Febrile Seizures

Authors: Dr Sally Ackerman & Dr Jo Wilmshurst

Section Editor: Dr Baljit Cheema

Introduction
Approach
Is it a SIMPLE or COMPLEX Febrile seizure?
Determine the source of the fever and treat appropriately
Treat the fever
Should a Lumbar Puncture be done?
Antibiotic Treatment
What other investigations should be done?
Counsel the parents
When to Discharge from the EC
Key Concepts

Introduction

• Most common seizures of childhood - occur in 2-5% of children between age of 6 mth -5 yrs
  Peak incidence between 12-18 months
• Differentiating Simple v Complex febrile seizures is critically important (see below) Simple febrile seizures are not associated with intracranial infection, metabolic disturbance or a history of afebrile seizures. But there should be a high suspicion of these underlying factors in a child who presents with Complex febrile seizures.
• Risk factors for simple febrile seizures include viral infections, a family history of febrile seizures and certain vaccinations (DTP, MMR).
• Most patients with febrile seizures present after resolution of the seizure as the majority of simple febrile  seizures last 2-3 minutes, and return to full alertness within an hour of the seizure.

Approach

Terminate the seizure (see Seizure: Active Guideline)

• Airway, high flow O2, check glucose
• If IV access: Lorazepam 0.1 mg/kg or Diazepam 0.25 mg/kg or Midazolam 0.25mg/kg if seizure duration > 5 minutes
• If no IV access: Buccal Midazolam 0.5mg/kg or Diazepam 0.5 mg/kg per rectum
• If still convulsing after 10 minutes - repeat benzodiazepine (ideally IV)
• if still convulsing after further 10 min give Phenobarbitone 20mg/kg IV (or IM if no IV line)

Is it a SIMPLE or COMPLEX Febrile seizure?

Determine the source of the fever and treat appropriately

• Thorough history and examination to identify the source of the fever
• URTIs most common source of infection – treat as clinically indicated
• Urine dipstix if source of fever not obvious
• Exclude meningitis and encephalitis. In children under the age of 18 months, the signs of meningism may be subtle or absent

Treat the fever

• The presence of fever may contribute to irritability and make the clinical assessment more difficult
• Oral antipyretics if tolerated: Paracetamol 4-6 hly of Ibuprofen 8 hly (give paracetamol suppository if too sleepy to take oral medication)

Should a Lumbar Puncture be done?

• LP NOT ROUTINE - BUT is indicated if
  • child < 18 months and/or
  • no clinical source of the fever and/or
  • findings from the history or physical examination are concerning for intracranial infection
• If clinically indicated start treatment for bacterial meningitis immediately after the LP (IV Ceftriaxone 100mg/kg daily or Cefotaxime 50mg/kg 6 hly)
• Remember contraindications for LP: focal seizures, raised ICP, clotting disorder, unstable child or suspected TBM (need CT Brain before LP)

Antibiotic Treatment

• Not routinely indicated
• If clinically indicated start treatment for bacterial meningitis immediately after the LP (IV Ceftriaxone 100mg/kg daily or Cefotaxime 50mg/kg 6 hourly)

What other investigations should be done?

• Routine FBC, CRP and Blood culture not indicated unless intracranial infection/bacteraemia suspected
• Routine electrolytes, Ca, Mg and PO4 not indicated unless clinical abnormalities suspected. Routine EEG in the EC is not indicated.
• CT scan if persistently depressed level of consciousness, focal neurological signs, focal seizure

Counsel the parents

• Counselling of the parents should be the mainstay of therapy
• Explain that the condition is common, the risk of recurrence and prognosis
• Recurrence Risk
  • Overall febrile seizure recurrence risk is 30-35%
  • Almost all recurrences take place within 2 years
  • Increased risk in children < 1 year (up to 65%), lower risk in older children
  • Other factors include first degree relative with febrile seizures, low grade fever at time of seizure, short duration between fever onset and seizure, abnormal development before first seizure, first degree relative with non-febrile seizures
  • Overall risk of subsequent epilepsy in SFS is only slightly above that of general population (1-2%)
  • Risk of epilepsy between 5-15% if CFS, abnormal developmental history or a family history of epilepsy, up to 50% if more than one risk factor
• Prognosis
  • Simple - Excellent, no known effects on IQ, academic performance or behavioural abnormalities
  • Complex - Depends on underlying neurological condition
• Can it be prevented?
  • Antipyretics at the onset of fever do not prevent recurrence of febrile seizures (parents should not feel guilty if subsequent seizures occur)7
  • Advise to give Paracetamol for febrile illnesses.
  • Advise recovery position to ensure patent airway during seizures
  • Continuous or intermittent anti-epileptic not recommended after first simple febrile seizure¹
  • Consider rectal Diazepam (see above) if child presented with febrile status- discuss with senior colleague

When to Discharge from the EC

All children need a period of observation after presentation; may go home if:

• Normal level of alertness within an hour of the event
• Clear source of the fever (and can be treated with oral antibiotics)
• Child does not appear toxic, distressed, or haemodynamically unstable
• Parents reassured

For CFS consider observation for at least 24 hrs as these children are at higher risk of multiple seizures within index illness & the majority will take place within 24 hrs

Key Concepts

• The majority of febrile seizures occur on the first day of illness and stop within 5 minutes.
• Early abortive treatment is warranted in prolonged febrile seizures as febrile status epilepticus rarely stops spontaneously and is associated with increased morbidity and a higher rate of later epilepsy.
• The diagnostic workup for a child with simple febrile seizure is the same as that for an age matched febrile patient who did not have a seizure; these children are not at higher risk for bacteraemia.
• Measuring serum electrolytes and CSF analysis have no role in managing patients older than 18 months with simple febrile seizures; an LP should be considered in patients younger than 18 months
• Complex febrile seizures suggest the possibility of significant underlying central nervous system pathology and these patients require a comprehensive evaluation.
• Patients with a simple febrile seizure have a 30% incidence of recurrence; subsequent use of antipyretics at fever onset does not lower the recurrence rate.
• Patients who have had a simple febrile seizure have a 1-2% lifetime risk of developing epilepsy versus a 0.4% risk in the general population. Prophylactic AEDs are not associated with a reduced risk of epilepsy in children with febrile seizures.

References

1. American Academy of Paediatrics Steering Committee on Quality Improvement and management, Subcommittee on Febrile  Seizures. Febrile Seizures: clinical practice guideline for the long-term management of the child with simple febrile seizures. Paediatrics 2008;121(6):1281-1286
2. Oluwabusi T, Sood SK. Update on the Management of Simple febrile seizures: Emphasis on minimal intervention. Curr Opin Pediatr 2012;24:259-265
3. Hampers LC, Spina LA. Evaluation and Management of Paediatric Febrile seizures in the Emergency Department. Emerg Med Clin N Am 2011;29:83-93
4. Batra P, Gupta S, Gomber S, Saha A. Predictors of Meningitis in Children presenting with First Febrile Seizures. Pediatr Neurol 2011;44(1):35-39
5. Graves RC, Oehler K, Tingle LE. Febrile Seizures: Risks, Evaluation, and Prognosis. American Family Physician 2012;85(2):149-153
6. Fishman MA. Febrile Seizures.Topic last updated 23 Aug 2012. www.uptodate.com