EEG in Febrile Convulsions

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.

Predictive Value of Epileptiform Discharges for Subsequent Epilepsy After Febrile Seizures

The predictive value of epileptiform discharges for subsequent epilepsy after febrile seizures was studied in 140 children: 72 children (51%) had simple febrile seizures and 68 children (49%) had complex febrile seizures. Electroencephalography (EEG) was performed in 103 children (74%), it was normal in 66 (47%) and with epileptiform patterns in 37 patients (26%). At follow-up in 2017, 10 children developed epilepsy, 1 had a single epileptic seizure, 9 of them had epileptiform EEGs. Of the patients with normal EEGs after complex febrile seizures, none developed epilepsy, and 92% of patients with normal EEGs after recurrent febrile seizures did not develop epilepsy. Therefore, patients with normal EEGs were unlikely to develop epilepsy. Fifteen percent of patients with complex and 31% of patients with recurrent febrile seizures and epileptiform EEGs developed epileptic seizures. The positive predictive value of epileptiform discharges was low in complex and twice as high in recurrent febrile seizures.

Early postictal electroencephalography and correlation with clinical findings in children with febrile seizures

PURPOSE

Electroencephalography (EEG) is frequently ordered for patients with febrile seizures despite its unclear diagnostic value. We evaluated the prevalence of abnormal EEGs, the association between clinical findings and abnormal EEGs, and the predictive value of EEG for the recurrence of febrile seizures.

METHODS

Data were collected on 230 children who were treated for febrile seizures at Kyung Hee University Medical Center from 2005 to 2009. EEGs were recorded after 1-2 days of hospitalization when children became afebrile. EEG patterns were categorized as normal, epileptiform, or nonspecific relative to abnormalities. The patients' medical records were reviewed, and telephone interviews with the families of the children were conducted to inquire about seizure recurrence. The relationships between clinical variables, including seizure recurrence, and EEG abnormalities were evaluated.

RESULTS

Of the 131 children included, 103 had simple and 28 had complex febrile seizures. EEG abnormalities were found in 41 children (31%). EEG abnormalities were more common in children with complex than simple febrile seizures (43% vs. 28%), but the difference was not statistically significant. Logistical regression analysis showed that having multiple seizures in a 24-hour period was significantly predictive of abnormal EEG (odds ratio, 2.98; 95% confidence interval, 1.0 to 88; P=0.048). The frequency of recurrence did not differ significantly in the normal (31%) and abnormal (23%) EEG groups.

CONCLUSION

Multiple seizures within 24 hours were predictive of abnormal EEG in children with febrile seizures. Abnormal EEG was not predictive of febrile seizure recurrence.

Risk for developing epilepsy and epileptiform discharges on EEG in patients with febrile seizures

PURPOSE

The aim of the present study was to investigate the correlation between epileptiform discharges on EEGs after febrile seizures and the prognosis of patients in terms of the development of epilepsy and recurrence of febrile seizures. This study also evaluated the characteristics of epileptiform discharges and EEG changes on follow-up examination. methods: This study consisted of 36 children who presented to our hospital with febrile seizures and whose electroencephalograms (EEG) showed epileptiform discharges. The development of epilepsy and the recurrence of febrile seizures were compared between the study group (n=36) and the control group (n=87), which included children with febrile seizure but with normal EEG findings.

RESULTS

No significant correlation was detected between the recurrence rate of febrile seizures in patients with normal EEG (23 out of 87, 26.4%) findings and that of patients whose EEGs showed epileptiform discharges (12 out of 36, 33.3%) [adjusted OR 0.67 (0.26-1.68)]. However, 9 (25.0%) out of 36 patients with epileptiform discharges on EEG had epilepsy compared to 2 patients (2.3%) in the control group. The correlation was statistically significant [crude OR 10.88 (2.47-47.88) and adjusted OR 8.75 (1.49-51.6)].

CONCLUSION

Epileptiform discharges on the EEGs of patients with febrile seizures are important predictive risk factors of the development of epilepsy.

EEG characteristics predict subsequent epilepsy in children with febrile seizure

The role of electroencephalography (EEG) in the work-up of febrile seizure (FS) remains controversial. We investigated the importance of EEG characteristics, especially the localizations of paroxysmal discharges, as predictors for subsequent epilepsy. Patients were referred from the outpatient department for EEG within 7-20 days after the seizure. EEGs were classified as paroxysmally abnormal based on the presence of spikes, sharp waves, or spike-wave complexes, whether focal or generalized, that were considered abnormal for age and state. Of 119 patients with FS, 26 (21.8%) revealed paroxysmal abnormality on EEG and 9 (7.6%) developed epilepsy. Of nine patients with later epilepsy, 6 (66.7%) revealed paroxysmal EEG abnormality. Of 26 patients with paroxysmal abnormality, 6 (23.1%) developed epilepsy. Of 10 patients with generalized paroxysmal spike and wave activity, one (10%) developed epilepsy. Of seven patients with rolandic discharge (RD), two (28.5%) developed epilepsy. Of four patients with paroxysms in the frontal region, three (75%) developed epilepsy. Of five patients with paroxysms in the occipital region, none developed epilepsy. Compared with generalized EEG foci, the relative risk (RR) for patients with frontal EEG foci was 27.0. Patients with frontal EEG paroxysms had a significantly higher risk of developing epilepsy than those with paroxysms in other regions of EEG foci (p=0.035). These findings suggest that patients with FS presenting with frontal paroxysmal EEG abnormalities may be at risk for epilepsy. In patients with frontal paroxysmal EEG abnormalities, serial EEG should be performed, even though it does not contribute to treatment.

