Studies on Convulsive Disorders in Young Children: I. Incidence of Febrile and Nonfebrile Convulsions by Age and Other Factors

Abstract

I n a cohort of 18,500 newborn infants, those who had experienced one or more convulsions were studied. Data were available for the unaffected as well as for the affected children. All families were members of a prepaid medical care program that provides comprehensive medical care.By five years of age, two percent of the 18,500 children had had one or more febrile convulsions; one percent had had nonfebrile convulsions. The incidence of the first nonfebrile seizure was highest during the first month of life; febrile convulsions reached a high peak during the second year of life.The risk of a febrile convulsion was equal for boys and girls but that of a nonfebrile seizure was higher for boys. The nonfebrile group had an excess of children with birth weights between 1500 and 2500 g, especially those whose gestational age was 37 weeks or more. The distribution by birth weight and gestational age of the febrile group was similar to that of the entire cohort.Multiple episodes occurred in one-third of the children of the febrile group and in three-quarters of the nonfebrile group. About 3 % of the children with febrile seizures later developed nonfebrile convulsions; about 7% of the nonfebrile group had initially a febrile seizure. Nearly 31 % in the nonfebrile group and 7 % in the febrile group had severe congenital anomalies; in the entire cohort only 3 % had such an anomaly before they reached age five. Among the children in the nonfebrile group were 10% with cerebral palsy and 16% with mental retardation including 5 % with both disorders. SpeculationAs the cohort of 18,500 children grows older, a certain number of them will develop real epilepsy. This study provides three distinct groups: children who had febrile convulsions, those who had nonfebrile convulsions, and those who had no seizures in early childhood. The future follow-up of these groups will provide the necessary data for determining the relative rates of developing epilepsy associated with the convulsion experience in early childhood.

A double blind, randomized, active controlled study to assess the safety, tolerability and immunogenicity of measles, mumps rubella, and varicella vaccine (MMRV) manufactured using an alternative process

“…Based on literature review, the incidence of febrile seizures in the second year of life is reported to be 1 to 2 per 1000 children per month in the general population (estimated prior to the introduction of many of the vaccines in the current pediatric schedule). [23][24][25][26][27][28][29] In addition, the number of febrile seizures observed in the MMRV AMP group is consistent with what would be expected for children in this age range based on estimates from incidence rates and times of follow-up. The observed imbalance between groups in the numbers of first occurrences of febrile seizures outside the primary safety period is not likely to be related to any true incidence difference between the groups.…”

Are MRI‐detected brain abnormalities associated with febrile seizure type?

“…We undertook a study to determine the frequency of MRI-detected brain abnormalities andFebrile seizures (FS) are common, affecting 2-5% of children by 6 years of age (van den Berg & Yerushalmy, 1969;Verity et al, 1985) and are associated with an increased risk of subsequent epilepsy. Epilepsy develops in 2-4% of children with a history of FS, four times more fre- (Nelson & Ellenberg, 1978;Annegers et al, 1979;Verity et al, 1985).…”

Epilepsy: some epidemiological aspects

“…While a specific association of childhood febrile seizures with temporal lobe epilepsy remains to be established, there is little doubt that early febrile seizures are associated with an excess risk of subsequent recurrent afebrile seizures generally (Van den Berg & Yerushalmy, 1969;Hauser & Kurland, 1975;Nelson & Ellenberg, 1976). The aetiological question is whether febrile seizures 'kindle' later seizures, whether they indicate an epileptic predisposition, or whether both processes are involved.…”

“…The rate for the remainder of the first year stabilized at a monthly rate of about 0-20 per 1000 and continued to decline unevenly thereafter. By the age of 5, about 10 per 1000 of the cohort had had at least one afebrile fit (Van den Berg & Yerushalmy, 1969).…”