The epidemiology of seizure disorders in infancy and childhood: definitions and classifications.

Seizures are one of the most common neurological symptoms that occur in infancy and childhood. They represent many different disorders with many different causes. Neonatal seizures occur in ~1.5% of neonates, febrile seizures in 2-4% of young children, and epilepsy in up to 1% of children and adolescents. Seizures provoked by other acute insults such as head trauma also occur although their precise frequency in children is hard to estimate. Ultimately, seizures are symptoms of various neurological insults and conditions. Although neonatal seizures, febrile seizures, and epilepsy overlap to a degree in that children with neonatal or febrile seizures are at increased risk of epilepsy, these different disorders have somewhat different risk factors and their own epidemiology. Furthermore, to the extent that environmental (e.g., infections, malnutrition) and medical system factors (vaccinations, prenatal care) and population genetics play roles, very different risks and patterns are seen in different areas of the world. Within each of these sets of disorders, designated as neonatal or febrile seizures and epilepsy, there are many highly specific conditions that, especially in the case of epilepsy, may have considerable implications for treatment and prognosis and consequently may require care from a specialist.