Febrile Seizures: A-to-Z Guide from Diagnosis to Treatment to Prevention

Introduction to febrile seizures:

The first febrile seizure is usually 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 febrile seizures cause death, brain damage, epilepsy, mental retardation, a decrease in IQ, or learning difficulties.

In fact, some evidence suggests that children who have had febrile seizures end up brighter than their peers, on average!

What are febrile seizures?

Some children have seizures or convulsions when they have fevers.

Febrile seizures are brought on by the sudden stimulation of many brain cells at once. Experts argue over whether febrile seizures are triggered by the height of the fever or by the rate of rise. I suspect that both play a role. Most febrile seizures 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.

Who gets febrile seizures?

Febrile seizures occur in 3 to 5 percent of otherwise healthy children between the ages of 6 months and 5 years. Toddlers are the most commonly affected. Most febrile seizures are triggered by a fever over 103 F.

Sometimes febrile seizures run in families.

Although febrile seizures are common, many parents have never seen one until it happens to their child.

Most febrile seizures are brought on by fevers arising from viral upper respiratory infections, ear infections, or roseola. Meningitis causes less than 0.1 percent 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 drops.

What are the symptoms?

A febrile seizure may be as mild as rolling of the eyes or stiffening of the limbs. Quite often a fever triggers a full-blown convulsion that involves the whole body.

These seizures may begin with the sudden sustained contraction of muscles on both sides of a child’s body — usually the muscles of the face, trunk, arms, and legs. A haunting, involuntary cry or moan often emerges from the child, from the force of the muscle contraction. The contraction continues for seemingly endless seconds, or tens of seconds. The child will fall, if standing, and may pass urine. He may vomit. He may bite his tongue. The child will not be breathing, and may begin to turn blue. Finally, the sustained contraction is broken by repeated brief moments of relaxation — the child’s body begins to jerk rhythmically. The child is unresponsive to the parent’s screams.

Are they contagious?

Febrile seizures are not contagious, although the infections causing the high fevers are often contagious.

How long do febrile seizures last?

A simple febrile seizure stops by itself within a few seconds to 10 minutes, sometimes 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 one third of the children who have had a febrile seizure will have another one with a subsequent fever (about 2/3 won’t). Of those who do, about half will have a third seizure. Few have more than three.

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.

Most children outgrow febrile seizures by age 5.

A small number of children who have had a febrile seizure do go on to develop epilepsy, but not because of the febrile seizures. Children who would develop epilepsy anyway will sometimes have their first seizures during fevers. This is because fever is one of the triggers that makes a seizure more likely in a child who is already prone to epilepsy.

These are usually prolonged, complex seizures. Previous neurologic problems and a family history of epilepsy also make future epilepsy more common. About 2 percent of these high-risk children will develop epilepsy compared to about 1 percent in the general population. The number of febrile seizures has no correlation with future epilepsy.

How are they diagnosed?

The febrile seizure is diagnosed by observation, history, and physical exam. Sometimes additional tests are necessary to determine the underlying cause of the fever.
EEGs and brain imaging are usually not needed following a simple febrile seizure.

How are they treated?

During the seizure, leave your child on the floor. You may want to slide a blanket under him if the floor is hard. Move him only if he is in a dangerous location. Loosen any tight clothing, especially around the neck. If possible, open or remove clothes from the waist up. If he vomits, or if saliva and mucus build up in the mouth, turn him on his side or stomach. Don’t try to restrain your child or try to stop the seizure movements. Don’t try to force anything into his mouth to prevent him from biting his tongue, as this increases the risk of injury.

Focus your attention on bringing the fever down. Inserting rectal acetaminophen (Tylenol) is a great first step — if you happen to have some. Don’t try to give him anything by mouth. Apply cool washcloths to the forehead and neck. Sponge the rest of his body with lukewarm (not cold) water. Cold water or alcohol may make the fever worse.

After the seizure is over and your child is awake, give him the normal dose of ibuprofen (Motrin or Advil) or acetaminophen (Tylenol).

Children should see a doctor as soon as possible after their first febrile seizure. If the seizure ends quickly, drive him to an emergency room when it is over. If the seizure is lasting several minutes, call 911 to have an ambulance bring him to the hospital.

After the seizure, the most important step is to identify the cause of the fever.

How can febrile seizures be prevented?

To prevent future febrile seizures, give acetaminophen (Tylenol) and/or ibuprofen (Motrin or Advil) at the first sign of a fever. (You may want to keep acetaminophen suppositories on hand). Then sponge your child with lukewarm water. Give him cool liquids to drink — both to lower the temperature and to keep him well hydrated.

Because febrile seizures can occur as the first sign of illness, prevention is often not possible. Neither an initial nor a recurrent febrile seizure suggests that your child is not being properly cared for.

Related concepts:

Febrile convulsions