Nested Case-Control Study of Children Presenting with First Afebrile Seizure at KKH: Seizure Recurrence and Comorbidities

Abstract

Introduction: First afebrile seizures are common in Singapore (incidence 24 per 100,000 person-years). We determined the seizure recurrence risk after first afebrile seizure, the risk factors at presentation and evaluated the quality of life of these children. Methods: Nested case-control study of children presenting with their first afebrile seizure from 2002 to 2004. Risk factors were measured at initial presentation. This follow-up study administered standardised telephone questionnaires to patients/caregivers seven years later. Subjects with only one afebrile seizure (1AS) were compared to those with recurrent afebrile seizures (RAS) for birth history, risk factors, developmental delay, school status, initial electroencephalogram (EEG), neuroimaging and initial seizure episode using Fisher's exact test. Quality of life was screened with a questionnaire. Results: Of 103 eligible subjects, 54 responded with seizures recurring in 21 (38.9%). Initial seizure frequency was yearly at 57.9%. The RAS group had more risk factors ( P =0.013) and greater frequency of abnormal initial development ( P <0.005), abnormal neurological examination in this population ( P =0.033) and abnormal current development ( P =0.028). Quality of life differed in behavioural changes ( P =0.022) and parental relationship with spouses ( P =0.004). EEG and neuroimaging were not predictive. Number of initial seizure episodes showed a significant difference between 1AS and RAS groups ( P =0.037). Conclusion: Abnormal development and neurological examination are risk factors for seizure recurrence after the first afebrile seizure. Children with more than four seizures during the initial seizure presentation may be at an increased risk of seizure recurrence. Recurrent seizures affect quality of life of both the affected child and the family.