Evaluation of the child who convulses with fever

Abstract

Febrile seizures result from age-dependent hyperexcitability of the brain that is induced by fever. Although there are important genetic influences that render a febrile child more likely to develop seizures, it is the fever per se that causes the seizure. Of primary importance in the diagnostic assessment of such children are efforts directed at finding the cause of the fever. Once found, the cause should be treated specifically, e.g. antibacterials for otitis media, and/or symptomatically, e.g. antipyretics for viral pharyngitis. It is essential to exclude underlying meningitis in all children with febrile seizures, either clinically or, if any doubt remains, by lumbar puncture. In as many as one child in six with meningitis, seizures are the presenting sign, and in one-third of these patients, meningeal signs and symptoms may be lacking. The great majority of such cases of meningitis are bacterial in origin, and delay in diagnosis can result in serious neurologic morbidity, and even death.In the child who convulses with fever, it is always important to consider that something in addition to the fever has caused the child to have a seizure. Infection that has gone unnoticed, such as meningitis or encephalitis, as well as a systemic illness, head trauma, intoxication, electrolyte imbalance, low blood sugar, or a phakomatoses, can cause seizures. One must also consider the possibility that the child with a febrile seizure has epilepsy, and that fever has simply triggered a seizure recurrence in a child who also experiences unprovoked seizures.Thus, based on the specifics of each case, the diagnostic evaluation of the child with a febrile seizure can be very limited or moderately comprehensive. Imaging studies are necessary only in selected cases. The electroencephalogram is of limited value. The primary concern is always the need to exclude meningitis. Therefore, a lumbar puncture should be carried out, except in those cases where the possibility of CNS infection seems truly remote.