Indian Write- Ups

[Q.1] What is febrile seizure ?

Febrile seizure is an event in infancy of childhood, usually occurring between 3 months and 5 years of age, associated with fever but without evidence of intracranial infection.

[Q.2] What is the incidence of febrile seizure ?

Febrile seizure is the commonest neurological problem in pediatrics. 2.5% of all children will experience one or more convulsions with febrile illness before the age of 5 years. In developing countries because of infections, it may be higher.

[Q.3] What is the etiology of febrile seizures ?

Fever due to any cause can give rise to seizures in genetically susceptible children. Fever is usually more than 102 degree F but even at a lower temperature, it can precipitate seizures.

Common causes of febrile seizure are upper respiratory infections, otitis media, pheumonia, influenza like diseases, gastroenteritis and urinary tract infections. Bacterial and parasitic infections like typhoid, dysentery, malaria are less common. Sometimes it follows vaccination induced fever.

Family history of febrile seizures in parents, other sibs and relatives is present in 35-40% suggesting genetic predisposition as an important causative factor in febrile seizures.

[Q.4] What are the various type of febrile seizures ?

There are two types, typical/simple and atypical/complex. Typical is characterised by generalised tonic clonic seizures, occurring once in 24 hours of fever at the onset, not lasting for more than 15 minutes, and not followed by post ictal manifestations.

Atypical is characterised by unilateral convulsions with or without Todd’s paralysis, lasting for more than 15 minutes and occurs frequently during a febrile episode. Status lasting for a long time can occur in both atypical and typical varieties. Occurrence of febrile seizures after 24 hours of fever is unusual and another etiology should be sought. Atypical seizures are common in children with prior CNS and family history of epilepsy.

[Q.5] Should EEG be performed in febrile seizures ?

EEG is usually asked for in febrile seizures. As such it is not helpful in children with first or recurrent seizures. Quite often it shows non specific abnormalities. Spike and wave abnormalities are not a guide to treatment and prognosis as to the future development of epilepsy.

[Q.6] Should neuroimaging be performed in febrile seizures ?

Neuroimaging is not needed in febrile seizures. In those children with prior CNS abnormalities, it may show structural abnormalities in few cases.

[Q.7] What is the differential diagnosis of febrile seizures ?

Most important condition to rule out is meningoencephalitis. Lumbar puncture may be normal in very early cases of meningitis and some of the encephalopathies may have normal lumber puncture.

Sometimes fever may be associated with severe rigors, delirium or syncope which should not be interpreted as seizures. Fever triggered epilepsy should be considered in febrile seizures after 6 years of age.

[Q.8] Should a lumber puncture be done in all cases of febrile seizures ?

LP is mandatory in all cases of convulsions in patients below 6 months of age, because pyogenic meningitis is common and febrile seizures are rare. It should be done in all cases with first episode of febrile seizures between 6-18 months age, are signs of meningitis are not obvious. Some of the pediatricians avoid LP and observe. Above the age of 18 months, signs of meningitis are usually obvious and LP should be done in selected cases.

[Q.9] What is the incidence of recurrent febrile seizures and future epilepsy?

Risk of recurrence is 30% after 1st seizure, 40% after 3 seizures and in 5% more recurrences. Future epilepsy occurs in 1% of typical and 10% of atypical febrile seizures and is common with abnormal neurodevelopment prior to febrile seizures and in those with family history of epilepsy. Those with febrile convulsive status are likely to develop CNS insult.

[Q.10] What is the management of febrile seizures?

One must try to bring the fever with antipyretics and sponging, and treat the cause of fever. If the child is convulsing, either I.V. or per rectal diazepam should be used in doses of 0.3 – 0.5 mg/kg, depending on whether veins are accessible or not. Prophylactic treatment for seizures is divided into:

• Prevention of seizures during febrile episode (Intermittent therapy)
• Prevention of recurrences (continuous prophylaxis)
  
  
  • A first sign of fever, oral or per-rectal diazepam should be used (0.5/kg/dose), three times a day for first 24 hours. Oral clonozepam or clobazam are also helpful. Parents should be properly instructed to carry out the treatment at home.
  • For prevention of recurrences, phenobarbitone in doses of 3-5 mg/kg/day or sodium valproate in doses of 20 mg/kg/day have been found to be useful but side effects of hyperactivity and hepatotoxicity respectively and problems with compliance have led many to give up continuous therapy and prefer intermittent therapy. Optimal duration for continuous therapy is one year or up to the age of 3 years whichever is earlier. Future epilepsy can never be prevented by continuous therapy.