A febrile seizure is one that occurs when a child has a fever. A common question I get from parents when a child is ill is how high is too high for a fever. Most parents worry about fever because of the risk of the fever triggering a febrile seizure in their child. About 1 in 25 children between ages 6 months and 5 years of age will have at least one febrile seizure. One third of children who have one febrile seizure will have additional febrile seizures.
The thought in the past about febrile seizures was that it was caused by high fever. However, recently it has been discussed that it is not the height of the fever. It is actually how fast the fever rises or drops that can trigger a seizure in a child.
These seizures are generalized seizures that cause arm and leg jerking, in addition to eyes rolling up or to the side. A simple febrile seizure generally occurs during the first hours of a fever and lasts less than 15 minutes. Usually, only one seizure occurs during a 24 hour period, however, some children may have seizures during fever that last longer or may have multiple seizures during the 24 hours. This is classified as a complex febrile seizure.
If your child has a seizure, you should lay them on their side. You should take off your child’s clothing and use lukewarm rags to cool them down. Do not place any items in the child’s mouth. If your child turns blue, you should call 911. After the seizure, most children will sleep for a period of time. If your child has a seizure, you should contact your pediatrician or take your child to be evaluated to find the cause of the fever.
Children with febrile seizures do not usually need any anti-epileptic medicines unless they are found to have other underlying epilepsy. Most children do not need additional work-up after a first simple febrile seizure. If your child has a complex seizure or has seizure without fever, your pediatrician may refer you to a neurologist or schedule an EEG to rule out other causes of seizure. Children usually outgrow febrile seizures by age 5.
Some children only ever experience one febrile seizure. The risk of recurrence goes up if your child is under 1 when they experience their first seizure. Other risk factors for recurrence include seizure at low temperature and family history of febrile seizures.
Only about 1% of children who have febrile seizures will go on to have other types of seizure or epilepsy. This number increases to 2-5% in children with complex febrile seizures and children with other underlying neurological disorders.
So, how do we prevent febrile seizures? There have been no studies that show that anti-fever medications help prevent febrile seizures, although we do recommend aggressive fever treatment in those children who have experienced them in the past. Children who have frequent febrile seizures can use rectal diazepam when they have fever in order to attempt to prevent seizure. The most effective prevention is to prevent illness which triggers fever. This can be difficult since we cannot keep children in all the time.
Febrile seizures are scary for the parents and witness. However, they do not cause brain damage or long-term aftereffects. If your child has a seizure, use supportive care to get through the seizure and then have them evaluated.