Nonfebrile illness seizures: a unique seizure category?

Purpose: To describe the clinical characteristics of children with a first-time nonfebrile seizure in the setting of mild illness and to test the hypothesis that these seizures are associated with illness characterized by diarrhea.
Methods: This retrospective cohort study was performed in a pediatric emergency department. Patients ages 6 months to 6 years who were evaluated with first-time seizures were eligible for inclusion. Subjects were divided into three groups on the basis of symptoms accompanying their seizure: febrile (temperature, >38.0 degrees C with seizure), unprovoked (no symptoms of illness), and nonfebrile illness (no fever at the time of seizure, but other symptoms of illness present).
Results: Of the 323 children with first-time seizures, 247 (76%) had febrile seizure, 37 (12%) had unprovoked seizures, and 39 (12%) had nonfebrile illness seizures. Children with nonfebrile illness seizures were more likely than children with febrile seizures to have diarrheal illnesses accompanying their seizure (44 vs. 16%; p=0.001). Frequency of cough, rhinorrhea, and rash did not differ significantly between children with febrile and nonfebrile illness seizures. Diagnostic testing for infectious etiologies was not performed frequently in either group.
Conclusions: Nonfebrile illness seizures may represent a distinct group of seizures with unique epidemiology. Further study to define this seizure group better is warranted.