Understanding the differences in prevalence of epilepsy in tropical regions

Epilepsy is a frequent chronic neurologic disorder that affects nearly 70 million people worldwide. The majority of people with epilepsy live in developing countries, where epilepsy remains a major public health problem. Wide prevalence differences exist among various populations across sub-Saharan Africa, Latin America, and Asia. In particular, prevalence is lower in Southeast Asia than in sub-Saharan Africa and Latin America. Methodologic problems alone do not seem to explain these differences shown in recent review papers. The distribution of numerous risk or etiologic factors such as infectious diseases with neurologic sequel, head injuries, or genetic factors could explain these differences. Stigmatization of people with epilepsy could lead to underestimating the prevalence of epilepsy, even in well-conducted studies. It is important to standardize the process of epidemiologic monitoring of epilepsy in order to improve the reliability in data comparison. Understanding the reasons for these differences is a crucial issue for eventually raising new hypotheses or prevention strategies.     

Etiologic factors and clinical features of symptomatic epilepsy: focus on pediatric cases

We discuss the presumptive etiologic factors of symptomatic epilepsy from the clinical standpoint, based on our experience of 383 inpatients with epilepsy, with a focus on children. The main (top three) presumptive etiologic factors in partial epilepsy are intracranial infection, cerebral malformation and perinatal brain damage. In generalized epilepsy, the main presumptive etiologic factors are perinatal brain damage, intracranial infection, and cerebral malformation. As regards presumptive etiologic factors in partial epilepsy, cerebral malformation was most common in frontal lobe epilepsy, initial convulsive status in temporal lobe epilepsy and perinatal brain damage in occipital lobe epilepsy. Electroclinical characteristics of severe myoclonic epilepsy in infancy, the most intractable epilepsy syndrome in infancy, is the focus and recent advances of genetic research are introduced.     

Comparing the cost of epilepsy across eight European countries

To observe the degree to which prices for medical services and anti-epileptic drugs (AEDs) vary between eight European Union (EU) countries, to identify the factors that are likely to contribute to these variations and to consider the validity of international cost-of-illness comparisons. Cost-of-illness study methodology has been used to estimate the national cost of epilepsy in several developed countries. The validity of comparing these studies is unknown. Eight EU member countries were selected. Charges and prices were obtained for important aspects of medical care of patients with epilepsy including AEDs. The perspective taken was that of the major health care payer within each country. Prices were validated by a local panel of doctors expert in treating epilepsy. Prices for similar services were compared between countries. Charges and prices levied to health service payer vary widely between the eight countries considered. The cheapest and most expensive medical services vary by as much as 24 times, whereas the price of AED varies up to 4.4 times. These wide variations suggest that prices do not reflect the true cost of providing these important aspects of epilepsy treatment. International comparisons between national cost-of-illness estimates relying on such prices should be interpreted with caution.     

Epidemiologic classification of seizures associated with neurocysticercosis: observations from a sample of seizure disorders in neurologic care in India

AIMS: To determine the etiologic role of neurocysticercosis (NC) in a hospital-based sample of epilepsies divided according to International League Against Epilepsy (ILAE) epidemiological criteria and number of seizures prior to presentation. METHODS: A sample comprising 1026 consecutive patients with either definite seizures or epilepsy attending a Neurology Outpatient Service was divided into four subgroups: single seizure (n = 314), incident epilepsy (n = 127), prevalent epilepsy (n = 398) and recurrent acute symptomatic seizures (RASS) (n = 175). The etiologic contribution of NC to each of the subgroups was examined with imaging studies. RESULTS: Neurocysticercosis was diagnosed on imaging studies in 34.6% of patients with seizure disorder of any type, 59.2% of those with a single seizure, 23.7% of those with recurrent seizure disorder, 92.0% of those with RASS, none of cases of incident epilepsy and 2.0% with prevalent epilepsy. A diagnosis of NC was significantly associated with single seizures (P < 0.001). CONCLUSIONS: Imaging abnormalities consistent with NC are frequently noted in persons presenting with a single seizure in neurologic care in NC-endemic countries like India. The probability of diagnosing NC diminishes with increasing numbers of seizures. Among samples of individuals with recurrent-unprovoked seizures, it is rare for imaging to demonstrate lesions of NC.     

