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Convulsions - Afebrile

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Incidence

The prevalence of epilepsy is 0.5%. Many more children will have an isolated seizure.

A seizure should always be considered a symptom. The history, examination and any investigations should focus on identifying the presence of underlying pathology or provoking factors and assessing the risk for future seizures.

All Children Require

  1. Detailed history obtaining the sequence of events, including the presence or absence of focal features and the level of awareness throughout the seizure. Consider arrhythmic cause for generalized seizures especially occurring at night or during or following exercise
  2. Family history of evidence of young sudden death, familial epilepsy or arrhythmic disorders.
  3. Detailed physical examination, including BP and neurological examination
  4. Blood glucose and calcium measurement.
  5. Neuro-imaging is not usually required acutely. Imaging should be considered for focal seizures or when focal deficits are noted on examination or EEG suggests underlying structural pathology.
  6. A 12 lead ECG for evidence of long QT syndrome (not needed for focal seizures)
  7. An EEG (as an outpatient) is recommended after the first non-febrile generalised tonic clonic seizure.
    If the EEG is normal the risk of recurrence within the next 12 months is about 15% but if it is abnormal the risk of recurrence is about 40%.
  8. Outpatient follow-up

Management

  1. Explanation of risk of recurrence
  2. All caregivers need to know the principles of first aid management:
    a) The child should be laid on the floor away from objects that may cause harm
    b) Forceful attempts should not be made to open the child's mouth
    c) Phone for ambulance if seizure lasts longer than 5 minutes
    d) Place in left lateral (recovery) position during post ictal period
  3. Reasonable precautions to be discussed with caregivers include:
    a) Supervision by an adult when the child has access to water (this includes bathing)
    b) Avoid bike riding in heavy traffic
    c) Not climbing to heights greater than one metre.
  4. Usually long term treatment with an anti-convulsant is not indicated after the first non-febrile seizure
  5. Discuss the use/ need for emergency medication
    a) Rectal diazepam
      - 0.3-0.5 mg/kg/dose. (max dose usually 10mg) Onset of action 5-10 mins.
      - Dose may only be repeated under medical supervision.
      - Delayed respiratory depression may occur after rectal administration.
    b) Buccal midazolam
      - 0 - 16kg    Dose of 0.2 to 0.3 mg/kg/dose
      - 16 - 32kg  Dose of 5mg
      - 32kg +      Dose of 10mg

View or download a Plan for Emergency Management of Seizures using rectal diazepam (Stesolid).

View or download a Caregivers guide to administering buccal midazolam.

Recurrence Risk

The recurrence rate after a child's first afebrile seizure is 30% . This is increased in children with neurological disabilities. Following a second afebrile seizure the risk of recurrence is considerably higher, approximately 75%

The EEG is helpful in predicting the risk of recurrence (see above).

Indications for Starting Therapy

Anticonvulsants are not indicated after the first seizure. Some authorities consider starting anticonvulsant therapy after a single seizure if there is a family history of epilepsy, or in the presence of neurological or developmental abnormalities. There is no evidence that delaying therapy until after the second seizure is associated with poorer control of seizures in the long term.

Starting Anticonvulsant Medication

The drug of choice is determined by the seizure type or most likely seizure syndrome.

A history of the seizure, detailing the sequence of events, including the presence or absence of focal features and the level of awareness throughout the seizure is therefore very important.

The anti epileptic drug commenced should be decided upon the physician providing ongoing follow-up. Prescribers should be aware of side effects of any medications prescribed. The two most commonly prescribed first line anti convulsant medications are carbamazepine (Tegretol) and sodium valproate (Epilim). Important side effects to be aware of include liver dysfunction, bleeding, fetotoxicity / teratogenicity (Epilim) and rash. Anticonvulsants are rarely associated with Steven's Johnson Syndrome (SJS), and medication should be discontinued if a rash develops. The risk of SJS in patients on carbamazepine is slightly higher among among Asian patients; particularly descendents of Han Chinese.

Both drugs should be commenced at low doses building to therapeutic doses over 2-3 weeks. This reduces the risk of adverse side effects.

Carbamazepine

Maintenance doses should be between 15-20 mg/kg/day.

This should be started gradually as follows:

  • 5 mg/kg/day in two divided doses for seven days
  • Then 10 mg/kg/day in two divided doses for seven days
  • Then 15 mg/kg/day in two divided doses for seven days

The usual maximum is 1200 mg/day in up to three divided doses.

One month after starting carbamazepine check the full blood count and platelet count, liver function tests and drug levels.

Sodium Valproate

Maintenance dose are usually 20 - 30 mg/kg/day

This should be started gradually as follows:

  • 5 mg/kg/day in two divided doses for five days
  • Then 10 mg/kg/day in two divided doses for five days
  • Then 15 mg/kg/day in two divided doses for five days
  • Then 20mg/kg/day in two divided doses for five days

FBC and LFTs should be checked prior to starting treatment and at one month. There is usually no benefit in monitoring Epilim levels. Epilim levels may be useful if you suspect poor adherence to therapy or toxicity.

A package of parent information leaflets prepared by The Child Neurology Department Christchurch Hospital - Kids & Epilepsy Kit, including information on epilepsy, EEGs, MRIs and several different anti-convulsants can be accessed under Information for Families.

Click on the image below for a blank Medication Dosing Schedule you can complete for your patient.

Medication Schedule

Criteria for referral to Neurology

Referral to neurology should be considered for the following:

  • When there is diagnostic doubt as to the nature of the seizures and/or seizure syndrome (also consider arrhythmic collapse as a possible cause & consider referral to cardiology)
  • Behavioural or developmental regression
  • When seizures are not controlled within 2 years or failure of second antiepileptic drug
  • New onset seizures in a child < 6 months
  • Infantile spasms
  • Structural lesion on imaging
  • Individuals with specific syndromes such as Sturge-Weber syndrome, Tuberous Sclerosis, Rasmussen's encephalitits and hypothalamic hamartoma
  • Psychological or psychiatric co-morbidity
  • Unacceptable side effects on medication

Information for Families

References

Practice parameter: Treatment of the child with a first unprovoked seizure. Subcommittee of American Academy of Neurology and the Practice Committee of the Child Neurology Society. Neurology 2003;60:166-1755

The first seizure and its management in adult and children. Pohlmann-Eden B, Beghi E, et al. British Medical Journal 2006;332:-343

Risk of recurrent seizures after two unprovoked seizures. Hauser WA, et al. N Engl J Med 1998;338:429-434

The risk of seizure recurrence after a first unprovoked afebrile seizure in childhood: an extended follow-up. Shinnar S, Berg AT, Moshe SL, et al. ; Pediatrics 1996;98:216-225.

CG20 Epilepsy in adults and children: NICE guideline; 27 October 2004

Epilepsy NZ website: http://www.epilepsy.org.nz/

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Document Control

  • Date last published: 01 August 2008
  • Document type: Clinical Guideline
  • Services responsible: Paediatric Neurology
  • Author(s): Claire Spooner
  • Editor: Greg Williams
  • Review frequency: 2 years

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