Febrile Seizures and Primary Human Herpesvirus 6 Infection

Primary human herpesvirus 6 infection is acquired mainly during the first two years of life and is often associated with febrile seizures. The aim of the present study was to investigate in Greece the frequency and clinical characteristics of primary human herpesvirus 6 (HHV-6) infection in hospitalized children with febrile seizures. Children aged from 6 months to 5 years without known neurologic disease were examined for primary HHV-6 infection, by real-time polymerase chain reaction in acute-phase plasma and by indirect immunofluorescent assay for antibody titers in acute and convalescent serum. Of 65 children included in the analysis, 55 experienced the first febrile episode of seizures and 10 the second. Primary HHV-6 infection was verified in 10 of 55 children with a first febrile episode (18%), whereas none of the 10 children with a second episode of seizures had primary HHV-6 infection. Eight children were infected with HHV-6 type B and two with type A. None of the 85 control subjects had primary HHV-6 infection, but 49% had immunoglobulin G antibodies against the virus. These findings suggest that primary HHV-6 infection is frequently associated with febrile seizures in children in this geographic region and should be considered, especially for a first episode of febrile seizures. (Ioanna Laina, Vassiliki P.et al. In Peditric Neurology, January 2010, Volume 42, Issue 1, Pages 28-31)

Antipyretic agents may not prevent febrile seizures, according to the results of a randomized, placebo-controlled, double-blind trial reported in the September issue of the Archives of Pediatrics & Adolescent Medicine.

"The general assumption has been that fever is the key factor in the initiation of a febrile seizure, and it has, therefore, been supposed that the administration of antipyretic agents during febrile episodes will prevent seizures and their recurrences by the lowering of the fever," write Teemu Strengell, MD, from the University of Oulu in Oulu, Finland, and colleagues. "This has not proved to be the case in clinical trials, however."

The goal of this study was to assess the effectiveness of different antipyretic agents and their highest recommended doses for preventing febrile seizures. At 5 hospitals, each of which was the only pediatric hospital in its region, 231 children who had their first febrile seizure between January 1, 1997, and December 31, 2003, were enrolled and observed for 2 years.

During follow-up, all febrile episodes were treated first with either rectal diclofenac or placebo, and after 8 hours, treatment was continued with oral ibuprofen, acetaminophen, or placebo. The primary endpoint of the study was recurrence of febrile seizures.

Of 851 febrile episodes occurring during follow-up, 89 were associated with a febrile seizure. Of the 231 children enrolled, 54 (23.4%) had recurrent febrile seizures. The treatment groups did not differ significantly in the main measure of effect, and the effect estimates were similar. The rate of febrile seizure recurrence was 23.4% (46/197) in those receiving antipyretic agents and 23.5% (8/34) in those receiving placebo (difference, 0.2; 95% confidence interval [CI], −12.8 to 17.6; P = .99).

Independent of the medication given, fever was significantly higher during the episodes with seizure vs those without seizure (39.7°C vs 38.9°C; difference, 0.7°C; 95% CI, −0.9°C to −0.6°C; P < .001).

"Antipyretic agents are ineffective for the prevention of recurrences of febrile seizures and for the lowering of body temperature in patients with a febrile episode that leads to a recurrent febrile seizure," the study authors write.

Limitations of this study include inability to exclude the possibility of a lesser effect that could be detected with a greater sample size. Parents were permitted to give their child an extra dose of open-label acetaminophen for temperature greater than 40.0°C, which could cause some dilutional bias.

"Because antipyretic agents are effective during a febrile episode that does not lead to a seizure, their use should not differ between patients with and without previous febrile seizures," the study authors conclude. "Parents should be informed about the inefficacy of antipyretic agents during a febrile episode that leads to a febrile seizure and about the benign nature of febrile seizures themselves."

Special State Grants for Health Research in the Department of Pediatrics and Adolescence in the Oulu University Hospital supported this study. The study authors have disclosed no relevant financial relationships.

Arch Pediatr Adolesc Med. 2009; 163:799-804. (From  Medscape Pediatrics, September 10, 2009 )