Idiopathic first seizure in adult life: who should be treated?

First seizure from sleep: Clinical features and prognosis

OBJECTIVES

Patients with a first-ever unprovoked seizure commonly have subsequent seizures and identifying predictors of recurrence has important management implications. Both prior brain insult and epileptiform abnormalities on electroencephalography (EEG) are established predictors of seizure recurrence. Some studies suggest that a first-ever seizure from sleep has a higher likelihood of recurrence. However, with relatively small numbers and inconsistent definitions, more data are required.

METHODS

Prospective cohort study of adults with first-ever unprovoked seizure seen by a hospital-based first seizure service between 2000 and 2015. Clinical features and outcomes of first-ever seizure from sleep and while awake were compared.

RESULTS

First-ever unprovoked seizure occurred during sleep in 298 of 1312 patients (23%), in whom the 1-year cumulative risk of recurrence was 56.9% (95% confidence interval [CI] 51.3-62.6) compared to 44.2% (95% CI 41.1-47.3, p < .0001) for patients with first-ever seizure while awake. First-ever seizure from sleep was an independent predictor of seizure recurrence, with a hazard ratio [HR] of 1.44 (95% CI 1.23-1.69), similar to epileptiform abnormalities on EEG (HR 1.48, 95% CI 1.24-1.76) and remote symptomatic etiology (HR 1.47, 95% CI 1.27-1.71). HR for recurrence in patients without either epileptiform abnormalities or remote symptomatic etiology was 1.97 (95% CI 1.60-2.44) for a sleep seizure compared to an awake seizure. For first seizure from sleep, 76% of second seizures also arose from sleep (p < .0001), with 65% of third seizures (p < .0001) also from sleep. Seizures from sleep were less likely to be associated with injury other than orolingual trauma, both with the presenting seizure (9.4% vs 30.6%, p < .0001) and first recurrence (7.5% vs 16.3%, p = .001).

SIGNIFICANCE

First-ever unprovoked seizures from sleep are more likely to recur, independent of other risk factors, with recurrences also usually from sleep, and with a lower risk of seizure-related injury. These findings may inform treatment decisions and counseling after first-ever seizure.

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.

An Evidence Based Approach to the First Unprovoked Seizure

The objective is to illustrate the creation and structure of a particular type of Evidence Based Care (EBC) summary that has direct clinical relevance, the Critically Appraised Topic (CAT). The process consists of a step-by-step application of the EBC principles to a common neurological problem, ie., a patient presenting with a first, unprovoked generalized seizure. This includes asking a focused clinical question about prognosis for recurrence and the role of antiepileptic drugs; searching the literature to answer the question; selecting the relevant evidence (a meta-analysis about prognosis and a randomized controlled trial about therapy); appraising the literature for its validity and usefulness; and applying the results to the clinical scenario. The result is a one-page, user friendly CAT whose title states a declarative answer to the clinical question. It also contains a description of the literature search and of the evidence, the clinical bottom lines derived from the evidence, and general comments.

Clinicians' guide to evaluating diagnostic and screening tests in psychiatry

The emphasis on the evidence base of treatments may diminish awareness that critical appraisal of research into other aspects of psychiatric practice is equally important. There is a risk that diagnostic tests may be inappropriate in some clinical settings or the results of a particular test may be over-interpreted, leading to incorrect diagnosis. This article outlines the method of critically evaluating the validity of articles about diagnostic and screening tests in psychiatry and discusses concepts of sensitivity, specificity and predictive values. The use of likelihood ratios in improving clinical certainty that a disease is present or absent is examined.

Mobile EEG in epilepsy

The sensitivity of routine EEG recordings for interictal epileptiform discharges in epilepsy is limited. In some patients, inpatient video-EEG may be performed to increase the likelihood of finding abnormalities. Although many agree that home EEG recordings may provide a cost-effective alternative to these recordings, their use is still not introduced everywhere. We surveyed Dutch neurologists and patients and evaluated a novel mobile EEG device (Mobita, TMSi). Key specifications were compared with three other current mobile EEG devices. We shortly discuss algorithms to assist in the review process. Thirty percent (33 out of 109) of Dutch neurologists reported that home EEG recordings are used in their hospital. The majority of neurologists think that mobile EEG can have additional value in investigation of unclear paroxysms, but not in the initial diagnosis after a first seizure. Poor electrode contacts and signal quality, limited recording time and absence of software for reliable and effective assistance in the interpretation of EEGs have been important constraints for usage, but in recent devices discussed here, many of these problems have been solved. The majority of our patients were satisfied with the home EEG procedure and did not think that our EEG device was uncomfortable to wear, but they did feel uneasy wearing it in public.

