Neurology - Febrile Convulsions Flashcards
Defintion
Febrile convulsions or seizure is triggered by fever, most commonly secondary to viral infection, in otherwise normal children.
The exact threshold required to trigger a convulsion varies between individuals but in general, as the child grows older, the threshold increases and the risk therefore decreases.
Types of febrile convulsions
Simple febrile convulsions (70%) all of the following:
- <15 minutes
- Generalised tonic-clonic: stiffening of muscles, loss of consciousness and limb jerking
- No focal features
- No recurrence within 24 hours
Complex febrile convulsions (30%), one of the following:
- >15 minutes
- Focal features e.g. seizures affecting one side of the body
- Recurrence within 24 hours for the same febrile illness
- Incomplete recovery within 1 hour
Febrile status epilepticus
- > 30 minutes
Epidemiology
Focal convulsions have an incidence of 5% in the developed world:
- Young children : most commonly occurs between 6 months and 5 years old
- Pyrexia
- Viral infection : the most common underlying cause of pyrexia, although it can be caused by a bacterial infection
- Male gender
- Family history
Signs
- Pyrexia: often children have a fever > 39 °C
- Normal neurological examination after the seizure
Symptoms
The majority of febrile convulsions follow a benign course, with children returning completely back to normal within an hour of the event. Most seizures last < 5 minutes and most commonly tonic-clonic.
- Fever
- Seizure: simple or complex
- Symptoms of underlying infection e.g. upper respiratory tract infection, urinary tract infection or otitis media
Diagnosis
Not routinely recommended - mainly clinical
Tests to rule out other causes of seizures + find source of infection
Consider doing:
- Blood glucose
- U + E
- Blood culture
- CXR
- LP
- MRI + EEG
Acute Management
0 minutes - ABCDE
- Maintain airway = manual manoeuvres e.g. jaw thrust or head/chin lift, airway adjuncts or intubation
- Basic life support e.g. recovery position
- High flow oxygen (if in hospital)
- Check glucose (if in hospital)
> 5mins - BENZODIAZEPINE RESCUE MEDICATION
- Buccal MIDAZOLAM or rectal DIAZEPAM
- Only given if advised by specialist for child with recurrent seizures
- Call ambulance if, 10 minutes after the first dose
= Seizure not stopped
= Child ongoing twitching
= Another seizure has begun before the child regains consciousness
- If benzodiazepines have not been previously advised by a specialist, parents should call an ambulance if the seizure lasts > 5 minutes
> 15 mins - Should be in hospital
- IV LORAZEPAM
- If still in prehospital setting, buccal midazolam or rectal diazepam repeated
> 25 mins - PHENYTOIN OR PHENOBARBITAL
> 45 mins - Rapid sequence induction and transfer to the ICU
Management after febrile seizure
- Anti-epileptics and antipyretics are not recommended: these have not proven effective at reducing recurrence of febrile convulsions .
Antipyretics e.g. paracetamol = keep the child comfortable
Refer to paediatrics: all children with their first febrile convulsion, a complex febrile convulsion or with an underlying neurodevelopmental issue should be referred
Advice and benzodiazepines : parents of children with recurrences should be taught about the use of rectal diazepam or buccal midazolam. An ambulance should be called if the seizure lasts > 5 minutes
Complications
- Recurrence of febrile convulsions
- Epilepsy: the risk of developing epilepsy is only slightly higher if the child has a simple febrile seizure
Risk factors for recurrent febrile convulsions
Age < 18 months
Temperature > 40°C
Fever duration < 1 hour before seizure onset
Family history
Risk for child developing epilepsy
Family history of epilepsy
Complex febrile seizure
Background of neurodevelopmental disorder
- A child with all 3 of these risk factors has a very significant risk of developing epilepsy (50%) whilst a child with no risk factors only has a 2.5% risk
