What is a Febrile Seizure (Convulsion)?

A seizure (convulsion, fit) occurs when the electrical activity of the brain is temporarily abnormal and as a result the body has abnormal movements or sensations. A febrile seizure (convulsion, fit) is a seizure that occurs in association with a fever.

Who gets febrile convulsions (seizures)?

Febrile convulsions are not uncommon - 3 or 4 out of every 100 children will have them. They occur between the ages of 5 months and 5 years. If there is a history of febrile convulsions in the family - say you or your partner had febrile convulsions as a child - it is likely your child will have them.

What happens in a febrile seizure (convulsion)?

The usual scenario is that your child becomes unconscious - if he is sitting or standing, he will fall to the ground - and then his body will go very stiff before he starts twitching his arms and legs. This is usually short-lived - lasting seconds to minutes - and then he is drowsy for 10 - 30 minutes. Often he will then wake up and be his normal self.

This all takes place within the context of an illness associated with fever. The most common cause of the fever is an upper respiratory tract infection.

Does a febrile convulsion (seizure) cause brain damage?

No. It is very scary to see your child have a convulsion. It is so scary to watch that many parents think their child is going to die. The good news is that febrile convulsions do not cause brain damage and children don't die. In most cases, children recover perfectly well and there are no long-term consequences.

What is a benign febrile convulsion (seizure)?

We use that term when the convulsion is a generalized convulsion associated with a febrile illness in a child between the ages of 5 months and 5 years, that lasts less than 15 minutes.
A generalized seizure is one where the child is unconscious and has stiffening of the body and then twitching (convulsing) of both arms and legs. This is what occurs in most children.

What is a complex febrile seizure (convulsion)?

This is a seizure associated with a fever that has some characteristics that mean it cannot be described as benign. For example,

• your child may have had twitching (convulsing) on one arm only, so we would call that focal
• the convulsion may have lasted more than 15 minutes
• there may have some residual neurological abnormalities afterwards - such as a temporary paralysis
• your child may be younger than 5 months or older than 5 years

Are febrile seizures (convulsions) always caused by minor infections?

Generally they are due to viral illnesses. Sometimes a child with bacterial infection, such as a urinary tract infection or pneumonia, will have a febrile convulsion. You will recognize that they have other symptoms related to those infections.

A child with meningitis (infection of the covering of the brain) might have a fever and a convulsion but we would not call this a febrile convulsion as the seizure is due to irritation of the covering of the brain caused by the meningitis.

How can I tell the difference between a febrile convulsion and a seizure due to meningitis?

Generally, your child will be seen by a doctor who will make this decision.

If your child has a fever and a seizure and is older than 18 months, there would be other signs of meningitis, such as a stiff neck.

In infants less than 18 months, it is more difficult to tell and so these children usually need a test to look for meningitis so we can be sure they don't have it - we call this test a lumbar puncture and it involves a small needle inserted into the back to get some spinal fluid - it sounds worse than it is.

Do all infants less than 18 months need a lumbar puncture when they have a febrile convulsion (seizure)?

To consider a lumbar puncture in these infants is generally the rule but there are exceptions. The usual exception is the case where by the time the baby is seen they are wide awake and playing after the seizure. This behavior would be very unlikely in a child with meningitis, so we wouldn't need to put them through the lumbar puncture.

Do children who get febrile convulsions (seizures) have epilepsy later in life?

Most children (99 out of 100) who have febrile seizures (convulsions) do not get epilepsy later in life. This is especially true is your child has no underlying neurological condition and if there is no history of epilepsy in your family.

Will my child have another febrile convulsion (seizure)?

If your child has already had one febrile seizure, they could have another. The risk of a second convulsion is said to be 30% (so 30 out of 100 children who have had one febrile convulsion will have a second one). So most children do not have further convulsions.