When should a sleep-deprived EEG be performed following a presumed first seizure in adults?

OBJECTIVES

To evaluate the effect of the interval between the seizure and the EEG recording on the yield of early sleep-deprived EEG (SD-EEG) in patients admitted following a presumed first seizure.

MATERIALS AND METHODS

We retrospectively reviewed the EEG recordings and medical records of patients admitted to the Neurology Department in Assaf Harofeh Medical Center because of a presumed first seizure during a 3-year period between 2006 and 2009 and who had a SD-EEG following a first routine EEG without epileptiform discharges (EDs).

RESULTS

The study group included 78 patients aged 18-78 years (mean 35 ± 17). Previous seizures were recognized through repeated history in 32 (41%) patients. EDs were recorded in the SD-EEG in 16 (21%) patients: 13/46 (28%) with a SD-EEG performed within 3 days following the seizure and 3/32 (9%) with a later SD-EEG (P = 0.042) and in 10/32 (31%) patients in whom previous seizures were recognized and 6/46 (13%) with a first seizure (P = 0.05).

CONCLUSIONS

EDs in the SD-EEG following a first diagnosed seizure occur more commonly when the test is performed within 3 days following a first seizure or when previous seizures are recognized.

How confident are we of the diagnosis of epilepsy?

The diagnosis of a first seizure or epilepsy may be subject to interobserver variation and inaccuracy with possibly far-reaching consequences for the patients involved. We reviewed the current literature. Studies on the interobserver variation of the diagnosis of a first seizure show that such a diagnosis is subject to considerable interobserver disagreement. Interpretation of the electroencephalogram (EEG) findings is also subject to interobserver disagreement and is influenced by the threshold of the reader to classify EEG findings as epileptiform. The accuracy of the diagnosis of epilepsy varies from a misdiagnosis rate of 5% in a prospective childhood epilepsy study in which the diagnosis was made by a panel of three experienced pediatric neurologists to at least 23% in a British population-based study, and may be even higher in everyday practice. The level of experience of the treating physician plays an important role. The EEG may be helpful but one should be reluctant to make a diagnosis of epilepsy mainly on the EEG findings without a reasonable clinical suspicion based on the history. Being aware of the possible interobserver variation and inaccuracy, adopting a systematic approach to the diagnostic process, and timely referral to specialized care may be helpful to prevent the misdiagnosis of epilepsy.

Evidence-based medicine

Evidence-based medicine (EBM) has become a watchword for "the new" medical practice in the new century. Whether it represents a paradigm shift or simply a codification of the scientific method in medicine will be debated for years to come. Regardless of the place of EBM in medicine, this "movement" has served an important role in moving physician practice into the realm of becoming more scientific (albeit empirical) and transparent. There are still many problems to be addressed in the global application of the best evidence for medical practice. These include low-quality studies, delays in implementation of clear-cut improvements, outright fraud and deceit, and wariness on the part of physicians to change their practice. By working to understand the underpinnings of EBM (basic statistical concepts and critical thinking) we can advance the practice of medicine along the moral high road of science.

Interobserver reliability of visual interpretation of electroencephalograms in children with newly diagnosed seizures

The reliability of visual interpretation of electroencephalograms (EEG) is of great importance in assessing the value of this diagnostic tool. We prospectively obtained 50 standard EEGs and 61 EEGs after partial sleep deprivation from 93 children (56 males, 37 females) with a mean age of 6 years 10 months (SE 5 mo; range 4 mo-15 y 7 mo) with one or more newly diagnosed, unprovoked seizures. Two clinical neurophysiologists independently classified the background pattern and the presence of epileptiform discharges or focal non-epileptiform abnormalities of each EEG. The agreement was substantial for the interpretation of the EEG as normal or abnormal (kappa 0.66), almost perfect for the presence of epileptiform discharges (kappa 0.83), substantial for the occurrence of an abnormal background pattern (kappa 0.73), and moderate for the presence of focal non-epileptiform discharges (kappa 0.54). In conclusion, the reliability of the visual interpretation of EEGs in children is almost perfect as regards the presence of epileptiform abnormalities, and moderate to substantial for the presence of other abnormalities.

