Serum sodium levels do not predict recurrence of febrile seizures within 24 hours

Prediction of recurrent febrile seizures risk during the same febrile illness in children at a single tertiary centre in Turkiye

BACKGROUND

This study aimed to develop a risk prediction model based on association rule mining to predict recurrent febrile seizures (RFS).

METHODS

This is a retrospective observational study that examined the medical records of 105 children who were followed up with febrile seizure (FS) in a tertiary paediatric emergency department between October 2022 and December 2023. Children were divided into RFS and simple FS groups. RFS was defined as seizures occurring more than once within 24 hours of the first FS in the same febrile illness. Risk factors associated with RFS were determined by univariate and multivariate analyses. χ2, Mann-Whitney U, receiver operating characteristics (ROC), multiple logistic regression and Classification Based on Association Rules Algorithm (CBA) analyses were applied to the dataset to obtain high-level outputs.

RESULTS

RFS was detected in 32 out of 105 cases with FS (30.5%). Potential risk factors contributing to the development of RFS were seizure duration, number of recurrent seizures, family history, body temperature, time from fever onset to seizure, time from seizure onset to arrival at the emergency department, hyponatraemia, osmotic pressure and low haemoglobin level. The CBA algorithm obtained a total of 11 classification rules for the two patient groups. Additionally, the cut-off values obtained from CBA and ROC analysis showed satisfactory consistency. The CBA model achieved 97% overall accuracy classification performance.

CONCLUSION

The developed CBA model shows good predictive ability for RFS. The relevant model can be used as a risk estimation tool to identify children at risk of developing RFS.

Clinical and laboratory parameters associated with febrile seizure recurrence within the first 24 h: a ten-year cohort study

Introduction

We assessed clinical and laboratory parameters associated with early recurrence of febrile seizure in patients presenting at the Emergency Department with a first episode.

Methods

Case series of patients admitted to the emergency department with the first episode of febrile seizure for ten consecutive years. Exclusion criteria were focal features and prolonged duration (>15 min).

Results

We included 693 patients, 284 (41%) female. Median age of 20 (IQR 15-27) months. Fifty-two (8%) patients had a recurrence within 24 h. At univariate analysis, patients with recurrent seizures had higher use of antipyretics (88% vs. 74%, P = 0.03, OR 2.6, 95% CI: 1.1-7.7), higher median maximal body temperature (39.3 °C, IQR 38.9-39.9, vs. 38.9, IQR 38.4-39.3, P < 0.001, OR 2.3, 95% CI: 1.5-2.6) and presented with a lower proportion of respiratory tract infections (54% vs. 70%, P = 0.02) compared to patients without recurrence. A maximal body temperature equal to or higher than 39 °C was associated with a higher recurrence (11% vs. 4%, P < 0.001, OR 2.9, 95% CI: 1.6-5.6). Hyponatremia was not associated with a risk of recurrence. The multivariate analysis confirmed a direct association with body temperature (OR 2.3, 95% CI: 1.5-3.7, P < 0.001), and an inverse association with respiratory tract infections (OR 0.4, 95% CI: 0.2-0.9, P = 0.01), while antipyretic use was not correlated (OR 1.9, 95% CI: 0.8-5.2, P = 0.2).

Conclusions

High body temperature and respiratory tract infections were (directly and inversely) associated with recurrences. Consideration of these conditions might help for anticipating the probability of recurrence.

Risk factors for acute encephalitis and early seizure recurrence in complex febrile seizures

