Original articleFebrile Seizures
Section snippets
Epidemiology
Febrile seizures are the most common type of seizure in childhood. In children younger than 5 years, febrile seizures occur in 5% to 10% of East Indians (Waruiru & Appleton, 2004), 6% to 9% of Japanese (Chiu, Tse, Lau, & Peiris, 2001), 2% to 5% of Whites (Srinivasan, Wallace, & Scheffer, 2005), and 0.35% to 1.5% of Chinese (Chung, Wat, & Wong, 2006). Febrile seizures are most common in children between 6 months and 3 years of age, with a peak incidence around 18 months (Leung and Robson 1991,
Etiology and Pathogenesis
There is a genetic predisposition to febrile seizures. The risk for the development of a febrile seizure is approximately 20% when a sibling is affected, and the risk increases to 33% when both parents also are affected (van Zeijl, Mullaart, & Galama, 2002). The concordance rate is approximately 35% to 69% in monozygotic twins and 14% to 20% in dizygotic twins (Shinnar and Glauser 2002, Babl et al 2006). The genes that might increase the risk for a febrile seizure have been mapped to
Clinical Manifestations
The majority of febrile seizures occur within 24 hours of the onset of fever (Leung and Robson 1991, Mukherjee and Mukherjee 2002). Seizures that occur 3 or more days after the onset of a fever should be suspect. Most children have a temperature of at least 39°C at the time of a seizure (Leung & Robson, 1991). A simple febrile seizure is usually generalized, is associated with tonic-clonic movements and rolling back of the eyeballs, lasts for a few seconds to a few minutes, and is followed by a
Clinical Evaluation
A detailed history is necessary to determine the source of the fever, the relationship of the seizure to the onset of fever, and the type of seizure (Leung & Robson, 1991). The history also should include whether the child was recently immunized, treated with an antibiotic, or attended day care. Fever is common in childhood and might occur coincidentally with a more serious underlying cause of seizure. As such, inquiry should be made about developmental milestones, ingestion of toxins, trauma
Diagnostic Studies
In the absence of an atypical history or physical examination, blood tests usually are not necessary. A complete blood cell count and blood tests for electrolytes, glucose, calcium, phosphorous, magnesium, creatinine, and urea nitrogen are not helpful in the evaluation of a child with a febrile seizure. Children with febrile seizures have a similar risk for occult bacteremia as do those with fever alone (Shah et al., 2002). A complete blood cell count is indicated in children who appear ill.
Complications and Prognosis
The overall prognosis for children with febrile seizures is excellent. The risk of epilepsy is low. By the age of 7 years, epilepsy will develop in approximately 0.9% of children who experience a simple febrile seizure, compared with 0.5% of children who do not have a history of a febrile seizure (Baumann, 1999). Risk factors for the development of epilepsy include an antecedent neurologic or developmental abnormality, a positive family history of epilepsy, a complex febrile seizure, and an
Management
We recommend that every parent take a community CPR course. A child with a seizure should be placed in a semi-prone position to decrease the risk of aspiration (Leung & Robson, 1991). A febrile seizure usually is self-limited, and intervention to stop the seizure usually is unnecessary. A seizure that is ongoing when the child arrives at a medical facility is an indication to initiate therapy. The seizure can be terminated with intravenous diazepam (0.2 mg/kg) or lorazepam (0.05 mg/kg) (
Prevention
Several studies have shown that daily administration of phenobarbital (5 to 8 mg/kg/day for children <2 years of age and 3 to 5 mg/kg/day for children >2 years of age) or valproic acid (10 to 15 mg/kg/day in divided doses) is effective to prevent febrile seizures (Millar 2006, Srinivasan et al 2005, Wheless et al 2005). Adverse effects of phenobarbital include transient sleep disturbances, daytime drowsiness, fussiness, attention deficit, hyperactivity, decreased memory, and impaired cognitive
Parental Education
Febrile seizures provoke appreciable anxiety in parents and older siblings. Parental anxiety often is due to poor parental knowledge, which can be improved with an educational intervention program (Huang, Liu, & Huang, 1998). Parents should be reassured of the benign nature and excellent prognosis of febrile seizures. They also should be reassured that the child will not die during a seizure and that treatment often is unnecessary, but that the child should be assessed at the time of each
Conclusion
Febrile seizures are common in children between 6 months and 3 years of age. Most of these children have an excellent outcome with no sequelae. The major risk is recurrence. Prophylactic anticonvulsant therapy is not recommended for the majority of children with febrile seizures. Parental education and counseling should be provided.
Alexander K.C. Leung is Clinical Associate Professor, Department of Pediatrics, the University of Calgary, and Medical Director, The Asian Medical Centre, an affiliate with The University of Calgary Medical Clinic, Calgary, Alberta, Canada.
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Alexander K.C. Leung is Clinical Associate Professor, Department of Pediatrics, the University of Calgary, and Medical Director, The Asian Medical Centre, an affiliate with The University of Calgary Medical Clinic, Calgary, Alberta, Canada.
W. Lane M. Robson is Medical Director of The Childrens’ Clinic, Calgary, Alberta, Canada.
Reprints are not available from the author.