Febrile seizures Health Article

Definition

A febrile seizure is a convulsion in a child triggered by a fever. These convulsions occur without any brain or spinal cord infection or other nervous system (neurologic) cause.

Alternative Names

Seizure - fever induced

Causes, incidence, and risk factors

About 3% - 5% of otherwise healthy children between ages 9 months and 5 years will have a seizure caused by a fever. Toddlers are most commonly affected. Febrile seizures often run in families.

Most febrile seizures occur in the first 24 hours of an illness, and not necessarily when the fever is highest. The seizure is often the first sign of a fever.

Febrile seizures are usually triggered by fevers from:

• Ear infections
• Roseola
• Upper respiratory infections caused by a virus

Meningitis causes less than 0.1% of febrile seizures but should ALWAYS be considered, especially in children less than 1 year old, or those who still look ill when the fever comes down.

A child is likely to have more than one febrile seizure if:

• There is a family history of febrile seizures
• The first seizure happened before age 12 months
• The seizure occurred with a fever below 102 degrees Fahrenheit

Symptoms

A febrile seizure may be as mild as the child's eyes rolling or limbs stiffening. Often a fever triggers a full-blown convulsion that involves the whole body.

Febrile seizures may begin with the sudden contraction of muscles on both sides of a child's body -- usually the muscles of the face, trunk, arms, and legs. The child may cry or moan from the force of the muscle contraction. The contraction continues for several seconds, or tens of seconds. The child will fall, if standing, and may pass urine.

The child may vomit or bite the tongue. Sometimes children do not breathe, and may begin to turn blue.

Finally, the contraction is broken by brief moments of relaxation. The child's body begins to jerk rhythmically. The child does not respond to the parent's voice.

A simple febrile seizure stops by itself within a few seconds to 10 minutes. It is usually followed by a brief period of drowsiness or confusion. A complex febrile seizure lasts longer than 15 minutes, is in just one part of the body, or occurs again during the same illness.

Febrile seizures are different than tremors or disorientation that can also occur with fevers. The movements are the same as in a grand mal seizure.