Edema surrounding calcified intracranial cysticerci: clinical manifestations, natural history, and treatment

Multiple calcified neurocysticercosis with several and repetitive episodes of perilesional edema: A case report

Calcified neurocysticercosis, the final stage of the disease, was until recently regarded as residual inactive scarring, with no clinical relevance in most cases. However, episodes of inflammatory reaction around calcifications associated with clinical symptoms have recently been described. We report here the 20-year radiological follow-up of a patient presenting 16 calcifications with multiple episodes of asynchronous inflammatory phenomena around several of them, not always associated with clinical symptomatology. This case is unique, showing the possibility of chronicity of this phenomenon, and the need to better understand the factors involved in determining the best management.

Impact of perilesional edema on severity of migraine in patients with calcified neurocysticercosis: A prospective evaluation

OBJECTIVES

Recent research has sparked increasing interest in the role of neuroinflammation in the pathogenesis of migraine. We hypothesize that perilesional edema, an imaging marker of inflammation caused by an immune response in the brain parenchyma surrounding calcified neurocysticercosis (NCC), may influence migraine pathophysiology. This study was designed to explore the potential impact of perilesional edema on migraine severity and treatment response.

BACKGROUND

Cranial imaging of patients with primary headache may sometimes reveal calcified lesions indicative of calcified NCC. These lesions were once considered incidental and harmless findings. However, recent studies have shown that such calcifications are more frequently associated with headaches. Some research suggests that patients with calcified brain lesions experience more frequent and severe migraine compared to those without these lesions, though the pathophysiology underlying this association remains unclear.

METHODS

This single-center, prospective cohort study was conducted at King George Medical University, India, from September 2022 to September 2024. A total of 80 patients with migraine with calcified NCC were enrolled. Cranial magnetic resonance imaging with contrast was used to detect perilesional edema. Patients were divided into two groups based on the presence (Group A) or absence (Group B) of perilesional edema. Both groups were assessed for migraine frequency, severity, and disability using standard scales. They were treated with standard migraine therapy and followed up for 3 months. Statistical analysis was performed to compare migraine characteristics, treatment responses, and disability between the two groups.

RESULTS

Perilesional edema was observed in six of the 80 patients (7.5%). At presentation, Group A (those with perilesional edema) experienced more frequent migraine, with a mean (standard deviation [SD]) of 22.5 (4.4) days/month, compared to Group B (those without perilesional edema), which averaged 8.2 (2.7) days/month. The headaches in Group A were also more severe, as indicated by higher median visual analog scale scores (median [interquartile range, IQR] in Group A of 10.0 [8.5-10.0] and 7 [7.0-8.0] in Group B, p < 0.001). Disability scores were significantly higher in Group A, with higher median scores on the Migraine Disability Assessment Scale (median [IQR] score in Group A of 43 [40.5-48.5] and 21.5 [17.0-26.3] in Group B, p < 0.001) and six-item Headache Impact Test (median [IQR] score in Group A of 66 [64.25-71.23] and 57 [54.8-62.0] in Group B, p < 0.001) scales. Although both groups showed improvement over 3 months of treatment, Group A continued to experience greater migraine severity. In Group A, the mean (SD) headache frequency was 22.5 (4.4) at presentation, 14.0 (1.6) at 30 days, 10.7 (1.6) at 60 days, and 9.2 (2.0) at 90 days (p < 0.001). Similarly, in Group B, headache frequency decreased over time, with a mean (SD) of 8.2 (2.7) at presentation, 3.8 (1.7) at 30 days, 2.3 (1.0) at 60 days, and 1.9 (1.0) at 90 days (p < 0.001). After 30 days, there was a significant reduction in the use of abortive medications, with more patients in Group B (56/74 [76%]) showing a favorable response compared to Group A (2/6 [33%]; p = 0.046; odds ratio 0.16, 95% confidence interval 0.03-0.95).

CONCLUSIONS

Our study found that among patients with migraine with calcified NCC, those with perilesional edema experienced more severe and harder-to-treat migraine compared to those without perilesional edema. These findings suggest that perilesional edema may influence the underlying mechanisms of migraine, leading to more severe migraine episodes.

Management of calcified cysticerci in the brain parenchyma: treating the dead parasite

INTRODUCTION

Calcifications are the end stage of many parenchymal brain cysticerci and may occur either spontaneously or as the result of treatment with cysticidal drugs. These lesions, traditionally considered inert and asymptomatic, have been associated with several complications that seem to be mostly related to brain damage and inflammation ensuing as the result of the exposure of the host's immune system to parasitic antigens trapped within calcifications.

AREAS COVERED

This review, based on the search of different electronic databases up to May 2024, focuses on the reported correlates and complications of calcified cysticerci (chronic headaches, seizures/epilepsy, hippocampal atrophy/sclerosis, gliomas), and the different interventions developed for their prevention and treatment. Common analgesics, non-steroidal anti-inflammatory drugs, corticosteroids, and antiseizure medications have been used with success but, with the exception of the latter, these drugs offer temporary relief of symptoms and support for their use is based on level 3 evidence.

