Saturday 16 May 2009

Guidelines Issued for Management of Simple Febrile Seizures in Children

The American Academy of Pediatrics (AAP) has issued a clinical practice guideline for the long-term treatment of children who have simple febrile seizures and has published these recommendations in the June issue of Pediatrics.

"Febrile seizures are the most common seizure disorder in childhood, affecting 2% to 5% of children between the ages of 6 and 60 months," write Patricia K. Duffner, MD, chairperson, Steering Committee on Quality Improvement and Management, Subcommittee on Febrile Seizures, and colleagues from the AAP. "Simple febrile seizures are defined as brief (< 15-minute) generalized seizures that occur once during a 24-hour period in a febrile child who does not have an intracranial infection, metabolic disturbance, or history of afebrile seizures. This guideline (a revision of the 1999 . . . AAP practice parameter). . . addresses the risks and benefits of both continuous and intermittent anticonvulsant therapy as well as the use of antipyretics in children with simple febrile seizures."

The goals of implementing this practice guideline include the following:

* Optimizing understanding by practitioners of the scientific basis underlying the use or avoidance of various proposed treatments of children with simple febrile seizures.
* Improvement in the health of children with simple febrile seizures by avoidance of treatments likely to cause adverse effects and without proven ability to improve children's long-term outcomes.
* Cost reduction by avoiding treatments not likely to significantly improve children's long-term outcomes.
* Assisting the practitioner in caregiver education regarding the low risks associated with simple febrile seizures.

In children between the ages of 6 and 60 months, a simple febrile seizure is a benign and common event, and nearly all children have an excellent prognosis. Except for a high rate of recurrence, no long-term sequelae of simple febrile seizures have been identified.

Although the risk that children with simple febrile seizures will develop epilepsy is extremely low, it is slightly higher than that in the general population. Because epilepsy most likely results from genetic predisposition rather than structural damage to the brain caused by recurrent simple febrile seizures, there is no evidence that prophylactic treatment of children with simple febrile seizures would reduce the risk.

Antipyretics are not effective in the prevention of recurrence of febrile seizures. However, studies to date suggest that continuous anticonvulsant therapy with phenobarbital, primidone, or valproic acid and intermittent therapy with diazepam effectively decrease recurrence of febrile seizures. The relatively minor risks linked to simple febrile seizures do not justify the potential toxicity of the above-mentioned antiepileptic drugs.

Therefore, on the basis of the risks and benefits of the therapies shown to be effective, the committee concluded that neither continuous nor intermittent anticonvulsant therapy is recommended for children who have 1 or more simple febrile seizures.

"In situations in which parental anxiety associated with febrile seizures is severe, intermittent oral diazepam at the onset of febrile illness may be effective in preventing recurrence," the guidelines authors write. "Although antipyretics may improve the comfort of the child, they will not prevent febrile seizures. . . . Because the risks associated with simple febrile seizures, other than recurrence, are so low and because the number of children who have febrile seizures in the first few years of life is so high, to be commensurate, a proposed therapy would need to be exceedingly low in risks and adverse effects, inexpensive, and highly effective."

Four potentially adverse outcomes that could theoretically follow a simple febrile seizure are a decline in IQ, an increased risk for epilepsy, the risk for recurrent febrile seizures, and death. Decrease in cognitive or academic performance, inattention, and behavioral abnormalities have not been linked to recurrent simple febrile seizures. A study showed no difference in learning except in those children who had neurologic abnormalities before their first seizure.

In children with simple febrile seizures, the risk for the development of epilepsy by the age of 7 years is approximately 1%, which is the same as in the general population. However, children with multiple simple febrile seizures beginning at age 12 months or younger and with a family history of epilepsy are at higher risk, with generalized afebrile seizures developing in 2.4% by 25 years of age. However, no study has shown that successful treatment of simple febrile seizures can prevent this later development of epilepsy, and there is no evidence to date that simple febrile seizures can cause structural damage to the brain.

Recurrence rate is high for simple febrile seizures and varies with age: approximately 50% for children younger than 12 months when they have their first simple febrile seizure, and approximately 30% for those older than 12 months. Of those children who do have a second febrile seizure, 50% have a chance of having at least 1 additional recurrence.

Although there is a theoretic risk for death from a simple febrile seizure caused by injury, aspiration, or cardiac arrhythmia, this has never been reported.

