Febrile convulsions

Seizures are the most commonly seen neurological disorder in children (including syncope, febrile convulsions, epilepsy).  Around 3% of all children will have had a seizure associated with febrile illness (commonly chicken pox, common cold, croup etc) by age 5.  Febrile seizures (by definition) occur in children aged 3 months – 5 years old; boys > girls (6:4).


Often familial (4-5 fold increase if sibling or parent has had one) although rarely autosomal dominant.  Delayed neonatal discharge (>28 days) seems to also be a factor.  The role of nursery and playgroup (in infection spread) will obviously increase the chances.  Parents may also report a slow/delayed development, although whether this is causing a seizure or whether the two are associated with another factor is not certain.

Febrile Seizures

Seizures are a malfunction in the brain’s electrophysiology, causing altered consciousness; involuntary movements and changes in perception, posture and behaviour.  Seizures can be classed as simple or complex:

  • Simple seizures are the most common and present as a generalised (whole body) convulsive seizure without focal signs, lasting <15 mins and occur < 1/day.  They account for around 30-59% of febrile seizures.
  • Complex seizures are >15mins long, have focal features OR will recur in 24 hours.


Parents may come in worried about their child after one simple seizure.  It is important to reassure them that this is almost always harmless and no investigation is required.  A child should only be investigated if:

  • they are <12 months old
  • Hx of antibiotic treatment
  • suspected CNS infection
  • complex seizure
  • signs of raised ICP


At home, it is important to time the seizure, positioning the child in the lateral position and maintaining the airway/ draining secretions if possible.  Do not put anything (including fingers) in the mouth.  If it lasts longer than 5 mins, it is suitable to administer emergency medications if they are available.  Hospital management is almost identical, but with the addition of oxygen (facial high flow) at the 5 min mark, and possibly an antipyretic e.g. paracetamol (orally or rectally).

Emergency medications

  • Rectal diazepam (0.5mg/kg – max 10mg for a child <10 kg)- fast onset (1-5 mins), minimal side effects and long half life BUT not generally acceptable route of admission (only really used in children <24 months or <10 kg)
  • Buccal midazolam (0.25mg/kg- max 10mg again)- also fast onset and few side effects (also just as effective) but shorter half life (duration of action is around 4 hours)
  • Intranasal midazolam (0.25mg/kg) – newer but practically identical to buccal form.

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