Early management of adults with an uncomplicated first generalised seizure

A literature review of first seizures in adults was performed and a management algorithm was constructed. This review highlights the importance of a thorough history and examination, routine biochemistry and haematology, an electrocardiogram, selected neuroimaging, discharge planning with driving and lifestyle advice, and follow-up in a specialist clinic.

Meta-analysis of EEG test performance shows wide variation among studies

BACKGROUND

EEG results are used for counseling patients with seizures about prognosis and deciding on medications. Published sensitivities of interictal EEG vary widely.

OBJECTIVE

To account for variation in test characteristics between studies.

METHODS

Meta-analysis. Medline search, 1970 to 2000, of English language studies. Standard methods for meta-analysis of diagnostic test performance were used to determine the ability of EEG results to distinguish between patients who will and will not have seizures. Using linear regression, the authors assessed the influence of readers' thresholds for classifying the EEG as positive, sample probability of seizure, percent of subjects with prior neurologic impairment, percent treated, and years followed.

RESULTS

Twenty-five studies involving 4,912 EEG met inclusion criteria. Specificity (range 0.13 to 0.99) and sensitivity (range 0.20 to 0.91) of epileptiform EEG interpretations varied widely and were heterogeneous by chi(2) analysis (p < 0.001 for each). Diagnostic accuracy of EEG and the thresholds for classifying EEG as positive varied widely. In the multivariate model, differences in readers' thresholds accounted for 37% of the variance in EEG diagnostic accuracy, and no other reported factors were significant.

CONCLUSION

This analysis suggests that there is wide interreader variation in sensitivity and specificity of EEG interpretations, and that this variation influences the ability of EEG to discriminate between those who will and will not have seizure recurrences. In clinical practice, interpreting the degree to which a positive EEG result predicts increased seizure risk in an individual patient is difficult. Interpreting EEG with higher specificity yields more accurate predictions.

Epilepsy and motor vehicle driving--a symposium held in Québec City, November 1998

BACKGROUND

This report summarizes an invitational symposium on epilepsy and Canadian laws governing motor vehicle driving held in Québec City in November 1998.

METHODS

Invited neurological experts from Canada, the USA, and Europe; and representatives of provincial and territorial licensing bodies, the Canadian Council of Motor Transport Administrators, the Canadian Medical Protective Association, and the Canadian Medical Association participated. An edited version of transcribed audiotapes was prepared. Specific issues discussed were whether or not a physician should be required to report a patient with epilepsy to the licensing authority (mandatory reporting), the nature and quantification of the risks posed by epileptic drivers, and what would be a reasonable law regulating driving by people with epilepsy in Canada.

RESULTS

The consensus among medical experts was that mandatory reporting should be abolished in Canada and that a 6-12 month seizure-free period was appropriate before most patients could return to driving private cars. Experts also believed that these standards should be uniform across Canada. There was strong disagreement with the recommendation of the Canadian Medical Association that all such drivers be reported to provincial licensing authorities even in provinces without mandatory reporting rules.

CONCLUSIONS

Physicians should be familiar with and follow the rules regarding epilepsy and driving in the provinces where they practice. Nevertheless, current evidence is against mandatory physician reporting of drivers with epilepsy and the neurologists recommended that this be abolished throughout Canada. Shorter seizure-free intervals should also be considered before resuming driving of private cars.

Treating epilepsy in the elderly: safety considerations

The incidence of epilepsy increases with advancing age. Epilepsy in the elderly has different aetiologies from that in younger populations, cerebrovascular disease being the most common condition associated with seizures. Partial seizures are the predominant seizure type in older patients. A diagnosis of epilepsy in the elderly is based mainly on the history and is frequently delayed. In addition, seizure imitators are especially frequent. In many cases ancillary tests for diagnosis may show normal age-related variants, sometimes making results difficult to interpret. Treating epilepsy in the elderly is problematic due to a number of issues that relate to age and comorbidity. The physical changes associated with increasing age frequently lead to changes in the pharmacokinetics of many anticonvulsants. The treatment of epilepsy in the elderly is also complicated by the existence of other diseases that might affect the metabolism or excretion of anticonvulsants and the presence of concomitant medications that might interact with them. Moreover, specific trials of anticonvulsants in the aged population are scarce. General guidelines for treatment include starting at lower doses, slowing the titration schedule, individualising the choice of anticonvulsant to the characteristics of the patient, avoiding anticonvulsants with important cognitive or sedative adverse effects, and where possible, treating with monotherapy.

Seizure recurrence in adults after a newly diagnosed unprovoked epileptic seizure

PURPOSE

To investigate the risk of seizure recurrence after a newly diagnosed unprovoked epileptic seizure in an adult population-based cohort.

