A febrile seizure is a convulsion that occurs in some children with a high temperature (fever). The vast majority of febrile seizures are not serious. Most occur with common illnesses such as ear infections and colds. Full recovery with no permanent damage is usual. The main treatment is aimed at the illness that caused the fever.
What causes a febrile seizure and who has them?
A febrile seizure is sometimes called a febrile convulsion. Any illness that causes a high temperature (fever) can cause a febrile seizure. Most occur with common illnesses such as ear infections, coughs, colds, flu and other viral infections. Serious infections such as pneumonia, kidney infections, meningitis, etc are much less common causes.
About 5 in 100 children have a febrile seizure sometime before their 6th birthday. They most commonly occur between the ages of 18 months and 3 years. They are rare in children aged under 3 months and over the age of 6 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 out of 20 cases
Febrile seizures most often occur early in the illness when the child's temperature is starting to rise.
The child may look hot and flushed and their eyes may appear to roll backwards. They may appear dazed. The body may go stiff, then generally twitch or shake (convulse). The child becomes unconscious and unresponsive. Some children may wet themselves during the febrile seizure.
It does not usually last long. It may only be a few seconds and it is unusual for it to last more than five minutes. The child may be sleepy for some minutes afterwards.
Within an hour or so the child will usually appear a lot better. This happens when their temperature has come down. Another feature of a simple febrile seizure is that it does not recur within the same febrile illness.
Complex febrile seizure - occurs in about 4 out of 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 focal (used to be called partial) 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 out of 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.
- Lay the child on their side with their head tilted back slightly (the recovery position). This will make sure the child doesn't swallow any sick (vomit) and helps to keep their airway clear.
- 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). When the child has recovered enough to swallow, give a drink and some paracetamol or ibuprofen. However, there is no evidence that lowering the child's temperature will prevent further seizures.
What should happen after immediate first aid?
Call an ambulance if a seizure lasts more than five minutes (this includes small twitching movements, even if large jerking movements have stopped).
You should also contact a doctor urgently, or ring for an ambulance if:
- The child does not improve quickly once a short seizure is over.
- 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 are worried the child may have a serious illness as the cause of the high temperature (fever). See separate 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.
In all cases, the child should be seen by a doctor as soon as possible after a seizure. This is to check the child, diagnose the underlying illness and provide any treatment if required.
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 back passage (rectum) or a medicine called midazolam into the side of the mouth. These medicines 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 in itself is not usually dangerous. Full recovery is usual. Most illnesses which cause high temperature (fever) and febrile convulsions are the common coughs, colds and viral infections which are not usually serious.
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.
However a fever may make your child feel uncomfortable and irritable. The following are things that you can do that may bring the temperature down and make your child feel more comfortable:
- You can give paracetamol to lower a temperature. You can buy paracetamol in liquid form, or melt-in-the-mouth tablets, for children. It comes in various brand names. The dose for each age is given with the medicine packet. Note: paracetamol does not treat the cause of the fever. It merely helps to ease discomfort. You do not need to use paracetamol if your child is comfortable and not distressed by the fever, aches or pains.
- Keep the child very lightly dressed, or take all their clothes off if the room is warm.
- Give lots of cool drinks.
Will it happen again?
Only one seizure occurs in most cases. However, a second seizure may occur during a future feverish illness. 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 3 years old, the chance of having more than one seizure becomes much less likely.
Does a febrile seizure cause any permanent damage?
Full recovery is usual with no after-effects. One study that followed children who 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 high temperature (fever). There is a separate set of leaflets that explain epilepsy in more detail.
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. Immunisations are very important for your child's health. A febrile seizure is extremely unlikely to happen again after a future immunisation.
Dr Tim Kenny
Dr Colin Tidy
Dr Adrian Bonsall