[First epileptic crisis. Analysis of risk factors for recurrence]

Prognosis of adults and children following a first unprovoked seizure

BACKGROUND

Epilepsy is clinically defined as two or more unprovoked epileptic seizures more than 24 hours apart. Given that, a diagnosis of epilepsy can be associated with significant morbidity and mortality, it is imperative that clinicians (and people with seizures and their relatives) have access to accurate and reliable prognostic estimates, to guide clinical practice on the risks of developing further unprovoked seizures (and by definition, a diagnosis of epilepsy) following single unprovoked epileptic seizure.

OBJECTIVES

1. To provide an accurate estimate of the proportion of individuals going on to have further unprovoked seizures at subsequent time points following a single unprovoked epileptic seizure (or cluster of epileptic seizures within a 24-hour period, or a first episode of status epilepticus), of any seizure type (overall prognosis). 2. To evaluate the mortality rate following a first unprovoked epileptic seizure.

SEARCH METHODS

We searched the following databases on 19 September 2019 and again on 30 March 2021, with no language restrictions. The Cochrane Register of Studies (CRS Web), MEDLINE Ovid (1946 to March 29, 2021), SCOPUS (1823 onwards), ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). CRS Web includes randomized or quasi-randomized, controlled trials from PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP), the Cochrane Central Register of Controlled Trials (CENTRAL), and the Specialized Registers of Cochrane Review Groups including Epilepsy. In MEDLINE (Ovid) the coverage end date always lags a few days behind the search date.

SELECTION CRITERIA

We included studies, both retrospective and prospective, of all age groups (except those in the neonatal period (< 1 month of age)), of people with a single unprovoked seizure, followed up for a minimum of six months, with no upper limit of follow-up, with the study end point being seizure recurrence, death, or loss to follow-up. To be included, studies must have included at least 30 participants. We excluded studies that involved people with seizures that occur as a result of an acute precipitant or provoking factor, or in close temporal proximity to an acute neurological insult, since these are not considered epileptic in aetiology (acute symptomatic seizures). We also excluded people with situational seizures, such as febrile convulsions.

DATA COLLECTION AND ANALYSIS

Two review authors conducted the initial screening of titles and abstracts identified through the electronic searches, and removed non-relevant articles. We obtained the full-text articles of all remaining potentially relevant studies, or those whose relevance could not be determined from the abstract alone and two authors independently assessed for eligibility. All disagreements were resolved through discussion with no need to defer to a third review author. We extracted data from included studies using a data extraction form based on the checklist for critical appraisal and data extraction for systematicreviews of prediction modelling studies (CHARMS). Two review authors then appraised the included studies, using a standardised approach based on the quality in prognostic studies (QUIPS) tool, which was adapted for overall prognosis (seizure recurrence). We conducted a meta-analysis using Review Manager 2014, with a random-effects generic inverse variance meta-analysis model, which accounted for any between-study heterogeneity in the prognostic effect. We then summarised the meta-analysis by the pooled estimate (the average prognostic factor effect), its 95% confidence interval (CI), the estimates of I² and Tau² (heterogeneity), and a 95% prediction interval for the prognostic effect in a single population at three various time points, 6 months, 12 months and 24 months. Subgroup analysis was performed according to the ages of the cohorts included; studies involving all ages, studies that recruited adult only and those that were purely paediatric.

