Febrile convulsions are a type of seizure that occurs in children with a high fever. They are not caused by epilepsy or other underlying neurological pathology, such as meningitis or tumours. By definition, febrile convulsions occur only in children between the ages of 6 months and 5 years.
Simple Febrile Convulsions
Simple febrile convulsions are generalised, tonic clonic seizures. They last less than 15 minutes and only occur once during a single febrile illness.
Complex Febrile Convulsions
Febrile convulsions can be described as complex when they consist of partial or focal seizures, last more than 15 minutes or occur multiple times during the same febrile illness.
In order the make a diagnosis of a febrile convulsion, other neurological pathology must be excluded. The differential diagnoses of a febrile convulsion are:
- Meningitis, encephalitis or another neurological infection such as cerebral malaria
- Intracranial space occupying lesions, for example brain tumours or intracranial haemorrhage
- Syncopal episode
- Electrolyte abnormalities
- Trauma (always think about non accidental injury)
A typical presentation is a child around 18 months of age presenting with a 2 – 5 minute tonic clonic seizure during a high fever. The fever is usually caused by an underlying viral illness or bacterial infection such as tonsillitis. Once a diagnosis of a febrile convulsion has been made, look for the underlying source of infection.
In the febrile child the first stage is to identify and manage the underlying source of infection and control the fever with simple analgesia such as paracetamol and ibuprofen. Simple febrile convulsions do not require further investigations and parents can be reassured and educated about the condition. Complex febrile convulsions may need further investigation.
Give parents advice on managing a seizure if a further episode occurs:
- Stay with the child
- Put the child in a safe place, for example on a carpeted floor with a pillow under their head
- Place them in the recovery position and away from potential sources of injury
- Don’t put anything in their mouth
- Call an ambulance if the seizure lasts more than 5 minutes
The first seizure should always result in a trip to hospital for assessment, however if parents are confident in subsequent events and can safely manage the child at home then they can visit their GP at the next available opportunity.
Febrile convulsions do not typically cause any lasting damage. One in three will have another febrile convulsion. The risk of developing epilepsy is:
- 1.8% for the general population
- 2-7.5% after a simple febrile convulsion
- 10-20% after a complex febrile convulsion
Last updated January 2020