Calcified Neurocysticercosis and Headache in an Endemic Village: A Case-Control Study Nested to a Population-Based Cohort

Efficacy and safety of antiparasitic therapy for neurocysticercosis in rural Tanzania: a prospective cohort study

PURPOSE

Neurocysticercosis is common in regions endemic for Taenia solium. Active-stage neurocysticercosis can be treated with antiparasitic medication, but so far no study on efficacy and safety has been conducted in Africa.

METHODS

We conducted a prospective cohort study on treatment of neurocysticercosis in Tanzania between August 2018 and January 2022. Patients were initially treated with albendazole (15 mg/kg/d) for 10 days and followed up for 6 months. Additionally in July 2021, all participants who then still had cysts were offered a combination therapy consisting of albendazole (15 mg/kg/d) and praziquantel (50 mg/kg/d). Antiparasitic treatment was accompanied by corticosteroid medication and anti-seizure medication if the patient had experienced epileptic seizures before treatment.

RESULTS

Sixty-three patients were recruited for this study, of whom 17 had a complete follow-up after albendazole monotherapy. These patients had a total of 138 cysts at baseline, of which 58 (42%) had disappeared or calcified by the end of follow-up. The median cyst reduction was 40% (interquartile range 11-63%). Frequency of epileptic seizures reduced considerably (p < 0.001). Three patients had all active cysts resolved or calcified and of the remaining 14, eight received the combination therapy which resolved 63 of 66 cysts (95%). Adverse events were infrequent and mild to moderate during both treatment cycles.

CONCLUSION

Cyst resolution was unsatisfactory with albendazole monotherapy but was very high when it was followed by a combination of albendazole and praziquantel.

Does Calcified Neurocysticercosis Affect Migraine Characteristics and Treatment Responsiveness? A Case-Control Study

Recently, inflammation and free-radical release has been described in the surrounding brain parenchyma of seemingly inert calcified lesions of neurocysticercosis. These free radicals can induce migraine by stimulating calcitonin gene-related peptide release. This stipulated mechanism led us to hypothesize that calcified neurocysticercosis may increase migraine severity. This case-control study included patients (migraine with calcified neurocysticercosis) and control subjects (migraine without calcified neurocysticercosis) in a 1:1 ratio. Headache frequency, visual analog scale (VAS) score, and Migraine Disability Assessment (MIDAS) score were assessed at baseline and at the end of 3 months. To compare treatment responsiveness between patients and control subjects, we treated both groups identically so that difference in treatment would not confound the results. Each group comprised 78 patients. Baseline headache frequency (11.3 ± 3.3 versus 7.9 ± 3.4), VAS score (7.5 ± 1.1 versus 6.0 ± 1.2), and MIDAS score (15 ± 7.6 versus 9.6 ± 4.5) were significantly greater in patients than control subjects. Interestingly, the change from baseline to the end of 3 months in headache frequency (6.0 ± 1.7 versus 2.8 ± 1.4), VAS score (2.6 ± 0.02 versus 1.4 ± 0.01), and MIDAS score (8.3 ± 5.0 versus 3.6 ± 2.0) were significantly greater in patients than control subjects. Our study emphasizes that calcified lesions of neurocysticercosis are not inert, and cause an increase in the frequency and severity of migraine attacks. Interestingly, these patients also showed a better response to treatment with amitriptyline, possibly resulting from its anti-inflammatory action. Further studies are warranted to explore possible inflammatory mechanisms in calcified neurocysticercosis, which influences migraine physiology.

Epidemiological, clinical and radiological characteristics of people with neurocysticercosis in Tanzania-A cross-sectional study

BACKGROUND

Neurocysticercosis (NCC) is common among people with epilepsy in low-resource settings. Prevalence of NCC and radiological characteristics of patients with NCC vary considerably even within small areas but differences have been poorly characterized so far.

METHODS

We conducted a cross-sectional study between August 2018 and April 2020 in three district hospitals in southern Tanzania (Ifisi, Tukuyu and Vwawa). Patients with and without epileptic seizures were included in this study. All patients were tested with a novel antibody-detecting point-of-care test for the diagnosis of Taenia solium cysticercosis. All test positives and a subset of test negatives had a further clinical work-up including medical examination and computed tomography of the brain. NCC was defined according to the Del Brutto criteria. We assessed epidemiological, clinical and radiological characteristics of patients with NCC by presence of epileptic seizures and by serology status.

