Febrile Seizures

IMPORTANT POINTS

1. Most children who have febrile seizures do very well, and the risk of epilepsy is low.

2. The earlier the age at which the first febrile convulsion occurs, the more likely are recurrences.

3. Diagnostic laboratory tests never should be routine. Neuroimaging rarely is indicated.

4. Meningitis always should be ruled out, either clinically or by lumbar puncture if indicated.

5. Treatment has not been shown to reduce the risk of later epilepsy and carries a risk of side effects.

Definition

Febrile seizures are the most common convulsive disorder in young children. As defined in a 1980 National Institutes of Health consensus conference, a febrile seizure is: “An event in infancy or early childhood, usually occurring between three months and five years of age, associated with fever but without evidence of intracranial infection or defined cause. Seizures with fever in children who have suffered a previous nonfebrile seizure are excluded. Febrile seizures are to be distinguished from epilepsy, which is characterized by recurrent nonfebrile seizures.” This definition excludes seizures that accompany neurologic illnesses, such as meningitis, encephalitis, or toxic encephalopathy. Seizures in these instances do not carry the same prognosis as febrile seizures because the underlying illness may affect the central nervous system.

Febrile seizures have been discussed in the medical literature since the time of Hippocrates, but it was not until the middle of the present century that they were recognized as a separate syndrome distinct from epilepsy. An early classification proposed by Livingston divided them into “simple febrile seizures” and“ epilepsy triggered by fever.” He included in the latter definition febrile seizures that were prolonged or focal or that occurred in a child who has a family history of epilepsy. These definitions no longer are used because it has become clear through prospective epidemiologic studies that there is not nearly as great a …