MATERIAL AND METHODS

A total of 107 patients aged >or=17 years with a newly diagnosed unprovoked epileptic seizure (index seizure) were prospectively identified for the period 1985-87. Patients were followed until the date of death or to the end of 1996 with a median follow-up of 10.3 years for surviving cases. Overall cumulative recurrence rates and possible influencing variables were calculated.

RESULTS

At 750 days after the index seizure the recurrence was 58%, and after that no events occurred. Recurrence risk was significantly higher when index seizure was remote symptomatic or preceded by two or more seizures. No other study variable predicted seizure recurrence.

CONCLUSION

Etiology and the occurrence of seizures before the index seizure after a newly diagnosed unprovoked epileptic seizure predict seizure recurrence. Thus, particular consideration should be given to these factors in the decision of whether or not to initiate antiepileptic treatment.

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.

Initiation and discontinuation of antiepileptic drugs

The issues of when to initiate and discontinue antiepileptic drugs (AEDs) are reviewed using an approach that emphasizes weighing the relative risks and benefits of the therapeutic decisions. The majority of children and adults who present with a first unprovoked seizure will not experience further seizures. Treatment reduces recurrence risk but does not alter long-term prognosis. Treatment should be deferred until a second seizure has occurred. The majority of children and adults who are seizure free for two or more years on medications will remain so when medications are withdrawn. The risk of reoccurrence is somewhat higher in adults. The consequences of recurrence are much more significant in adults. Most children who are seizure free on medications should have at least one attempt at medication withdrawal. In adults, the decisions need to be individualized based on a variety of factors including age, sex, occupation, and the presence or absence of risk factors for reoccurrence.

Recurrence after a first untreated seizure in the Hong Kong Chinese population

PURPOSE

There is wide variation in the reported prognosis after a first unprovoked generalized tonic-clonic convulsion and in the risk factors that are associated with recurrence. Estimates for the risk of recurrence range from 26 to 71%. We investigated the likelihood of a second attack in Hong Kong Chinese patients.

METHODS

One hundred thirty-two patients with a first convulsion that was unexplained by acute neurological or medical causes were retrospectively ascertained. Patients' demographic details, potential risk factors for recurrence, and current seizure status were recorded. Survival analysis was performed using the Kaplan-Meier procedure.

RESULTS

The cumulative probability of a second attack at 1, 2, 3, and 4 years was 30, 37, 42, and 47%, respectively. Seizures in patients with abnormal computer tomography scans of the brain were associated with an increased risk of recurrence on multivariate analysis.

CONCLUSIONS

Thirty percent of the sample population experienced a second seizure after 1 year. An additional 17% continue to be at risk of a second convulsion during the next 3 years.

Clinical aspects and biological bases of drug-resistant epilepsies

The definition of drug-resistant epilepsy (DRE) is elusive and still controversial owing to some unresolved questions such as: how many drugs should be tried before a patient is considered intractable; to which extent side-effects may be acceptable; how many years are necessary before establishing drug resistance. In some cases, the view of epilepsy as a progressive disorder constitutes another important issue. Despite the use of new antiepileptic drugs (AEDs), intractable epilepsy represents about 20-30% of all cases, probably due to the multiple pathogenetic mechanisms underlying refractoriness. Several risk factors for pharmacoresistance are well known, even if the list of clinical features and biological factors currently accepted to be associated with difficult-to-treat epilepsy is presumably incomplete and, perhaps, disputable. For some of these factors, the biological basis may be common, mainly represented by mesial temporal sclerosis or by the presence of focal lesions. In other cases, microdysgenesis or dysplastic cortex, with abnormalities in the morphology and distribution of local-circuit (inhibitory) neurons, may be responsible for the severity of seizures. The possible influence of genes in conditioning inadequate intraparenchimal drug concentration, and the role of some cytokines determining an increase in intracellular calcium levels or an excessive growth of distrophic neurites, constitute other possible mechanisms of resistance. Several hypotheses on the mechanisms involved in the generation of DRE have been indicated: (a) ontogenic abnormalities in brain maturation; (b) epilepsy-induced alterations in network, neuronal, and glial properties in seizure-prone regions such as the hippocampus; (c) kindling phenomenon; (d) reorganization of cortical tissue in response to seizure-induced disturbances in oxygen supply. Such hypotheses need to be confirmed with suitable experimental models of intractable epilepsy that are specifically dedicated, which have until now been lacking.

