Febrile seizures (febrile fits, fever fits, febrile convulsions) are a common childhood condition, where a child may experience a seizure after developing a fever (100.4 F or higher).
In easy terms, a seizure is a disruption in the normal electrical activity of the brain. Under normal conditions, signals in the brain and elsewhere in the nervous system are carried through small electrical signals, called impulses. A seizure occurs when this normal pattern is interrupted by erratic signals. This causes the body to act abnormally, which leads to erratic physical movement and behavior.
Watching your child have a seizure is one of the most distressing events a parent can experience. Although traumatic to watch, febrile seizures are relatively harmless, as opposed to other causes of seizures such as epilepsy.
Normally, the type of seizure experienced by children suffering a febrile seizure is ‘tonic clonic’, which describes loss of consciousness in the patient, along with stiffening of the body and twitching of arms and legs. Children may also wet themselves and salivate excessively at the mouth.
Febrile seizures can be of two types:
Simple seizures are experienced by 9/10 patients. The patient may experience loss of consciousness, but the overall symptoms do not last more than 15 minutes, and the patient experiences only one episode in 24 hours during that course of illness.
A complex febrile seizure is, as the name suggests, more complex. The patient may experience the episode for longer than 15 minutes, may not recover fully from the seizure within an hour, he/she may experience only a partial seizure (in one part of the body as opposed to the whole body – also known as a focal seizure), and may have more than 1 episode in 24 hours.
Febrile seizures are relatively common, with 1/20 children experiencing at least 1 seizure in their childhood. The commonest age for febrile seizures is between the ages of 6 months to 3 years, with the average age being 18 months. Apart from family history, no other causes of febrile seizures have yet been identified.
Many parents worry that if their child has one or more febrile seizures, they will develop epilepsy when they get older. Epilepsy is a condition where a person has repeated seizures (fits) without fever.
While it is true that children who have a history of febrile seizures have an increased risk of developing epilepsy, it should be stressed that the risk increase is still quite small.
For example, it is estimated that children with a history of simple febrile seizures have a 1 in 50 chance of developing epilepsy in later life. Children with a history of complex febrile seizures have a 1 in 20 chance of developing epilepsy in later life.
The three commonest causes of febrile convulsions are :
influenza (common cold)
The first two are viral infections while the third is usually bacterial.
There is a slightly increased risk (1 in 4000 patients) of a child developing febrile seizures after an MMR infection.
SIGNS AND SYMPTOMS
Febrile seizures often occur during the first day of a fever, which is defined as a high temperature of 38ºC (100.4ºF) or above. There appears to be no direct connection between the extent of your child’s fever and the start of a seizure. Seizures can develop even after a mild temperature, and may not develop at all with an extremely high temperature.
Simple febrile seizures can sometimes occur at the time of a rapid rise in temperature. In these cases, it is common to only realise that your child is ill when they have the seizure.
Alternatively, seizures can occur as your child’s temperature drops from a previously high level.
During simple febrile seizures, your child’s body will become stiff and their arms and legs will begin to twitch. They will lose consciousness and they may wet or soil themselves. Your child may also vomit and foam at the mouth. The seizure usually lasts for less than five minutes.
Following a febrile seizure, your child may be sleepy for up to an hour afterwards.
If your child is having a febrile seizure, immediately place them in recovery position ( on the left side, with legs brought up to the abdomen). This stops them from ingesting any vomit, and eases breathing by preventing the tongue from falling back in the mouth.
Stay with them during the course of the seizure so you can document the time of onset and ending of the seizure. If the seizures last longer than 5 minutes, CALL AN AMBULANCE.
DO NOT PUT any object or your hand into the mouth of the person experiencing the seizure.
If the seizure ends within 5 minutes, remove any extra layers of clothing on the patient and make them comfortable.
If they are able to, give them fever-lowering medication such as paracetamol or ibuprofen.
It is not recommended that your child is given a prescription of regular medicines to prevent further febrile seizures. This is because the adverse side effects associated with many medicines outweigh any risks that are associated with the seizures themselves. Regular medicine is not likely to prevent recurrence of further febrile seizures.
COMPLICATIONS OF FEBRILE SEIZURES
There is no evidence to suggest that febrile seizures cause any lasting damage, such as brain damage or learning difficulties. However, a very small number of children who have febrile seizures go on to have epilepsy.
The risk of a child developing epilepsy after a simple febrile seizure is 1.5%. However, the risk rises to 2.5% if the child was under 12 months old when they had their first seizure (in those who had multiple simple seizures).
The risk of developing epilepsy increases with each of the following factors:
- neurological abnormalities, or a developmental delay before the onset of febrile seizures
- a family history of epilepsy
- a brief fever (less than one hour) before the seizure
- complex seizures.