Febrile seizure

DEFINITION

A febrile seizure is a convulsion in a child that may be caused by a spike in body temperature, often from an infection. Your child’s having a febrile seizure can be alarming, and the few minutes it lasts can seem like an eternity.

Febrile seizures represent a unique response of a child’s brain to fever, usually the first day of a fever. Fortunately, they’re usually harmless and typically don’t indicate an ongoing problem. You can help by keeping your child safe during a febrile seizure and by comforting him or her afterward.

Call your doctor to have your child evaluated as soon as possible after a febrile seizure.

CAUSES

A high body temperature causes most febrile seizures.

Infection

Usually the fevers that trigger febrile seizures are caused by a viral infection, less commonly by a bacterial infection. Viral infections such as the flu and roseola, which often are accompanied by high fever, appear to be most associated with febrile seizure.

Post-immunization seizures

The risk of febrile seizures may increase after some childhood immunizations, such as the diphtheria, tetanus and pertussis or measles-mumps-rubella vaccinations. A child can develop a low-grade fever after a vaccination. The fever, not the vaccination, causes the seizure.

SYMPTOMS

Febrile seizure symptoms can range from mild — staring — to more severe shaking or tightening of the muscles.

A child having a febrile seizure may:

• Have a fever higher than 100.4 F (38.0 C)
• Lose consciousness
• Shake or jerk arms and legs

Febrile seizures are classified as simple or complex:

• Simple febrile seizures. This more common type lasts from a few seconds to 15 minutes. Simple febrile seizures do not recur within a 24-hour period and are generalized, not specific to one part of the body.
• Complex febrile seizures. This type lasts longer than 15 minutes, occurs more than once within 24 hours or is confined to one side of your child’s body.

Febrile seizures most often occur within 24 hours of the onset of a fever and can be the first sign that a child is ill.

When to see a doctor

See your child’s doctor as soon as possible after your child’s first febrile seizure, even if it lasts only a few seconds. Call an ambulance to take your child to the emergency room if the seizure lasts longer than 10 minutes or is accompanied by:

• Vomiting
• A stiff neck
• Breathing problems
• Extreme sleepiness