Seizure disorders among relatives of Kenyan children with severe falciparum malaria

Malaria infection and the risk of epilepsy: a meta-analysis

Epilepsy, a chronic disease of the central nervous system, is highly prevalent in malaria-endemic regions. Therefore, several studies have evaluated the associations between malaria infection and epilepsy development. A meta-analysis of observational studies published from inception to 10 May 2022 has been conducted to synthesize and pool the existing data on this topic. The relevant publications were systematically searched in PubMed/Medline, Scopus, Embase and Web of Science database collections. A random-effects meta-analysis model (REM) was utilized to generate the pooled odds ratio (OR) at 95% confidence intervals (CIs). The between-studies heterogeneity was assessed with I2, as well as several subgroups, meta-regression and sensitivity analysis were performed to identify the source of heterogeneity. Overall, 17 eligible studies containing 6285 cases and 13 909 healthy controls were included. The REM showed a significant positive association between malaria infection and epilepsy development (OR 2.36; 95% CI 1.44–3.88). In subgroup analyses, significant positive associations were observed in studies that: epilepsy was the outcome in the follow-up of patients with cerebral malaria (OR 7.10; 95% CI 3.50–14.38); used blood smear to diagnose malaria (OR 4.80; 95% CI 2.36–9.77); included only children (OR 3.92; 95% CI 1.81–8.50); published before 2010 (OR 6.39; 95% CI 4.25–9.62). Our findings indicated that patients with malaria, especially those with cerebral malaria, are at a high risk of epilepsy development; however, further well-designed and controlled studies are needed to verify the strength of the association.

Epileptogenesis in Common Parasitic Infections

Purpose of the review

Neurocysticercosis (NCC) has been well recognized as a leading cause of epilepsy. More recently, studies of other parasitic diseases such as cerebral malaria (CM) and onchocerciasis are yielding novel insights into the pathogenesis of parasite-associated epilepsy. We compare the clinical and electrophysiological findings in epilepsy associated with these highly prevalent parasites and discuss the mechanisms involved in epileptogenesis.

Recent Findings

Electrophysiological and imaging biomarkers continue to emerge, and individuals who are at-risk of developing parasite-associated epilepsies are being identified with greater reliability. While both Taenia solium and Plasmodium falciparum directly affect the brain parenchyma, Onchocerca volvulus is not known to invade the central nervous system. Thus, the causal association between O. volvulus and epilepsy remains controversial.

Summary

Both NCC and CM have a well-defined acute phase when the parasites directly or indirectly invade the brain parenchyma and lead to local inflammatory changes. This is followed by a chronic phase marked by recurrent seizures. However, these stages of epileptogenic process have not been identified in the case of O. volvulus.

Management of Seizures in Children with Falciparum Malaria

Falciparum malaria is the most common cause of convulsions in children admitted to hospital in malaria endemic areas. Detection of convulsions requires close monitoring and one should be on the look out for signs of subtle convulsions. About a third of acute seizures in children with cerebral malaria, do not manifest as convulsions, but as changes in eye deviation, salivation and/or eye deviation. It is important to terminate convulsions lasting more than 5 min, since prolonged convulsions are associated with neurological deficits in survivors of children with severe malaria. Initial management should include putting the child into the left lateral position, checking the blood glucose and administering oxygen if hypoxic. The benzodiazepines, particularly diazepam, are used as the initial anticonvulsants. Phénobarbital and Phenytoin are used as second-line treatments. Prompt and effective management of falciparum malaria associated convulsions may contribute to a better outcome in children with severe malaria.

Neurological and behavioral manifestations of cerebral malaria: An update

Neglected tropical diseases are a group of tropical diseases endemic in poor countries even though medical treatment and cures are available. They are considered a global health problem due to the severity of the physiological changes they induce in their hosts. Malaria is a disease caused by Plasmodium sp. that in its cerebral form may lead to acute or long-term neurological deficits, even with effective antimalarial therapy, causing vascular obstruction, reduced cerebral blood flow and many other changes. However, Plasmodium falciparum infection can also develop into a cerebral malaria (CM) disease that can produce neurological damage. This review will discuss the mechanisms involved in the neuropathology caused by CM, focusing on alterations in cognitive, behavior and neurological functions in human and experimental models.

The genetic risk of acute seizures in African children with falciparum malaria

Purpose

It is unclear why some children with falciparum malaria develop acute seizures and what determines the phenotype of seizures. We sought to determine if polymorphisms of malaria candidate genes are associated with acute seizures.

