Simple Febrile Seizure

Simple febrile seizure is a generalised seizure associated with fever (38.0 C or above) not caused by central nervous system infection or metabolic disturbance, in a child aged 6 months to 5 years with no previous afebrile seizure.

• Simple febrile seizure criteria (all must be present): generalised tonic clonic activity without focal features; duration under 15 minutes; occurs once in a 24 hour period (no recurrence in the same febrile illness); full recovery to baseline within an hour; no neurological abnormality.
• Occurs in 2 to 5 percent of children (up to 8 percent in some regions); peak at 12 to 18 months; boys slightly more than girls.
• Causes of fever: viral upper respiratory infection, otitis media, roseola, gastroenteritis (shigella), urinary tract infection, post-immunisation fever (MMR at days 5 to 12, DTP), tonsillitis; malaria in endemic areas.
• Risk factors: family history of febrile seizures, daycare attendance, iron deficiency, zinc deficiency, prenatal exposures, neonatal discharge after 28 days, developmental delay, rapid temperature rise (the seizure often occurs in the first hours of fever).
• Recurrence: about 30 percent after the first, 50 percent if onset under 12 months, 10 percent have three or more. Risk factors for recurrence: age under 18 months at onset, fever of short duration before seizure (under 1 hour), fever below 40 C at seizure, family history of febrile seizures, family history of epilepsy.
• Long term: risk of subsequent epilepsy about 1 to 2 percent (compared with 0.5 to 1 percent in the general population); no effect on intelligence, behaviour or school performance; mortality is not increased.

• Sudden loss of consciousness, tonic stiffening and rhythmic clonic jerking of all limbs, eyes rolling up, cyanosis, urinary incontinence, lasting seconds to a few minutes, followed by drowsiness for up to 15 to 30 minutes; the child then returns to normal.
• The seizure commonly occurs in the first day of fever, sometimes before the parent notices fever.
• Examination after recovery: temperature, source of fever (ears, throat, chest, urine, skin, rash), alertness, meningism, fontanelle, neurological examination (tone, reflexes, Todd paresis absent), growth and development, hydration.
• Red flags (consider meningitis, encephalitis, malaria, epilepsy, metabolic cause): persistent drowsiness beyond 1 hour, meningism, bulging fontanelle, non-blanching rash, focal signs, seizure lasting over 15 minutes, recurrence, hypoglycaemia, signs of dehydration, age under 12 months (meningitis can be subtle), age over 5 years, recent antibiotic use (can mask meningitis), incomplete immunisation, travel to malaria zone, immunosuppression.

• Clinical diagnosis after exclusion of serious causes.
• Investigations are guided by findings, not by the seizure alone:
  • Capillary blood glucose in all children.
  • Urinalysis and culture where there is no source.
  • Malaria rapid test and blood smear in any child in or from an endemic area (consider cerebral malaria).
  • Electrolytes, calcium, magnesium if prolonged seizure or vomiting and diarrhoea.
  • Full blood count, CRP, blood culture in a child who looks unwell.
  • Lumbar puncture: strongly consider in children under 12 months, those with meningism, persistent altered consciousness, or recent antibiotics, or when immunisations against Haemophilus influenzae type b and Streptococcus pneumoniae are incomplete; consider in those 12 to 18 months because signs may be absent.
  • EEG, CT and MRI brain are not routinely indicated for a typical first simple febrile seizure.

• Acute seizure (first aid and emergency management):
  • Place the child on their side in the recovery position on a safe flat surface, loosen clothing, note the time, do not restrain, do not put anything in the mouth, remove hazards; give oxygen if cyanosed.
  • Most seizures stop within 5 minutes. If still seizing at 5 minutes, give a benzodiazepine:
    • Midazolam buccal 2.5 mg (6 months to under 1 year), 5 mg (1 to under 5 years), 7.5 mg (5 to under 10 years), 10 mg (10 years and over); or intranasal midazolam 0.2 mg/kg (maximum 10 mg); or
    • Diazepam rectal 0.5 mg/kg (usually 5 mg for 10 to 15 kg, 10 mg for over 15 kg); or
    • Lorazepam 0.1 mg/kg intravenously (maximum 4 mg) or diazepam 0.25 to 0.4 mg/kg intravenously (maximum 10 mg) if access exists.
  • If seizure continues 5 to 10 minutes after the first benzodiazepine, give a second dose in hospital with airway support; then second line agents (levetiracetam 40 mg/kg intravenously over 10 minutes, or phenytoin 20 mg/kg intravenously over 20 minutes, or phenobarbital 20 mg/kg).
  • Check glucose; if below 3 mmol/L, give 2 mL/kg of 10 percent dextrose intravenously.
• Treat the cause of fever: antibiotics for bacterial infection; malaria treatment if positive.
• Antipyretics: paracetamol 15 mg/kg every 4 to 6 hours or ibuprofen 5 to 10 mg/kg every 6 to 8 hours for comfort only; they do not prevent recurrence.
• Admission or observation: first seizure with any red flag, age under 12 months, parental anxiety, difficult access to care, or incomplete recovery; otherwise discharge home after a period of observation (1 to 2 hours) once the child has returned to baseline and a source is identified.
• Prophylaxis: continuous antiepileptic drugs (phenobarbital, valproate) are not recommended for simple febrile seizures (risks outweigh benefits). Intermittent oral clobazam 0.5 to 1 mg/kg/day in two divided doses for the duration of fever (2 to 3 days; maximum 20 mg per day) or oral diazepam 0.3 mg/kg every 8 hours (maximum 0.9 mg/kg/day) at the onset of fever is reserved for recurrent, prolonged seizures or severe parental anxiety; sedation and ataxia may mask evolving illness.
• Parent education: reassure that most children do not develop epilepsy and have normal development; teach first aid; give written instructions; advise to call emergency services if seizure lasts over 5 minutes, repeated seizures, breathing difficulty, injury, or the child does not recover; consider a rescue buccal midazolam supply with training for those with prolonged or repeated seizures.
• Vaccination: continue the schedule; give paracetamol after vaccination if febrile.
• Follow up in primary care in 1 to 2 weeks; refer to paediatric neurology if atypical features, developmental concerns, or recurrence frequency is high.