The somatic comorbidity of epilepsy: A weighty but often unrecognized burden

A range of medical and neurologic disorders occurs more frequently in people with epilepsy than in the general population and constitutes its somatic comorbidity. Common examples include cardiac, gastrointestinal, and respiratory disorders; stroke; dementia; and migraine. Alzheimer's disease and migraine are not only more common in epilepsy but are also risk factors for the development of seizures, suggesting a bidirectional association and shared disease mechanisms. Less well-appreciated associations with epilepsy include Parkinson's disease and obstructive sleep apnea. The association between epilepsy and other conditions can be due to a variety of interacting genetic, biologic, and environmental factors. We propose an etiologic classification of comorbidity into uncertain (coincidence or unknown), causal (cause), shared risk factors (common disease mechanisms or shared predisposing risk factors), and resultant (consequence). Co-occurrence of other conditions in a person with epilepsy can complicate diagnosis or have adverse prognostic implications. Management of these conditions may facilitate the treatment of epilepsy, as in the case of obstructive sleep apnea. The presence of somatic disorders in epilepsy is associated with increased health care needs, poorer health-related quality of life, and premature mortality. Prevention, identification, and adequate treatment of comorbid disorders in epilepsy should be an important part of epilepsy management at all levels of care.     

Tropical myeloneuropathies: the hidden endemias

Tropical myeloneuropathies include tropical ataxic neuropathy and tropical spastic paraparesis. These disorders occur in geographic isolates in several developing countries and are associated with malnutrition, cyanide intoxication from cassava consumption, tropical malabsorption (TM), vegetarian diets, and lathyrism. TM-malnutrition was a probable cause of myeloneuropathies among Far East prisoners of war in World War II. Clusters of unknown etiology occur in India, Africa, the Seychelles, several Caribbean islands, Jamaica, and Colombia. Treponemal infection (yaws) could be an etiologic factor in the last two. Tropical myeloneuropathies, a serious health problem, are multifactorial conditions that provide unsurpassed opportunities for international cooperation and neurologic research.     

Hemorrhagic stroke in the tropics

With the increasing industrialization of countries in the tropical and subtropical regions, cerebrovascular disease is becoming an increasingly recognized cause of morbidity and mortality. The incidence of hemorrhagic stroke versus ischemic stroke is unclear as data regarding hemorrhagic stroke in developing countries of the tropical and subtropical regions, especially in the English literature, continues to be sparse. As in the developed world, however, the major etiologies for hemorrhagic stroke in developing countries relate to typical vascular risk factors and, to a lesser extent, central nervous system vascular malformations, medications, and infectious etiologies.     

Etiologies of epilepsy: a comprehensive review

Epilepsy is a heterogeneous disorder, the symptoms of which are preventable and controllable to some extent. Significant inter- and intra-country differences in incidence and prevalence exist because multiple etiologic factors are implicated. Many past reviews have addressed sole etiologies. We considered a comprehensive view of all etiologies (genetic/structural/metabolic) to be significant for both the developing and the developed world as well as routine clinical/epidemiology practice. We therefore carried out a comprehensive search for peer-reviewed articles (irrespective of year, region and language; chosen based on novelty and importance) for each etiology. This article was felt to be essential since newer etiologic knowledge has emerged in recent years. Many new genetic links for rarer epilepsy forms have emerged. Epilepsy risk in limbic encephalitis, mechanisms of Alzheimer's-related epilepsy and the genetic basis of cortical malformations have been detailed. An etiological approach to epilepsy in combination with the conventional classification of epilepsy syndromes is required to gain knowledge.     

