Nonfebrile Illness Seizures: A Unique Seizure Category?

Abstract

Summary: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• 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.The distinction between febrile seizures and unprovoked seizures has led to major changes in the clinical management of young children with a first seizure. By definition, a febrile seizure must be accompanied with a temperature of ≥100.4• F (38 • C), whereas children with unprovoked seizures are afebrile and have no significant signs of illness (1,2). Children having illnesses with minimal to no elevation of temperature are in a grey area and traditionally have not been thought to belong in either of the aforementioned groups; accordingly, they have been largely excluded from prognostic studies of first-time seizures. As a result, little descriptive information about these patients is available, and virtually no information exists that would inform clinical management and parent counseling.Recently, Lee and Ong (3) published the first controlled study of nonfebrile seizures occurring in the setting of illness. This study was performed in Singapore and demonstrated that diarrhea occurred more frequently in the setting of first-time nonfebrile illness seizures than in firsttime febrile seizures. In addition, several case reports have been published of nonfebrile seizures occurring with mild gastroenteritis where medically significant electrolyte abnormalities and dehydration were absent (4-7). These studies raise intriguing questions about the epidemiology and etiology of first-time nonfebrile seizures occurring in the setting of mild illness.We performed a retrospective pilot study with two aims: (a) to compare the clinical features of children with a firsttime nonfebrile seizure in the settin...

Protective Association Between Rotavirus Vaccination and Childhood Seizures in the Year Following Vaccination in US Children

“…However, these nonfebrile seizures may be etiologically most relevant to acute gastroenteritis infections and less genetically influenced than febrile seizures. Retrospective studies of first-time seizures occurring with mild acute illness found that diarrhea or gastroenteritis was a common feature of illness in children with first-time seizures, and was more common in children with nonfebrile seizures compared to children with febrile seizures (38%–52% vs 11%–16%, P < .001) [22, 43, 44]. …”

Childhood Febrile Seizures: Overview and Implications

“…Eighty percent of those pediatric seizure patients are diagnosed with febrile seizures, and 20% are diagnosed with afebrile seizures 48-50. Seizures of any type are usually a manifestation of a number of underlying pathologic conditions to differentiate between them, careful history taking, physical examination, and laboratory work-up are usually required.…”

Redefining Outcome of First Seizures by Acute Illness

“…3,4 The low incidence of unprovoked seizures in our study patients may have resulted from our structured and detailed in-person interviews regarding patient symptoms. Seizures that occurred in children with an illness, especially those without an associated fever, may have been mis-classified as unprovoked seizures in previous studies in which medical records were used for case identification.…”

“…1,2 Reports have suggested the presence of another, distinct category of provoked seizures, nonfebrile-illness seizures (or "afebrile benign convulsions"), which are not associated with a fever but occur in the presence of other symptoms of infection. 3,4 For parents whose child has had a first-time seizure, and for the physicians who treat them, the most salient concern once the child is stabilized regards the risk of recurrence. That risk has been well defined for febrile seizures but remains poorly defined for nonfebrile-illness seizures.…”

“…5 Retrospective analyses and case reports have shown that a subset of these seizures may be associated with diarrheal illness and that children who suffer a first seizure associated with a nonfebrile illness may have a lower risk of seizure recurrence compared with children with an unprovoked first seizure. 3,4,[6][7][8][9][10][11][12][13][14][15][16][17] However, prospective, systematically collected data are scarce in regard to the long-term prognosis of children with nonfebrileillness seizures, and few studies have included comprehensive viral testing on children with first-time seizures.…”