Febrile Seizures 

1. Definition 

Febrile seizure (FS) = seizure occurring in children 6 months–5 years with fever ≥38°C, without evidence of CNS infection, metabolic cause, or prior afebrile seizures.

  • Peak age: 12–18 months
  • Most common seizure disorder in childhood

2. Classification 

A. Simple Febrile Seizure (≈ 70–80%)

  • Generalized tonic-clonic
  • Duration <15 minutes
  • Single episode in 24 hours
  • No postictal neurological deficit

B. Complex Febrile Seizure

Any ONE of:

  • Focal onset/features
  • Duration >15 minutes
  • Recurrent within 24 hours
  • Postictal focal deficit (Todd’s paresis)

C. Febrile Status Epilepticus

  • Seizure lasting >30 minutes
    (or ≥5 minutes for practical definition)

3. Epidemiology & Risk Factors

Incidence

  • Occurs in 2–5% of children (higher in Asians)

Risk Factors

  • Family history of febrile seizures
  • Rapid rise in temperature (NOT absolute height)
  • Viral infections:
    • HHV-6 (roseola)
    • Influenza
  • Post-vaccination (rare, benign)

4. Pathophysiology

  • Immature brain → increased neuronal excitability
  • Fever → cytokines (IL-1β) → ↓ seizure threshold
  • Genetic predisposition (polygenic)

5. Clinical Features

Typical Presentation

  • Sudden generalized tonic-clonic seizure
  • Occurs early in febrile illness
  • Postictal drowsiness

Red Flags (Suggest NOT simple FS)

  • Age <6 months or >5 years
  • Signs of meningitis
  • Persistent altered sensorium
  • Focal neurological signs

6. Differential Diagnosis 

  • CNS infection → meningitis, encephalitis
  • Epilepsy (first presentation)
  • Electrolyte disturbances (Na, Ca)
  • Hypoglycemia
  • Breath-holding spells
  • Rigors (NOT seizure)

7. Evaluation (AAP / NICE)

A. Clinical Assessment (MOST IMPORTANT)

  • Focus on identifying source of fever
  • Rule out CNS infection

B. Lumbar Puncture 

Indications:

  • Signs of meningitis
  • Age 6–12 months with incomplete immunization
  • Pretreated with antibiotics (masked meningitis)

C. NOT Routinely Required

  • EEG 
  • Neuroimaging 
  • Blood tests  (unless clinically indicated)

8. Acute Management

A. During Seizure

  1. ABC stabilization
  2. Recovery position
  3. Oxygen if needed

B. If Seizure >5 minutes

  • First-line: Benzodiazepines
    • IV lorazepam
    • Rectal diazepam
    • Buccal/intranasal midazolam

C. Treat Fever

  • Paracetamol (comfort only, does NOT prevent recurrence)

9. Long-Term Management

A. Simple Febrile Seizure

  • No antiepileptic drugs required
  • Reassurance is key

B. Intermittent Prophylaxis (Rarely Used)

  • Buccal midazolam / rectal diazepam during fever

C. Continuous Prophylaxis (NOT recommended)

  • Avoid:
    • Sodium valproate
    • Phenobarbital
      (due to side effects > benefits)

10. Prognosis

Recurrence Risk

  • Overall: 30–35%
  • Higher if:
    • Age <1 year
    • Family history
    • Low-grade fever at onset

Risk of Epilepsy

  • General population: ~1%
  • After febrile seizures:
    • Simple: ~1–2%
    • Complex: 4–6%

11. Complications

  • Generally benign
  • Rare:
    • Febrile status epilepticus → hippocampal injury
    • Later temporal lobe epilepsy (controversial)

12. Parental Counseling 

  • Reassure:
    • Benign condition
    • No effect on intelligence or development
  • Educate seizure first aid
  • When to seek help:
    • Seizure >5 minutes
    • Recurrent episodes
    • Signs of meningitis

13. Vaccination & Febrile Seizures

  • Slight risk after:
    • MMR
    • DTP

BUT:

  • Vaccination should NOT be withheld