Febrile seizures (febrile convulsions) are fits that can happen when a child has a fever. They most often happen between the ages of six months and three years. This page has information on febrile seizures, including signs, causes and what to do during a seizure.
Signs of a febrile seizure
It can be frightening and distressing to see your child having a seizure, particularly if it's their first one.
The fits are usually harmless. Almost all children make a complete recovery afterwards.
As a precaution, you may still need to take your child to the nearest hospital or dial 999 for an ambulance - see what to do during a seizure below.
A febrile seizure usually lasts for less than five minutes. If your child is having a febrile seizure, they will usually:
- become stiff and their arms and legs may begin to twitch
- lose consciousness and may wet or soil themselves
They may also vomit and foam at the mouth. Their eyes may also roll back.
After the seizure, your child may be sleepy for up to an hour afterwards. A straightforward febrile seizure like this will usually only happen once during your child's illness.
Occasionally, febrile seizures can last longer than 15 minutes. Symptoms may only affect one area of your child's body.
These are known as complex febrile seizures. The seizure sometimes happens again within 24 hours or during the period your child is ill.
What to do during a febrile seizure
If your child is having a febrile seizure you can protect them from hurting themselves by:
- cushioning their head with your hands or soft material
- removing harmful objects from nearby, or if this is not possible, moving them away from immediate danger
- not restraining them or putting anything in their mouth, (this could cause injury or choking)
- staying with them
- trying to make a note of how long the seizure lasts
When the seizure stops, check their airway and place them in the recovery position.
Take your child to the nearest emergency department or dial 999 for an ambulance if:
- your child is having a fit for the first time
- the seizure lasts longer than five minutes and shows no signs of stopping
- you think the seizure is being caused by another serious illness – for example, meningitis
- your child is having breathing difficulties
While it's unlikely that there's anything seriously wrong, it's important to get your child checked.
You should also contact your GP or GP out of hours service if your child shows signs and symptoms of dehydration. Dehydration is a lack of fluid in the body.
- a dry mouth
- sunken eyes
- a lack of tears when crying
- a sunken fontanelle – the soft spot usually found at the top of a young child's head
Seeing a doctor
Febrile seizures can often be diagnosed from a description of what happened. It's unlikely a doctor will see the seizure, so telling them the following information can help:
- how long the seizure lasted
- what happened – such as body stiffening, twitching of the face, arms and legs, staring, and loss of consciousness
- whether your child recovered within one hour
- whether they've had a seizure before
Further tests, such as a blood or urine (pee) sample, may be needed if the cause of your child's illness isn't clear.
Further testing and observation in hospital is also usually recommended if your child's symptoms are unusual or they're having complex febrile seizures. This is particularly so if they're younger than 18 months old.
The tests that may be recommended include:
- an electroencephalogram (EEG) – this measures your child's electrical brain activity by placing electrodes on their scalp; unusual patterns of brain activity can sometimes suggest epilepsy
- a lumbar puncture – where a small sample of cerebrospinal fluid (CSF) is removed for testing; CSF is a clear fluid that surrounds and protects the brain and spinal cord
A lumbar puncture can be used to find out whether your child has an infection of the brain or nervous system.
Causes of febrile seizures
The cause of febrile seizures is unknown. They're linked to the start of a fever, a high temperature of 38C (100.4F) or above.
There may also be a genetic link to febrile seizures. The chances of having a seizure are increased if a close family member has a history of them.
In most cases, the high temperature is caused by an infection. Common examples are:
In rare cases, febrile seizures can occur after a child has a vaccination.
Recurring febrile seizures
About a third of children who have had a febrile seizure will have another one during a later infection. This often happens within a year of the first one.
This is more likely if:
- the first febrile seizure happened before your child was 18 months old
- there's a history of seizures or epilepsy in your family
- before having their first seizure, your child had a fever that lasted less than an hour or their temperature was under 40C (104F)
- your child previously had a complex febrile seizure (more than one seizure during their illness)
- your child attends a day care nursery – this increases their chances of developing common childhood infections, such as the flu or chickenpox
It's not recommended your child is given a prescription of regular medicines to prevent further febrile seizures.
There may be exceptional circumstances where medication to prevent recurrent febrile seizures is recommended. Your GP, or a specialist, will offer advice on this, if this is necessary.
Febrile seizures and epilepsy
Many parents worry that if their child has one or more febrile seizures, they'll develop epilepsy when they get older.
Epilepsy is a condition where a person has repeated seizures without fever.
While it's true that children who have a history of febrile seizures have an increased risk of developing epilepsy, it should be stressed that the risk is still small.
If you have concerns, your GP will be able to give you more information.
More useful links
The information on this page has been adapted from original content from the NHS website.
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