The treatment gap in epilepsy: the current situation and ways forward

This article is a summary of a workshop held by the ILAE concerning the issue of the epilepsy treatment gap in developing countries. The gap is defined in terms of those people with epilepsy who are not being appropriately treated and is the result of an array of medical, political, social, economic, and cultural factors. The situation regarding the treatment gap for various countries is reviewed, along with some of its causes. Although the overall gap is estimated to be large, a number of recent projects and interventions have been effective in delivering appropriate treatment to people with epilepsy in underresourced countries of the developing world. It is hoped that these may be transferable elsewhere and that, combined with the ILAE/IBE/WHO Global Campaign against Epilepsy and increased support from the worldwide epilepsy community, the treatment gap will begin to be bridged.     

Concepts of absence epilepsies: discrete syndromes or biological continuum?

There are two current approaches to the clinical conceptualization of the generalized epilepsies. The syndromic approach attempts to subdivide the patient population into relatively homogeneous groups, largely on the basis of clinical and EEG criteria. In contrast, the neurobiological approach aims to formulate a unique profile for each patient by incorporating particulars of the patient onto the background of knowledge regarding the etiologic factors important in generalized epilepsy. The value of these two approaches is discussed with regard to the dual aims of, first, improving the understanding of generalized epilepsy, and second, providing a precise diagnosis, an accurate prognosis, and optimal treatment for the patient.     

Epilepsy in Developing Countries: A Review of Epidemiological,Sociocultural, and Treatment Aspects

Summary: : In this report, aspects of epilepsy that differ in developing and in developed countries are reviewed. This is inevitably an incomplete and impressionistic survey, because data on many aspects in developing countries are scarce, and because it is difficult to generalise meaningfully about the enormous diversity of countries and populations that make up the developing world. Epidemiological studies of prevalence and incidence are reviewed with an emphasis on the problems inherent in work in this area in developing countries. Data concerning seizure type, aetiology, and severity of seizures in the Third World are contrasted with those from developed countries. Sociocultural aspects of epilepsy have been poorly studied, and yet are fundamental to effective medical management. The social effects of epilepsy and the local perceptions of cause and of treatment are discussed from work in Africa, Asia, and South America. The principles and success of treatment in the Third World may differ considerably in developing and developed countries. In the Third World, medical manpower is scarce, and epilepsy is managed essentially by primary care resources, without specialised investigations or personnel. The principles of drug therapy may not be understood by patients, and the supply of drugs is often erratic; and these are major reasons for poor compliance with treatment. World Health Organisation (WHO) initiatives have stressed the extensive use of paramedical personnel and of an essential drugs list, but this emphasis may be misdirected, and in practice neither proposal has achieved much success. The recommendation that phenobarbital be extensively used in the Third World, because of its cheapness and efficacy, is also of doubtful merit, as there are well-known and major drawbacks to the widespread use of this drug. Computations of treatment gap figures in three developing countries suggest that between 80–94% of patients with active epilepsy are not receiving anticonvulsant therapy, and cost is only one of a number of reasons for this. The key to improvements in medical treatment lie with a better understanding of the patients' cultural concepts of epilepsy and its treatment, improved drug supply and availability, and efforts to improve education amongst general practitioners and other primary care medical personnel.     

Mortality of Epilepsy in Developing Countries

Summary:  During the last two decades, there has been a renewed interest in studying epidemiology of epilepsy in developing countries. While there are data on prevalence of epilepsy from many developing countries, there is very little information on the mortality of epilepsy in these same populations. This is because incidence studies of epilepsy are difficult to perform, death certificates are unreliable and often unavailable, and the cause of death is difficult to determine. We report on several studies of mortality in epilepsy in developing countries: Ecuador; the Parsi community of Bombay; a semiurban community in Vasai, India; Mali; Martinique; and Africa. Overall, these studies in general illustrate excess mortality among people with epilepsy when compared with the general population.     