RESULTS

In all three district hospitals, more than 30% of all people with epileptic seizures (PWE) had NCC lesions in their brain (38% in Vwawa, 32% in Tukuyu and 31% in Ifisi). Most PWE with NCC had multiple lesions and mostly parenchymal lesions (at least 85%). If patients were serologically positive, they had in the median more lesions than serologically negative patients (15 [interquartile range 8-29] versus 5 [1.8-11]), and only serologically positive patients had active stage lesions. Furthermore, serologically positive PWE had more lesions than serologically positive people without epileptic seizures (10.5 [7-23]), and more often had active lesions. PWE diagnosed with NCC (n = 53) were older, and more commonly had focal onset seizures (68% versus 44%, p = 0.03) and headache episodes (34% versus 14%, p = 0.06), which were also stronger than in PWE without NCC (p = 0.04).

CONCLUSION

NCC is common among PWE. A combination of clinical and serological factors could help to establish an algorithm to identify patients potentially suffering from active NCC, who benefit from further clinical investigation including neuroimaging.

Human Neurocysticercosis: An Overview

Human cysticercosis is caused by ingestion of T. solium eggs from taenia carriers. Neurocysticercosis (NCC), defined as the infection of the CNS and the meninges by the larval stage of Taenia solium, is the most common helminthic infection of the CNS worldwide. Parasites may lodge in brain parenchyma, subarachnoid space, ventricular system, or spinal cord, causing pathological changes that account for the pleomorphism of this disease. Seizures/epilepsy are the most common clinical manifestation, but other patients present with headache, focal deficits, intracranial hypertension, or cognitive decline. Accurate diagnosis of NCC is possible after interpretation of clinical data together with findings of neuroimaging studies and results of immunological tests. However, neuroimaging studies are fundamental for diagnosis because immunological test and clinical manifestations only provide circumstantial evidence of NCC. The introduction of cysticidal drugs changed the prognosis of most NCC patients. These drugs have been shown to reduce the burden of infection and to improve the clinical course of the disease in many patients. Efforts should be directed to eradicate the disease through the implementation of control programs against all the steps in the life cycle of T. solium, including carriers of the adult tapeworm, infected pigs, and eggs in the environment.

A scoping review of burden of disease studies estimating disability-adjusted life years due to Taenia solium

Background

Taenia solium is the most significant global foodborne parasite and the leading cause of preventable human epilepsy in low and middle-income countries in the form of neurocysticercosis.

Objectives

This scoping review aimed to examine the methodology of peer-reviewed studies that estimate the burden of T. solium using disability-adjusted life years.

Eligibility criteria

Studies must have calculated disability-adjusted life years relating to T. solium.

Charting methods

The review process was managed by a single reviewer using Rayyan. Published data relating to disease models, data sources, disability-adjusted life years, sensitivity, uncertainty, missing data, and key limitations were collected.

Results

15 studies were included for review, with seven global and eight national or sub-national estimates. Studies primarily employed attributional disease models that relied on measuring the occurrence of epilepsy before applying an attributable fraction to estimate the occurrence of neurocysticercosis-associated epilepsy. This method relies heavily on the extrapolation of observational studies across populations and time periods; however, it is currently required due to the difficulties in diagnosing neurocysticercosis. Studies discussed that a lack of data was a key limitation and their results likely underestimate the true burden of T. solium. Methods to calculate disability-adjusted life years varied across studies with differences in approaches to time discounting, age weighting, years of life lost, and years of life lived with disability. Such differences limit the ability to compare estimates between studies.

Conclusions

This review illustrates the complexities associated with T. solium burden of disease studies and highlights the potential need for a burden of disease reporting framework. The burden of T. solium is likely underestimated due to the challenges in diagnosing neurocysticercosis and a lack of available data. Advancement in diagnostics, further observational studies, and new approaches to parameterising disease models are required if estimates are to improve.

Neurocysticercosis. A frequent cause of seizures, epilepsy, and other neurological morbidity in most of the world

Neurocysticercosis is endemic in most of the world and in endemic areas it accounts for approximately 30% of cases of epilepsy. Appropriate diagnosis and management of neurocysticercosis requires understanding the diverse presentations of the disease since these will vary in regards to clinical manifestation, sensitivity of diagnostic tests, and most importantly, therapeutic approach. This review attempts to familiarize tropical neurology practitioners with the diverse types of neurocysticercosis and the more appropriate management approaches for each.

Clinical characteristics of migraine in patients with calcified neurocysticercosis

BACKGROUND

Patients with neurocysticercosis (NCC) may have an increased frequency of migraine. We studied the characteristics of migraine attacks in patients with calcified NCC on brain imaging.

METHODS

Of 350 migraine patients who visited our outpatient department from January 2016 through June 2018, 166 had undergone brain imaging. Seventy-two patients with migraines had calcified NCC. The migraine attacks of the patients with calcification (MiC) were compared with those of 94 patients without calcification (MiNC).