Methods

Logistic regression was used to investigate genetic associations with malaria-associated seizures (MAS) and complex MAS (repetitive, prolonged, or focal seizures) in four MalariaGEN African sites, namely: Blantyre, Malawi; Kilifi, Kenya; Kumasi, Ghana; and Muheza, Tanzania. The analysis was repeated for five inheritance models (dominant, heterozygous, recessive, additive, and general) and adjusted for potential confounders and multiple testing.

Key Findings

Complex phenotypes of seizures constituted 71% of all admissions with MAS across the sites. MAS were strongly associated with cluster of differentiation-ligand-rs3092945 in females in Kilifi (p = 0.00068) and interleukin (IL)-17 receptor E-rs708567 in the pooled analysis across the sites (p = 0.00709). Complex MAS were strongly associated with epidermal growth factor module-containing mucin-like hormone receptor (EMR)1-rs373533 in Kumasi (p = 0.00033), but none in the pooled analysis. Focal MAS were strongly associated with IL-20 receptor A-rs1555498 in Muheza (p = 0.00016), but none in the pooled analysis. Prolonged MAS were strongly associated with complement receptor 1-rs17047660 in Kilifi (p = 0.00121) and glucose-6-phosphate dehydrogenase-rs1050828 in females in the pooled analysis (p = 0.00155). Repetitive MAS were strongly associated with EMR1-rs373533 in Kumasi (p = 0.00003) and cystic fibrosis transmembrane conductance receptor-rs17140229 in the pooled analysis (p = 0.00543). MAS with coma/cerebral malaria were strongly associated with EMR1-rs373533 in Kumasi (p = 0.00019) and IL10-rs3024500 in the pooled analysis across the sites (p = 0.00064).

Significance

We have identified a number of genetic associations that may explain the risk of seizures in >2,000 cases admitted to hospitals with MAS across four sites in Africa. These associations differed according to phenotype of seizures and site.

Incidence of epilepsy: a systematic review and meta-analysis

OBJECTIVE

To estimate the pooled incidence of epilepsy from published studies and investigate sources of heterogeneity in the estimates.

METHODS

We searched online databases for incidence studies and used meta-analytic methods to analyze the data.

RESULTS

Thirty-three articles met the entry criteria. The median incidence of epilepsy was 50.4/100,000/year (interquartile range [IQR] 33.6-75.6), while it was 45.0 (IQR 30.3-66.7) for high-income countries and 81.7 (IQR 28.0-239.5) for low- and middle-income countries. Population-based studies had higher incidence estimates than hospital-based studies (p = 0.02) while retrospective study design was associated with lower estimates than prospective studies (p = 0.04).

CONCLUSION

We provide data that could potentially be used to assess the burden and analyze the trends in incidence of epilepsy. Our results support the need for large population-based incidence studies of epilepsy.

Multicultural challenges in epilepsy

Epilepsy is a common neurological condition throughout the world. Its care involves medical expertise, but may also bring different cultural challenges. We discuss clinical, social and psychological outcomes in different cultural settings. We point out differences and similarities in epilepsy epidemiology (etiology and risk factors, prognosis, and natural history), disparities in care and health services, and cultural influences and traditional beliefs, with special respect to practical issues and possible transcultural misunderstandings. We also discuss the relevance of multicultural issues to clinicians working in developed countries.

The economic costs of malaria in four Kenyan districts: do household costs differ by disease endemicity?

BACKGROUND

Malaria inflicts significant costs on households and on the economy of malaria endemic countries. There is also evidence that the economic burden is higher among the poorest in a population, and that cost burdens differ significantly between wet and dry seasons. What is not clear is whether, and how, the economic burden of malaria differs by disease endemicity. The need to account for geographical and epidemiological differences in the estimation of the social and economic burden of malaria is well recognized, but there is limited data, if any, to support this argument. This study sought to contribute towards filling this gap by comparing malaria cost burdens in four Kenyan districts of different endemicity.

METHODS

A cross-sectional household survey was conducted during the peak malaria transmission season in the poorest areas in four Kenyan districts with differing malaria transmission patterns (n = 179 households in Bondo; 205 Gucha; 184 Kwale; 141 Makueni).

FINDINGS

There were significant differences in duration of fever, perception of fever severity and cost burdens. Fever episodes among adults and children over five years in Gucha and Makueni districts (highland endemic and low acute transmission districts respectively) lasted significantly longer than episodes reported in Bondo and Kwale districts (high perennial transmission and seasonal, intense transmission, respectively). Perceptions of illness severity also differed between districts: fevers reported among older children and adults in Gucha and Makueni districts were reported as severe compared to those reported in the other districts. Indirect and total costs differed significantly between districts but differences in direct costs were not significant. Total household costs were highest in Makueni (US$ 19.6 per month) and lowest in Bondo (US$ 9.2 per month).