Epidemiology, aetiology, and clinical management of epilepsy in Asia: a systematic review

Epilepsy is a significant, but often underappreciated, health problem in Asia. Here, we systematically review the literature on epidemiology, aetiology, and management of epilepsy in 23 Asian countries. Prevalence estimates are available for only 11 countries from door-to-door surveys and are generally low. Figures for annual incidence in China and India are similar to those in the USA and Europe but lower than those reported from Africa and Latin America. There is a peak in incidence and prevalence in childhood, but a second peak in elderly people, as seen in developed countries, has not been documented. The main causes are head injuries, cerebrovascular disease, CNS infections, and birth trauma. Availability of epilepsy care depends largely on economic factors. Imaging and neurophysiological facilities are available in most countries, but often only in urban centres. Costly drugs, a large treatment gap, limited epilepsy surgery, and negative public attitude to epilepsy are other notable features of management in Asia. An understanding of the psychosocial, cultural, economic, organisational, and political factors influencing epilepsy causation, management, and outcome should be of high priority for future investigations.     

Epilepsy Care in Developing Countries: Part II of II

Although 80% of people with epilepsy reside in resource poor, developing countries, epilepsy care in these regions remains limited and the majority of epilepsy patients go untreated. Cost-effective, sustainable epilepsy care services, delivering first-line antiepileptic drugs through established primary health care facilities, are needed to decrease these treatment gaps. Neurologists with local experience and knowledge of the culture, who are willing to serve as educators, policy advisors, and advocates, can make a difference. This is Part II of a two-part article. Part I reviewed the burden of epilepsy and the current state of resources for treatment in developing countries, while Part II will now discuss various aspects of care in these countries.     

Factors predicting outcome of surgery for intractable epilepsy with pathologically verified mesial temporal sclerosis

PURPOSE: To examine the subgroup of patients with medically intractable epilepsy receiving temporal lobectomies who have pathologically verified mesial temporal sclerosis (MTS) and to determine the relation of demographic and clinical factors, results of diagnostic testing, and details of the surgical procedure with prognosis for achieving control of seizures. METHODS: All patients receiving surgical treatment for intractable epilepsy between 1991 and 1998 at the University of Washington were reviewed. There were 118 patients who met inclusion criteria of adequate pathological analysis showing MTS without a progressive process and a minimum of 1-year follow-up. RESULTS: Only personal history of status epilepticus demonstrated significant (p = 0.0276) prediction of outcome, increasing the risk of surgical failure. No other factors were significant predictors of outcome, including history of febrile seizures, possible etiologic factors, EEG, magnetic resonance imaging (MRI) or neuropsychological testing results, or extent of resection. CONCLUSIONS: Many factors that have been previously described to predict favorable outcome in the overall group of patients receiving temporal lobe resections for intractable epilepsy are, in fact, predictors of MTS and lose their predictive value when the subgroup of patients with confirmed MTS is examined. Neurosurgical treatment of MTS can be very effective even in the presence of significant etiologic factors, or of bilateral or extratemporal abnormalities on EEG or MRI.     

Profile of pediatric hemiparesis

Our objective was to determine the clinical spectrum of pediatric hemiparesis by identifying the relative frequency of various diagnoses and comorbid conditions seen in these children. Case records of all patients with hemiparesis in a single practice over an 11-year period were reviewed with reference to clinical features, etiologic determination, and comorbid conditions. Ninety-two children were identified: 73 (79.3%) had a congenital hemiparesis and 19 (20.7%) had an acquired hemiparesis. An abnormal perinatal history (P = .003), prematurity (P = .016), and younger age at onset of symptoms (P < .001) were associated with a congenital hemiparesis. The overall etiologic yield was 83.7% (82.2% in the congenital and 89.5% in the acquired). The top four etiologic entities were cerebrovascular ischemia (40.2%), periventricular leukomalacia (18.5%), intracranial hemorrhage (16.3%), and cerebral dysgenesis (13%). Factors predictive of establishing an underlying etiology included birth prior to 34 weeks' gestation (P = .034), global developmental delay (P = .048), epilepsy (P = .024), and having appropriate imaging modalities (P = .001). Half of these children had a concurrent global developmental delay, associated epilepsy (odds ratio 3.67; 95% confidence interval 1.40-9.72), and prematurity (odds ratio 5.41; 95% confidence interval 1.56-18.80). A third of these children developed epilepsy. Multivariate predictive factors for epilepsy included global developmental delay (odds ratio 4.20; 95% confidence interval 1.44-12.27), cerebrovascular ischemia (odds ratio 5.10; 95% confidence interval 1.76-14.77), and term birth (odds ratio 3.87; 95% confidence interval 1.20-12.56). The majority of children with hemiparesis have a congenital etiology. The diagnostic yield is higher than previously reported; however, specific underlying etiologies need to be better determined. Comorbid conditions of global developmental delay and epilepsy have a high prevalence in this population, contributing to overall morbidity.     

