First seizure with fever at 18 months
An 18-month-old girl is brought to the emergency department 40 minutes after a generalised tonic–clonic seizure that lasted about two minutes. She had been febrile since the previous evening (39.4 °C axillary) with coryzal symptoms. She is now alert, playful and drinking. Immunisations are up to date, including MMR at 12 months. Weight 11 kg; temperature now 38.1 °C, heart rate 130, capillary refill under 2 seconds, chest clear, ears normal. There is no neck stiffness, the fontanelle is closed and there is no rash. She has had no previous seizures. Her 4-year-old brother had a febrile seizure at 2 years. The parents are frightened: the father is convinced the child has epilepsy and wants an MRI and an EEG tonight, while the mother asks whether antipyretics given every four hours could have prevented this.
1. Classify this event and justify which investigations, if any, you would perform in the emergency department.
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This is a simple febrile seizure: age 6–60 months, generalised, under 15 minutes, single within 24 hours, no focal features, and a normal post-ictal examination in a child who is now alert and playing.
Do not do routinely: electrolytes, calcium, glucose (unless obtunded or the seizure was prolonged), full blood count, blood culture, EEG, CT or MRI. None of these change management in a well-appearing child with a first simple febrile seizure, and an EEG in the immediate post-ictal period is uninterpretable and does not predict recurrence.
Do look for the source of fever: otoscopy, throat, chest, skin, and a urine sample if no focus is found - urinary tract infection is a common occult cause at this age.
Meningitis must be considered in every febrile child who seizes. She is fully immunised, older than 12 months, has no neck stiffness, no rash and no persisting altered consciousness, so lumbar puncture is not indicated. It would be indicated below 12 months (meningeal signs are unreliable), at 12–18 months if immunisation is incomplete or antibiotics have already been given, or at any age with meningeal signs, shock or failure to return to baseline.
If she remains well and drinking, discharge after observation with clear safety-netting is appropriate. Admission is for diagnostic uncertainty, a complex seizure, or a child not back to baseline.
2. How would you counsel the parents about recurrence, epilepsy risk and fever control?
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Give concrete numbers, because vague reassurance does not work.
- Recurrence: about one child in three has another febrile seizure. Risk is higher if the first occurred under 18 months, if there is a family history, if the seizure came soon after the fever began, and if the peak temperature was relatively low. She has two of those factors, so prepare them for around a 35–40% chance.
- Epilepsy: the risk after simple febrile seizures is roughly 2% by school age against a background of about 1%. Reassure them that the seizure did not damage her brain, will not affect her intelligence, and does not require long-term medication.
- Fever control: antipyretics given round the clock do not prevent recurrence - the seizure is triggered by the rate of temperature rise, not the height of the fever. Paracetamol or ibuprofen should be used only for her comfort. Prophylactic diazepam at the start of each illness reduces recurrence but causes sedation and is not routine; consider it only for recurrent prolonged seizures.
Give a written first-aid plan: place her on her side, time the seizure, put nothing in the mouth, do not restrain. Call an ambulance if it lasts more than 5 minutes. Ensure they know where to go and whom to call, and offer a follow-up appointment, since parental anxiety - not the seizure - is the main morbidity here.
3. What features would change your management, and what would you do differently if the seizure had lasted 12 minutes?
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Features that change the pathway: focal onset or focal features; duration over 15 minutes; a second seizure within 24 hours (all define a complex febrile seizure); age under 12 months; incomplete immunisation or recent antibiotics; meningeal signs, shock or persisting drowsiness; a known neurodevelopmental disorder; unexplained bruising or an inconsistent history. Any of these shift the child from discharge to investigation, lumbar puncture and/or admission.
A 12-minute seizure is a different emergency. It is a prolonged febrile seizure and the priority is airway, breathing, circulation, oxygen, and a capillary glucose.
- Give a benzodiazepine promptly - buccal midazolam 0.3–0.5 mg/kg (about 5 mg in this 11 kg child) or rectal diazepam 0.5 mg/kg - and reassess after 5 minutes.
- If still seizing, repeat the benzodiazepine once only, and secure IV access for IV lorazepam 0.1 mg/kg.
- If seizures continue beyond about 10 minutes of benzodiazepine therapy, treat as status epilepticus: escalate to levetiracetam 40 mg/kg or phenytoin 20 mg/kg with cardiac monitoring, and involve senior and anaesthetic support.
- Once stabilised, perform a lumbar puncture and bloods, admit for observation, and arrange EEG only if recovery is atypical.
- Afterwards, discuss a rescue benzodiazepine prescription and a written emergency plan with the parents.