Evaluation of the patient with seizures: an evidence based approach

Statistics tell us that as many as 1 in 20 members of the population will suffer a seizure at some point in their lifetime, a figure which becomes even more likely if one lives to the age of 80. Thus, a careful evidence based approach to the patient with seizure is immensely useful to the emergency physician. The authors evaluate current studies on the subject, discuss seizures as they relate to specific patient groups, and, ultimately, make recommendations on this important subject.

Epileptology of the first-seizure presentation: a clinical, electroencephalographic, and magnetic resonance imaging study of 300 consecutive patients

BACKGROUND

Prognosis and treatment of the first seizure depends on identification of a specific epilepsy syndrome, yet patients with first seizures are generally regarded as a homogeneous group. We studied whether it is possible to diagnose specific epilepsy syndromes promptly by use of standard clinical methods, electroencephalography (EEG) and magnetic resonance imaging (MRI).

METHODS

300 consecutive adults and children presented with unexplained seizures. We systematically collected clinical data from patients and witnesses, and attempted to obtain an EEG within 24 h of the seizure. Where the EEG was negative, a sleep-deprived EEG was done. MRI was done electively.

FINDINGS

A generalised or partial epilepsy syndrome was clinically diagnosed in 141 (47%) patients. Subsequent analysis showed that only three of these clinical diagnoses were incorrect. Addition of the EEG data enabled us to diagnose an epilepsy syndrome in 232 (77%) patients. EEG within 24 h was more useful in diagnosis of epileptiform abnormalities than later EEG (51 vs 34%). Neuroimaging showed 38 epileptogenic lesions, including 17 tumours. There were no lesions in patients for whom generalised epilepsy was confirmed by EEG. Our final diagnoses were: generalised epilepsy (23% of patients); partial epilepsy (58%); and unclassified (19%).

INTERPRETATION

An epilepsy syndrome can be diagnosed in most first-seizure patients. Ideally, an EEG should be obtained within 24 h of the seizure followed by a sleep deprived EEG if necessary. MRI aids diagnosis and should be done for all patients except for those with idiopathic generalised epilepsies and for children with benign rolandic epilepsy.

The single seizure. To treat or not to treat?

It is generally accepted that anticonvulsant therapy should be offered once a patient has experienced 2 or more seizures. However, there is controversy over whether treatment should be offered after a single seizure. The type of epileptic event that has occurred may determine whether or not a single episode will bring the individual to medical attention. In individuals who experience a single seizure, there is significantly increased risk of recurrence if neurological or paroxysmal electroencephalogram abnormalities are present or if the seizure is partial. Anticonvulsant therapy, if taken as prescribed after a single seizure, will substantially reduce the risk of seizure recurrence. Unless a further seizure would hold little disadvantage, early treatment probably offers distinctly more benefit than hazard. No data are available to indicate the most appropriate duration of therapy after a single seizure.

Prospective optimization of patient selection for emergency cranial computed tomography: univariate and multivariate analyses

RATIONALE AND OBJECTIVES

To determine if the clinical variables that are important for selecting patients for emergency cranial computed tomography (CT) are population dependent.

METHODS

Prior to obtaining scans, physicians working in an emergency department in a level II trauma center completed a form describing the indication for the CT examination. These data were matched to the CT scan results and analyzed statistically using univariate and multivariate methods. These results were compared with a prior study at a level I trauma center.

RESULTS

Of 551 patients having cranial CT, neurologic examination was positive in 340 and CT scan was positive in 122. The neurologic examination correlated strongly with the results of the CT scan (P < 0.00001). In this patient population, the most important clinical predictors of 17 abnormal CT scans from the 211 patients without positive neurologic examinations were seizure and a history of neoplasm. These high-yield variables differ from our prior retrospective study in which intoxication and amnesia were the important predictors in patients with negative examinations. The difference in predictors between the populations most likely results from different prevalences of trauma and ischemic disease.

CONCLUSIONS

Abnormal neurologic examination is the most important criterion available to select patients for emergency cranial CT. Other variables (eg, seizure, amnesia, intoxication, and history of neoplasm) that help select patients without neurologic findings appear to be population dependent.