Role of early EEG and neuroimaging in determination of prognosis in children with complex febrile seizure

BACKGROUND

The present study investigates the role of early use of EEG in children with no known neuropathology prior to the first CFS, and the contribution made by computed tomography (CT) and magnetic resonance imaging (MRI) to treatment and prognosis.

METHODS

Over a period of 7 years, the authors evaluated 159 children (age range: 2 months-5 years) who were being treated for CFS at Haydarpasa Numune Training and Research Hospital, Pediatrics Clinic, Istanbul, Turkey, and who had no previously known neurological disorder. Patients who presented with febrile seizure were determined to have CFS if they fulfilled the following criteria: <3 months of age when seizure occurred, duration of seizure >/=15 min, more than one seizure occurred during a single episode of illness, or focal seizures and postictal neurological deficit was found. EEG was performed on all patients. CT was performed on the patients who had postictal neurologic deficit or focal seizures. Cranial MRI was performed on patients who had focal findings in their EEGs.

RESULTS

Electroencephalogram abnormality was found in 71 cases; 51 of these were diagnosed with epilepsy during follow up. Six of the 16 cases whose EEGs were abnormal between days 2 and 6 were diagnosed with epilepsy. Twenty of the 30 cases whose EEGs were abnormal between days 7 and 10 were diagnosed with epilepsy. All 25 cases who had abnormal EEGs after day 11 were diagnosed with epilepsy. CT was performed for 36 patients, of which five were found to have pathological changes. Pathological changes were detected in two of the nine patients who had cranial MRI. Patients who received CT or MRI were all diagnosed with epilepsy during follow up.

CONCLUSION

The results suggest that if neurological examination of CFS patients are normal after their clinical status has stabilised, EEG should be performed after 7 days at the earliest, however for the most accurate diagnosis EEG should be performed 10 days after CFS. The most important predictor for neuroimaging was found to be detection of postictal neurologic deficit. MRI had no advantages over CT in first treating CFS in the emergency unit.

Clinical and electroencephalographic characteristics of children with febrile seizures plus

OBJECTIVES

Febrile seizures plus (FS+) are attracting attention for their corresponding genetic abnormalities, and are defined as febrile seizures (FS) continuing beyond 6 years of age (late FS) or those associated with afebrile seizures. We tried to elucidate their clinical and EEG characteristics as compared with those of children having only FS.

SUBJECTS AND METHODS

We reviewed clinical records in a pediatric neurology clinic to identify 31 patients with FS+ (group FS+) and 51 with only FS (group FS). Their family history of seizures, clinical features and EEG findings were compared.

RESULTS

A family history of seizures was noted in 14 patients (45.2%) of group FS+ and in 24 (47.1%) of group FS. In group FS+, 19 patients had late FS, 11 had afebrile seizures, and the remaining one had both types of seizures. Two patients had seizures induced by TV/video-game as well, and another suffered from absences. Epileptic EEG abnormalities, which included diffuse spike-waves and focal spikes, were noted in 13 patients (41.9%) of group FS+ and 12 (23.5%) of group FS.

CONCLUSIONS

The clinical and EEG characteristics of the children having FS+ were diverse, without significant differences from those with FS except for the seizures types.

The value of early postictal EEG in children with complex febrile seizures

PURPOSE

To assess the usefulness of an early postictal EEG in neurologically normal children with complex febrile seizures.

METHODS

We conducted a retrospective chart review of all neurologically normal children who were hospitalized over a period of 2.5 years after complex febrile seizures, and had an EEG up to 1 week after the seizure.

RESULTS

Thirty-three patients (mean age, 17.8 months) qualified for inclusion into the study. Twenty-four patients were qualified as complex cases based on one factor (prolonged in 9, repetitive in 13, and focal in 2). Nine other patients had two complex factors: in six patients, the seizures were long and repetitive; in two patients, the seizures were focal and repetitive; and in one patient, the seizures were long, focal, and repetitive. Thirteen (39%) patients experienced prior febrile seizures. All 33 patients had a normal postictal sleep EEG. Our results indicate with a 95% probability that the true rate of abnormalities in an early postictal EEG performed on otherwise normal children with complex febrile seizures is 8.6% or less.

CONCLUSIONS

The yield of abnormalities of an early postictal EEG in this population is low and similar to the reported rate of abnormalities in children with simple febrile seizures. The routine practice of obtaining an early EEG in neurologically normal children with complex febrile seizures is not justified.

Practical guidelines for physicians in the management of febrile seizures

Recent studies have shown that adequate medication can prevent the recurrence of febrile seizures (FS). It has also been clarified that the vast majority of, though not all, FS patients follow a benign course. Then, questions arise as to whether or not FS should be prevented, particularly in light of the risks of side effects from drugs. Which kinds of FS can be prevented, if necessary? The guidelines presented here are aimed primarily at helping general practitioners in considering how to manage FS most appropriately. The guidelines stress that judgements should be individualized, while referring to a few specific 'warning factors'. The guidelines follow a 'laissez-faire' principle for the majority of FS cases, whereas intermittent therapy with diazepam and continuous medication with either phenobarbital or valproate are indicated in other limited cases meeting respective definite criteria.