EXPERT OPINION

Several strategies may reduce the severity of clinical consequences of calcified cysticerci. Probably, the most relevant intervention would be the prevention of their occurrence or reduction in their size. In this view, the use of bisphosphonates appears as a potential option that needs to be tested in humans.

Calcified cerebral toxoplasmosis associated with recurrent perilesional edema causing neurological manifestations in an HIV-infected individual: case report with a decade-long follow-up

Four cases of people living with HIV/AIDS (PLWHA) with calcified cerebral toxoplasmosis associated with perilesional edema causing a single episode of neurological manifestations have recently been reported. Here, we describe the first detailed description of perilesional edema associated with calcified cerebral toxoplasmosis causing three episodes of neurological manifestations in a PLWHA, including seizures in two of them. These recurrences occurred over approximately a decade. Throughout this period, the patient showed immunological and virological control of the HIV infection, while using antiretroviral therapy regularly. This case broadens the spectrum of an emerging presentation of calcified cerebral toxoplasmosis, mimicking a well-described finding of neurocysticercosis in immunocompetent hosts.

Current Role of Surgery in the Treatment of Neurocysticercosis

Neurocysticercosis (NCC) is a common parasitic disease of the central nervous system (CNS) in low- and middle-income countries. The infection is pleomorphic, caused by the larval form of the cestode, Taenia solium, and part of the heterogeneity of its clinical presentations is associated with the localization of the parasite within the CNS. Changes in the current epidemiological trends of NCC indicate that extra-parenchymal NCC is proportionally becoming more frequent. Extraparenchymal NCC is commonly accompanied by raised intracranial hypertension due to hydrocephalus, which is an emergency requiring cyst extirpation by surgical intervention to relieve the symptoms. Although less frequent, parenchymal cysts may also reach giant sizes requiring urgent surgical treatment. Finally, there is an advancement in the comprehension of the association between NCC and epilepsy-and patients with drug-resistant seizures are candidates for surgical treatment. In this narrative review, we summarize the present state of knowledge to update the current trends in the role of surgery in the treatment of NCC.

Calcified Neurocysticercosis: Demographic, Clinical, and Radiological Characteristics of a Large Hospital-Based Patient Cohort

Neurocysticercosis (NCC), the infection of the central nervous system caused by Taenia solium larvae (cysticerci), is a major cause of acquired epilepsy worldwide. Calcification in NCC is the most common neuroimaging finding among individuals with epilepsy in T. solium-endemic areas. We describe the demographic, clinical, and radiological profiles of a large hospital cohort of patients with calcified NCC in Peru (during the period 2012-2022) and compared profiles between patients with and without a previous known diagnosis of viable infection. A total of 524 patients were enrolled (mean age at enrollment: 40.2 ± 15.2 years, mean age at symptom onset: 29.1 ± 16.1 years, 56.3% women). Of those, 415 patients (79.2%) had previous seizures (median time with seizures: 5 years, interquartile range (IQR): 2-13 years; median number of seizures: 7 (IQR: 3-32)), of which 333 (80.2%) had predominantly focal to bilateral tonic-clonic seizures; and 358 (68.3%) used antiseizure medication). Patients had a median number of three calcifications (IQR: 1-7), mostly located in the frontal lobes (79%). In 282 patients (53.8%) there was a previous diagnosis of viable infection, while 242 only had evidence of calcified NCC since their initial neuroimaging. Most patients previously diagnosed with viable infection were male, had previous seizures, had seizures for a longer time, had more calcifications, and had a history of taeniasis more frequently than patients without previously diagnosed viable infection (all p < 0.05). Patients with calcified NCC were heterogeneous regarding burden of infection and clinical manifestations, and individuals who were diagnosed after parasites calcified presented with milder disease manifestations.

Epilepsy Due to Solitary Calcified Cysticercus Granuloma

The calcified stage of the neurocysticercosis (NCC) is the common cause of acquired epilepsy in low and middle income countries in people aged > 20 years. Approximately 30% of adult onset seizures and epilepsy are attributable to NCC. In India and some of the Latin American countries, epilepsy due to solitary calcified NCC is the common adult onset epilepsy. The current evidence suggests that the calcified cysticercus granuloma is probably the epileptogenic focus. The mechanisms involved in the epileptogenic process are not well understood; Focal-onset seizures with or without impaired awareness are the common seizure type. Focal-onset seizure can evolve to bilateral tonic-clonic seizure. Seizure outcome with anti-seizure medication, most often with monotherapy, is very good. The seizure disorders associated with various stages of NCC can be preventable.

Clinical characteristics and management of neurocysticercosis patients: a retrospective assessment of case reports from Europe

OBJECTIVES

Neurocysticercosis (NCC) is a parasitic disease caused by the larval stage of the tapeworm Taenia solium. NCC mainly occurs in Africa, Latin America and South-East Asia and can cause a variety of clinical signs/symptoms. Although it is a rare disease in Europe, it should nonetheless be considered as a differential diagnosis. The aim of this study was to describe clinical characteristics and management of patients with NCC diagnosed and treated in Europe.