The purpose of this study is to elucidate risk factors for central nervous system infection and early seizure recurrence in children with febrile seizures (FSs) and thus facilitate outpatient management of complex FS. This single-center, retrospective cohort study investigated 688 children (6-60 months old) with FSs in Japan during 2011-2021. We investigated the incidence and clinical manifestations of children with acute encephalitis or bacterial meningitis. Logistic regression modeling was used to examine risk factors for seizure recurrence within 24 h. Among children with recurrent FSs, the distribution of intervals between first and second FS was assessed. Among 145 children with complex FSs, 2 patients (1.4%) had acute viral encephalitis and none had bacterial meningitis. Acute encephalitis was found in 2 of 8 patients (25%) with FSs prolonged ≥30 min and 2 of 3 patients (67%) requiring ≥2 intravenous anticonvulsants to stop seizures. Seizure recurrence within 24 h was observed in 16% of participants and was independently associated with preceding use of diazepam and family history of FS. In 82% of patients with FS recurrence within 24 h, early recurrences occurred within 8 h of the first seizure.      Conclusion: Patients with prolonged or refractory FSs are still indicated for hospital admission due to the risk of acute encephalitis. FS patients with a family history of FS may be managed safely by 8-h observation or single-dose rectal diazepam as prophylaxis against early recurrent seizure. What is Known: • Hospitalization has been recommended for children with complex febrile seizures due to the increased risk of central nervous infections. • Recent studies showed low incidences of bacterial meningitis (<1%) in children with complex febrile seizures in the presence of routine immunization. What is New: • Acute encephalitis was identified in 1.4% of children with complex febrile seizures, characterized by prolonged seizures ≥30 min and refractory seizures. • Early recurrent seizures may be safely managed by prophylactic diazepam or 8-h expectant observation.

The baseline risk of multiple febrile seizures in the same febrile illness: a meta-analysis

The baseline risk for multiple febrile seizures within the same febrile illness is largely unknown. Estimates range from 5 to 30%. Imprecise estimates can lead to incorrectly powering studies investigating the management of febrile seizures. To estimate the risk of multiple febrile seizures in the same febrile illness, we systematically reviewed and conducted a meta-analysis of studies from January 2000 to December 2021 that contained data for the number of children for both simple and complex febrile seizures in the same febrile illness. We searched MEDLINE, EMBASE, and Web of Science for randomized, quasi-randomized, prospective, and retrospective trials that involved children with febrile seizures. A total of 23,131 febrile illnesses with febrile seizures met the inclusion criteria. The estimated baseline risk of multiple febrile seizures in the same febrile illness was 17% (95% CI, 16-19%). However, the 30 cohorts that included both admitted and non-admitted patients had a lower percentage of multiple FSs within the same illness (14%; 95% CI, 12-15%) than the 30 cohorts that enrolled only admitted patients (20%; 95% CI, 16-25%).

CONCLUSION

Researchers can use estimates in this paper to design future studies. Taking into the account the substantial heterogeneity between countries and studies, clinicians could cautiously use our estimates in their clinical assessment and be better able to set parental expectations about a child's chances of having another febrile seizure during the current illness.

TRIAL REGISTRATION

PROSPERO CRD42020191784. Registered July 18, 2020.

WHAT IS KNOWN

• There is renewed interest in the diagnostic workup and prophylactic treatment of febrile seizures to prevent repeat seizures in the same febrile illness. • There is a lack of accurate estimates of the baseline risk for multiple febrile seizures in the same illness to properly design studies investigating management.

WHAT IS NEW

• This study provides the most robust estimates for the baseline risk for multiple febrile seizures in the same illness.

Hyponatremia and Recurrent Febrile Seizures During Febrile Episodes: A Meta-Analysis

Several studies have investigated the potential effects of hyponatremia on recurrent febrile seizures (RFS) during febrile illness. Because findings were inconsistent across studies, we aimed to evaluate the serum sodium levels in febrile seizures (FS) of children with or without RFS during the same episode.

We conducted electronic searches in three databases (PubMed, EMBASE, Cochrane Library) and one scholarly search engine (Google Scholar) up to June 2021 for studies on FS. Screening was done based on the titles and abstracts of primary studies. Then, eligibility was reviewed based on the abstracts. Finally, in order to match the inclusion and exclusion criteria, full-text articles were evaluated by two authors and inconsistencies were discussed. Data extraction was carried out by two independent authors. The extracted variables were author's name, article title, journal name, year of publication, study location, study design, sample size, and mean and standard deviation of blood Na concentration in FS. We performed a risk of bias assessment of included studies using the Newcastle-Ottawa Scale (NOS). The effect size was calculated using the standardized mean difference (SMD), and random-effects models were used for the analysis.

A total of 12 articles were included with a single outlier. This analysis suggested that serum sodium level was lower in patients with RFS during the same febrile episode than in those with single FS, with SMD of -0.70, (n=1784; 95% CI: -1.03, -0.36; Z=-4.10, p<0.01; I² 86.67%, p<0.01). In the sensitivity analysis, no significant change was observed in pooled SMD. The optimal cutoff value of serum sodium level was 134.72 mmol/L with an area under the receiver operating characteristic curve of 0.81 (95% CI: 0.61, 1.00), with sensitivity of 80.0% and specificity of 70.0%.

