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Febrile seizure or febrile convulsion is the most common neurological complication that occurred in late infancy and early childhood
what is the definition of febrile seizure?
According to a consensus conference taken in 1980 sponsored by the National Institute of Health, USA, defined a febrile seizure is an event occurring between 3 months and 5 years of age, associated with fever but without any evidence of intracranial infections or defined causes. Till now it is the most widely accepted definition.
Characteristics of the fever that triggers the seizure
- A rapid rise in body temperature
- A rectal temperature of 38 degrees centigrade or oral temperature 36 degrees centigrade
It is now known that the rapid rise of temperature is more important than the height of temperature reached.
What are the types of febrile seizures?
Broadly classified into two types. One is simple which constitutes almost 90 percent of febrile seizures.
The other one is a complex febrile seizure.
Simple febrile seizure has the following characteristics:
a) Generalized which is again 3 types
1. Tonic-clonic seizure
2.Only tonic with the child becoming stiff and rigid with uprolling of eyeballs.
3. Only clonic
b) It usually lasts not more than 15 minutes
c) Only one seizure in one febrile episode
d) Postictal manifestations are virtually absent
The rest 10 to 20 percent have complex febrile seizures which are characterized by
a) Focal in nature
b) Last more than 15 minutes
c) Within 24 hours there may be multiple recurrences
what is the incidence of febrile seizure?
- 90 percent of febrile seizures occur in children after 6 months of age and before three years.
2. The peak incidence is at about 18-22 months.
3.Febrile seizures are more common in boys than girls
The recurrence rate: After a fit, though the child looks normal there is a chance of recurrence. The risk factors for recurrence are
1.Age less than 18 months at the time of first seizure
2. A low-temperature threshold
3.Family history of febrile seizure is positive
4.If the seizure occurs within 1 hour of onset of fever.
Are there any chances of developing epilepsy in the future?
The incidence of afebrile seizure or convulsion or epilepsy following a febrile seizure is around 2 to 4 percent. These depend on the following factors once again:
1.Family history of epilepsy
2.If the child is a C.P. (cerebral palsy) child
3.Febrile seizure with pre-existing brain damage
Clinical presentation of febrile seizure
- Sudden onset preceded by a brief febrile episode
- The child appears well after the seizure though few children present with the postictal phase.
- Most seizures occur within twenty-four hours after onset of fever
- The most important findings are the rise of temperature and occasional Todd’s palsy.
Diagnosis of febrile seizure
Diagnosis is solely made on clinical grounds.
The CNS infection should be kept in mind, especially if the age is below one year.
The presence of undue irritability, drowsiness, or coma following the febrile seizure should lead one to investigate and exclude intracranial infections like meningitis, encephalitis, cerebral malaria, etc.
Actually, no investigations are needed for the diagnosis of febrile
But if there is any suspicion of intracranial infections then the doctor usually goes for the following investigations:
1.Lumber puncture: Lumbar puncture is done for CSF ( cerebrospinal fluid) analysis.
2.EEG or Electroencephalogram :
3.Neuroimaging: Especially for those children with neurodevelopmental delays are seen.
4.Haematological: Routinely not required but sometimes needed to evaluate the cause of fever.
How febrile seizure is treated?
1. Treatment during the interictal period: Most of the time febrile seizure subsides by the time the patient arrives at the Doctor’s clinic, as it usually lasts for a brief period.
In this condition, the patient should be explained about the benign nature of the disease and they should be reassured.
But the child should be kept in the hospital for few hours because there may be a recurrence of the seizure.
During discharge, the following advice should be given
a) If there is a recurrence of seizure, the child should be placed in a semi-prone to one side with head little lower than the trunk.
b) Sponging with tepid water should be done to bring down the temperature.
c) Overcrowding should be avoided
d) Nothing should be put inside the mouth
e) If possible rectal diazepam or intranasal midazolam can be administered.
f) To contact a doctor or shift to the nearest hospital if the seizure does not subside after 5 minutes.
2. Treatment of an ongoing seizure:
a) The child should be placed in a semi-prone position on one side with head slightly lower than the trunk. A.ll clothes should be loosened.
b) oxygen should be started if the seizure is lasting for a prolonged time.
c) Diazepam .3-.5 mg/kg ( maximum 10 mg/kg) is very good in controlling the seizure.It should be given very slowly i.v.
If there is no response then the same can be repeated after 15 minutes.
Alternatively Lorazepam, Midazolam can also be tried with good results.
If the child does not respond then a loading dose of phenobarbitone or phenytoin should be given. 15 MG/KG for both is usually enough.
prevention of recurrence
This is the most important question. Is it possible to prevent the recurrence? How serious is the febrile seizure recurrence??
The following things should be done to try to prevent the recurrence.
A) Always be prepared if fever start, don’t be panic.
B) Try to control fever with paracetamol, give every 4 hourly with or without fever( 10 to 15 mg/kg/dose) for the first 48 hours.
C) Per rectal diazepam every 12 hourly can be given. The recommended dose is .5mg/kg. Oral diazepam can also be given but if given orally then it should be 8 hourly. The dose for oral diazepam is .6 -.8 mg/kg/dose.
D)Another drug oral clobazam is also successful for prophylactic therapy.The dose is 5mg to 15 mg/kg/day.
E) Prophylactic therapy should be continued for at least 72 hours.