Febrile Seizures: What you need to know

The International League Against Epilepsy (ILAE) defines febrile seizure as “a seizure occurring in childhood after one month of age; associated with a febrile illness not caused by an infection of the central nervous system, without previous neonatal seizures or a previous unprovoked seizure and not meeting the criteria for other acute symptomatic seizures”

The peak incidence  is seen at 18 months and is most common between ages of six months and six years.  Generalized Tonic-Clonic Seizure are by far the most common seizure type accounting for 80% of all seizure types. Staring accompanied by stiffness or floppiness, rhythmic jerking movements without prior stiffening, focal stiffness or jerking are the other common seizure types.

Simple febrile seizure refers to short generalized seizure, of duration <15 minutes which does not recur within 24 hours. Another variant of this disease is complex febrile seizure. A focal, or generalized and prolonged seizure of duration greater than 15 minutes, recurring more than once in 24 hours, and/or associated with postictal neurologic abnormalities, more frequently a postictal palsy (Todd’s palsy), or with previous neurologic deficits are markers of this subtype.

Febrile status epilepticus is a subgroup of complex febrile seizures with seizures lasting more than 30 minutes and occur in about 5% of cases.

The most pertinent question here is to know whether this seizure is a febrile seizure or seizures with fever. Febrile seizure occurs due to an age-related and predominantly genetic benign susceptibility to epileptic fits precipitated by fever without evidence of intracranial infection or other cause.  Children who have suffered a previous non-febrile seizure are excluded.

The risk factors that generate febrile seizures among children are; brain temperature, fever mediators, genetic factors.

Will this child face a rough tide?

The answer depends on whether the seizure is a simple or complex febrile seizure.  Also, knowing the predictors of recurrent febrile seizure and knowing the predictors of later epilepsy are very important.

Risk of Recurrence

Risk factors for recurrence include early age of onset (<15 months), epilepsy in first-degree relatives, febrile seizures in first-degree relatives, frequent febrile illness, low temperature at the onset of the febrile seizure.

Recurrence frequency is 10% in patients with no risk factors, 25–50% in the presence of 1–2 risk factors, 50 – 100% in the presence of 3 or more risk factors.

Abnormal neurological or developmental status before the first seizure, and focal febrile seizure with impaired awareness are the significant risk factors for later epilepsy.

The risk of epilepsy is estimated at around 1–1.5% in patients with Focal febrile seizure with preserved awareness. The risk of epilepsy in subjects with Focal febrile seizure with impaired awareness is, instead, estimated between 4 and 15%.

What is the treatment strategy?

Majority of the children require only intermittent prophylaxis with anti seizure medications to be taken only during periods of febrile illness. However certain redflags if identified requires daily treatment with medications as per advice of treating Neurologist or Epileptologist.