A Febrile convulsion is defined as a seizure in the presence of a fever. Febrile convulsions occur largely between the ages of 6 months and five years and are excluded as a diagnosis in the presence of CNS infection or electrolyte imbalance. They can occur early in a viral infection, when fever is rising fastest. Febrile convulsions are twice as common in males than in females. Between 2% and 4% of European children have a febrile convulsion and the peak incidence is age 18 months.
Giving an explanation to a parent concerning a febrile convulsion is a common OSCE station, therefore this article is organised around common questions that a parent may have about their child's convulsion.
What has caused my child's febrile convulsion?
A distinct cause of febrile convulsions is not currently known, therefore the ideas, concerns and expectations of an (understandably concerned) parent should be managed appropriately with a clear explanation as to the nature of the convulsion. It should be explained that a febrile seizure is in response to a sharp rise in temperature, rather than a prolonged high temperature itself. Causes of fevers associated with febrile convulsions can include:
- Viral infections
- Otitis Media
Rarely, post-immunisation febrile convulsions have been noted, and are particularly distressing for the parent.
Will there be permanent damage to my child following their seizure?
There are two distinct categories of febrile convulsion: Simple febrile seizure: This is a seizure lasting less than 15 minutes that does not reoccur in 24 hours, and is tonic-clonic, involving the entire body. Complex febrile seizure: This is a seizure lasting longer than 15 minutes, which may occur within 24 hours, may not involve the whole body or may feature an incomplete recovery after one hour.
Simple febrile seizures, which make up the vast majority of childhood febrile convulsions, usually do not feature any lasting damage and there is a full recovery in the child in less than one hour. There is no significantly greater risk of development of epilepsy to the child than there is for the general population (around 3% compared to 1%).
Will this happen again to my child?
The risk factors for repeat seizures include:
- Younger age at first seizure
- Earlier in infection at first seizure
- Family history of repeated febrile convulsions
- Past medical history of focal neurology or developmental delay
Parents should be aware of the risk of repeat seizures. After one seizure, there is a 10% increase in risk, after two seizures, there is a 25% increase in risk, and after 3 seizures, there is a 33% increase in risk.
What should I do if my child has another seizure?
Firstly, it is important to reassure parents and offer them advice concerning the viral illness in their child (managing temperature with fluids and paracetamol etc). If the parent witnesses another febrile convulsion, it is advisable to clear the area around the child so that no injury occurs. Whilst it may initially appear useless or even cruel, it can be very helpful in the diagnostic process for the parent to film the child's seizure on their camera phone, to be later shown to their GP or hospital staff. A 'watch and wait' stance is usually advised to parents concerning the seizures, but if they are prolonged, rectal or buccal diazepam may aid in seizure cessation. If this is unsuccessful, or if the seizure lasts for longer than 5 minutes, an ambulance should be called.