The place of the EEG and imaging in the management of seizures

Images

Decision analysis in the clinical neurosciences: a systematic review of the literature

Clinical decision analysis can be a useful scientific tool for individual patient management, for planning of clinical research and for reaching consensus about clinical problems. We systematically reviewed the decision analytic studies in the clinical neurosciences that were published between 1975 and July 1994. All studies were assessed on aspects of clinical applicability: presence of case and context description, completeness of the analysed strategies from a clinical point of view, extendibility of the analyses to different patient profiles, and up-to-date-ness. Fifty-nine decision analyses of twenty-eight different clinical problems were identified. Twenty-eight analyses were based on the theory of subjective expected utility, twelve on cost-effectiveness analysis. Four studies used ROC analysis, and fifteen were risk-, or risk-benefit analyses. At least six studies could have been improved by more elaborately disclosing the context of the clinical problem that was addressed. In eleven studies, the effect of different, yet plausible assumptions was not explored, and in eighteen studies the reader was not informed how to extend the results of the analysis to patients with (slightly) different clinical characterisitics. All studies had, by nature, the potential to promote insight into the clinical problem and focus the discussion on clinically important aspects, and gave clinically useful advice. We conclude that clinical decision analysis, as an explicit, quantitative approach to uncertainty in decision making in the clinical neurosciences will fulfill a growing need in the near future.

How do we manage the first seizure in adults?

This paper reports an audit of the management of a first generalised seizure in a small district general hospital and describes the management policies of 95 general physicians and 82 neurologists. The audit studied 56 patients who presented in 1990-93 after witnessed generalised convulsions without focal neurological signs or previous history of seizures. Their ages ranged from 16 to 89 (mean 38) and 47 of them were men. In 31% alcohol was incriminated in the seizure. Blood tests were done in most patients but gave little useful information. Skull and chest radiographs were taken in fewer patients but were unhelpful. An electroencephalogram was done in 77% but failed to influence management in any, and only 2 of the 50 computed tomography scans performed led to a change in management. Only 21% received the correct advice about driving. A questionnaire sent to 130 general physicians and 109 neurologists sought their policy on the management of patients after a first generalised seizure. Completed forms were received from 95 physicians and 82 neurologists (response rate 74%). Half of physicians and neurologists perform a computed tomogram on all patients while one-third scan patients only above a certain age. Neurologists perform significantly more electroencephalograms (86% vs 65%) while many more physicians order a chest radiograph (73% vs 16%). About 80% of physicians compared with about 30% of neurologists ask for routine blood tests of haematology and biochemistry. Only 4% of physicians and 1% of neurologists routinely start anticonvulsant treatment.

The management of epilepsy in the 1990s. Acquisitions, uncertainties and priorities for future research

The pharmacological treatment of epilepsy has made considerable progress during the last decade, due to improved knowledge of the clinical pharmacology of individual drugs, acquisition of new information on the factors affecting response and need for drug treatment, and development of promising new agents. Once a clinical diagnosis of epilepsy has been made (which generally requires the occurrence of more than one seizure), treatment should be started with a single drug selected on the basis of seizure type and tolerability profile. Although there are important regional differences in prescribing patterns and individual circumstances may dictate alternative choices, carbamazepine is generally regarded as the preferred treatment for partial seizures (with or without secondary generalisation) while valproic acid (sodium valproate) is usually the first choice in most forms of generalised epilepsies. To achieve therapeutic success, the daily dosage must be tailored to meet individual needs, and there is suggestive evidence that in some patients the dosage prescribed initially may be unnecessarily large. Plasma antiepileptic drug concentrations may aid in the individualization of dosage, but should not be regarded as a substitute for careful monitoring of clinical response. Although overall about 70% of patients can be completely controlled, response rate is influenced by a number of factors, the most important of which are seizure type and syndromic form. The importance of a correct syndromic classification for rational drug selection has been poorly assessed and represents a major area for future research. Patients who do not respond to the highest tolerated dose of the initially prescribed drug may be switched to monotherapy with an alternative agent or may be given add-on treatment with a second drug. Appropriate prospective trials are required to assess the merits of either strategy. If add-on therapy is selected and the patient becomes seizure free, it may be possible to discontinue the drug prescribed initially and reinstitute monotherapy. Only a minority of patients are likely to require multiple drug therapy, and it remains to be established whether specific drug combinations are more effective than others. Until further information becomes available, the new agents should be reserved for patients failing to respond to the conventional treatments of first choice. Patients whose seizures cannot be controlled by available drugs should be reassessed, and polytherapy should be maintained only when there is clear evidence that benefits outweigh possible adverse effects. In many patients who have been seizure free for at least 2 years it may be possible to gradually discontinue all medications.(ABSTRACT TRUNCATED AT 400 WORDS)

Clinical prediction of emergency cranial computed tomography results

STUDY PURPOSE

To determine the ability of clinicians to predict the results of emergency head computed tomography (CT) scans.

