Retrospective study of late febrile seizures

Clinical Predictive Factors of Pathological EEG in Children with Febrile Seizures and Their Association with Subsequent Epileptic Seizures

The objective of this study was to identify clinical parameters predicting either a pathological EEG or a subsequent epileptic seizure (SES), based on the relation between paroxysmal EEG abnormalities and clinical features in children who presented at least one febrile seizure (FS). We collected data of children who presented to our department during the period 2013 to 2018 for EEG recording as part of their febrile seizure assessment. Only children aged between 1 month to 5 years were included. Both the clinical and EEG data were retrospectively collected and statistically studied. We performed a detailed analysis of the EEG recordings. SES was identified for patients with sufficient follow-up. A total of 120 children were included in the study, of whom 48% had EEG abnormalities. Psychomotor retardation (p = 0.002), completion of an EEG within 7 days of the last FS (p = 0.046), and late age (> 3 years) of the first FS onset (p = 0.021) were significantly associated with a pathological EEG. In multivariate analysis, performing early EEG (< 7 days from the last FS) (odds ratio [OR]: 2.35; p = 0.043; confidence interval [CI]: 1.028–5.375) and psychomotor retardation (OR: 4.19; p = 0.008; CI: 1.46–12) were independent predictors of a pathological EEG. Of 120 patients, 45 had a follow-up. However, only 10 (22.22%) had SES. Children with SES tended more to have a psychomotor delay, compared with children without SES (50% vs. 14.28%, p = 0.029). Moreover, the percentage of initial abnormal EEG in patients with SES was significantly higher than those without SES (70% vs. 34.28%, p = 0.05). Even though some FS characteristics predict EEG abnormalities, they are not always associated with SES. We highlight the importance of performing an EEG in the group of children who had both FS and psychomotor retardation. This is most likely the group at the highest risk of developing epilepsy.

Clinical findings in patients with febrile seizure after 5 years of age: A retrospective study

OBJECTIVE

Febrile seizures (FSs) typically occur in infants and children between 6 and 60 months of age. Rarely, FS can occur in late childhood (late FS [LFS]; >5 years of age); however, the clinical features of LFS remain unclear. We aimed to clarify the clinical features of LFS.

METHODS

We retrospectively analyzed data from patients with LFS who visited Hirakata City Hospital between January 2004 and December 2014. We defined LFS as a seizure accompanied by fever (temperature ≥38 °C) occurring after 5 years of age, without a central nervous system infection.

RESULTS

A total of 505 patients (349 boys, 156 girls: 5-14 years old) were included. A history of FS before 60 months of age was observed in 319 of 460 patients (69.3%) with sufficient information about previous FS history among the 505 patients enrolled. LFS was more likely to occur in males (69.1%). Seizure duration was ≤15 min in 87.4% of cases. A family history of FS in first-degree relatives was observed in 103/327 cases (31.5%). Among LFS cases, 45% occurred at 5 years of age, and 92.1% experienced only one seizure after 5 years of age. The number of seizure episodes gradually lessened with age, decreasing drastically to 5.6% of cases older than 9 years.

CONCLUSIONS

Our findings suggest that sex differences, seizure duration, and family history were similar for LFS and FS. Over 90% patients with LFS experienced no recurrence after 5 years of age. Further study is needed to verify the recurrence rate of LFS.

Subsequent afebrile seizure in children who have a first seizure with fever after 6 years of age

The objective was to evaluate the risk and the risk factors associated with subsequent afebrile seizures in 31 children who experienced their first seizure with fever after 6 years of age. The children were classified into two groups. Group I comprised children with their first seizure with fever after 6 years of age (n = 15). Group II comprised children who had febrile seizures before 5 years of age and who had recurrent seizures with fever after 6 years of age (n = 16). Of these 31 children, 7 (22.5%) had subsequent afebrile seizure. The cumulative probability of subsequent afebrile seizure was 13.3% at 6 months and 36 months in group I; in group II, the cumulative probability was 12.5% at 6 months, 18.8% at 18 months, 25% at 24 months, and 31.3% at 36 months. There was no significant difference in the risk for subsequent afebrile seizures between the two groups. There were no risk factors associated with an increased risk of subsequent afebrile seizures. If the first seizure with fever occurred after 6 years of age, this was a significant risk for subsequent afebrile seizure; the risk of seizure recurrence in this group appears to be similar to children who have persistent febrile seizures after 6 years of age, but far below that of children with first epileptic seizure.

