistent seizures, and the prognosis for those who develop infantile spasms is even worse. The prognosis is also worse for those with early onset and combined brain damage.