Febrile seizures

Definition

A febrile seizure is a convulsion in a child triggered by a fever. Such convulsions occur without any underlying brain or spinal cord infection or other neurologic cause.

Alternative Names

Causes

About 3-5% of otherwise healthy children between the ages of 9 months and 5 years will have a seizure caused by a fever. Toddlers are most commonly affected. There is a tendency for febrile seizures to run in families. Most occur well within the first 24 hours of an illness, not necessarily when the fever is highest. The seizure is often the first sign of a fever.

The first febrile seizure is one of life's most frightening moments for parents. Most parents are afraid that their child will die or have brain damage. Thankfully, simple febrile seizures are harmless. There is no evidence that simple febrile seizures cause death, brain damage, epilepsy, mental retardation, a decrease in IQ, or learning difficulties.

Most febrile seizures are triggered by fevers from viral upper respiratory infections, ear infections, or roseola. Meningitis causes less than 0.1% of febrile seizures but should ALWAYS be considered, especially in children less than one year old or those who still look ill when the fever comes down.

A simple febrile seizure stops by itself within a few seconds to 10 minutes, usually followed by a brief period of drowsiness or confusion. Anticonvulsant medicines are generally not needed.

A complex febrile seizure is one that lasts longer than 15 minutes, occurs in an isolated part of the body, or recurs during the same illness.

About a third of children who have had a febrile seizure will have another one with a subsequent fever. Of those who do, about half will have a third seizure. Few children have more than three febrile seizures in their lifetime.

If there is a family history, if the first seizure happened before 12 months of age, or if the seizure happened with a fever below 102, a child is more likely to fall in the group that has more than one febrile seizure.

References

Leung AK, Robson WL. Febrile seizures. J Pediatr Health Care. 2007 Jul-Aug;21(4):250-5.

Warren CR. Evaluation and management of febrile seizures in the out-of-hospital and emergency department settings. Ann Emerg Med. 2003; 41(2): 215-222.

Jankowiak J. Seizures in children with fever: Generally good outcome. Neurology. 2003; 60(2): E1-2.