Prognosis of childhood epilepsy: a community-based study in Copparo, Italy

The epidemiology of the epilepsies in children

The epilepsies are a heterogeneous collection of neurological conditions and syndromes characterized by recurrent, unprovoked, paroxysmal seizure activity. There are several types of epileptic seizures and syndromes that are unique to children, including infantile spasms, Lennox-Gastaut syndrome and absence seizures. Febrile seizures and neonatal seizures, while not epilepsy, are relatively common types of seizures in infants and children and are likely markers of risk of later epilepsy. Thus, it is important to consider the epidemiological features of the epilepsies as they occur specifically in infants and children. The purpose of this review is to summarize what is currently known about the epidemiology of the childhood epilepsies and to identify promising areas for further population-based studies. The epilepsies are an important cause of neurological morbidity in children. The average annual rate of new cases (incidence) of epilepsy is approximately 5-7 cases per 10,000 children from birth to age 15 years, and in any given year, about 5 of every 1,000 children will have epilepsy. There is evidence that the incidence of the epilepsies in some populations of children may be decreasing over time, and this possibility merits further investigation. Factors that are known to increase risk of the epilepsies in children include congenital malformations of the central nervous system (CNS), moderate or severe head trauma, CNS infections, certain inherited metabolic conditions, and genetic factors. However, these account for only 25% to 45% of cases, and thus, the etiology of most cases of the epilepsies remains obscure. The paucity of well-controlled etiological studies is due largely to formidable methodological problems in conducting epidemiological studies of the epilepsies. The prognosis for seizure control is generally good, although children with remote symptomatic seizures and those with additional neurological disabilities do less well.

Update on the epidemiology and prognosis of pediatric epilepsy

Epilepsy is among the most common serious neurologic disorders in childhood. Epidemiologic studies over the past few decades have greatly increased current knowledge of the incidence and prognosis of seizures. Newer epidemiologic studies have used population- or community-based cohorts, and careful attention has been given to etiology and specific epilepsy syndromes, the two most important factors affecting prognosis. Risk of epilepsy is highest in patients with an associated serious neurologic abnormality, such as mental retardation or cerebral palsy. More than two thirds of patients with childhood-onset epilepsy ultimately achieve remission. Of those attaining remission on medications, approximately 70% remain seizure free when medications are discontinued. Mortality is increased in patients with epilepsy, but the increased mortality risk in childhood-onset epilepsy is primarily seen in patients with neurologic abnormalities or intractable epilepsy. Although long-term seizure outcomes are generally favorable, childhood-onset epilepsy is associated with adverse long-term psychosocial outcomes, even in patients attaining remission. This review summarizes recent data on the epidemiology and prognosis of pediatric epilepsy.

Risk factors for development of status epilepticus in dogs with idiopathic epilepsy and effects of status epilepticus on outcome and survival time: 32 cases (1990-1996)

OBJECTIVE

To identify risk factors for episodes of status epilepticus (SE) in dogs with idiopathic epilepsy and determine how SE affects long-term outcome and survival time.

DESIGN

Retrospective study.

ANIMALS

32 dogs with idiopathic epilepsy.

PROCEDURE

Information on signalment, seizure onset, initiation of treatment, anticonvulsants administered, number of episodes of SE, overall seizure control, and long-term outcome was obtained from medical records and through telephone interviews. Differences between dogs that did and did not have episodes of SE were evaluated statistically.

RESULTS

19 (59%) dogs had 1 or more episodes of SE. Body weight was the only variable significantly different between dogs that did and did not have episodes of SE. Thirteen dogs (9 that did not have episodes of SE and 4 that did) were still alive at the time of the study and were > or = 10 years old. Six of the 19 (32%) dogs that had episodes of SE died of causes directly attributed to the seizure disorder. Mean life spans of dogs that did and did not have episodes of SE were 8.3 and 11.3 years, respectively. Survival time was significantly different between groups.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that a substantial percentage of dogs with idiopathic epilepsy will have episodes of SE. Dogs with greater body weights were more likely to have episodes of SE, and early appropriate seizure treatment did not appear to decrease the risk that dogs would have episodes. Most dogs with idiopathic epilepsy had an expected life span, but survival time was shorter for dogs that had episodes of SE.

The prognosis of epilepsy

The cardinal question for a person developing seizures is 'What is the likelihood that they will go away?' 'Prognosis' refers to the possible outcomes of a disease and the frequency at which they can be expected to occur. Prognostic factors may include demographic features, disease-specific indicators (e.g. seizure frequency, aetiology of epilepsy) or co-morbidity. Such factors do not necessarily cause the outcome, but they are associated strongly with the outcome measured. They are distinct from risk factors--which are associated with the initial development of the disorder. Ideas about the outcome for epilepsy have been altered radically in the past century by study of its epidemiology. The prognosis for epilepsy comprises a number of measurable end-points: the prediction of recurrence after a single unprovoked seizure, the chance of remission after the diagnosis of epilepsy and the risk of premature death.

