Febrile convulsions

Febrile convulsions are a type of fit (seizure) that can happen when a child, usually between the ages of six months and five years, has a high temperature. One in 50 children will have had a febrile convulsion by the time they are five years old. Therefore it is a very common illness, which children usually outgrow without any lasting effects.

What causes febrile convulsions?

Febrile convulsions can occur when children develop a high temperature of 38°C or more. We still do not know the reason why febrile convulsions happen, but we do know that they are more common if someone else in the family has had them. The high temperature is usually due to common viruses which cause ear, throat or chest infections. It can also be due to bacterial infections, such as urine infections.

What are the signs and symptoms of febrile convulsions?

A febrile convulsion can be very frightening for parents and/or caregivers to watch. However they are not harmful to your child and do not cause brain damage. A febrile convulsion looks like an epileptic seizure (fit). The child will suddenly become stiff and lose consciousness. Both arms and legs may start jerking or twitching, their eyes may roll back and they may wet or soil themselves. After a convulsion it is normal for children to sleep for a short period of time. 

Febrile convulsions are described as ‘simple’ or ‘complex’. A ‘simple’ convulsion lasts less than 15 minutes and does not happen again during the same illness. A ‘complex’ convulsion lasts longer than 15 minutes, affects only one side or part of the body and/or recurs within 24 hours or during the same illness.

How are febrile convulsions diagnosed?

A febrile convulsion is diagnosed by taking a full medical history from the child’s parents and/or caregivers. If someone else was looking after the child at the time of the convulsion, it is important that they are available to give a description to the medical team about what happened. A physical examination will then be carried out. This will involve measuring the child’s temperature, pulse, heart rate, breathing rate, sugar level and blood pressure. 

The doctor will listen to the child’s heart and lungs, feel their tummy and assess their level of alertness. The doctor may ask for a blood or urine sample to help identify the source of infection. If there are concerns that the fever may have been caused by a serious bacterial infection such as meningitis, a lumbar puncture and additional tests may be performed. 

If the febrile convulsion is categorised as ‘complex’ or the child shows symptoms or signs that are not typically seen in children with febrile convulsions, the doctor may request additional tests such as an electroencephalogram (EEG) to look at brainwave activity.

What should I do when a child is having a febrile convulsion?

When a child is having a febrile convulsion, it is important to put them in a safe position and stay with them while the convulsion is happening. The safest position is the recovery position, on their side with their head tilted backwards. Do not put anything in their mouth – this is more dangerous than the risk that they bite their tongue. 

If it is the child’s first febrile convulsion, they should be reviewed by a doctor even if the convulsion was brief, to confirm the diagnosis and ensure the child is well. If the child has had febrile convulsions before, you may not need to take them to hospital if they recover quickly and are well. However, if the convulsion lasts longer than five minutes or if the child does not recover quickly – call 999.

Can febrile convulsions be prevented?

Unfortunately we have not found any way to prevent febrile convulsions from occurring. However, if your child is feeling unwell, you could give them a dose of paracetamol according to the instructions on the bottle. It will help them feel better and may reduce their temperature, but does not prevent a febrile convulsion occurring. It is not advised to cool your child down using cold water, fans or by removing clothing as this could cause them to develop a chill.

Can a child have more than one febrile convulsion?

Yes, around one third of children will go one to develop another febrile convulsion during their childhood and some children may have several febrile convulsions. While they are worrying for parents it is important to remember that they do not cause any lasting effects in most cases. Only a small number of children go on to develop epilepsy – this is more likely if the child has a ‘complex’ convulsion.

Compiled by: 
The General Paediatrics team in collaboration with the Child and Family Information Group
Last review date: 
January 2014
Ref: 
2013F1622