RESULTS

Side-locked headaches were seen in 48.6% of the MiC patients. Aura preceding the migraine attack was more common in the MiC group than in the MiNC group (22.22% vs 7.4%; p=0.001). The MiC group had fewer headache episodes per month (5 vs 6; p<0.0001) with fewer common associated features (62.5% vs 84.1%; p=0.006). They also required fewer drugs for secondary prophylaxis (2 vs 3; p=0.002).

CONCLUSIONS

Some of the clinical characteristics of migraine attacks are sufficiently different in patients with and without NCC. This may suggest some influence of NCC in the pathophysiology of migraine to account for alterations in the clinical manifestations of the disease. Whether this difference could be inferred as NCC having a causative role in migraine needs further research.

Pattern of Comorbid Headache Among Children with Epilepsy Treated for Neurocysticercosis

The present cross-sectional study was designed to describe the pattern of comorbid headache among children with epilepsy (CWE) secondary to neurocysticercosis (NCC). Children aged 6 to 14 y (n = 70) already diagnosed with neurocysticercosis on a minimum follow-up of six months were consecutively enroled in the study over a period of four months. Majority of them were boys [41 (58%)] with a mean (SD) age of 9.8 (3.2) y. Headache was reported by 24 (34.2%) children. Only one child among them qualified the diagnosis of migraine as per International Classification of Headache Disorders (ICHD)-3 criteria. The proportion of children with and without headache was comparable among those with active or inactive lesion [p = 0.21]; single or multiple lesions [p = 0.78]; and stages of NCC [p = 0.23]. The proportion of children with headache was similar irrespective of the activity and the number of NCC lesions. This alerts the pediatrician to evaluate the headache and consider migraine among CWE treated for NCC.

Assessing the burden and spatial distribution of Taenia solium human neurocysticercosis in Ecuador (2013-2017)

Background

Estimating the burden of neglected tropical diseases is a valuable tool to support policymakers in the resource allocation for control and elimination of these diseases. Spatial analysis allows to identify the geographical distribution patterns of infectious and parasitic diseases within a country and allows to assess their possible correlation with other health disorders. Despite being neurocysticercosis (NCC) considered as the most important parasitic disease of the nervous system, few efforts have been addressed to assess the real burden of NCC in endemic countries, to date, there are no studies estimating the burden of NCC in South America. In this study we aimed to use the Disability Adjust Life Years (DALY) and spatial indicators as tools to measure the impact of human neurocysticercosis in Ecuador between 2013 and 2017.

Methods

Mortality, morbidity and spatial data from the national agency of statistics were used to estimate the burden of disease of NCC during a five-year period (2013–2017). NCC cases and its two main sequelae, epilepsy and migraine headache, were stratified by sex and age group to calculate the DALY associated to NCC using the DALY package in R. SATSCAN software was used to assess spatial clusters of NCC and its possible neurological sequelae as epilepsy, status epilepticus, migraine and hydrocephalus.

Principal findings

The burden of human neurocysticercosis ranged from 56201 [95% CI 29961–89333] to 59612 [95% CI 31854–94689] DALY per year, corresponding to 3.54 to 3.56 DALY per 1000 population. Average yearly incidence rates per 10 000 person-years were 0.23 [95% CI 0.21–0.26] for NCC, 4.89 [95% CI 4.78–5.00] for epilepsy, 0.130 [95% CI 0.11–0.15] for status epilepticus, 0.62 [95% CI 0.58–0.66] for migraine headache, and 1.02 [95% CI 0.98–1.07] for hydrocephalus. Most important significant spatial clusters (p<0.0001) were located in the southern region of the highlands of the country.

Conclusion/Significance

This is the first study in South America to calculate estimates for burden of NCC and one of the few using spatial analysis to show the importance of sequelae other than epilepsy that play an important role in the impact of human neurocysticercosis.

Taenia solium-neurocysticercosis (NCC) is a neglected parasite infection in humans causing a variety of neurological sequelae like epilepsy, and chronic headache. The purpose of this study was to estimate the burden of NCC in Ecuador using official nation-wide databases from the National Institute of Statistics and Census (INEC) for the period of 2013–2017, and to assess for spatial clusters of four neurological disorders associated with NCC. The burden of NCC measured in Disability Adjusted Life Years (DALY) was estimated in 3.54 to 3.56 DALY per 1000 population. Several significant spatial clusters for augmented risk of disease were identified along the country for NCC and its sequelae, most of which converged in the southern Sierra provinces. Our study suggests a possible spatial correlation between the presence of NCC cases and a higher prevalence of neurological conditions like epilepsy, status epilepticus, migraine, and hydrocephalus in several ‘hot spots’ of the southern provinces of Ecuador, indicating possible areas where the application of preventive measures is necessary to reduce cysticercosis transmission rates.