METHODS

Clinicians requesting cranial CT scans from the emergency department prospectively filled out a form detailing their patients' complaints, possible diagnoses, and the likelihood of finding those diagnoses on CT. The results of the scans were catalogued according to diagnosis and classified as acutely abnormal, chronically abnormal, or normal.

RESULTS

Analysis of 536 consecutive patients showed a significant direct correlation between clinical prediction of CT abnormality and scan results. No definite differences in the ability to predict scan results were observed among different physician training levels. Thirty-six patients had acute abnormalities on CT despite a clinical prediction of remote or low likelihood.

CONCLUSION

Although clinical predictions of CT abnormality correlate with actual CT results, the correlation is not adequately refined to rely on for selection of patients for emergency cranial CT scans.

Epileptic seizures in 1902 patients: a perspective from a consultant neurological practice (1961-1991)

Over a 30 year period, a total of 1902 persons with at least one epileptic seizure was referred to a consultant neurological practice. The type of seizure that was present was not determined in 10.6%, was generalised in 33.3%, partial in 53.9%, infantile convulsions in 1.1%, and 'generalised-partial' in 1.2%. The latter category probably represented the coincidence of generalised seizures (overt or as an EEG trait) and partial seizures in occasional individuals. At presentation, 13.9% of the series had experienced only a solitary seizure (80% of these a tonic-clonic fit). Compared with the rest of the series, solitary seizure sufferers more often went at least 1 year seizure free (78.6% v. 40.2%, for those with known outcomes), and were known to have been able to cease therapy after 3-5 years without seizures (26.5% v. 12.5%). Established seizure disorders (first seizure more than 1 year earlier, at least three tonic-clonic fits and/or at least 10 less severe seizures) were already present at referral in 996 persons (52.4%). Of these persons, a minimum of 9.1% were able to cease therapy after 3-5 years seizure free. In the whole series, at least 274 persons (14.4%) ceased therapy after a mean of 4.72 +/- SD 3.05 years without seizures. The outcome was unknown in 50: seizures recurred in 20.5% of the remaining 224 who were followed for at least 1 year (in 70% the recurrence was within 1 year of withdrawing therapy). Even one tonic-clonic fit at any time increased the chance of a failed withdrawal of therapy, while seizure control with anticonvulsant monotherapy, earlier age at first seizure and earlier age at seizure control correlated with a successful withdrawal of therapy.

Current treatment strategies in selected situations in epilepsy

Several special situations in the management of epilepsy require specific treatment strategies. Recurrence rates after a single seizure vary between 26 and 71%. Antiepileptic drug (AED) therapy should be initiated after a first seizure only when a definitive diagnosis of epilepsy can be made. Although several AEDs have been shown to be anti-epileptogenic in animal models, no data yet prove the efficacy of any AED in preventing the development of post-traumatic or postoperative epilepsy. Therefore, there is no rational basis for prophylactic treatment with AEDs. The incidence of epilepsy rises dramatically after the age of 50 years. Similtaneously, many physiological changes increase the potential for adverse effects and drug interactions when AEDs are used in the elderly. Careful attention to changing pharmacokinetic parameters is necessary when that group of patients is being managed. Pregnancy also brings about physiological changes that may either increase or decrease the seizure frequency. The risk of fetal malformations is approximately double in children born to mothers with epilepsy compared with children born to nonepileptic mothers. The risk is dose-dependent and increases with the number of AEDs. All AEDs may cause fetal malformations; valproate and carbamazepine increase the risk of spina bifida. Nonetheless, the best AED for a woman who wants to become pregnant is the AED that best controls her seizures, which should be given at the lowest possible effective dose. Discontinuation of AEDs can be considered after 2-4 years of complete seizure control. Most of the risk of relapse occurs within the first 6 months. Status epilepticus (SE) is a medical emergency. The most common form of SE is generalized convulsive status epilepticus, in which the patient may present with either overt or subtle convulsions. Because of the potential for neuronal damage, all electrical as well as clinical seizure activity must be completely stopped for treatment of SE to be considered successful.

