A febrile seizure occurs when a child has a high fever, most commonly above 38.3°C (101°F), and usually on the first day of a rapid rise in body temperature. A febrile seizure is usually seen in children between 6 months and 3 years of age, although they can occur in children to 5 years of age.

There are 2 types of febrile seizures: simple and complex.

Simple febrile seizures are more common and relatively harmless. They usually last less than 15 minutes and have no after-effects. A neurological examination following a simple seizure will yield no abnormalities.

Complex febrile seizures may be more threatening: they can occur at body temperatures lower than 38.3°C and can last longer than 15 minutes. Only 1 side of the body is affected during a complex febrile seizure and neurological reports may indicate abnormalities.

In both cases, febrile seizures pose no threat of mental retardation, cerebral palsy, learning disabilities, or death. The incidence of febrile seizures does not indicate a possibility of developing epilepsy: less than 2% of children who experience febrile seizures will develop an epilepsy later in life. Febrile seizures are classed as incidents rather than as a condition.

Overall, the incidence of febrile seizures is higher in males than in females.

There are a number of possible causes of febrile seizures. A fundamental cause for all febrile seizures is a vulnerability of the brain to an oncoming seizure. Children have a higher susceptibility to seizure activity in the brain — a lower seizure threshold — because of their age and the immaturity of their body’s immune system. Complicated by a rapidly rising fever and possibly the general condition of health, a febrile seizure may occur. Several other factors may increase the risk of seizure: a family history of seizures, chronic maternal ill health, parental fertility problems, breech birth, Caesarean birth, small birth weight, developmental delay, and cerebral problems may increase the incidence of febrile seizures. Smoking and drug intake (including anti-epileptic drugs) during pregnancy can further increase the risk.

Febrile seizures will be experienced by only 3-4% of children and only with a fever. With no family history of seizures, chances are very low for your child to have a febrile seizure. Certain precautions, including the use of medication, will reduce this chance.

Reducing the child’s body temperature will lower the seizure risk. [To do this, cover the child’s exposed body with wet (not ice cold) cloths: evaporating water lowers temperature. Fanning will speed up the cooling process. After drying the child’s body, an analgesic is often prescribed to help stabilize the child’s body temperature. Such drugs should be kept to the minimum prescribed by your physician.]

Medications specific to febrile seizures, such as phenobarbital, offer another option. Phenobarbital is the most effective medication to prevent febrile seizures. Remember that it takes several days to accumulate an effective level of the drug in the blood and in the brain. Taking phenobarbital daily to maintain a specific amount in the blood may reduce the occurrence of febrile seizures. Because phenobarbital may cause hyperactivity, behavioral problems, sleep disturbances, hindered development of intelligence, and learning disabilities, it is usually prescribed only after many febrile seizures have occurred.

Although a seizure can be terrifying to a parent, stay calm and try to accurately assess the situation. A febrile seizure is usually mild and brief, often manifesting no more than a slight slumping and loss of consciousness, or a rolling of the eyes back in the head. Sometimes there may be convulsive stiffening and jerking, but there is no need to panic.

Protect the child from sharp, hot, or otherwise dangerous objects. Loosen tight clothing. Do not put anything in the child’s mouth. Do not restrict his/her movements. Roll the child on his/her side and try to keep everyone relaxed.

A febrile seizure produces no lasting effects. Only 25-30% of children who experience one will ever have another. Only when a seizure occurs within the child’s first year AND there is a family history of febrile seizures or epilepsy AND if it was a complex seizure will the chances of another incident increase to 80% or above. Otherwise, the chances of another incident are reduced to as low as 10%. Febrile seizures are rare; recurrence even rarer.

Febrile seizures have no lasting effects and children outgrow them after 5 years of age. Febrile seizures do not indicate the development of epilepsy.