Introduction
Febrile seizures (FS) are the most common seizures that occur with a temperature of 38 ºC or higher in the absence of a history of prior a FS. It is seen with afebrile illness not caused by a central nervous system infection or any metabolic imbalance. FS are usually seen between the ages of 6 and 60 months (1-3). According to the literature, there are no cognitive adverse effects of having FS. These patients do not have any increased risk of abnormalities of attitude, attention or school performance compared with age-matched controls (2). Although FS are usually benign and self-limiting, parents feel great fear and concern about them. Also, the risk of epilepsy after FS increased between 3% to 7% compared with nearly 0.5% of the general population which makes FS a significant health problem (4,5).
Methodological differences might be a factor, but the prevalence of FS varies in different parts of the world (2). Higher prevalences are found in Japan and Guam (8% and 14%, respectively), whereas, the prevalence in Europe and United States is reported between 2% and 6.9% (6-9). The prevalence of FS in Turkey was found to be between 3.5% and 12.8% in previous studies (10-15). These differences are thought to be due to genetic, geographic and environmental factors. Also, due to socio-economic and environmental factors of population change through time, the prevalence of FS might have changed. However, there has been no recent study about the prevalence of FS among Turkish children.
The objective of this study is to find out the prevalence, clinical and some epidemiological features of the FS among Turkish children aged from 6 to 7 in the center of İzmir city.
Materials and Methods
A cross-sectional study was conducted in first and second grade primary school children in the metropolitan area of İzmir. Information on the study population was obtained from the Bureau of Statistics of the Provincial Education Administration of İzmir (16). The primary school grade 1 and 2 population consisted of 65.866 children in 2015 in İzmir. Taking into consideration the prevalence rate detected by Aydin et al. (15) in 2008 of 9.7%, with ±1 standard deviation (SD) with a 99% confidence interval, we planned to assess 5.340 students for this study. Nine districts in İzmir city center were the clusters for our study, and a cluster-sampling method was used. Randomly chosen schools from the sample frame were represented proportionally to their size. Taking into account those questionnaires that would not be replied and returned, instead of 5.340, we distributed 5.501 questionnaires. Together with the questionnaire, a consent/approval form was sent to the families of the sample population.
After Dokuz Eylül University Ethics Committee (approval number: 2015/28-15) was received, written permission was obtained from the Provincial Education Administration and Governor of İzmir City and then the study was performed.
We planned to collect data for our study via the questionnaire to be answered by the parents of first and second grade students in the 2015-2016 educational year. The survey, which had 30 questions, was prepared according to the guidelines for epidemiologic studies on epilepsy, which were proposed by the Commission on Epidemiology and Prognosis, International League Against Epilepsy in 1993, and also according to the current literature about epilepsy. To minimize any memory difficulties, we added an option as “I do not remember” to the survey and these data were accepted as missing data. Teachers sent questionnaires to the parents, who were asked to return them within five days via the children. The response rate was 69.2%, and 3.806 questionnaires were returned out of 5.501 sent.
The survey had questions about some demographic features of the children and FS episodes. The main independent variables of the study were age and gender of children, the FS history of children, the reason for fever, type of treatment conducted by the parents during the FS, admission to a medical unit, the medicine recommended and also a story of FS and epilepsy throughout the family.
FS were defined as seizures that occur in children aged between six months and six years, accompanied by a fever (at least 38 °C before the onset of the seizure) without signs of an intracranial infection (3). Cases with intracranial infections such as encephalitis or meningitis, or intoxication as a reason for the fever, and those who had a history of an afebrile seizure were excluded from the study.
Data were analyzed using SPSS version 21.0 for Windows software (SPSS Inc., Chicago, IL). Results were reported as mean ± SD values or n (%) where appropriate. The statistical significance level was set at a p value <0.05. The normality of data distribution was checked using the Kolmogorov–Smirnov test in the whole group and the subgroups. Statistical analysis was done by using t-test for measurable variables and χ2 test for countable variables.
