Elsevier

Pediatric Neurology

Volume 30, Issue 3, March 2004, Pages 201-206
Pediatric Neurology

Original article
Clinical and electroencephalographic follow-up after a first unprovoked seizure

https://doi.org/10.1016/j.pediatrneurol.2003.08.002Get rights and content

Abstract

We studied the role of clinical and electroencephalographic factors in the follow-up of children and adolescents after a first unprovoked seizure, and their correlation with recurrence and risk for epilepsy. We conducted a 24-month follow-up of 109 patients aged 1 month to 16 years who had a first unprovoked seizure. We analyzed the characteristics of the first seizure, perinatal history, family history of seizures, electroencephalographic patterns and their influence on seizure recurrence, and calculated risk for subsequent epilepsy. Fifty-six patients (51.4%) had recurrent seizures. The bivariate statistical analysis revealed that maternal prenatal disease (relative risk = 2.02, P = 0.03) and an abnormal electroencephalogram (relative risk = 2.89, P = 0.0003) were significantly associated with seizure recurrence. Other factors (male sex, partial first seizure, vaginal delivery, family history of seizures, and sleep state) approached statistical significance. Logistic regression revealed that the only variable significantly associated with recurrence was an abnormal electroencephalographic pattern on the first examination (relative risk = 2.48, P = 0.003). Cumulative risk ranged from 50–68% at 24 months when the first electroencephalogram was abnormal, and from 26–36% when it was normal. We concluded that the electroencephalogram may have an important diagnostic value in the prognosis of epileptic seizure recurrence in children and adolescents.

Introduction

Seizure and epilepsy are not synonymous: epilepsy refers to recurrent unprovoked seizures [1], [2]. The onset of epilepsy usually occurs in childhood, and that explains the concern about the risk for recurrence after the first seizure [3], [4], [5]. Several factors predictive of recurrence have been pointed out—age of onset, sex, perinatal and family history, characteristics of the seizure, whether the child was awake or asleep at the time of seizure, and electroencephalographic epileptiform patterns—but no consensus has been reached [6], [7], [8], [9], [10], [11], [12].

Few studies about the risk factors for epilepsy [8], [10], [13] or the incidence and prevalence of epilepsy in Brazil have been conducted so far: some studies revealed prevalence rates of 1/1000 in the general population and 8/1000 among children 5 to 14 years of age [14], [15]. Therefore the purpose of this study was to evaluate clinical and electroencephalographic factors associated with the recurrence of seizures in childhood.

Section snippets

Methods

We followed a cohort of 109 children and adolescents age 1 month to 16 years who were consecutively observed 24 to 72 hours after the seizure at the Epilepsy Outpatient Service, Hospital de Clínicas de Porto Alegre, Brazil, from July 1999 to June 2002. Patients were included in the study if they had a first unprovoked seizure or multiple seizures occurring within 24 hours, and if they were not taking antiepileptic drugs. Either one parent or the person responsible for the child signed an

Demographic characteristics

Patients' ages ranged from 1 month to 16 years (mean = 6 years; S.D. = 1 year and 6 months). Most patients were 6 to 12 years of age. Seventy patients (64.2%) were male, and 39 (35.8%) female. Ninety-two patients (84.4%) were Caucasian, and 17 (16.5%), non-Caucasian. The educational level of patients matched age distribution, and the predominant educational level for parents was 8 years (68 parents, 62.4%). Table 1 summarizes the demographic characteristics and relative risk for subsequent

Discussion

According to the literature on epilepsy in childhood, the incidence of seizures is highest among Caucasian males 1 to 38 months old [8], [10], [18], [19], [20]. Camfield et al. [21] conducted a population-based study of the incidence of epilepsy in childhood and adolescence in Nova Scotia and found a rate of 48/100,000 in the 1- to 5-year age group, and 43/100,000 in the 6- to 10-year age group, with the lowest rates being observed in infants and adolescents. Hauser [22], however, conducted an

Acknowledgements

The authors thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico–CNPQ (Brazilian Agency for Scientific and Technological Development) for the support provided to the development of this study.

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