febrile fits

Clinical Practice Guidelines Management of Febrile Fits

Definations:
Febrile fits (F.C.) are defined as fits occurring in association with fever in children between 3 months and 6 years of age, in whom there is no evidence of intracranial pathology or metabolic derangement that could be the cause of the fit. Febrile fits, febrile convulsions and febrile convulsions are synonymous terms. Children with previous afebrile fits are excluded from this definition.

Magnitude of Problem
There is no comprehensive local epidemiological data. Studies in Western Europe quote a figure of 3-4 % of children  5 years experiencing febrile fits with higher figures of up to 8% in Japan. This makes febrile fits the single most common problem in paediatric neurology.

Types of Febrile Fits
Febrile fits are classified as either simple or complex. Simple febrile fits are short,  15 minutes, generalised fits that do not occur more than once in a febrile episode. Febrile fits that are either prolonged (  15 mins ) unilateral or recur within a single febrile episode are classified as complex. (Nelson &Ellenberg,1978)

Issues in management of Febrile Fits.
The major issues are:-

a) Risk of recurrent febrile fits.
b) Risk of subsequent afebrile, unprovoked fits or epilepsy.
c) Prognosis for neurological, motor, intellectual and behavioural outcomes.
d) Need for admission.
e) Investigations for the individual child.
f) Need for electroencephalogram (EEG).
g) Need for prophylactic treatment.
h) Type of prophylactic treatment to be used.

A)Risk of Recurrent Febrile Fits
Recurrence of febrile fits is the largest risk for children with this condition.
The risk factors for such recurrence are:
 Early age of onset ( 15 months)
 Epilepsy in a first degree relative
 Febrile fits in a first degree relative
 Low degree of fever (  40C) during first febrile fit.
 Brief duration between onset of fever and initial fit

A first complex febrile fit has not been consistently associated with an increased risk of recurrence. Children in nursery care are also at higher risk ( Berg et al 1997, Knudsen 1996 )

The overall risk of recurrence is 30-40% and half of these go on to get a second recurrence ( Aicardi ). However there is a range of risk. Those with O or 1 risk factor have a low risk of  10 %, whereas those with all risk factors have an almost 100% risk. The single most important risk factors is age at onset with children  1 year having a 50 % risk of recurrence compared to 28% for those above 1 year. Only 9-17% of cases have 3 or more recurrences.

Half of all recurrences occur within 6 months and 3 quarters have occurred by 1 year of the first febrile fit.

Most long lasting fits are the first episode (Aicardi ). Only 1.4 % of children with an initial brief F.C. developed a prolonged recurrence lasting 30 minutes or more, and none of these had had an afebrile fit at 7 years of age (Nelson & Ellenberg 1978).
However children with prior abnormal neurological development may have a much higher risk of a prolonged recurrence (Berg 1997)

In summary recurrent febrile fits are common especially among those with an early onset. Most of these are brief and the number of recurrences has no bearing on long term neurological, motor, intellectual or behavioural outcomes (Knudsen 1996).

B.Risk of Subsequent Afebrile Unprovoked Fits or Epilepsy

Non febrile fit follow F.C. in 2 to 7 % of cases, a rate that is 5-10 times higher than the population incidence of 0.4 – 0.8 %.

Conversely 10-15% of patients with epilepsy have a positive history for febrile fits compared to a population incidence for F.C. of 3-4 %.

The current feeling is that these children have inherited a lower threshold for fits that is manifested as F.C. during the age of susceptibility for this condition.

Initial concerns arising from neurosurgical series about the relationship between Mesial Temporal Sclerosis (MTS) and a preceding history of prolonged febrile fits have been challenged by the findings of more recent cohort studies of adolescents with epilepsy, with or without a prior history of febrile fits ( Berg 1999, Camfield 1994 ). A recent study has also shown MRI evidence of MTS in relations of patients with intractable partial fits secondary to this condition even through some of them have never experienced a fit, febrile or otherwise. ( Fernandez 1998 ). This and other reports of MRI evidence of MTS in children shortly after a febrile fit suggest that some individuals may have developmental hippocampal abnormalities that predispose to F.C. and later epilepsy.

In an individual child with febrile fits, features that predict a high risk of later non febrile fits are:-
1) Abnormal neurological development before first febrile fit.
2) Family history of idiopathic epilepsy
3) Complex febrile fits
4) Recurrent (> 3 ) simple febrile fits

All of the above suggest that the children concerned have inherited a tendency to epilepsy and possibly also to develop Mesial Temporal Sclerosis.

C. Prognosis for neurological, motor, intellectual and behaviour outcomes.
Two large cohort studies have shown that children who are developmentally normal at the time of their first febrile fit continue to develop normally at follow-up (Nelson & Ellenberg, Verity et al). There was no difference between those who had simple or complex febrile fit in this respect. Children with F.C. actually had better reading skills is one study (Verity). Another study showed that those who had experienced complex febrile fit actually did better academically than those with simple febrile fits, but the difference was not significant (Knudsen).

D. Need for admission.
Not all children with febrile fits need to be admitted. The main reasons for admission are:-
1) To exclude intracranial pathology especially infection
2) Fear of recurrent fits
3) To investigate and treat the cause of fever besides meningitis or encephalitis.
4) To allay parental anxiety, especially if they are staying far from the hospital.

