¹Pediatrician, Department of Pediatrics, Janakpur Provincial Hospital, Janakpur, NEPAL.

²Professor, Department of Pediatrics & Adolescent Medicine, BP Koirala Institute of Health Sciences, Dharan, NEPAL.

Email: thakurbaidhyanath70@gmail.com

 

RESULTS

During study period, 80 children with febrile seizure fulfilling inclusion criteria were evaluated. Out of 80 children with febrile seizure 44 (55%) were boys and 36 (55%) were girls. We observed boys: girls’ ratio as 1.2:1. Minimum age of presentation was 6 month and maximum age of presentation was 60 month with median age of presentation was less than 18 months (63%). Median age of onset of febrile seizure was 18 months with IQ range of 10-24 months. Febrile seizure is more common among children residing in rural area (61.2%) compared to the urban residence (38.8%).

 

Table 1: Age distribution

Mean temperature at presentation in present study was 100.51 ± 0.693⁰F. Level of temperature at seizure onset was 102.54±0.841⁰ F. Median gap between onset of fever and onset of seizure was 12 hours. Most of the cases of febrile seizure (46.3 %) occurred at a temperature ≥102⁰F (38.9⁰C).

Table 2: Fever characteristics among febrile seizure

Most of the febrile seizure occurred within 24 hours of the onset of fever with 57.5% of cases occurring within 12 hours of fever onset.

Table 3: Distribution of duration of seizure onset after fever

21.3% cases had recurrent febrile seizures in present study.

 

Table 4: Type of febrile seizure.

Of total cases one cases each were exposed to maternal smoking in-utero and drugs in form of oral and intravenous antibiotics and 19 cases had exposure to maternal alcohol in utero.

 

Table 5: Antenatal exposure to risk factors among cases and control

In present study, most common cause of fever among febrile seizures was upper respiratory tract infection (66%) followed by viral exanthematous fever (13%) and urinary tract infection (13%).

 

Table 6: Causes of fever in febrile seizure cases

Gestational age at delivery was 38.93 ± 1.73. Average birth weight was 2.77 ± 0.44 kg. 46% children had not received exclusive breast feeding during first six months.

 

Table 7: Obstetric factors and breastfeeding

Family history of febrile convulsion in first degree relative was 14%.

 

Table 8: Family history of febrile convulsion and epilepsy

Among febrile seizure patients 20 cases (25%) had moderate wasting and 3 case (3.8%) had severe wasting and stunting.

 

 

 

Table 9: Nutritional status distribution among cases

Mean hemoglobin in case group was 10.9±1.19 g/dl. 61cases (76.25%) were anemic out of which 46 cases (75.4%) had simple febrile seizure and 15 cases (24.6%) had complex febrile seizure.

 

Table 10: Anemia among febrile seizure patients

Rural residence (61.30%), home delivery (52.50%), bottle feeding (40%), maternal alcohol consumption (23.80%) and family history of febrile seizure (15%) were most common risk factors associated with febrile seizures in present study.

 

Table 11: Common risk factor among children with febrile seizure

We compared risk factors among simple febrile seizure and complex febrile seizure group . Level of temperature at seizure, maternal smoking, family H/O febrile seizure, gestational age(weeks), anemia, malnutrition, birth weight(Kg) were significant risk factors among complex febrile seizure patients as compared to simple febrile seizure patients.

 

Table 12: Comparison of risk factors among simple febrile seizure and complex febrile seizure group

 