Results
Of the sent 5.501 questionnaires, parents of 3.806 voluntarily completed and returned the survey (69.2%). Out of 3.806 cases, 30 were excluded from the study due to the diagnosis of intoxication, encephalitis, meningitis and history of afebrile seizure. Finally, 3.776 cases were assessed, 49.3% of them were boys. The median age of the children at the time of the survey was 7.0 years (range 5.0 to 8.5). Of the 3.776 investigated children, 181 (4.8%, 95% confidence interval 4.1% to 5.5%) were reported to have experienced at least one FS. Among them, 98 were boys and 83 were girls. Some demographic characteristics are shown in Table I. We found a slightly higher prevalence of FS in boys compared to girls (5.2% and 4.3%, respectively), but this was not significantly significant (p=0.183). The FS prevalence in six-year-old students was lower than in seven years old students (4.1% and 5.3%, respectively), but this difference was not statistically significant (p=0.105).
Our results showed that 28.5% of the children experienced their first FS between the ages of 18 months and three years old. Among children who had a FS history, 62.8% of them had a seizure within the first hour of the fever. Most of the parents report that their children had an upper respiratory tract infection as the reason for the fever, and 12.4% of them had a vaccination history at two weeks before the seizure. 94.4% of the parents (171/181) brought their child to the hospital, and medicine was recommended for 54.0% of those (Table II). Sixty-one (33%) children were reported to have experienced two or more FS episodes. 37.3% of the patients with recurrent FS had their first episode before 18 months of age. The first episode age did not significantly affect the recurrence risk for FS (p=0.327). 59.3% of the repeated cases were males, and there was no significant difference between males and females in recurrence risk (p=0.284).
The most common practices by parents during the seizure were admission to the nearest emergency room and giving a shower to the child in order to decrease the fever. (Table III). Only 4.4% of them turned the child’s head to the right or left side to open the airway. One parent attempted to perform cardiopulmonary resuscitation. There was no significant difference in attitudes between parents with single FS and multiple FS (p>0.05).
Seizure history among family members of FS subjects is shown in Table IV. Among the 181 FS subjects, 29.0% of them gave a history of FS for their parents. Approximately 20% of them had a history of convulsive disorders within their immediate family and relatives.
Discussion
FS is the most common type of childhood seizure disorders. Most cases of FS are benign and self-limiting, and in general, treatment is not recommended (2). Our study was a school-based, cross-sectional prevalence survey of a history of FS in children between the ages of 6 and 7 in İzmir. The prevalence of FS in our study was found to be 4.8%. Our result is similar to the literature from Western countries (2,6-9) while our prevalence rate is lower than Asian and African countries (17-20). The cause for higher prevalence rates in Asian and African countries is not known. It is hypothesized that it may be due to a different genetic predisposition as well as the influence of environmental factors (21). FS prevalence rates in our country were reported as 4.5% and 3.5% in two previous studies which are similar to our result (11,14). On the other hand, the prevalence rate in primary school children in Diyarbakır was found to be 8.9% (12). We found a lower prevalence rate compared to the study by Aydin et al. (15) in which the prevalence was 9.7% in İzmir. Moreover, in another study, researchers reported the FS prevalence as 12.8% in İzmir (22). These differences might be due to methodological variations between studies. Also, the reduction in the prevalence of FS within the similar population, like our study and the study by Aydin et al. (15), may be partly as a result of the improved education of parents’ behaviors towards a child with fever. Unfortunately, we did not have any information about parents’ fever attitudes in our study.
There were some studies that found that males have a slightly higher frequency of FS (male to female ratio, 1.1:1 to 2:1) (2,20). Like these studies, there were more boys than girls with FS, 1.2:1 in our study (17,20,23-25). There is no explanation for this male predominance, but some researchers considered that boys have a predisposition to the febrile illnesses that may cause FS (2,9,17,19). On the other hand, this prevalence rate difference between boys and girls was not statistically significant in our study like most other studies (2,17).