CONCLUSIONS

Cost burdens are the product of complex relationships between social, economic and epidemiological factors. The cost data presented in this study reflect transmission patterns in the four districts, suggesting that a relationship between costs burdens and the nature of transmission might exist, and that the same warrants more attention from researchers and policy makers.

Cerebral malaria and epilepsy

Malaria, one of the most common parasitic diseases worldwide, is responsible for more than one million deaths among African children every year. Its neurological form, known as cerebral malaria (CM) is a potential cause of epilepsy in malaria-endemic regions of the world, primarily made up for the most part by the sub-Saharan Africa. Herein, we review recent African studies that examine the association between CM and epilepsy. Three studies suggest a modestly strong association between CM and epilepsy. Furthermore, there appears little doubt that this association is causal. Speculative considerations that may explain this causal association are discussed in this review. Additional research is however required in order to determine the clinical and electrographic behavior, the underlying structural and molecular basis, and course and outcome of this condition.

Haptoglobin HP2-2 genotype, alpha-thalassaemia and acute seizures in children living in a malaria-endemic area

Polymorphisms of the haptoglobin (HP) gene and deletions in alpha-globin gene (alpha-thalassaemia) are common in malaria-endemic Africa. The same region also has high incidence rates for childhood acute seizures. The haptoglobin HP2-2 genotype has been associated with idiopathic generalized epilepsies and altered iron metabolism in children with alpha-thalassaemia can potentially interfere with neurotransmission and increase the risk of seizures. We investigated the hypothesis that the HP2-2 genotype and the common African alpha-globin gene deletions are associated with the increased risk of seizures. 288 children aged 3-156 months admitted with acute seizures to Kilifi District Hospital (Kenya), were matched for ethnicity to an equal number of community controls. The proportion of cases (72/288 [25.0%]) and controls (80/288 [27.8%]) with HP2-2 genotype was similar, p=0.499. The allele frequency of HP2 gene in cases (49.3%) and controls (48.6%) was also similar, p=0.814. Similarly, we found no significant difference between the proportion of cases (177/267 [66.3%]) and controls (186/267 [69.7%]) with deletions in alpha-globin gene (p=0.403). Among cases, HP2-2 polymorphism and deletions in alpha-globin gene were neither associated with changes in the type, number or duration of seizures nor did they affect outcome. We conclude that the HP2-2 polymorphism and deletions in alpha-globin gene are not risk factors for acute seizures in children. Future studies should examine other susceptibility genes.

Prevalence, incidence and risk factors of epilepsy in older children in rural Kenya

BACKGROUND

There is little data on the burden or causes of epilepsy in developing countries, particularly in children living in sub-Saharan Africa.

METHODS

We conducted two surveys to estimate the prevalence, incidence and risk factors of epilepsy in children in a rural district of Kenya. All children born between 1991 and 1995 were screened with a questionnaire in 2001 and 2003, and those with a positive response were then assessed for epilepsy by a clinician. Active epilepsy was defined as two or more unprovoked seizures with one in the last year.

RESULTS

In the first survey 10,218 children were identified from a census, of whom 110 had epilepsy. The adjusted prevalence estimates of lifetime and active epilepsy were 41/1000 (95% CI: 31-51) and 11/1000 (95% CI: 5-15), respectively. Overall two-thirds of children had either generalized tonic-clonic and/or secondary generalized seizures. A positive history of febrile seizures (OR=3.01; 95% CI: 1.50-6.01) and family history of epilepsy (OR=2.55; 95% CI: 1.19-5.46) were important risk factors for active epilepsy. After the second survey, 39 children from the same birth cohort with previously undiagnosed epilepsy were identified, thus the incidence rate of active epilepsy is 187 per 100,000 per year (95% CI: 133-256) in children aged 6-12 years.

CONCLUSIONS

There is a considerable burden of epilepsy in older children living in this area of rural Kenya, with a family history of seizures and a history of febrile seizures identified as risk factors for developing epilepsy.

Burden, features, and outcome of neurological involvement in acute falciparum malaria in Kenyan children

CONTEXT

Plasmodium falciparum appears to have a particular propensity to involve the brain but the burden, risk factors, and full extent of neurological involvement have not been systematically described.

OBJECTIVES

To determine the incidence and describe the clinical phenotypes and outcomes of neurological involvement in African children with acute falciparum malaria.

DESIGN, SETTING, AND PATIENTS

A review of records of all children younger than 14 years admitted to a Kenyan district hospital with malaria from January 1992 through December 2004. Neurological involvement was defined as convulsive seizures, agitation, prostration, or impaired consciousness or coma.

MAIN OUTCOME MEASURES

The incidence, pattern, and outcome of neurological involvement.