The mortality and morbidity of febrile seizures

Approaches to the treatment and investigation of febrile seizures have changed since the main reference studies on outcomes were conducted in the 1960s and 1970s. We have, therefore, conducted a systematic review of literature from the past 15 years to see whether outcomes have also changed. We found that simple febrile seizures do not carry a risk of death, but there is a very small risk of death after complex febrile seizures (CFSs), particularly febrile status epilepticus. There is no evidence that SUDEP (sudden unexpected death in epilepsy) occurs in association with febrile seizures. The risk of later epilepsy after a febrile seizure lies between 2.0% and 7.5%, and the risk of developing epilepsy after CFSs is estimated at around 10-20%. There is no evidence of any risk of hippocampal or mesial temporal sclerosis (HS/MTS) in association with simple febrile seizures. Serial imaging has shown that HS/MTS develops in 0-25% of patients over time after prolonged febrile seizures; the range in prevalence reflects selection bias in different studies. The overall risk of HS/MTS associated with CFSs is around 3%. Approximately 40% of patients with medically refractory temporal lobe epilepsy and HS/MTS on neuroimaging have a history of febrile seizures.

Etiologies and outcomes of status epilepticus in children

PURPOSE

Status epilepticus (SE) is a medical emergency with significant associated mortality and morbidity. This study was conducted to determine the etiology and outcome of SE in children.

METHODS

All patients from 1 month to 15 years old with SE admitted to Nemazee Hospital, Shiraz, Iran, the main pediatric hospital in the area, between 1999 and 2004, were studied in a retrospective cross-sectional study. Outcomes were rated according to the Glasgow Outcome Score (GOS).

RESULTS

In all, 135 patients (76 boys, 59 girls) were studied. The most common cause of SE was fever. Etiology of SE did not differ significantly between various age groups and also between boys and girls (P=0.736 and P=0.156, respectively). Fourteen patients died in hospital and 81 were discharged in good health. Outcome did not differ significantly between the age groups (P=0.695) or between boys and girls (P=0.386). When classified as good (GOS=5) and bad (GOS=1-4), outcome was significantly correlated with etiology of SE (P=0.017). Prolonged febrile seizures had the best, and symptomatic SE the worst, outcome.

DISCUSSION

In this study, even in children above 3 years of age, fever was the most common cause of SE. This is noteworthy and heralds the need to pay more attention to febrile seizures, especially in children at risk for their occurrence. Outcome was not related to age and sex, but etiology of SE significantly influenced outcome.

Retrospective study of febrile seizures: subsequent electroencephalogram findings, unprovoked seizures and epilepsy in adolescents

A retrospective questionnaire to determine the prevalence of febrile seizures was given to adolescents (16- and 17-year-olds) in the final 2 years of secondary school at the five schools in Alexandroupolis, Greece. Parents were interviewed, and clinical and electroencephalographic examinations were performed in all adolescents with a history of febrile seizures. Of 1708 adolescents, 56 (3.3%) had experienced at least one febrile seizure. Of these, 44 (78.6%) were simple and 12 (21.4%) were complex febrile seizures. Recurrent seizures occurred in 22 cases (39.3%), and the mean age at onset was 25.1 months. There was a positive first-degree family history in eight cases (14.3%) and this increased to 27.3% in cases with recurrent seizures. Two of the adolescents (3.6%) had had one unprovoked seizure before the age of 3 years, and another two children developed epilepsy. Epileptiform electroencephalogram discharges were observed in only one case (1.8%) with generalized tonic-clonic epilepsy.