Febrile Seizures

A febrile seizure is a seizure occurring with fever in a child approximately 6 months to 5 years old, without CNS infection, acute metabolic disturbance, or a previous afebrile seizure explaining the event.

A simple febrile seizure is generalized, lasts less than 15 minutes and occurs once within 24 hours.

A complex febrile seizure is focal, lasts 15 minutes or longer, or recurs within 24 hours.

Most febrile seizures are benign. The critical clinical task is distinguishing an uncomplicated febrile seizure from meningitis, encephalitis, metabolic disturbance or another neurological emergency.

Simple febrile seizures are generalized and followed by relatively rapid return toward baseline.

Features requiring more cautious assessment include:

• Focal seizure activity
• Prolonged seizure
• Repeated seizures within the same illness
• Persistent reduced consciousness
• Neck stiffness
• Bulging fontanelle
• Petechial or purpuric rash
• Focal neurological deficit
• Persistent vomiting
• Significant irritability or toxic appearance

Diagnosis is clinical.

Identify the source of fever and assess specifically for CNS infection.

Routine EEG, CT, MRI and extensive laboratory investigation are unnecessary after a typical simple febrile seizure in a neurologically normal child.

Lumbar puncture is indicated when meningitis or encephalitis is clinically suspected, not merely because a febrile seizure occurred.

Check glucose in a child who is still convulsing, significantly unwell or has persistent altered consciousness.

If the seizure has stopped spontaneously, emergency anticonvulsant treatment is unnecessary.

A seizure continuing beyond 5 minutes should be treated as an acute prolonged seizure with a benzodiazepine.

Treat the underlying febrile illness.

For discomfort:

Paracetamol 10 to 15 mg/kg PO every 6 to 8 hours as required, maximum 75 mg/kg/day, without exceeding the adult maximum.

Antipyretics improve comfort but do not reliably prevent another febrile seizure.

Routine long term anticonvulsant prophylaxis is not recommended after simple febrile seizures.