DISCUSSION

Febrile seizures are not associated with problem behavior or executive functioning in preschool children, but the results suggest that children with recurrent febrile seizures might be at risk for delayed language development.⁶ Increased incidence was noted in children from rural area. Higher incidence of infections in rural setting due to poor hygiene and living conditions, low Socioeconomic status and lack of knowledge regarding febrile seizure in rural population of Nepal may be the contributing factors.⁷ The simple type is characterized by a single episode of generalized tonic-clonic seizure lasting less than 15 min within 24 hrs. of onset of fever. A complex febrile seizure is more prolonged (>15 min), is focal, and/or recurs within 24 hr. Febrile status epilepticus is a febrile seizure lasting >30 min. Present study showed incidence of simple febrile seizure as 72.5%, complex febrile seizure as 27.5% and febrile status as 2.55%. Leung et al. in their study found simple febrile seizure in 85%.⁸ In present study we noted that febrile seizure increases with temperature level and most febrile seizure (46.3 %) occurred at a temperature ≥102⁰F (38.9⁰C). Mahyar et al. in Iranian hospital-based study found that the mean temperature at seizure onset was 38.9±0.37⁰C.⁹ Sadlier et al. mentioned that the temperature of at least 380C is required for seizure onset.¹⁰ Elevating brain temperature in itself alters many neuronal functions, including several temperature-sensitive ion channels and causes seizures.¹¹ We noted that the median duration of seizure onset after fever was 12 hours with Inter Quartile range of 6-20 hours. Mukherjee et al. mentioned that the incidence of febrile seizure occurring within 1hr of fever onset is 21% between 1- 24 hrs. is 57% and after 24 hrs in 22%.¹² Shrestha et al.⁷ in a retrospective hospital-based study found majority of children developed seizure within 24 hours of onset of fever with mean of 9.3 (±7.4). In present study recurrent episode of febrile convulsion was found in 21.3%. Offringa et al. stated thirty per cent of children have recurrent febrile seizures during subsequent illnesses.¹³ Knudsen et al. pointed out approximately 30% to 40% of children who experience a febrile seizure will have a recurrence, but less than 10% will have three or more recurrences.¹⁴ Talebian et al. found recurrences in twelve children (24%) out of the fifty.¹⁵ Risk factor for recurrence for febrile seizure are Age <1 yr., Duration of fever <24 hrs., Day care, Male gender, Lower serum sodium. Having no risk factors carries a recurrence risk of about 12%; 1 risk factor, 25-50%; 2 risk factors, 50-59%; 3 or more, 73-100%.¹⁶ In this study the important causes of fever are Upper respiratory tract infection, viral exanthema, Urinary tract infection, acute gastroenteritis and pneumonia. Berg et al. found Nonspecific cause in 26%,otitis media in 65% gastroenteritis in 9% invasive bacterial infection in 6%.¹⁷ Rantala et al. found URTI in 67%, gastroenteritis in 10%,otitis media in 7%, exanthema subitum in 9%.¹⁸ In Iranian hospital-based study found upper respiratory tract infections 53.8%,gastroenteritis in 24.4%, acute otitis media in 9%, urinary tract infection in 6.4%, and pneumonia in 3.8%.⁹ The cause of fever varies among different geographical location depending upon prevalence, disease pattern and hospital presentations of different diseases. Viral infections were presumed in majority of these children with upper respiratory tract infection based on clinical features and the course of illness. Viral URTI is the most common cause of febrile seizure. HHV 6 and HHV 7 are most commonly implicated viral cause of febrile seizure.^19,20 In present study 23% children with febrile seizures had history of maternal alcohol ingestion. Ingestion of alcohol during pregnancy has also been reported to have two-fold risk of developing febrile seizures with a strong dose-response relationship.²¹ The hypothesis behind alcohol as a risk factor for febrile seizure is supported by low to moderate average alcohol intake may affect fetal brain development, especially if large volumes are consumed on single occasions and high peak blood concentrations are reached.²² Khet et al. found an indirect correlation between in incidence of febrile convulsion and length of breast- feeding.²³ Akhodian et al. suggested that exclusive breast-feeding in the first 6 months of life does not have a significant effect on febrile seizure, but it may protect children from complex febrile seizure which is a predisposing factor for epilepsy.²⁴ Greenwood et al. in a British cohort study found increase incidence of febrile convulsion in a non-breast fed group.²⁵ A positive family history for febrile seizures can be elicited in 5-25% of patients with febrile seizures.^13,17 In addition to the positive history in a first or second degree relative, monozygotic rather than in dizygotic twins, human herpes virus-6 infection²⁰, influenza viral infection²⁶ and iron deficiency anemia²⁷. The febrile seizure gene have been mapped to chromosomes 2q23-34, 5q14-15, 6q22-24,8q13-21, 18p11.2, 19p13.3, and19q.²⁸ The risk of subsequent epilepsy is for Simple febrile seizure 1%, Neurodevelopmental abnormalities 33%,Focal complex febrile seizure 29%, Family history of epilepsy 18%,Fever <1 hr before febrile seizure 11%, Complex febrile seizure, any type 6%, and Recurrent febrile seizures 4%.¹⁶Level of temperature at seizure, maternal smoking, family H/O febrile seizure, gestational age(weeks), anemia, malnutrition, birth weight(Kg) were significant risk factors among complex febrile seizure patients as compared to simple febrile seizure patients. Nelson et al. in US cohort prenatal risk factor study mentioned that the risk of a complex seizure was approximately the same for the first as for each subsequent febrile seizure.²⁹ Rural residence (61.30%), home delivery (52.50%), bottle feeding (40%), maternal alcohol consumption (23.80%) and family history of febrile seizure (15%) were most common risk factors associated with febrile seizures in present study. Present study was observational, small sample size, hospital-based study. Large sample, comparative studies will be helpful to identify risk factors for febrile seizures.

 

CONCLUSION

The commonest risk factor associated with febrile convulsion in this study were nonexclusive maternal breast feeding, family history of febrile seizure, maternal alcohol consumption and rural residence. Febrile seizures are multifactorial in origin, still can be prevensted by strong supervision of children with positive family history, excusive breast feeding for 6 months and avoidance of alcohol consumption during pregnancy.

 

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