An Ambispective Cohort Study to Assess Seizure Recurrences in Children with Calcified Parenchymal Neurocysticercosis

Calcified neurocysticercosis (NCC), previously thought to be a dead end, is an important risk factor for seizure recurrences. We studied the pattern of seizure recurrences and associated radiological findings in children with calcified NCC. In this ambispective cohort study, we enrolled children (age 1-15 years) with calcified NCC attending the pediatric NCC clinic between January 2017 and December 2017. Retrospective data were collected from the hospital records, and all enrolled children were prospectively followed up till June 2018. The study group divided into two groups: 1) children first presenting with calcified granuloma and 2) children presented with ring-enhancing lesion (REL) and transformed into the calcified lesion during follow-up imaging. During the study period (January 2017-December 2017), 520 children with NCC were screened and 128 with calcified NCC were enrolled. The mean age was 10.8 ± 3.2 years, and 63% were boys. Among 128 children, 40 (31%) had calcified granuloma and 88 (69%) had REL transformed to calcified granuloma. Sixty-one (49%) children had seizure recurrence: 22 (58%) within calcified granuloma group and 39 (45%) within REL transformed to calcified granuloma group (P = 0.18). Seizure recurrence was associated with the presence of perilesional edema (PE) in 35 (57.4%) children on computed tomography scan. The median interval between two seizure recurrences was 30 (17-56) months, and the median antiepileptic drug-free interval was 17 (12-22) months. The total duration of continued seizures was 42 (26-58) months, slightly longer in children with REL transformed to calcified granuloma group (42, 95% CI: 18-66 months) in comparison to calcified granuloma group (35, 95% CI: 10-60 months, P = 0.32). To conclude, children with calcified NCC have seizure recurrences over a prolonged period. Seizure recurrences are intermittent and may be interspersed with a prolonged period of quiescence in between. The presence of PE and contrast enhancement around the lesion during seizure recurrence suggests lesion reactivation.

Estimating the association between being seropositive for cysticercosis and the prevalence of epilepsy and severe chronic headaches in 60 villages of rural Burkina Faso

Background

Individuals diagnosed with neurocysticercosis often present with epilepsy and sometimes with progressively worsening severe chronic headaches (WSCH). While cross-sectional associations between seropositivity to cysticercal antigens and epilepsy have been reported, few large scale studies have been conducted in West Africa and none have measured the association between seropositivity to cysticercal antigens and headaches. This study aimed at filling these knowledge gaps by estimating the strength of the cross-sectional association between seropositivity to cysticercal antigens and the prevalence of epilepsy and WSCH in 60 villages of Burkina Faso, West Africa.

Methodology/Principal findings

Baseline data from a cluster randomized controlled trial collected from January 2011 to February 2012 in 60 villages across three provinces in Burkina Faso were used. Between 78 and 80 individuals were screened for epilepsy and WSCH in each village, and those screened positive were confirmed by a physician. Seventy-five percent of all participants were asked to provide a blood sample to test for Taenia solium cysticercus circulating antigens. Hierarchical multivariable logistic models were used to measure the association between seropositivity to cysticercal antigens and epilepsy (lifetime and active) as well as WSCH. Among 3696 individuals who provided a blood sample, 145 were found to have epilepsy only, 140 WSCH only and 19 both. There were positive associations between seropositivity to cysticercal antigens and active epilepsy (prevalence odds ratio (POR): 2.40 (95%CI: 1.15–5.00)) and WSCH (POR: 2.59 (1.34–4.99)).

Conclusions/Significance

Our study is the first to demonstrate a cross-sectional association between seropositivity to cysticercal antigens and WSCH in a large community-based study conducted in West Africa. The measured cross-sectional association had a strength similar to the ones previously observed between seropositivity to cysticercal antigens and lifetime or active epilepsy. As a result, preventing new cysticercosis cases in communities may reduce the prevalence of these two important neurological disorders.

Taenia solium is a parasite that can be transmitted between humans and pigs in areas with poor sanitation and pig management practices. When this parasite infects the human brain, it can cause epilepsy or severe headaches. Our study aimed to measure the association between being seropositive to cysticercal antigens and having epilepsy (lifetime and active) or severe headaches in 60 villages of Burkina Faso. We found that active epilepsy and severe headaches were associated with seropositivity to cysticercal antigens. These results confirm prior studies which suggested an association between being seropositive for cysticercal antigens and these two neurological symptoms. Preventing cysticercosis could reduce new cases of these two neurological symptoms from occurring.