If child can be observed for 6-8 hour in a casualty ward, most of these concerns can be addressed, a child that is running around normally a few hours after a fit with fever is unlikely to have meningitis. Seventeen percent of meningitis present with a febrile fit .
Hence the child should only be discharged from the observation ward when the underlying cause for the fever has been ascertained to be a minor illness only requiring outpatient care. Ideally the patient should be examined by a pediatric medical officer before the decision is made not to admit him/her.
If a decision is made to send the child home the parents should be given clear instructions what to do in case the fit recurs or the fever persists.

Need for further investigations
The need for blood counts, lumbar puncture, urinalysis, chest x-ray, blood culture etc., will depend on clinical assessment of the individual case. Measurement of serum calcium and electrolytes are rarely necessary in children with febrile fits.

F) Need for Electroencephalogram (EEG)
Although many EEG changes have been reported in children with febrile fits, both in recordings shortly after the fits and in interictal records, these findings do not help in the management of the individual child and have no consistent prognostic value. Hence an EEG is not indicated in children with febrile fits. This also applies for those with multiple recurrences and features of complex febrile fits.

G) Need for prophylactic treatment in F.C. and
The major concern in febrile fits is prolonged fits leading to status epilepticus that might possibly result in neurological sequelae.

Febrile fits are a frightening experience for caregivers and some of them may seek prophylactic treatment to prevent a recurrence.

F.Type of prophylaxis

There are 3 options
a) Continuous daily anticonvulsant therapy. Phenobarbitone and sodium valporate have been used successfully to prevent recurrences. However both these drugs have considerable side effects, namely behavioural, sedative and possibly cognitive for phenobarbitone and a distinct risk of hepatotoxity with sodium valporate. These risks are not in keeping with the benign nature of febrile fits. Hence it is now universally agreed to abandon the practice of prescribing daily anticonvulsants for children with F.C.

b) Prophylaxis during febrile episodes.
There are two approaches, to administer antipyretics with onset of fever and to give rectal diazepam suppositories with onset of fever.
Giving antipyretics is indicated by virtue of patient comfort, but has not been shown to reduce the recurrence rate of F.C. Giving rectal diazepan suppositories has been shown to be effective if fever is detected early and there is good compliance with the 8 hourly administration of this preparation. The last 2 limitations have been shown in large studies to render this approach ineffective. Often caregivers are not aware of fever until the child has fitted.

c) Rectal Diazepam solution to limit the duration of a febrile fit.
In this approach, caregivers are advised how to position and care for a fitting child, and to administer rectal diazepam solution at 0.5 mg/kg if the fit lasts more than 5 minutes. There are 2 commercially available strengths of rectal diazepam, namely 5mg and 10mg. Children older than 5 years should receive 10 mg. The side effects of diazepam in this situation are drowsiness, lethargy and ataxia. Respiratory depression has not been documented with this dose of diazepam in this situation. However as diazepam may conceal signs of meningoencephalitis the child should be examined by medical personnel and observed for a few hours if there is any doubt of an intracranial infection. If the parents do not have diazepam at home this can be administered at the family doctors clinic or at a hospital casualty.
Intramuscular diazepam is not useful as effective blood levels are only reached after almost an hour and the levels tend to be erratic. However if the rectal preparation of diazepam is not available the intravenous preparation can be administered rectally at the same dose. This is to avoid doctors wasting time trying to get intravenous access in a chubby fitting child. Rectally administered diazepam has an onset of action of 1-3 minutes and the effects last for about 10 minutes. If the fits recur after 10 minutes the diazepam can be repeated rectally or intravenously. If the fits persist or recur after that, then the child should be treated as a case of status epilepticus.
Midazolam however can be given intramuscularly in doses of 0.3-0.5mg/kg and has been shown to achieve therapeutic levels in 3 minutes.

Current Recommendation (See also Appendix 1)
Based on the above discussion, the following approached is recommended:
a) Parents of children with febrile fits should be counselled on the benign nature of this condition.
b) They should be taught effective measures of temperature control such as tepid sponging with tap water and antipyretic administration. Paracetamol is still the safest antipyretic and can be given at a dose of 15 mg/kg 6 hourly. Alternately NSAIDs can also be used. The mechanism of action of tepid sponging namely heat loss from the body surface should be explained to the parents.

c) The parents should also be advised on first aid measures during a fit, if this was to recur namely:

i) Do not panic, remains calm. Note time of onset of fit.
ii) Loosen the child’s clothing especially around the neck
iii) Place the child in the left lateral position with the head lower than the body.
iv) Wipe any vomitus or secretion from the mouth
v) Do not insert any object into the mouth even if the teeth are clenched
vi) Do not give any fluids or drugs orally
vii) Stay near the child until the fit is over and comfort the child as he/she is recovering.
viii)The caregiver of children with a high risk of recurrence, ie more than 3 risk factors, should be supplied with a preparation of diazepam rectal solution at 0.5 mg/kg of the childs weight. They should be advised on how to administer this in case the fit last more than 5 minutes.
ix) Rectal Diazepam solution is a list C item in the Ministry of Health’s drug list and hence should be available in all government health facilities.
ix) In the event that the fit is not aborted by rectal diazepan they should seek urgent medical help to stop the fit before status epileptics develops.
x) If the fit is aborted, they should also seek medical advise to determine the cause of the fever.

These recommendations apply both to children who have had a simple or a complex febrile fit.

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