Febrile seizures

Febrile seizures occur during an acute febrile illness for which no cause can be found. This type of seizure affects 2–4% of children aged 3 months to 5 years.
Genetic factors are involved with both autosomal dominant and polygenic inheritance. During febrile seizures, most children have respiratory tract infections. There is a substantial risk of occurrence in the 24 h after receiving the diphtheria-pertussis-tetanus vaccine and in the 8–14 days after the measles, mumps, and rubella vaccine.
Febrile seizures are classed as simple when they are generalised, do not recur within the same illness, and last less than 15 min. Febrile seizures are termedcomplex when they have focal features, are repeated within the same illness, and are prolonged (>15 min). Neurological abnormalities predispose to complex febrile seizures, which, in turn, have a higher risk of subsequent epilepsy.
Lumbar puncture is advised if there are signs of meningism or the child is younger than 18 months. Neuroimaging should be reserved to children with prolonged postictal unresponsiveness or focal deficits.
Most febrile seizures are short but those lasting longer than several minutes should be treated with rectal diazepam. Recurrence risk is 30–40%. Prophylactic treatment is only justified in children who have had a prolonged febrile seizures. Rectal diazepam at the onset of a new FS should be preferred to continuous oral valproate or phenobarbital. Intermittent prophylaxis at times of fever is discouraged. About 3–6% of children with febrile seizures will have epilepsy later in life, especially idiopathic generalised epilepsies.

If you have a child who you think may have this condition and you would like us to review the diagnosis or provide genetic testing please contact us at neuroscience@meyer.it.