In our study, we found that FS was mostly seen at the ages between 18 months and 3 years, similar to the contemporary literature (17,19,20,26). We also found that most of the FS cases had a fever of 39 °C or more and seizure occurred within the first hour of the fever. These findings are similar to the previous studies (2,7,9,18-20). In our study, the most common reason of the fever among the FS cases was upper respiratory tract infections. Studies from the Western world, Japan, and our neighbors found similar results (5-8,18,27,28). On the other hand, bacterial meningitis and severe falciparum malaria were the most common infections found in FS cases in Africa (17). FS may recur in approximately 30% of the cases with a first episode, and we found a similar FS recurrence rate to the contemporary literature (2,18,20).
A significantly increased risk for FS was found for children of whom there was a history of FS in the parents or/and siblings (2,9). According to the literature, 25% to 40% of the cases had a positive family history for FS (2,29). 29% of the parents and 13.4% of the siblings had a history of FS in our study. A family history of FS is considerably higher among FS cases in our study, and this is concordant with the literature.
Although FS is one of the benign diseases seen in childhood, parents can perceive FS as a traumatic and highly dangerous event. It is essential to reduce parental concerns to improve their responses to FS at home. Parental attitudes toward FS are important for children’s first aid during the seizure. Sixty-three percent of parents brought their child directly to the hospital in our study. In a similar study in Japan, 91% of parents brought their child directly to the hospital by ambulance after an emergency call (30). Also, in Korea it is found that during a FS, 86.5% of the parents rushed the child to an emergency department (31). These results show us that although parental FS knowledge has significantly improved, most parents still panic and rush their child to doctors without giving first aid to the child. Only 4.4% of them turned the child’s head to the right or left side to open the airway. In our study, this result did not change between parents who have children with a single FS and parents who have children with recurrent FS. According to our results, although most parents had thought that they had an appropriate approach during the seizure of their children, most of them had false or insufficient information about seizure management at home. These results might be due to an inappropriate education of parents or a variation in the quality of information given by health care professionals in İzmir.
Study Limitations
We have several limitations. Firstly, our study was carried out as a school-based survey. Data was collected by questionnaire. There was no clinical evaluation. Therefore, febrile reactions might have been perceived as a FS by parents. Secondly, because we used a questionnaire method, recall bias might have interfered with the results. On the other hand, a population-based questionnaire method remains the most practical method for assessing these parameters in large groups. Moreover, to reduce recall bias, we did this study on 6-7 years old children. Thirdly, although schooling until the 8th grade is obligatory in Turkey, some low-income families do not send their children to school. They choose to send them to work, and this might affect the results. Along with that, use of a school-based questionnaire method enabled us to find cases who could not access health care facilities because of social, cultural or financial problems. So, due to this, we thought that our study design enabled us to find more realistic results on the prevalence of FS.
Conclusion
In conclusion, the FS prevalence determined in our study is lower than the study within a similar population done by Aydin et al. (15) in 2008. Our study supports findings that the prevalence of FS in our country is similar to developed countries but lower than the developing Asian communities. It was thought that increasing the awareness of febrile illness of parents and the advancing healthcare systems in our country may have decreased the FS prevalence within the last 8 years in İzmir. Our school-based population study enabled us to know the prevalence rate of FS, but repeated studies are needed to follow-up the effect of changing socio-economic factors on FS prevalence.
Acknowledgements: We gratefully acknowledge the help of the Bureau of Statistics of the Provincial Education Administration of İzmir.
Ethics
Ethics Committee Approval: The study was approved by the Dokuz Eylül University Local Ethics Committee (approval number: 2015/28-15).
Informed Consent: Written and verbal consent was obtained from the patients who participated in this study.
Peer-review: Internally peer-reviewed.
Authorship Contributions
Concept: M.A., T.İ., A.E., A.A., Design: M.A., D.L., A.A., Data Collection or Processing: M.A., D.L., T.İ., Analysis or Interpretation: T.İ., D.L., A.E., A.A., Literature Search: M.A., T.İ., Writing: M.A., T.İ.
Conflict of Interest: No conflict of interest was declared by the authors.
Financial Disclosure: The authors declared that this study received no financial support.