"[This guideline] is designed to assist pediatricians by providing an analytic framework for decisions regarding possible therapeutic interventions in this patient population," the guidelines authors conclude. "It is not intended to replace clinical judgment or to establish a protocol for all patients with this disorder. Rarely will these guidelines be the only approach to this problem."

Pediatrics. 2008;121:1281-1286.
Clinical Context

Febrile seizures occur in 2% to 5% of children aged 6 to 60 months. Simple vs complex febrile seizures are distinguished by duration (less than vs more than 15 minutes), type (generalized vs focal), and frequency (once vs more than once in 24 hours).

According to Berg and colleagues in the April 1997 issue of the Archives of Pediatrics & Adolescent Medicine, the probability of recurrent simple febrile seizures is 50% for children younger than 12 months at the time of the first seizure and 30% for children older than 12 months. Nelson and Ellenberg reported in the November 4, 1976, issue of the New England Journal of Medicine that the risk for the development of epilepsy after a simple febrile seizure is 1% by age 7 years, which is the same risk for the general population. Subsequently, Annegers and colleagues noted in the February 26, 1987, issue of the New England Journal of Medicine that the risk for epilepsy is 2.4% by age 25 years in those with recurrent simple febrile seizures, age younger than 12 months at the time of the first febrile seizure, and a family history of epilepsy.
Study Highlights

* 65 additional articles were reviewed.
* Inclusion criteria were delineation of simple febrile seizures, matched treatment and control groups, and description of treatment adherence.
* The guidelines do not apply to children with history of neurologic insults, central nervous system abnormalities, complex febrile seizure, or afebrile seizures.
* Neither continuous nor intermittent anticonvulsants are recommended for children with simple febrile seizure, according to randomized controlled trials and diagnostic studies with minor limitations.
* Benefit of treatment (prevention of febrile seizures, which have no long-lasting harmful effects) is outweighed by the potential harm of treatment from anticonvulsant adverse effects.
* Continuous (daily) anticonvulsant treatment:
o Phenobarbital in the therapeutic range decreased the annual rate of recurrent febrile seizures from 25 per 100 subjects to 5 per 100 subjects.
o Phenobarbital adverse effects include hyperactivity, irritability, lethargy, sleep disturbances, and hypersensitivity.
o Behavioral adverse effects of phenobarbital can occur in 20% to 40% of patients.
o Doses of primidone at 15 to 20 mg/kg reduce the recurrence of febrile seizures, even if the derived phenobarbital level is subtherapeutic.
o Adverse effects of primidone include behavioral disturbances, irritability, and sleep disturbances.
o Treatment with valproic acid vs placebo reduces the occurrence of recurrent febrile seizure (4% vs 35%).
o Adverse effects of valproic acid include rare fatal hepatotoxicity (particularly if age < 2 years), thrombocytopenia, change in weight, gastrointestinal tract disturbances, and pancreatitis.
* Daily carbamazepine and phenytoin are not effective in the prevention of simple febrile seizures.
* Intermittent anticonvulsant treatment:
o Intermittent oral diazepam at the time of fever vs no treatment decreases the recurrence of simple febrile seizures (11% vs 30%) and might be indicated if parents have severe anxiety about recurrence.
o Intermittent agents that terminate a simple febrile seizure of less than 5 minutes' duration are rectal diazepam and intranasal or buccal midazolam.
o Administration of rectal diazepam at the time of fever to prevent seizure vs at onset of seizure to treat seizure did not affect long-term prognosis.
o Intermittent therapy might not be effective if seizure occurs before the fever is noted.
o Adverse effects of diazepam and midazolam are lethargy, drowsiness, and ataxia.
* Antipyretics, including aspirin, acetaminophen, and ibuprofen, do not reduce the risk for seizure recurrence.
* Adverse effects of acetaminophen include hepatotoxicity.
* Adverse effects of ibuprofen include respiratory failure, metabolic acidosis, renal failure, and coma.

Pearls for Practice

* Continuous phenobarbital, primidone, or valproic acid therapy and intermittent diazepam therapy are effective in the prevention of simple febrile seizures in children but are not recommended because the risk for anticonvulsant toxicity outweighs the possible benefits.
* Antipyretics are not effective in the prevention of recurrent febrile seizures in children.

Source : http://cme.medscape.com/viewarticle/575603?sssdmh=dm1.472244&src=nldne

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