Seizures in children have many causes. There is an important difference between something that causes seizures, such as a high fever in a young child, and something that causes epilepsy, such as a severe head injury.
Common causes of childhood seizures or epilepsy include:
Less common causes of childhood epilepsy include:
Extensive and careful studies have not found any evidence that immunizations cause epilepsy. However, a seizure may occur within several days of an immunization, especially if it is followed by a fever. In such cases, the child probably had an innocent febrile seizure. When the child receives subsequent immunizations, the parents should ask the doctor about using acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) before a fever develops. Children who have a single seizure following an immunization can usually receive further immunizations.
The outlook for seizures only partially depends on their cause. For example, two children may be infected with the same bacteria and both have meningitis, an infection of the membranes covering the brain and spinal cord. One child is left with severe epilepsy, but the other child develops easily controlled seizures. How can the different outcomes be explained? The bacterial infection in the first child may have been more widespread, involving sensitive areas of the brain, or the effects of the bacteria could have caused a small stroke, which then caused seizures. Or perhaps the first child had a genetic (hereditary) tendency to have seizures, and the infection brought this trait to the surface.
It remains uncertain why some children have seizures after incidents such as moderate head trauma while most others do not. “Seizure threshold” refers to the conditions necessary for the production of a seizure. In animals, the seizure threshold can be precisely defined by observing their response to certain chemicals or electrical stimulation. In human beings, the term “seizure threshold” is used in a more abstract sense. In persons who have a tendency to have seizures, the threshold is lower than in people who have a greater resistance, or higher threshold, against seizures. Genetic, hormonal, sleep, and other factors can influence an individual’s seizure threshold.