This result indicated a significant association between hyponatremia and RFS during the same febrile episode. Decreased serum sodium levels may be involved in seizure recurrence and may play a role in FS pathogenesis.

Body temperature predicts recurrent febrile seizures in the same febrile illness

BACKGROUND

The incidence of recurrent febrile seizures during the same febrile illness (RFS) is 14-24%. A pilot study found that body temperature and male sex were predictors of RFS. This study sought to validate body temperature as a predictor of RFS, calculate the optimal cut-off body temperature for predicting RFS, and identify the other predictors of RFS.

METHODS

This prospective cohort study enrolled children with febrile seizures aged 6-60 months who visited the emergency department at Atsugi City Hospital, Japan, between March 1, 2019, and February 29, 2020. Children who had multiple seizures, diazepam administration before the emergency department visit, seizures lasting >15 min, underlying diseases, or who could not be followed up were excluded. The optimal cut-off body temperature was determined using a receiver-operating characteristic curve.

RESULTS

A total of 109 children were enrolled, of whom 13 (11.9%) had RFS. A lower body temperature was significantly associated with RFS (P = 0.02). The optimal cut-off body temperature for predicting RFS was 39.2 °C. Children with RFS also had significantly lower C-reactive protein and blood glucose levels (P = 0.01 and 0.047, respectively), but none of the other factors considered were significantly associated with RFS.

CONCLUSIONS

This large prospective study confirmed that body temperature is a predictor of RFS. The optimal cut-off body temperature for predicting RFS was 39.2 °C. Low C-reactive protein level and blood glucose level might be predictors of RFS, but this needs to be confirmed in prospective multicenter studies.

The Association between Serum Sodium Levels and Febrile Seizures Recurrence: Is the Degree of Hyponatremia a Risk Factor?

Febrile seizures are common disorders in childhood. We evaluated the serum electrolyte levels and the associated factors in children with single and recurrent febrile seizures in 24 hours period of hospitalization. The medical records of children who were clinically diagnosed with febrile seizures and hospitalized were retrospectively revealed and analyzed. Data were collected for children aged 1 to 6 years including demographic parameters and serum electrolyte levels. A total of 244 children were enrolled in the study in which 209 were diagnosed with single febrile seizures and 35 of them with recurrent febrile seizures. Serum sodium levels were significantly lower in children with recurrent febrile seizure (138.5 ± 2.38 and 134.2 ± 3.55, p < 0.001). Correlation analysis revealed that mild hyponatremia is associated with recurrence of febrile seizure within 24 hours. However, receiver-operating characteristics analysis for hyponatremia showed lower sensitivity (50.3%) and specificity (43.1%) values for optimal cutoff value of 133.5 mmol/L of serum sodium level. Our study suggested that serum sodium levels were significantly lower in children with recurrent febrile seizures. However, because of its lower sensitivity and specificity values, mild hyponatremia cannot be used as an indicator for febrile seizure recurrence.

Acute Phase Serum Leptin, Adiponectin, Interleukin-6, and Visfatin Are Altered in Chinese Children With Febrile Seizures: A Cross-Sectional Study

Adipokines, including leptin, visfatin, adiponectin, and interleukin-6 (IL)-6, play multiple roles in the pathophysiology of epilepsy and febrile seizures (FS). We aimed to investigate the associations among plasma adipokines, mainly leptin, visfatin, adiponectin, or IL-6, and the prognosis of FS. This prospective cross-sectional study was conducted from January 2017 to December 2018 at the Wuxi Second People' Hospital China. The levels of serum leptin, visfatin, adiponectin, and IL-6 in 55 children with FS (FS group) were compared with 42 febrile children without seizure (FC group) and 48 healthy children (HC group) in an acute phase. The correlation with clinical indicators was determined by logistic regression analysis. Serum adiponectin and IL-6 levels were significantly higher in the FS group than in the FC and HC groups (p < 0.05), but there was no statistical difference between the FC and HC groups. In addition, logistic regression analysis showed that high concentrations of adiponectin and IL-6 were significantly associated with the occurrence of FS. For leptin and visfatin, they were significantly lower in the FS and FC groups than in the normal control group, but there was no statistical difference between the FS and FC groups. Our results suggest that higher plasma levels of IL-6 and adiponectin may serve as an additional biomarker in the early treatment or follow-up of the FS children.

