The relationship between febrile seizures and epilepsy

Actual insights into the clinical management of febrile seizures

Febrile seizures (FS) are a benign epileptic manifestation of infancy occurring between 3 months and 5 years of age and affecting an estimated 2-5 % of children. They have usually no important negative effects on motor and cognitive development. Simple FS (generalized seizures, lasting less than 10 min and single episodes during the same febrile event) have a benign prognosis in almost all cases and do not require an extensive diagnostic workup. In complex FS (focal semiology and lasting more than 10 min, more than one episode during the same febrile event), a more detailed clinical, electroencephalographic, laboratory, and neuroimaging evaluation is necessary because of a higher percentage of underlying detectable causes and a mildly higher risk for later development of epilepsy. Febrile status epilepticus is the most severe type of complex FS even if its morbidity and mortality is extremely low. Simple FS plus (more than one convulsive episode in 24 h) have the same benign prognosis of simple FS. Neither intermittent nor continuous prophylaxis is actually recommended both in simple and complex FS because its side effects outweigh its possible benefits.

CONCLUSION

This review summarizes recent developments into the clinical management of FS including a suggested algorithm for simple and complex FS, the concept of simple FS plus, the controversies about the relationships between FS and hippocampal sclerosis, the relationships between FS and complex syndrome such as Dravet syndrome, genetic epilepsy with FS plus or febrile infection-related epilepsy syndrome, and the results of recent epidemiologic studies on febrile status epilepticus.

Prognostic factors for subsequent epilepsy in children with febrile seizures

OBJECTIVE

Epilepsy following febrile seizures (FS) has been estimated between 2% and 7%. It concerns a prospective study in a large sample of children with a long-term follow-up. The aim of this study is to identify the prognostic factors that can lead children with FS to epilepsy.

METHODS

Children with a first episode of FS were included. We gathered information about prenatal and perinatal history, family history of FS and epilepsy in first- and second degree relatives, age at the time of the initial FS, dates of FS recurrences, focality, duration of the FS and recurrent episodes within the same febrile illness, height and duration of fever prior to the seizure, cause of the fever, and frequency of febrile illnesses. Patients were seen every 4-6 months and also at each recurrence.

KEY FINDINGS

A group of 560 children with a first FS met all entry criteria. Epilepsy was recorded at 5.4%. Statistical analysis was performed between children with epilepsy and those with no afebrile seizure. We analyzed FS recurrences in accordance with the occurrence of epilepsy. From the third FS recurrence and beyond, only focality continued to have prognostic value.

SIGNIFICANCE

Main prognostic factors for the development of epilepsy after FS are: (1) complex FS that increased the risk for epilepsy 3.6 times, (2) age at onset of FS beyond the third year of life that raised the risk 3.8 times, (3) positive family history of epilepsy 7.3 times, and (4) multiple episodes of FS about 10 times. Focality at the first and the second FS recurrence increased the risk of epilepsy about 9.7 and 11.7 times, respectively. Focality was the only factor that continued to be significant in further FS recurrences. A prognostic profile of each child with FS would be very useful for the follow-up of these children.

Febrile seizures: recent developments and unanswered questions

BACKGROUND

Febrile seizures (FS) are typically observed in infants and children affecting 2-5 % of the pediatric population and are the commonest seizures in childhood.

OBJECTIVES

The present review summarizes epidemiology, etiology, clinical picture, and diagnostic procedures as well as the therapeutic options and the different courses this disorder may take.

METHOD

An extensive review of literature is performed, while views and aspects towards the pathogenesis of FS are stated. Risk factors for multiple recurrences of FS and for subsequent epilepsy are analyzed. Questions regarding the treatment and follow-up of children with FS are answered.

RESULTS

Whereas the frequency of epilepsy following simple FS is estimated to be 1.0-2.2 % of patients, and thus does not differ from the risk of normal population, complicated FS are associated with an increased risk of subsequent epilepsy in 4.1-6.0 %. Febrile status epilepticus with focal symptoms may result in approximately 5 % of cases in complex partial epilepsy. Furthermore, multiple recurrences increase the risk for generalized epilepsy (>4 %). The immediate management of FS, intermittent prophylaxis, and the effectiveness of the treatment in combination with antipyretics are presented in detail.

CONCLUSION

FS can cause a great anxiety and even panic to parents and to the whole family. Parents should be educated about the benign condition and the good prognosis. Although much information has been gained, much remains to be learned.

A new locus for familial temporal lobe epilepsy on chromosome 3q

BACKGROUND

Temporal lobe epilepsy (TLE) is a common and heterogeneous focal epilepsy syndrome with a complex etiology, involving both environmental and genetic factors. Several familial forms of TLE have been described, including familial lateral TLE (FLTLE), familial mesial TLE (FMTLE) without hippocampal sclerosis, and FMTLE with hippocampal sclerosis. Mutations have been identified only in the leucine-rich, glioma-inactivated 1 (LGI1) gene on chromosome 10q22-q24 in FLTLE. Several loci have been mapped in families with FMTLE, but responsible genes have not been found. We report clinical evaluation in a large family with FMTLE and a new genetic locus.

METHODS

We conducted a genome-wide scan using 10cM-spaced microsatellite markers on a family with TLE. Seven individuals had TLE without antecedent FS; four other individuals had FS during childhood, but no subsequent epilepsy. Patients with TLE had infrequent simple partial, complex partial and secondarily generalized seizures that generally responded well to treatment. The proband had no hippocampal sclerosis. The mode of inheritance appeared to be autosomal dominant with incomplete penetrance. Linkage analysis was performed using the Genehunter software. Regions with LOD score>1 and those that were poorly informative in the first-pass scan were further genotyped.

RESULTS

Linkage was identified on chromosome 3q25-q26 in a 13cM region flanked by markers D3S1584 and D3S3520, with a peak LOD score of 3.23. This interval does not correspond to any previously known locus for familial epilepsy or FS. KCNAB1, encoding a voltage-gated, shaker-related potassium channel, and NLGN1, encoding a member of a family of neuronal cell surface protein were excluded as disease causing mutations.

CONCLUSION

We identified a novel locus for familial TLE with FS, providing additional evidence of the complexity and genetic heterogeneity of familial focal epilepsy.