A change in the concept of treatment of refractory epilepsy in children

  Children have a 0.4% chance of developing epilepsy, and once 2 or more regular antiepileptic drug regimens fail to effectively control seizures, there is less than a 5% chance that a further trial of other drugs will terminate the seizures in the long term. Population studies have found that 8-10% of children with newly diagnosed epilepsy develop drug-refractory epilepsy after 2 years. Furthermore, further follow-up reveals that a proportion of children who previously responded well to medication will again develop drug-refractory epilepsy. If imaging reveals a structural lesion in the child, the chances that the drug will control the epilepsy are even lower. As early as the 1970s, Falconer demonstrated that early surgical procedures could benefit children with epilepsy. However, subsequent studies in the 1980s and 1990s showed that there was usually a 10-15 year gap between the onset of the disease and the decision to perform surgery, an interval that many epileptologists found unacceptably long. For physicians treating children with epilepsy, they cannot be as comfortable as adult epileptologists, who also face the problems of childhood development. This 10-year delay can have a tremendous adverse effect on a child’s development if the epilepsy is poorly controlled or if the high doses of antiepileptic drugs have toxic effects.  In infants and children, poorly controlled epilepsy can lead to significant neurodevelopmental impairments, including cognitive, behavioral, psychosocial, and psychiatric disorders. the incidence of mental retardation in children with epilepsy occurring within 1 year of age is 83%. Because epilepsy can induce mental retardation, some researchers now view epilepsy as an “encephalopathy”. Studies have shown that refractory epilepsy under the age of 2 years, especially when seizures occur daily, is a risk factor for severe mental retardation. Control of epilepsy early in brain development is critical for intellectual development, and adolescent children with intractable epilepsy may have significant psychosocial impairment. In addition, we have to consider seizure-related disabling and mortality. The mortality rate of poorly controlled childhood epilepsy is 0.5% per year, and causes include sudden death in epilepsy, aspiration pneumonia, trauma, and persistent status epilepticus, among others.  Therefore, early surgical treatment needs to be considered for children with symptomatic epilepsy that is difficult to control with medications. It is unwise to delay surgery by over-testing various antiepileptic drugs. The goal of surgery is to stop catastrophic developmental disorders by controlling seizures, and the plasticity of the infant and child brain facilitates the recovery and reorganization of neurological function after surgery. Controlling epilepsy before the age of 8 or 10 years or eliminating the side effects of antiepileptic drugs, when possible, may allow the child to catch up with normal children and reduce developmental delays during the period of most active brain functional plasticity. In addition, successful surgery may improve psychosocial functioning and quality of life.  The current guidelines for the treatment of childhood refractory epilepsy are changing, with a rapid increase in the number of children with epilepsy receiving early surgical treatment. This is based on several advances: 1. Early diagnosis of drug-refractory epilepsy. Research has shown that early detection of “drug-refractory” features is important in the early treatment of childhood epilepsy. In order to make surgical decisions within a reasonable time frame, epileptologists must have a clear understanding of the natural course of childhood epilepsy syndromes and must distinguish between self-limiting symptoms, where remission is possible, and refractory cases, where remission is unlikely. conditions such as well-defined lesions on MRI often predict a poor outcome. In addition, young age of onset, mental retardation, neurological abnormalities, persistent status epilepticus, multiple seizure types, frequent seizures and significant focal EEG abnormalities at the onset of epilepsy are also risk factors for progression to drug-refractory epilepsy in children.  2. Advances in epileptic focus localization techniques. The EEG in children is more complex and ambiguous than in adults, and even limited imaging changes may show diffuse or multifocal abnormalities. Therefore, advances in neuroimaging are more predominant in children. High-resolution MRI can identify a greater number of gangliogliomas, embryonic dysplastic neuroepitheliomas, focal cortical dysplasia, and other neural migratory disorders. The increasing familiarity of pediatric epileptologists with such lesions has also greatly improved their diagnostic rates. advances in functional imaging such as PET-CT examinations and interictal and interictal SPECT examinations have also led to increasingly clear localization of epileptic foci in children.  3. Experience and confidence in the surgical treatment of infants and children is gradually accumulating. Decades of research and experience have confirmed that the efficacy of surgery for childhood epilepsy is at least comparable to that of adults. Moreover, there are specific epilepsy surgeries that should be used almost exclusively in pediatric patients, such as hemiplegic brain injury, Sturge-Weber syndrome, symptomatic infantile spasms, and others. Due to the presence of a specific pathological basis and strong neurofunctional plasticity, surgery in such children with epilepsy can be done very adequately, e.g. hemispherectomy surgery on one side of the brain, after which very good seizure control may be obtained, often to the point of seizure disappearance. Current data show that overall children and infants are not at significantly higher risk for epilepsy surgery than adult patients. However, special attention needs to be paid to the fact that infants with poor physical development have a higher perioperative mortality rate than adult patients.  4. Expanded indications for surgery in infants and children suitable for surgical treatment. In some children and infants, epilepsy may be due not only to severe congenital anomalies, but also to conditions that cause progressive neurological dysfunction, such as tuberous sclerosis, Sturge-Weber syndrome, Rasmussen’s encephalitis, and others. Some children may also suffer from so-called “catastrophic epilepsy” or epileptic encephalopathy, such as West syndrome and Lennox-Gastaut syndrome. In these syndromes, in addition to refractory epilepsy, the child also shows a generalized hypofunction of the higher cortex. Therefore, in these children, early surgical treatment is associated with salvage of developmental and cognitive function in addition to seizure control.  5. There is evidence that early surgical intervention can improve the long-term prognosis. Clearly, if children achieve satisfactory long-term outcomes with early surgical intervention, not only can the incidence of epilepsy-related events be reduced and the adverse effects of long-term antiepileptic medication be reduced, but psychosocial aspects can also be significantly improved. In addition, early surgery may also reduce the likelihood of further exacerbation of seizures due to the formation of secondary epileptic foci. From a developmental perspective, early childhood is a period of rapid development, yet very vulnerable and sensitive. Seizures and antiepileptic treatment during this time may lead to developmental delays or even regression, such as functional impairment, activity limitations, medication side effects, school dropout, overprotection, impaired self-esteem, and reduced social interaction. These factors may also lead to the development of a psychosocial “gap”. This “divide” may deepen over time as medications fail to control the seizures, and may be difficult to fill even after surgery to eliminate the seizures. It has been reported that infants and children with “catastrophic epilepsy” up to 2 to 3 years of age can experience “compensatory” rapid development after successful surgical treatment. Children with shorter histories were more likely to show postoperative increases in verbal IQ and operant IQ. In contrast, Meyer reported that 50 children with a mean age of 15.8 years and a mean history of 7.5 years who underwent temporal lobectomy showed no improvement in IQ despite a 78% postoperative seizure disappearance rate.  Of course, there are some arguments against early surgery, such as the possibility of spontaneous remission in children with epilepsy, the possibility of future pharmacological control, the possibility of serious irreversible complications from surgery, and the concern of higher surgical disability/mortality in infants. This is a reminder that early surgical treatment of childhood epilepsy is a very complex and rigorous issue that needs to be carried out cautiously and steadily, and requires evaluation and surgery in units with advanced equipment, strong technical skills, and very extensive experience, rather than blindly following the trend.