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SPSSC – Paediatric Presentations to the Accident and Emergency Department

 

Febrile Convulsions

 

 

Seizure: “A clinical event in which there is a sudden disturbance of neurological function in association with an abnormal or excessive neuronal discharge.” (Lissauer, 2002).

A febrile convulsion is a seizure occurring in a child aged from six months to five years, precipitated by a fever arising from infection outside the nervous system in a child who is otherwise neurologically normal. Febrile convulsions have long been recognised, but only in recent years more fully understood. Hippocrates, writing in the 4th century BC, described such a convulsion, clearly differentiating it from rigors and breath holding attacks. He noted that both generalised and partial seizures can occur, and realised that there was a strong association with age, high fever and a precipitating infection. (Great Ormond Street Hospital for Children NHS Trust).

 

Febrile convulsions are a common paediatric presentation to A&E departments, occurring in about 3% of children between the ages of six months and five years. The seizure usually occurs early on in a viral infection when the temperature is rising rapidly, and typically lasts less than five minutes. It is the abrupt rise in temperature rather than the high level that is important. The seizures are tonic or tonic-clonic, with loss of consciousness and muscular rigidity forming the tonic stage. This may be preceded by a frightened cry from the child. Cessation of respiratory movements and incontinence of urine and faeces may occur during this stage, which lasts about 30 seconds. The clonic stage that follows is characterised by repetitive movements of the limbs and face.

 

 

Management of the fitting febrile child:

Clothing should be removed and the child covered with a sheet.
The child should be placed on its side, or prone with its head to one side, since vomiting with aspiration is a hazard.
Rectal diazepam is the drug of choice, producing an effective blood concentration of anticonvulsant within ten minutes.
All children with a first febrile convulsion should be admitted to hospital to a) exclude meningitis and b) educate the parents.
A urine specimen should be taken to exclude infection, and a blood glucose level should be taken.
A lumbar puncture may be performed if the child is less than eighteen months old  shows signs of meningitis or sepsis.

 

Treatment of the febrile child:

Fever should be treated to promote the comfort of the child and to prevent dehydration. Paracetamol is the preferred anti-pyretic and fluid levels should be maintained. Ibuprofen can be given if the fever does not respond to paracetamol.
Rectal diazepam should be administered as soon as possible after the start of the convulsion, and should not be given after the convulsion has stopped.

 

 

Information should be supplied by the hospital to parents, explaining the nature of febrile convulsions, including information about the prevalence and prognosis. Parents should be instructed on the management of fever, the management of a convulsion and the administration of rectal diazepam. Finally, they should be reassured. During further febrile illnesses, parents should be advised to keep the childs temperature low, by removing warm clothing, tepid sponging and giving an antipyretic (paracetamol or ibuprofen) such as Calpol. Parents of children with an increased risk of seizure recurrence should be supplied with rectal diazepam to administer for any further seizure lasting more than five minutes. Parents should receive written as well as verbal advice on the first aid management of a further convulsion. Following convulsion, a doctor should always be consulted in order to determine that the cause is simply a viral infection, and not something more serious such as meningitis.

 

The overall risk of a further febrile convulsion is one in three, but the recurrence risk is higher if the first seizure occurs before one year of age and there is a positive family history. There is also a greater risk of recurrence if the first convulsion occurs at a relatively low body temperature, below 39°C. The chance of having another febrile convulsion in the following year is 30%. The risk of a second fit reduces every year and it becomes extremely rare after the child turns 6 years old. (NSW Health). A history of febrile convulsions in a first degree relative is associated with a recurrence risk of about 50%. If either parent suffered a febrile convulsion as a child, the risk of the child suffering one rises 10 to 20 per cent. If both parents and their child have at some point suffered a febrile convulsion, the risk of another child getting it rises 20 to 30 per cent. (Netdoctor). It is rare for any child to suffer recurrent febrile convulsions after the age of four years.

One in a thousand children may suffer a febrile convulsion after receiving the MMR vaccine. In these cases it occurs 8 to 10 days after the vaccination and is caused by the measles component of the vaccine. However, this causes only about one tenth of cases of febrile convulsion compared with measles itself. (Netdoctor). Children who are prone to febrile convulsions should follow the same programme of vaccination as all other children.

A family history of epilepsy is also associated with an increase in the risk of further febrile convulsions. It must be pointed out though that febrile convulsions are not epileptic fits. Febrile convulsions usually have a benign prognosis, but approximately 1% will go on to develop epilepsy in later life. Risk factors for the subsequent development of partial epilepsy are a prolonged seizure (longer than 30 minutes) or if seizures recur within the same illness.

 

 

References

 

Lissauer, T. & Clayden, G., Illustrated Textbook of Paediatrics, (Second Edition). Elsevier Science Ltd 2002.

 

www.NetDoctor.co.uk/diseases/facts/febrileconvulsions.htm

 

www.mhcs.health.nsw.gov.au/health-public-affairs/ mhcs/publications/6050.html -

 

www.ich.ucl.ac.uk/gosh_families/ask_dr_jane_collins/ body/febrile_convulsions.htm

 

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Last updated: November 14, 2003.