Remission of seizures and predictors of intractability in long-term follow-up

In an incidence cohort, remission and relapse rates and determinants were studied in 178 patients followed long-term. A comparative study of predictive factors was performed in 40 patients with histories of antiepileptic (AED)-drug-refractory epileptic seizures in the last 10 years of follow-up and compared with the other 138 cohort subjects. The two groups were cross-tabulated with 353 variables of family history, obstetric, developmental and seizure histories, and current medical and social status. Multivariate analyses were applied for control of confounding. Defined or probable remote symptomatic etiology of seizures, abnormal neurologic development/status, high initial seizure frequency, occurrence of status epilepticus, and poor short-term effects of AED therapy were significantly associated with long-term AED refractoriness. On logistic regression analyses, poor short-term outcome of AED therapy [odds ratio (OR) 3.6; 95% confidence interval (CI) 1.2-10.4], occurrence of status epilepticus (OR 11.4; 95% CI 3.2-41.0), high initial seizure frequency (OR 4.6; 95% CI 1.1-19.3), and remote symptomatic seizure etiology (OR 2.9; 95% CI 1.1-8.2) remained the only independent predictors of seizure intractability. These factors enable early assessment of need for epilepsy surgery.

Seizure patient selection for emergency computed tomography

STUDY PURPOSE

We evaluated the need for emergency noncontrast cranial computed tomography (CT) among patients presenting to an emergency department with a complaint of seizure.

METHODS

We retrospectively evaluated the medical records of 115 consecutive patients who presented to a trauma Level I ED with a complaint of seizure and underwent a noncontrast cranial CT.

RESULTS

Sixty patients had a known seizure disorder, 38 had new-onset seizure, and 17 had possible seizure. The results of the neurologic examination and CT could be compared in 105 of the patients. An abnormal neurologic examination predicted 19 of 20 positive CT scans (95%) and demonstrated a strong association with CT results (P < .00004). Only a history of malignancy correlated to CT findings (P < .008). No other catalogued variable showed a statistical relationship with CT findings.

CONCLUSION

Our data suggest that patients with either a history of malignancy or an abnormal neurologic examination at the time of examination in the ED will derive the greatest benefit from emergency CT.

Recurrence after a first unprovoked seizure. Is it still a controversial issue? First Seizure Trial Group (first)

The decision whether or not to start anticonvulsant treatment after a first unprovoked seizure is still an individual one for the patient concerned. Reliable estimates of the risk of seizure recurrence and identification of patients at a higher risk of recurrence are lacking, as critical comparison of studies is limited by the diversity of the target populations and study designs in published studies. The present review interprets the rates of recurrence after a first unprovoked seizure and prognostic factors and predictors of recurrence in the light of the methods used in individual published studies of seizure recurrence. The impact of drug treatment on the prognosis of the first seizure (prevention of recurrence and enhancement of long-term remission) is also assessed.

Gulf medical audit--an analysis of medical casualties evacuated to the UK from the Gulf during Operation Granby

The 61 personnel, 60 male, evacuated from the Gulf to Queen Elizabeth Military Hospital on medical grounds between late October 1990 and mid March 1991 are reviewed with particular regard to previous medical history, previous medication, and appropriate PULHHEEMS grading. The percentage evacuated was 0.24% of Army personnel involved in "Operation Granby" which is considered acceptably small.

Idiopathic first seizure in adult life: who should be treated?

OBJECTIVE

To assess the accuracy of the diagnosis, recurrence rate, and fate after the first recurrence in adult patients with an untreated idiopathic first seizure.

DESIGN

Hospital based follow up study.

SETTING

One university hospital and three general hospitals in The Netherlands.

PATIENTS

165 patients aged 15 years or more with a clinically presumed idiopathic seizure; diagnosis was based on a description of the episode according to prespecified diagnostic criteria.

MAIN OUTCOME MEASURES

Results of additional investigations and follow up regarding the accuracy of the diagnosis; first recurrence; and response to treatment after the first recurrence.

RESULTS

Computed tomography showed major abnormalities in 5.5% of the patients and follow up led to doubts about the initial clinical diagnosis in another 6%. Cumulative risk of recurrence was 40% at two years. The cumulative risk of recurrence at two years was 81% (95% confidence interval 66% to 97%) in patients with epileptic discharges on a standard or partial sleep deprivation electroencephalogram, 39% (27% to 51%) in patients with other electroencephalographic abnormalities, and 12% (3% to 21%) in patients with normal electroencephalograms. Treatment was initiated in most patients who had one or more recurrences; 40 (70%) patients were completely controlled, eight (14%) had sporadic seizures, and nine (16%) did not become free of seizures within one year despite treatment.

CONCLUSIONS

The decision to initiate or delay treatment should be based on electroencephalographic findings.