Predictors of recurrent febrile seizures during the same febrile illness in children with febrile seizures

Febrile seizures (FS) are common in childhood. Of children who experience an FS, 14-24% experience recurrence within 24 h, during the same febrile illness (RFS). The aim of this pilot study was to identify the predictors of RFS among children who experience FS. We conducted a retrospective cohort study of children aged 6-60 months, who visited the emergency department (ED) at Atsugi City Hospital in Japan for treatment of an FS between December 1, 2018 and February 28, 2019. Exclusion criteria included multiple seizures before visiting the ED, diazepam administration before visiting the ED or on departure, seizures lasting >15 min, underlying diseases such as epilepsy, and absence of laboratory test results. The primary outcome was RFS. Fifty-one patients fulfilled the inclusion criteria, of whom nine (17.6%) had RFS. The incidence of RFS was significantly higher in children with a body temperature ≤ 39.8 °C during the ED visit (P = .01). The combination of male sex and a body temperature ≤ 39.8 °C had a sensitivity, specificity and negative predictive value of 88.9%, 76.2%, and 97.0%, respectively. In conclusion, the incidence of RFS was 17.6%. The major predictors of RFS were male sex and a body temperature ≤ 39.8 °C.

Risk of low serum levels of ionized magnesium in children with febrile seizure

Background

Suboptimal intake of magnesium become prevalent due to the modern diet of processed food low in magnesium. Magnesium may modulate seizure activity by antagonizing excitatory calcium influx through the N-methyl-D-aspartate receptor. Although hyponatremia has been reported to be common in febrile seizures, the most common form of seizure, little is known about the status of serum ionized magnesium. We therefore investigated the status of serum ionized magnesium (iMg²⁺) in children with febrile seizures and compared with controls.

Methods

We included all patients from 1 to 6 years old who had presented with febrile seizure to the pediatric emergency department at the Korea University Guro Hospital from July 2016 to February 2017. The control group comprised patients admitted to the hospital with febrile respiratory tract infections, but with no history of febrile seizure. Clinical data, blood tests, and electroencephalogram (EEG) results were reviewed using the patients’ medical records.

Results

A total of 133 patients with febrile seizure and 141 control patients were analyzed in the present study. As a result, hypomagnesemia (< 0.50 mmol/L) was more common in patients with febrile seizure than in controls (42.9% vs. 6.9%, p < 0.001) and it was an independent risk factor for febrile seizure (OR, odds ratio = 22.12, 95% CI = 9.23–53.02, P < 0.001). A receiver operating curve analysis revealed that serum iMg²⁺ levels < 0.51 mmol/L predicted the presence of febrile seizures with a sensitivity of 45.1% and a specificity of 92.6% (AUC, area under the curve = 0.731, 95% confidence interval = 0.671–0.791). When the patients with febrile seizure were divided in terms of a serum iMg²⁺ concentration of 0.51 mmol/L, there was no difference in clinical features.

Conclusions

Hypomagnesemia was more common and serum iMg²⁺ level was lower in patients with febrile seizures than in controls. However, further evidence is needed for the causal relationship between low magnesium and febrile convulsions.

Febrile seizures: emergency medicine perspective

PURPOSE OF REVIEW

The review describes current evidence on the evaluation of febrile seizures in the acute setting, the need for further outpatient assessment, and predictors regarding long-term outcomes of these patients.

RECENT FINDINGS

New evidence has been added in support of limited assessment and intervention: evidence on low utility of lumbar puncture, emergent neuroimaging, and follow-up electroencephalography, as well as low yield for antipyretic prophylaxis and intermittent use of antiepileptic drugs. Finally, there is growing evidence regarding the genetic basis of both febrile seizures and vaccine-related seizures/febrile seizures.

SUMMARY

Routine diagnostic testing for simple febrile seizures is being discouraged, and clear evidence-based guidelines regarding complex febrile seizures are lacking. Thus, clinical acumen remains the most important tool for identifying children with seizures who are candidates for a more elaborate diagnostic evaluation. Similarly, evidence and guidelines regarding candidates for an emergent out-of-hospital diazepam treatment are lacking.