Febrile Seizures: A PLAB 2-Focused Clinical Review
- Ann Augustin
- May 28
- 3 min read
Updated: Sep 7
Definition:A febrile seizure is a seizure accompanied by fever (temperature >38°C by any method), occurring in children aged 6 months to 5 years (occasionally up to 6 years), with no evidence of CNS infection or acute neurological insult.References: AAP, 2011; Wilmshurst, 2015.
Types of Febrile Seizures
1. Simple Febrile Seizures
Generalized, tonic-clonic
Last less than 15 minutes
Occur only once in 24 hours (or during the same illness)
Full recovery within 1 hour
Most common type (about 70-80%)
2. Complex Febrile Seizures
Have any of the following:
Focal features: Movements affect only one limb or one side
Prolonged duration: Last more than 15 minutes
Recurrent: Occur more than once in 24 hours (or within the same illness)
Incomplete recovery within 1 hour
Less common (~20-30%)
Higher risk of subsequent epilepsy and recurrent febrile seizures compared to simple type
3. Febrile Status Epilepticus
Traditionally: Seizure lasting ≥30 minutes (or series of seizures without full recovery between them)
Current UK/EU guidelines: Any seizure lasting >5 minutes should be treated as status epilepticus (to prevent progression to 30 minutes and risk of neurological harm)
Accounts for 5% of all febrile seizures, but up to 52% of status epilepticus cases in children
Key Difference:
Complex febrile seizures are defined by focality, duration, and recurrence, but not all progress to status epilepticus.
Febrile status epilepticus is a prolonged seizure (lasting ≥5–30 minutes), and is considered a medical emergency.
Risk of Recurrence and Epilepsy
Recurrence:
After a first febrile seizure: ~32% risk of recurrence.
Of those who recur, 75% will do so within 1 year, 90% within 2 years.
Risk is higher with:
Age <18 months at first seizure (50% recurrence <12 months, 30% >12 months).
Family history of febrile seizures.
Low-grade fever (<39°C) at onset.
Short duration of fever before seizure (<1 hour).
Multiple seizures in 24 hours.
Attendance at daycare (increased exposure to viruses).
No risk factors: 4–14% recurrence.
All risk factors: up to 80% recurrence.
Progression to Epilepsy:
Simple febrile seizures: 1–2% risk (comparable to general population).
Complex febrile seizures: 6–8% risk.
Risk increases with:
Complex features.
Short duration of fever before seizure.
Family history of epilepsy.
Pre-existing neurodevelopmental abnormality.
Prognosis
Generally Benign:
Most children experience normal growth and development.
No evidence of long-term neurological or cognitive impairment after brief, simple febrile seizures.
Febrile Status Epilepticus:
Accounts for 25–52% of childhood status epilepticus, but only 5% of all febrile seizures.
Risks: prolonged/refractory seizures, possible hypoxia, and theoretical risk of hippocampal injury or temporal lobe epilepsy (evidence is inconclusive).
Prognosis worsens with longer seizure duration and pre-existing comorbidities.
Complications & Parental Concerns
Parental Anxiety:
Common, often due to fear of recurrence, uncertainty about seizure management, or concern about complications.
Important to provide clear education and reassurance.
First Fit Clinic & Parental Advice (UK Best Practice)
Refer to First Fit Clinic:
Essential after a child’s first seizure to exclude CNS infection, other underlying pathology, and to provide structured follow-up and education.
Parental Advice:
Place the child in the recovery position during a seizure; do not restrain or put anything in the mouth.
Seek emergency help if:
Seizure >5 minutes.
Recurrent seizures.
Child does not recover or has abnormal breathing/colour.
Concern for meningitis (e.g., stiff neck, photophobia, rash).
Antipyretics (paracetamol/ibuprofen) may relieve discomfort but do not prevent recurrence.
Prognosis is excellent for the majority; risk of developing epilepsy remains low.
Key References
NICE CKS – Febrile Seizure
AAP 2011, BMJ Best Practice 2022, Wilmshurst 2015, Patel 2015, Eilbert 2022
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