Topic Overview

A fever is a high body temperature. Average normal body temperature is 98.6°F (37°C) orally. It usually varies during the day from a low of 97.4°F (36.33°C)in the morning to a high of 99.6°F (37.56°C) in the late afternoon. Exercising, wearing too many clothes, taking a hot bath, or being out in hot weather can cause an increase in your temperature.

Fever (febrile) seizures are uncontrolled muscle spasms that can occur in children who have a rapid increase in body temperature. Sometimes you may not even know your child has a fever. Once a fever has reached a high temperature, the risk of a seizure is probably over. The rapid increase in body temperature in a short period of time is the cause of the febrile seizure.

A child having a seizure loses consciousnessand then stiffens the muscles and clenches the teeth. Jerking movements of the arms and legs may occur. The child's eyes may roll back. The child may stop breathing for a few seconds and might also vomit, urinate, or pass stools. It is important to protect the child from injury during a seizure.

Fever seizures usually last 1 to 3 minutes. After the seizure, the child may be sleepy. You can let the child sleep, but be watchful. The child also may seem confused after the seizure, but normal behavior and activity level should return within 60 minutes of the seizure.

A seizure is more likely to be a febrile seizure if:

• The seizure happened within 24 hours of the start of a fever.
• The seizure lasted less than 10 minutes.
• The seizure affected the entire body, not just one side.
• The child is between 6 months and 5 years old.
• The child does not have nervous system (neurologic) problems.
• The child has had a febrile seizure before.
• Febrile seizures can be frightening to see but usually do not cause any harm and do not cause long-term problems, such as brain damage, mental retardation, or learning problems.

Febrile seizures affect 2% to 4% of children. About 30% of children who have a febrile seizure will have another one, usually within a year of the first seizure. These seizures are not a form of epilepsy.