MAIN RESULTS

Fifty-eight studies (involving 54 cohorts), with a total of 12,160 participants (median 147, range 31 to 1443), met the inclusion criteria for the review. Of the 58 studies, 26 studies were paediatric studies, 16 were adult and the remaining 16 studies were a combination of paediatric and adult populations. Most included studies had a cohort study design with two case-control studies and one nested case-control study. Thirty-two studies (29 cohorts) reported a prospective longitudinal design whilst 15 studies had a retrospective design whilst the remaining studies were randomised controlled trials. Nine of the studies included presented mortality data following a first unprovoked seizure. For a mortality study to be included, a proportional mortality ratio (PMR) or a standardised mortality ratio (SMR) had to be given at a specific time point following a first unprovoked seizure. To be included in the meta-analysis a study had to present clear seizure recurrence data at 6 months, 12 months or 24 months. Forty-six studies were included in the meta-analysis, of which 23 were paediatric, 13 were adult, and 10 were a combination of paediatric and adult populations. A meta-analysis was performed at three time points; six months, one year and two years for all ages combined, paediatric and adult studies, respectively. We found an estimated overall seizure recurrence of all included studies at six months of 27% (95% CI 24% to 31%), 36% (95% CI 33% to 40%) at one year and 43% (95% CI 37% to 44%) at two years, with slightly lower estimates for adult subgroup analysis and slightly higher estimates for paediatric subgroup analysis. It was not possible to provide a summary estimate of the risk of seizure recurrence beyond these time points as most of the included studies were of short follow-up and too few studies presented recurrence rates at a single time point beyond two years. The evidence presented was found to be of moderate certainty.

AUTHORS' CONCLUSIONS

Despite the limitations of the data (moderate-certainty of evidence), mainly relating to clinical and methodological heterogeneity we have provided summary estimates for the likely risk of seizure recurrence at six months, one year and two years for both children and adults. This provides information that is likely to be useful for the clinician counselling patients (or their parents) on the probable risk of further seizures in the short-term whilst acknowledging the paucity of long-term recurrence data, particularly beyond 10 years.

Statistical models for longitudinal zero-inflated count data: application to seizure attacks

Background

Chronic non-communicable diseases:- such as epilepsy, are increasingly recognized as public health problems in developing and African countries. This study aimed at finding determinants of the number of epileptic seizure attacks using different count data modeling techniques.

Methods

Four common fixed-effects Poisson family models were reviewed to analyze the count data with a high proportion of zeros in longitudinal outcome, i.e., the number of seizure attacks in epilepsy patients. This is because, in addition to the problem of extra zeros, the correlation between measurements upon the same patient at different occasions needs to be taken into consideration.

Results

The investigation remarkably identified some important factors associated with epileptic seizure attacks. As people grow old, the number of seizure attacks increased and male patients had more seizures than their female counterparts. In general, a patient's age, sex, monthly income, family history of epilepsy andservice satisfaction were some of the significant factors responsible for the frequency of seizure attacks (P value<0.05).

Conclusion

This study suggests that zero-inflated negative binomial is the best model for predicting and describing the number of seizure attacks as well as identifying the potential risk factors. Addressing these risk factors will definitely contain the progression of seizure attack.

Evaluation of Seizure Frequency Distribution in Epileptic Patients with Normal and Abnormal Electroencephalogram in Al-Zahra Hospital of Isfahan

BACKGROUND

Epilepsy is a chronic neurological disorder characterized by seizure recurrence in patients. Electroencephalogram (EEG) has a diagnostic and prognostic role in the management of patients. Studies have shown a significant relation between seizure recurrence and abnormal EEG in newly diagnosed epileptic patients, and people with first episode of unprovoked seizure. The aim of this study is to evaluate seizure frequency in chronic epileptic patients on drug therapy based on normal or abnormal EEG.

MATERIALS AND METHODS

This prospective cohort study examined seizure recurrence in 59 epileptic patients (50.8% generalized, 49.2% focal) with normal and abnormal EEG. Data were recorded in patient medical file, and patients were followed by telephone call or visiting by neurologist.

RESULTS

In this study, 59 patients with a mean age of 29.58 ± 10.37 years were assessed that 42.4% of them were males and 57.6% were females. Seizure frequency in patient with specific abnormal EEG was significantly more than other patients (specific abnormal: 78.9%, nonspecific abnormal: 45.5%, and normal: 31%, P = 0.005). Seizure recurrence in patients on polytherapy was significantly higher than others (polytherapy: 76.9% and monotherapy: 27.3%, P < 0.001). In patient with abnormal imaging seizure, frequency was more than other patients which was nearly significant (P = 0.054).

