There are many causes of epilepsy, which are usually classified into two categories: idiopathic and symptomatic (secondary). (1) Idiopathic (primary) idiopathic epilepsy refers to a category of epilepsy in which there is no manifestation of organic or metabolic brain disease and the cause of the disease is still unclear, also known as true or primary epilepsy. As medical science continues to develop and progress, the causes of epilepsy continue to be discovered, and the proportion of primary epilepsy is shrinking, so some scholars refer to this type of epilepsy as cryptogenic epilepsy. In some cases, there are no significant structural changes or metabolic abnormalities in the brain, but they are related to genetic factors and have a tendency to occur in families. In idiopathic epilepsy, most of the seizures are generalized, such as generalized tonic clonic seizures, atonic seizures and myoclonic seizures. (2) Symptomatic (secondary) caused by a variety of organic brain lesions or metabolic disorders. (1) Congenital malformations: such as chromosomal malformations, congenital hydrocephalus, microcephaly, corpus callosum hypoplasia, cerebral cortical hypoplasia, etc. ②Prenatal and perinatal disorders: birth injuries are a common cause of symptomatic epilepsy in infancy.
Contusions, edema, hemorrhage, and infarction can also lead to localized cerebral sclerosis, which forms foci several years later. Patients with cerebral palsy are also often complicated by epilepsy. (iii) Sequelae of febrile convulsions: Severe and prolonged febrile convulsions can lead to brain damage including neuronal loss and gliosis, mainly in the medial temporal lobe, especially in the hippocampus. (iv) Craniocerebral injury: those with sequelae of epilepsy after craniocerebral injury are associated with depressed fractures, dural tears, and local neurological signs and memory impairment after long-term injury. Cases producing early epileptic seizures within a few weeks after injury are the most common. ⑤ Infections: seen in various bacterial meningitis, brain abscesses, granulomas, viral encephalitis, and parasitic diseases, such as cysticercus, schistosoma, and toxoplasma. Bacterial infections commonly include tuberculous meningitis, epidemic meningomyelitis, brucellosis encephalitis, arachnoiditis, and epidural abscesses. The acute phase can be one of the symptoms of its clinical manifestations, and late in the day, seizures and electroencephalographic epileptic discharges can also be left behind, and the seizures can be in the form of generalized or partial seizures. The common acute infections include epidemic B encephalitis, herpes simplex virus encephalitis, and herpes zoster virus encephalitis. In addition to seizures during the acute phase, acute infections may also result in cerebral softening, atrophic lesions and recurrent seizures during the recovery period. In chronic cases, partial or generalized seizures may occur during the progression of the disease. In addition, “sporadic encephalitis” due to viral infections is often associated with seizures or epilepsy as the main clinical manifestation. Parasitic infections: Common parasitic brain diseases include cerebral cysticercosis, cerebral encysticercosis, cerebral schistosomiasis, cerebral pulmonary schistosomiasis, cerebral toxoplasmosis, cerebral trichinosis and cerebral malaria. The most common cause of epilepsy in the north is cerebral cysticercosis, which is caused by the parasitic larvae of *cestode larvae in the brain. It often manifests as generalized tonic-clonic seizures and partial seizures. In the south, schistosomiasis of the brain is often the cause of seizures. (6) Poisoning: lead, mercury, carbon monoxide, ethanol, fenugreek, isoniazid poisoning, and systemic diseases such as gestational hypertensive syndrome and uremic syndrome can cause epilepsy. (7) Intracranial tumors (8) Cerebrovascular disease: Except for cerebrovascular malformations and subarachnoid hemorrhage, which produce epilepsy at a younger age, post-stroke epilepsy is more common in middle-aged and elderly people, especially cerebral embolism, cerebral thrombosis and multiple cavernous seizures. Hypertensive encephalopathy is also often associated with epilepsy. 9 Nutritional and metabolic disorders: epilepsy often occurs in children with rickets. In adults, hypoglycemia due to islet cell tumors, diabetes mellitus, hyperthyroidism, hypoparathyroidism, and vitamin B6 deficiency can lead to seizures. Degenerative diseases: Epilepsy is one of the main manifestations of tuberous sclerosis. Alzheimer’s disease is also often associated with epilepsy. The above are the more common causative factors, and patients may have one or more of them. On the other hand, the manifestations of the disease may be insidious. Therefore, even in those who are identified as having symptomatic epilepsy, the exact cause is often not certain.