Febrile convulsions are generalised seizures triggered by fever in otherwise normal children.
They are usually benign but can be frightening for parents and caregivers.
Epidemiology
Occur in 2–5% of children aged 6 months to 5 years.
Peak incidence: 14–18 months.
Slightly more common in boys.
Higher risk with a family history of febrile seizures.
Pathophysiology
Immature CNS with a lower seizure threshold.
Fever triggers neuronal hyperexcitability.
Often linked to viral infections (e.g., URTI, otitis media, roseola).
Risk factors:
- Rapid rise in temperature
- Family history
- Developmental delay
- Neonatal ICU stay
Types of Febrile Seizure
|
Type |
Features |
|
Simple |
Generalised tonic-clonic, <15 min, once in 24h, full recovery |
|
Complex |
Focal features, >15 min, multiple in 24h, slow/incomplete recovery |
|
Febrile Status Epilepticus |
Seizure >30 minutes |
⚠️ Red Flags
Signs of meningitis (e.g., neck stiffness, bulging fontanelle)
Focal neurological signs
Persistent vomiting
Persistent altered consciousness postictally
Seizure lasting >15 minutes or recurrence within 24 hours
Diagnosis and Investigations
Primarily a clinical diagnosis based on history and exam.
Simple febrile seizures usually need no extensive investigations.
Investigate if red flags are present:
- Bloods: FBC, U&Es, CRP, glucose
- Lumbar puncture: if meningitis/encephalitis suspected
- Neuroimaging (CT/MRI): if focal signs
- EEG: if concern about underlying epilepsy
Management
Acute seizure:
- Protect the airway and place it in a recovery position.
- If seizure >5 minutes ➔ treat with benzodiazepines.
Post-seizure care:
- Treat underlying infection.
- Paracetamol/ibuprofen for comfort (not for seizure prevention).
- Reassure parents: simple febrile seizures have excellent outcomes.
- Discharge once stable, with safety netting advice.
Referral needed if:
- First febrile seizure
- Prolonged or multiple seizures
- Complex seizure features
- Signs of serious illness
Safety Netting for Parents
Return if seizures last >5 minutes or recur within 24 hours.
Return if persistent fever, vomiting, drowsiness, or other signs of serious illness.
Provide written advice and support resources.
Prognosis
Excellent after simple febrile seizures — usually no long-term effects.
Recurrence risk:
- ~1/3 of children have another febrile seizure.
- 75% of recurrences happen within 1 year.
Higher recurrence risk if:
- First seizure <18 months old
- Family history
- Low fever at the time of seizure
- Short fever duration before seizure
Risk of developing epilepsy:
- Simple seizures: 1–2% risk (slightly higher than the general population).
- Complex seizures: 4–6% risk.
- Febrile status epilepticus: 10–15% risk.
Risk increases further with:
- Family history of epilepsy
- Neurodevelopmental abnormalities
- Abnormal EEG
Key Exam Tips
Simple seizure = generalised, short, single event, normal recovery.
Red flags = investigate for serious causes (e.g., meningitis).
Treat seizures >5 min with benzodiazepines.
Recurrence is common, but prognosis remains good in most cases.
Thank you to the joint editorial team of MRCEM Exam Prep for this ‘Exam Tips’ blog post.
