Refractory epilepsy refers to drug-refractory epilepsy, also known as intractable epilepsy, for which there is no uniform definition at home or abroad. It is usually defined as refractory epilepsy when there is no progressive CNS disease or occupying lesion, but the disease duration is long and the seizures cannot be controlled and daily life is affected after more than 2 years of regular antiepileptic treatment, trial of major antiepileptic drugs alone or in combination, reaching the maximum dose tolerated by the patient, and the blood concentration reaches the effective range. It is usually considered that ≥4 seizures per month are not effectively controlled. Is the definition of refractory epilepsy in children the same as in adults? In children, because epilepsy that is difficult to control can have a significant impact on the neurodevelopment and cognitive level of the child, the definition of epilepsy in children with refractory epilepsy takes a broader criterion, i.e., seizures have not been reduced by 50% in children with correctly diagnosed epilepsy after 6 months to 1 year of reasonable treatment with regular AEDs (2 or more). Is refractory epilepsy a rare disease? According to the survey, the prevalence of epilepsy in China is about 7‰, and it is projected that there are about 9 million patients with epilepsy in the country, of which 70%-80% can have their seizures controlled by medication, while 20%-30% are difficult to control by medication, i.e. refractory epilepsy. Refractory epilepsy cannot be said to be a rare disease. What kind of people are at risk for refractory epilepsy? Refractory epilepsy usually starts early, so children are the main victims of refractory epilepsy. Adults can also develop refractory epilepsy due to traumatic brain injury, brain tumors, and metabolic diseases. Studies have found a significant association between febrile convulsions, perinatal hypoxic asphyxia, and encephalitis and the occurrence of epilepsy, and these risk factors can precipitate refractory epilepsy. What can cause refractory epilepsy? There are many causes of refractory epilepsy, most of which have brain lesions, such as difficult birth, prematurity, ischemic-hypoxic encephalopathy, cortical dysplasia, hippocampal sclerosis, traumatic brain injury, tumors, tuberous sclerosis and other congenital developmental abnormalities, and genetic-metabolic diseases. The usual causative factors are mostly hyperthermia, encephalitis, and hypoxia.