Febrile and other occasional seizures

Seizures with fever that result from encephalitis or meningitis usually occur late in the course of febrile illness, and are focal and prolonged. Febrile seizures are by far the most common affecting 5% of the population, followed by posttraumatic seizures and those observed in the setting of a toxic, infectious, or metabolic encephalopathy. This chapter reviews the clinical presentation of the three most common forms, due to fever, trauma, and intoxication. Febrile seizures carry no cognitive or mortality risk. Recurrence risk is increased by young age, namely before 1 year of age. Febrile seizures that persist after the age of 6 years are usually part of the syndrome of Generalized epilepsy febrile seizures plus. These febrile seizures have a strong link with epilepsy since non-febrile seizures may occur later in the same patient and in other members of the same family with an autosomal dominant transmission. Complex febrile seizures, i.e., with focal or prolonged manifestations or followed by focal defect, are related to later mesial temporal epilepsy with hippocampal sclerosis; risk factors are seizure duration and brain malformation. Prophylactic treatment is usually not required in febrile seizures. Early onset of complex seizures is the main indication for AED prophylaxis. Early posttraumatic seizures, i.e., within the first week, are often focal and indicate brain trauma: contusion, hematoma, 24 hours amnesia, and depressed skull fracture are major factors of posttraumatic epilepsy. Prophylaxis with antiepileptic drugs is not effective. Various psychotropic drugs, including antiepileptics, may cause seizures.