Febrile seizure

Mc type of childhood seizure

2-5% of all children

6m to 5 years of age

Peak age - 12 to 18 months

Definition

• Nor related to CNS infection, previous seizure episodes, metabolic seizures
• Associated with fever at 38 C (nelson) or 38.4 - (AOCN 2021)
• 6 months to 60 months - nelson
• 6 months to 6 years - AOCN 2021 guidelines

Types

• Simple 75%
  • Non focal
  • Up to 15 mins
  • No recurrence in 24 hours
• Complex 25%
  • Not simple seizure

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• Febrile status - 30 mins or more
• Genetic epilepsy with febrile seizure plus - associated with familial history
• Febrile seizure with plus - does not regress beyond 6 years

Cause

• Unknown
• Positive family history
• SCN1A, SCN1B, SCN9B, CPA6
• Polygenic followed by autosomal dominant
• Immune dysregulation esp. febrile status epilepticus
  • Imbalance between two set of immune markers
  • Elevated IL1B, IL 8, IL6 (proinflammatory)
  • Decreased IL-IRA ( anti-inflammatory)
  • IL-IRA/IL8 ratio - potential biomarker for temporal lobe and hippocampal changes
• Virus
  • Associated with otitis media, URI by Herpes
  • GIT inflammation has protective role
  • Febrile status - HHV 6, HHV 7

Recurrence

• After 1 episode - 30%
• After 2 or more episodes - 50%
• Onset less than 1 year - 50 %

Risk factors of recurrence

• Major
  • Age less than 1 year
  • Duration of fever less than 1 year
  • Fever 38-39 C
• Minor
  • Family history
  • Complex febrile seizure
  • Day care
  • Male
  • Lower serum Na
• No risk factor - 12 %
• 1 risk factor - 25-50%
• 2 risk factors - 50 - 59%
• 3 risk factors or more - 75 - 100%

Risk factors for future epilepsy

• Simple febrile seizure - 1%
• Recurrent - 4%
• Complex non focal - 6%
• Fever <1 hr - 11%
• Family history - 18%
• Complex FS - 28%
• Neurodevelopmental issue - 33%

Clinical management

• Look clinically if it fit to febrile seizure
• Work up
  • CBC - CRP
    • Not need in simple FS
    • Needed in complex and focal FS
  • Blood, SE
    • Not needed in simple FS
    • Simple FS age less than 1 yr - S.Ca2+
  • No need to screen iron
  • Urine analysis
    • For all children less than 18 months with no focus of infection
    • Older children with signs of urine infectio
  • Neuroimaging
    • CT and MRI not needed in 1st episode of febrile seizure
    • Individualised for complex FS
    • MRI within 72 hrs
    • Follow-up not needed when 1st image is normal
  • 10% of children with febrile status develop U/L or B/L swelling of hippocampus
    • 71% of this children will long term hippocampal atrophy
  • EEG
    • Not need in simple FS
    • Done in complex FS - within 1 year
    • Min 30 mins (AOCN) 20 min (nelson)
    • Does not predict the future epilepsy
  • LP
    • All children with status
    • Signs and symptoms of meningitis
    • All children less than 12 months of age with FS esp. not HiB vaccinated
    • More than 12 month children pretreated with antibiotics
    • Prolonged action of BZD
    • Culture to be done only when meningeal signs present
    • Do neuroimaging before LP to rule out increased ICT

Management

• Domiciliary therapy
  • In home therapy
  • Parental education
  • Abortive medication to stop seizure if >3-5 min (AOCN) 5 min (nelson)
  • DOC midazolam (0.2 mg/kg) - intranasal preferred
  • Can be repeated after 5 mins
• Intermittent prophylaxis
  • Not advised after 1st episode
  • Can be considered in complex FS
  • Oral clobazam (0.5-1 mg/kg/day) in 2 divided doses x 3 days
  • Start from day of fever
• Continuous prophylaxis
  • Valproate x 2 years of seizure free period
  • No need for LFT
• Antipyretic
  • Does not prevent seizure
• No role in micronutrition like zinc