Febrile Seizures
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Direct answer
A febrile seizure occurs with fever of at least 38 degrees Celsius in a neurologically healthy child between six months and five years (peak 12-18 months), in whom CNS infection, metabolic derangement and prior afebrile seizures have been excluded. Simple seizures — the great majority — are generalised, last under 15 minutes, do not recur within the illness and leave no focal deficit; complex seizures have focal features, last beyond 15 minutes or recur within 24 hours. Acute care is positioning and timing, with a benzodiazepine only beyond about five minutes.
What you must remember
- Definition: fever of 38 degrees Celsius or more, age six months to five years, no CNS infection, no metabolic cause and no previous afebrile seizure — all conditions must hold.
- Simple versus complex: simple — generalised, under 15 minutes, one per illness, no focal features; complex — any focal feature, longer than 15 minutes, or recurrence within 24 hours, with higher later epilepsy risk.
- Acute management: turn the child to the side, protect from injury and time the seizure; past about five minutes, give buccal or intranasal midazolam or rectal diazepam, then hospital assessment.
- Investigation rules: a child who recovers fully after a simple seizure needs no EEG, neuroimaging or lumbar puncture — testing targets the fever source instead.
- Lumbar puncture considerations: for meningeal signs, or an incompletely immunised or pretreated infant under about a year — not routinely after a simple seizure in a well child.
- Recurrence: roughly a third of children have another febrile seizure, risk raised by young age at onset, family history and low fever degree.
- Prognosis: most never develop epilepsy, the risk rising mainly with complex features or family epilepsy; antipyretics do not prevent recurrence, and continuous antiepileptics are rarely justified.
Common confusion
The classic trap is missing meningitis: a seizing febrile child under one year who is irritable, has a bulging fontanelle or is incompletely immunised needs lumbar puncture, whereas the playful toddler after a brief generalised seizure does not. The second confusion is parental expectation of fever control — paracetamol and sponging comfort but have never prevented febrile seizures. A first seizure in an older child, or any focal onset, shifts the differential toward epilepsy instead.
Exam-focused takeaway
NEET-PG tests definitional precision and restraint: the age window, the four exclusions and the simple-versus-complex columns (15 minutes, focality, recurrence in 24 hours). Management stems ask the first step (side positioning and timing), the drug beyond five minutes (buccal midazolam or rectal diazepam) and — most often — which test is not needed (EEG, CT or routine LP after a simple seizure). Prognosis one-liners cover the one-in-three recurrence figure and the epilepsy risk with complex features.
Frequently asked questions
What defines a febrile seizure?
A seizure with fever of 38 degrees Celsius or more in a child of six months to five years, with no CNS infection, no metabolic cause and no prior afebrile seizures.
How do simple and complex types differ?
Simple seizures are generalised, under 15 minutes, solitary per illness and non-focal; complex seizures are focal, prolonged beyond 15 minutes or recurrent within 24 hours.
What is the immediate management?
Place the child on the side, protect from injury and time it; past five minutes, give buccal or intranasal midazolam or rectal diazepam.
Which children need a lumbar puncture?
Those with meningeal signs, or incompletely immunised or pretreated infants under a year — not the well child after a simple seizure.
What is the chance of recurrence and epilepsy?
About one in three recur, highest with young onset and family history; epilepsy stays uncommon, rising chiefly with complex seizures.