CONCLUSION

Abnormal EEG and number of anticonvulsant drugs have a role in seizure recurrence in epileptic patients.

Risk of recurrence after a first unprovoked seizure in children

OBJECTIVES

This study aimed to evaluate the first episode of unprovoked epileptic seizure in children and assess recurrence risk factors.

METHODS

This was a retrospective observational study, based on the analysis of medical records of patients admitted between 2003 and 2014, with first epileptic seizure, at the pediatric service of a secondary hospital. The data were analyzed using the SPSS 20.0 program.

RESULTS

Of the 103 patients, 52.4% were boys. The median age at the first seizure was 59 (1-211) months. About 93% of children were submitted to an electroencephalogram at the first episode and 47% underwent neuroimaging assessment. Treatment with an antiepileptic drug was started in 46% of patients. The recurrence rate was 38% and of these, 80% had the second seizure within six months after the first event. Of the assessed risk factors, there was a statistically significant association between seizure during sleep and recurrence (p=0.004), and between remote symptomatic etiology seizure and occurrence of new seizure (p=0.02). The presence of electroencephalogram abnormalities was also associated with the occurrence of new seizures (p=0.021). No association was found between age, duration of the seizure, and family history of epilepsy with increased risk of recurrence.

CONCLUSIONS

Most children with a first unprovoked epileptic seizure had no recurrences. The risk of recurrence was higher in patients with seizure occurring during sleep or remote symptomatic ones and those with abnormal electroencephalogram results.

Clinical and electroencephalographic follow-up after a first unprovoked seizure

We studied the role of clinical and electroencephalographic factors in the follow-up of children and adolescents after a first unprovoked seizure, and their correlation with recurrence and risk for epilepsy. We conducted a 24-month follow-up of 109 patients aged 1 month to 16 years who had a first unprovoked seizure. We analyzed the characteristics of the first seizure, perinatal history, family history of seizures, electroencephalographic patterns and their influence on seizure recurrence, and calculated risk for subsequent epilepsy. Fifty-six patients (51.4%) had recurrent seizures. The bivariate statistical analysis revealed that maternal prenatal disease (relative risk = 2.02, P = 0.03) and an abnormal electroencephalogram (relative risk = 2.89, P = 0.0003) were significantly associated with seizure recurrence. Other factors (male sex, partial first seizure, vaginal delivery, family history of seizures, and sleep state) approached statistical significance. Logistic regression revealed that the only variable significantly associated with recurrence was an abnormal electroencephalographic pattern on the first examination (relative risk = 2.48, P = 0.003). Cumulative risk ranged from 50-68% at 24 months when the first electroencephalogram was abnormal, and from 26-36% when it was normal. We concluded that the electroencephalogram may have an important diagnostic value in the prognosis of epileptic seizure recurrence in children and adolescents.

[Etiology of the epileptic seizures in Recife city, Brazil: study of 249 patients]

The etiological causes of the epileptic seizures presenting by 249 patients were studied, in a neurological clinic in Recife City, Brazil. The cause of the seizure was not identified in 43.0% of the patients. As suspected causal factors we found: ischemic cerebrovascular disease (ICVD, 17.3%), cysticercosis (8.8%), head trauma (HT, 6.8%), brain tumors (6.8%), hemorrhagic cerebrovascular disease (HCVD, 4.8%), vascular malformation (3.6%), other causes (8. 4%). In the patients with age less than 15-year-old, the most frequent cause was cysticercosis (10.3%), following vascular malformation (5.1%), and ICVD (5.1%). In the group between 15 and 45 years of age the major cause of seizure was cysticercosis (11.6%), following HT (10.7%), ICVD (4.5%), and brain tumors (3.6%). On the other hand, in the patients with more than 45-year-old the main cause was ICVD (36.7%), following brain tumors (12.3%), HCVD (11.2%), and cysticercosis (5.1%). Im conclusion, cerebrovascular disease was the most prevalent cause of epileptic seizures, considering all groups of patients. Although, cysticercosis was main cause found in the patients with less than 45 years of age.