Epilepsy Care in Developing Countries: Part I of II

Although 80% of people with epilepsy reside in resource poor, developing countries, epilepsy care in these regions remains limited and the majority of epilepsy patients go untreated. Cost-effective, sustainable epilepsy care services, delivering first-line antiepileptic drugs through established primary health care facilities, are needed to decrease these treatment gaps. Neurologists with local experience and knowledge of the culture, who are willing to serve as educators, policy advisors, and advocates, can make a difference. This is Part I of a two-part article. Part I reviews the burden of epilepsy and the current state of resources for treatment in developing countries, while Part II (to be published in Epilepsy Currents issue 10.5) will provide an “Overview of Care” in these countries.     

Animal models of focal cortical dysplasia and tuberous sclerosis complex: Recent progress toward clinical applications

Focal cortical dysplasia (FCD) and related malformations of cortical development (MCDs) represent an increasingly recognized cause of medically intractable epilepsy. However, the underlying mechanisms of epileptogenesis are poorly understood, and treatments for epilepsy due to various cortical malformations are often limited or ineffective. Animal models offer a number of advantages for investigating cellular and molecular mechanisms of epileptogenesis and developing novel, rational therapies for MCD-related epilepsy. This review highlights specific examples of how animal models have been useful in addressing several clinically relevant issues about epilepsy due to FCDs and related cortical malformations, including the pathologic and clinical features, etiologic factors, localization of the epileptogenic zone, neuronal and astrocytic contributions to epileptogenesis, and the development of antiepileptogenic therapies.     

Epilepsy and other convulsive disorders in Saudi Arabia: a prospective study of 1,000 consecutive cases

The pattern of epilepsy and other convulsive disorders in 1,000 consecutive Saudi nationals is described. These disorders were common with a hospital frequency rate of 8 per 1,000. Men were more frequently affected than women and 60% of the patients were under 10 years old at the onset of their illness. The epilepsies were the commonest type (74%). Febrile convulsions (20%) presented mainly between the ages of one and five years. Isolated seizures (3%) and acute symptomatic convulsions (3%) were uncommon. In the epileptic group, generalised seizures (71%) were more frequent than partial (29%) and complex partial seizures occurred mainly in those above 21 years old. Absences (4%), infantile spasms (3%) and atonic seizures (3%) were uncommon. No specific etiology of the epilepsy was determined in the majority of the cases (63%). The identified major etiologic factors of the epilepsies were perinatal encephalopathy (21%), cerebral trauma (11%), sequelae of meningitis or encephalitis (2%), brain tumors (0.5%), and vascular lesions such as stroke and arteriovenous malformation. Perinatal encephalopathy accounted for 40% of the epilepsies in children less than 5 years old, and trauma for 20% of those above 20 years old. A family history of epilepsy in close relations was obtained in 23% of the cases, and the consanguinity rate among the parents was 53%. The high incidence of associated perinatal encephalopathy found in this study suggests that perinatal factors play a major role in the pathogenesis of epilepsy in Saudi Arabia. The high frequency of cerebral trauma was also striking. Although consanguinity of the parents appeared not to be a major factor in the genetics of convulsive disorders in this environment, it might have potentiated the tendency of familial aggregation of convulsive disorders in this community. Consanguinity may be an important factor in the production of some of these disorders but its precise role has not been determined.