Long-term medical, educational, and social prognoses of childhood-onset epilepsy: a population-based study in a rural district of Japan

The long-term prognosis of childhood-onset epilepsy has rarely been studied in a general population. We examined the long-term medical, educational, and social outcomes in individuals with a history of childhood-onset epilepsy aged 20 years or older in a defined area of Japan. Furthermore, the patients' recognition of epilepsy as well as the parents' concerns about the prognosis of epilepsy were also surveyed. After a mean follow-up period of 18.9 years, we had sufficient data on 148 surviving patients aged 20-38 years (mean, 26. 0 years) and seven dead patients. The follow-up rate was 92.8%. In the overall group, the percentages of those who had had each of the following were as follows: (a) 5-year remission, 62.8%; (b) a relapse of seizures, 17.4%; (c) psychiatric complications, 2.7%; (d) mortality, 4.5%; (e) attendance at regular classes of an ordinary school during compulsory education, 71.6%; (f) entrance to high school, 65.5%; (g) employment, 67.4%; (h) marriage, 23.0%; and (i) acquisition of a driver's license, 54.7%. The educational and social variables of the control population were as follows: (e) 99.1, (f) 97.0, (g) 96.6, (h) 51.9, and (i) 94.8%. In the 99 patients of normal intelligence, the results of the same analysis were as follows: (a) 75.8, (b) 10.7, (c) 0, (d) 0.6, (e) 100, (f) 96.0, (g) 95.2, (h) 33.3, and (i) 77.8%, in contrast to the corresponding variables of the 49 patients with mental retardation, that is, (a) 36.7, (b) 44.4, (c) 8.2, (d) 12.2, (e) 14.3, (f) 6.1, (g) 20.4, (h) 2.0, and (i) 4.1%, respectively. The best predictors of seizure remission included an early response to therapy, a low frequency of seizures or an absence of status epilepticus prior to therapy, and normal mental development. As for the current awareness of epilepsy and its prognosis, nearly 40% of the patients did not know the true name of their illness, and the same proportion of parents were still anxious about the prognosis even if their children had been taken off medication. Our data show that the majority of patients with childhood-onset epilepsy have a favorable long-term medical prognosis in terms of seizure remission and psychiatric complications, whereas they have a higher mortality rate and lower levels of educational background as well as employment and marital status compared with the general population. However, except for the low marriage rate for the younger age group and the low rate of holding a driver's license, patients of normal intelligence appear to have more favorable long-term prognoses in terms of educational and social aspects as well. In Japan, individuals with epilepsy may not seek a driver's license because of the law.

Early predictors of intractability in childhood epilepsy: a community-based case-control study in Copparo, Italy

OBJECTIVES

To identify early predictors of intractability in childhood and adolescence epilepsy.

MATERIALS AND METHODS

We carried out a community-based case-control study using the incidence cohort of epileptic patients living in the district of Copparo, in the province of Ferrara, Italy. The comparative study was performed in 31 cases and 95 controls. Cases were patients who averaged at least 1 unprovoked seizure per month during an observational period of at least 2 years. Controls were subjects having achieved remission for at least 5 years regardless of current therapy.

RESULTS

Onset at age <1 year, remote symptomatic etiology and high frequency of seizures before therapy were found to be independent early predictors of intractability.

CONCLUSION

Our study suggested that the risk of developing intractable epilepsy may, to some extent, be predicted at the time of initial diagnosis in children with early-onset epilepsy of remote symptomatic etiology, especially if seizure propensity is initially high.

Intractable epilepsy in a population-based series of mentally retarded children

PURPOSE

The characteristics of intractable epilepsy were analyzed in a population-based study of active epilepsy in mentally retarded children aged 6-13 years.

METHODS

Diagnostic registers, EEG laboratory registers, and registers for the Education of the Subnormal were searched. Medical files were scrutinized. Clinical examinations and interviews with parents and caregivers or both were performed. EEG recordings, computed tomography (CT) and magnetic resonance imaging (MRI) of the CNS were reevaluated.

RESULTS

Forty-five percent (44 of 98) of the children with mental retardation (MR) and active epilepsy had intractable seizures, defined as one or more seizures every day or week. The median age at onset was 0.8 years, as compared with 3.0 years for those with controlled epilepsy. Predictive factors for frequent seizures were the number of seizure types, severe MR, status epilepticus (SE) and tonic seizures. Epileptiform EEG activity was present in 91%, and focal activity in 65%. Brain lesions were detected on CT and MRI in 70%, with generalized lesions in 60%. Concurrent focal epileptiform activity and focal brain lesions on CT/MRI were detected in 26%. The percentages and prevalence rates for infantile spasms (IS) and Lennox-Gastaut syndrome (LGS) were 18% (0.25 in 1,000) and 7% (0.06 in 1,000), respectively. One of 8 children with IS had had previous neonatal seizures, 3 had SE and 1 later developed LGS.

CONCLUSIONS

Children with MR and intractable epilepsy have a high frequency of severe MR and additional major neuroimpairments. EEG recordings frequently showed focal changes despite generalized lesions in neuroradiology.