Febrile seizures are seizures triggered by a fever.
Febrile seizures occur in about 2 to 5% of children younger than 6 years but most often occur in children aged 6 months to 3 years. A seizure that occurs in a child who has a fever and is 6 years old or older is not considered a febrile seizure.
Febrile seizures may run in families.
Most febrile seizures last much less than 15 minutes, and about two thirds of children who have a febrile seizure never have another one.
Febrile seizures may be simple or complex.
Simple: The entire body shakes (called a generalized seizure) for less than 15 minutes. Over 90% of febrile seizures are simple.
Complex: The entire body shakes for 15 minutes or more (constantly or with pauses), only one side of the body shakes (called a partial seizure), or seizures occur at least twice within 24 hours. Children who have complex febrile seizures are slightly more likely to develop a seizure disorder later during childhood.
Febrile seizures usually result from the fever itself. Most often, the fever is caused by an otherwise minor infection such as a viral respiratory infection or an ear infection. In such cases, the infection and the seizure are harmless. However, sometimes life-threatening brain infections, such as meningitis or encephalitis, also cause seizures, as well as fever.