Febrile convulsions are a common pediatric neurological disease, and it is important to prevent such a disease by controlling the risk factors that may recur. A recent report states that influenza virus infections have a high probability of a relationship with febrile convulsions; therefore, it is necessary to identify the clinical properties of febrile convulsions in relation to domestic influenza virus infections.

Between November 2005 and February 2008, children hospitalized because of febrile convulsions and subsequently confirmed to have influenza infections were enrolled as subjects (patient group, n=11). The control subjects were those admitted with influenza virus infections but no febrile convulsions (control group 1, n=46) and those who developed febrile convulsions without influenza virus infection (control group 2, n=53).

The patient group showed a higher maximum body temperature (39.3±0.5℃), more histories of past febrile convulsions (72.7%), and a shorter total duration of fever (2.9±1.2 days) than control group 1. When multivariate analysis was performed, the probability of febrile convulsions was found to be as high as 225.9 times in patients who had influenza virus infections with a past history of febrile convulsions (OR=225.9, 95% CI: 1.7-4780.0, P <0.05). When patients with febrile convulsions were compared based on the symptoms of influenza virus infections, the patient group showed a shorter duration of fever (0.9±0.7 days) before convulsion than control group 2; these convulsions were mostly a recurrence of febrile convulsions. When multivariate analysis was performed, the cases with a past history of febrile convulsions showed 5.5 times (OR=5.5, 95% CI: 1.2-25.1, P =0.03) the probability of convulsions when infected with the influenza virus, and this probabilit. decreased by 0.3 times over one-day increments of the febrile period until febrile convulsions (95% CI: 0.1-0.9, P =0.02). Maximum body temperature, total duration of fever, family history of febrile convulsions, and complex febrile convulsions did not show a statistical significance.

In cases of pediatric influenza virus infection, the past history of febrile convulsions could be identified within the risk factor of recurrent febrile convulsions. Therefore, influenza vaccination of children having a past history of febrile convulsions will be helpful to avoid the recurrence of these convulsions.