Febrile Seizure (Febrile Convulsion)

What causes a febrile seizure and who has them?

A febrile seizure is sometimes called a febrile convulsion. Any illness that causes a fever (high temperature) can cause a febrile seizure. Most occur with common illnesses such as ear infections, coughs, colds, flu, and other virus infections. Serious infections such as pneumonia, kidney infections, meningitis, etc, are less common causes.

About 3 in 100 children have a febrile seizure sometime before their 6th birthday. They most commonly occur between the ages of 18 months and three years. They are rare in children under six months and over the age of six years.

What does a febrile seizure look like?

Febrile seizures are classified into three types:

Simple febrile seizure - the most common type, occurs in about 15 in 20 cases

The child may look hot and flushed and their eyes may appear to roll backwards. They may appear dazed and then become unconscious. The body may go stiff, then generally twitch or shake (convulse). It does not usually last long. It may only be a few seconds, and is unusual for it to last more than five minutes. The child may be sleepy for some minutes afterwards but within an hour or so the child will usually appear a lot better when their temperature has come down. Another feature of a simple febrile seizure is that it does not recur within 24 hours or within the same febrile illness.

Complex febrile seizure - occurs in about 4 in 20 cases

This is similar to a simple febrile seizure, but has one or more of the following features:

• The seizure lasts more than 15 minutes, and/or ...
• The seizure recurs within 24 hours or within the same febrile illness, and/or ...
• The child is not fully recovered within one hour. This does not mean the seizure lasts more than an hour, but that it takes more than an hour for the child to look and behave more like their normal self, and/or ...
• The seizure has 'partial or focal features'. This means that rather than a generalised twitch or shaking, only a part of the body may shake. For example, just one arm or just one leg.

Febrile status epilepticus - occurs in less than 1 in 20 cases

This means the febrile seizure lasts for longer than 30 minutes.

What first aid should I do for a febrile seizure?

• Note the time it started.
• Lie the child on their side with their head in line with the body or slightly lower (the recovery position).
• Do not put anything into their mouth or shake the child.
• When the seizure stops, try to lower the child's temperature to make them more comfortable. To do this take off their clothes (if the room is warm). Then, when they have recovered enough to swallow, give a drink and some paracetamol or ibuprofen.

What should happen after immediate first aid?

The child should be seen by a doctor as soon as possible after a seizure for a check over to rule out serious illness. However, call a doctor or ambulance urgently if:

• The child does not improve quickly once a short seizure is over.
• A seizure lasts more than five minutes (this includes small twitching movements even if large jerking movements have stopped).
• Another seizure starts soon after the first one stops.
• The child has difficulty breathing.
• The child was not fully conscious before the seizure or one hour afterwards.
• You suspect a serious illness is the cause of the fever, for example, if you suspect meningitis. See leaflet called 'Fever (High Temperature) in Children' for details of symptoms to look out for.

No treatment is usually needed for the seizure itself if it stops within a few minutes. (However, treatment may be needed for the infection causing the fever.)

Sometimes the seizure lasts longer and a doctor may give a medicine to stop it. For example, a doctor may put a medicine called diazepam into the rectum (back passage) or a medicine called midazolam into the side of mouth. These drugs are absorbed quickly, directly into the bloodstream from within the rectum or mouth, and stop a seizure. Sometimes the parents of children who are prone to recurrent febrile seizures are taught how to use one of these medicines. They are then given a supply to have in case a further febrile seizure occurs.

Is a febrile seizure dangerous?

Although alarming, a febrile seizure is not usually dangerous. Full recovery is usual. Most illnesses which cause fever and febrile convulsions are the common coughs, colds, and virus infections which are not usually serious. However, the illness that causes the fever is sometimes serious, for example, pneumonia.

Can febrile seizures be prevented?

It may seem logical that if you keep a child's temperature down during a feverish illness it may prevent a febrile seizure. However, there is little scientific evidence to prove that this is so. (It is unclear what triggers the seizure. It is possibly some body chemical that is released during certain feverish illnesses rather than the temperature itself. Most children with a high temperature do not have a seizure.) However, it is common practice to keep a child cool when they have a feverish illness. This will make them feel more comfortable. Therefore, if a child appears hot, then the following will help to reduce the temperature:

• Keep the child very lightly dressed, or take all their clothes off if the room is warm.
• Give paracetamol, (for example, Calpol, Disprol, etc), or ibuprofen.
• Give lots of cool drinks.

Will it happen again?

Only one seizure occurs in most cases. In about 3 in 10 children who have a febrile seizure, a second seizure occurs with a future feverish illness. In less than 1 in 10 children who have a febrile seizure, three or more further seizures occur during future feverish illnesses. A future febrile seizure is more likely if the first occurs in a child younger than 15 months, or if there is a family history of febrile seizures in close relatives (father, mother, sister, brother). Once the child is past three years old, the chance of a recurrence becomes much less likely.

Therefore, recurrences are not common, but it is best to be prepared. For example, practice putting your child into the recovery position.

Does a febrile seizure cause any permanent damage?

Usually not. Full recovery is usual with no after-effects. (Sometimes the infection causing the seizure causes complications, but the seizure itself does not usually cause any damage.) Rarely, a seizure which lasts 30 minutes or more may cause some injury to the brain.

One study which followed up children who had had a febrile seizure found that “children who had febrile seizures did at least as well as, if not better than, children without febrile seizures on measures of intelligence, academic achievement, behaviour, and working memory”.

Is a febrile seizure a type of epilepsy?

No. Febrile seizures and epilepsy are two different conditions.

• The cause of a febrile seizure is related to the feverish illness and is not due to epilepsy or any brain abnormality.
• Epilepsy causes seizures without a fever. There is a separate set of leaflet that explain epilepsy in more detail.

Some parents wonder that if a child has a febrile seizure whether it can lead on to developing epilepsy. About 2 in 100 children who have a febrile seizure develop epilepsy in later childhood. This is very slightly higher than the chance of epilepsy developing in children who have not had a febrile seizure. But this is probably because a small number of children are prone to develop both epilepsy and febrile seizures. So, having a febrile seizure does not cause epilepsy to develop.

Should a child who has had a febrile seizure have immunisations?

Yes. Some children develop a fever following immunisation. A very small number of children develop a febrile seizure following an immunisation. However, this is very unlikely to cause any permanent harm, or to happen again after a future immunisation.