RESULTS

Of 58,239 children admitted, 19,560 (33.6%) had malaria as the primary clinical diagnosis. Neurological involvement was observed in 9313 children (47.6%) and manifested as seizures (6563/17,517 [37.5%]), agitation (316/11,193 [2.8%]), prostration (3223/15,643 [20.6%]), and impaired consciousness or coma (2129/16,080 [13.2%]). In children younger than 5 years, the mean annual incidence of admissions with malaria was 2694 per 100,000 persons and the incidence of malaria with neurological involvement was 1156 per 100,000 persons. However, readmissions may have led to a 10% overestimate in incidence. Children with neurological involvement were older (median, 26 [interquartile range {IQR}, 15-41] vs 21 [IQR, 10-40] months; P<.001), had a shorter duration of illness (median, 2 [IQR, 1-3] vs 3 [IQR, 2-3] days; P<.001), and a higher geometric mean parasite density (42.0 [95% confidence interval {CI}, 40.0-44.1] vs 30.4 [95% CI, 29.0-31.8] x 10(3)/microL; P<.001). Factors independently associated with neurological involvement included past history of seizures (adjusted odds ratio [AOR], 3.50; 95% CI, 2.78-4.42), fever lasting 2 days or less (AOR, 2.02; 95% CI, 1.64-2.49), delayed capillary refill time (AOR, 3.66; 95% CI, 2.40-5.56), metabolic acidosis (AOR, 1.55; 95% CI, 1.29-1.87), and hypoglycemia (AOR, 2.11; 95% CI, 1.31-3.37). Mortality was higher in patients with neurological involvement (4.4% [95% CI, 4.2%-5.1%] vs 1.3% [95% CI, 1.1%-1.5%]; P<.001). At discharge, 159 (2.2%) of 7281 patients had neurological deficits.

CONCLUSIONS

Neurological involvement is common in children in Kenya with acute falciparum malaria, and is associated with metabolic derangements, impaired perfusion, parasitemia, and increased mortality and neurological sequelae. This study suggests that falciparum malaria exposes many African children to brain insults.

Cerebral malaria and sequelar epilepsy: first matched case-control study in Gabon

PURPOSE

Cerebral malaria (CM) is suspected to be a potential cause of epilepsy in tropical areas. The purpose of this article was to evaluate the relationship between CM and epilepsy in Gabon.

METHODS

A matched case-control study was carried out on a sample of subjects aged six months to 25 years and hospitalized between 1990 and 2004 in three hospitals in Libreville, Gabon. Cases were defined as patients suffering from epilepsy and confirmed by a neurologist. Controls were defined as patients without epilepsy. The exposure of interest was CM according to WHO criteria.

RESULTS

In total, 296 cases and 296 controls were included. Of these, 36 (26 cases and 10 controls) had a CM history. The adjusted odds ratio (aOR) to develop epilepsy after CM was 3.9 [95% CI: 1.7-8.9], p<0.001. Additional risk factors were identified: family history of epilepsy: aOR=6.0 [95% CI: 2.6-14.1], p<0.0001, and febrile convulsions: aOR=9.2 [95% CI 4.0-21.1], p<0.0001.

CONCLUSIONS

This first case-control study on that issue suggests that epilepsy-related CM is an underrecognized problem. It emphasizes the need for further studies to better evaluate the role of convulsions during CM.

Increased Prevalence of Epilepsy Associated with Severe Falciparum Malaria in Children

PURPOSE

Multiple, prolonged, generalized, or focal seizures are common in children with severe malaria, with or without coma. In other contexts, such seizures have been associated with the development of epilepsy. The relation between falciparum malaria and epilepsy is undetermined; thus we measured the prevalence and characteristics of epilepsy in children with a history of severe malaria.

METHODS

We took a detailed epilepsy history from the parents of 487 children (aged 6-9 years) to compare the prevalence of epilepsy between three exposure groups: children with a history of cerebral malaria (CM), malaria and complicated seizures (M/S), or those unexposed to either complication. Each child had an EEG and was classified as having active, inactive, or no epilepsy.

RESULTS

An increased prevalence of epilepsy was seen in children previously admitted with CM [9.2%; OR, 4.4; 95% confidence interval (CI), 1.4-13.7] or M/S (11.5%; OR, 6.1; 95% CI, 2.0-18.3) compared with the unexposed group (2.2%). The most commonly reported seizure types were tonic-clonic (42%), focal becoming secondarily generalized (16%), and both (21%). Twenty-six percent of the active epilepsy group initially had EEG abnormalities.

CONCLUSIONS

These results suggest that children exposed to CM or M/S have an increased propensity for epilepsy relative to children unexposed to these complications. The prevalence of epilepsy associated with CM is similar to that reported after other severe encephalopathies. The prevalence associated with M/S is more than twice that reported after complicated febrile seizures.