METHODS

We conducted a systematic search of published and unpublished data on patients diagnosed with NCC in Europe (2000-2019) and extracted demographic, clinical and radiological information on each case, if available.

RESULTS

Out of 293 identified NCC cases, 59% of patients presented initially with epileptic seizures (21% focal onset); 52% presented with headache and 54% had other neurological signs/symptoms. The majority of patients had a travel or migration history (76%), mostly from/to Latin America (38%), Africa (32%) or Asia (30%). Treatment varied largely depending on cyst location and number. The outcome was favorable in 90% of the cases.

CONCLUSIONS

Management of NCC in Europe varied considerably but often had a good outcome. Travel and migration to and from areas endemic for T. solium will likely result in continued low prevalence of NCC in Europe. Therefore, training and guidance of clinicians is recommended for optimal patient management.

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.

Comparison of Seizure Characteristics and Recurrence Rates in Children with Viable Parenchymal Neurocysticercosis and Tuberculoma in India

Inflammatory granulomas (neurocysticercosis [NCC] and tuberculomas) are important causes of seizures in children and adults in the developing world. Although several studies have explored seizure characteristics individually in patients with either NCC or tuberculoma, none has compared the seizure recurrence rate between them. This study included patients aged 5 to 18 years with viable parenchymal NCC or tuberculomas who had completed regular follow-up of at least 12 months at a tertiary institute in India. Their baseline seizure and electroencephalographic characteristics, antiseizure medications (ASMs), and breakthrough seizure rates at 12, 24, and 52 weeks were noted. A total of 103 and 54 patients with active NCC and tuberculomas respectively were included. The number of patients who had at least one breakthrough seizure at 12, 24, and 52 weeks in both groups was comparable (P = 0.32, 0.27, and 0.13), and the vast majority were controlled on monotherapy (98% cases in each group). The proportion of patients who required an increase in the dose or change of ASMs or polytherapy, the proportion of children who had status epilepticus at or before 12 months, abnormal electroencephalogram at 12 months, and calcified and active granuloma in neuroimaging at 12 months were also comparable between the two groups (P > 0.05 for all). The number of patients who had ASM-related adverse events and discontinued ASM due to serious adverse events was comparable between both groups, except for hepatotoxicity in the tuberculoma group. The predictors for breakthrough seizures that were found to be statistically significant in the NCC group were the presence of perilesional edema in the baseline magnetic resonance imaging (P = 0.02) and more than five active granulomas (P = 0.01); predictors in the tuberculoma group were the presence of severe perilesional edema causing midline shift in the baseline magnetic resonance imaging (P = 0.01) and more than five active granulomas (P = 0.04). The recurrence rates of breakthrough seizures over the next 12 months in newly detected cases of active NCC and tuberculomas were comparable.

Case Report: Calcified Cerebral Toxoplasmosis Associated with Perilesional Edema in People Living with HIV/AIDS: Case Series of a Presentation Mimicking Neurocysticercosis

Perilesional edema, associated or not with neurological manifestations, is a well-characterized finding in cases of calcified neurocysticercosis. There are no previous reports of HIV-related calcified toxoplasmosis that mimics this presentation of neurocysticercosis. We report on five patients, four of them with new-onset neurological manifestations, who showed brain calcifications associated with perilesional edema. All cases had a history of HIV-related toxoplasmosis and current virological and immunological control of HIV infection. Similar to neurocysticercosis, brain calcified toxoplasmosis may cause perilesional edema and symptoms in people living with HIV/AIDS.

Improved Diagnosis of Viable Parenchymal Neurocysticercosis by Combining Antibody Banding Patterns on Enzyme-Linked Immunoelectrotransfer Blot (EITB) with Antigen Enzyme-Linked Immunosorbent Assay (ELISA)

The diagnosis of neurocysticercosis (NCC) depends on neuroimaging and serological confirmation. While antibody detection by enzyme-linked immunoelectrotransfer blot (EITB) fails to predict viable NCC, EITB banding patterns provide information about the host's infection course. Adding antigen enzyme-linked immunosorbent assay (Ag-ELISA) results to EITB banding patterns may improve their ability to predict or rule out of viable NCC. We assessed whether combining EITB banding patterns with Ag-ELISA improves discrimination of viable infection in imaging-confirmed parenchymal NCC. EITB banding patterns were grouped into classes using latent class analysis. True-positive and false-negative Ag-ELISA results in each class were compared using Fisher's exact test. Four classes were identified: 1, EITB negative or positive to GP50 alone (GP50 antigen family); 2, positive to GP42-39 and GP24 (T24/42 family), with or without GP50; and 3 and 4, positive to GP50, GP42-39, and GP24 and reacting to bands in the 8-kDa family. Most cases in classes 3 and 4 had viable NCC (82% and 88%, respectively) compared to classes 2 and 1 (53% and 5%, respectively). Adding positive Ag-ELISA results to class 2 predicted all viable NCC cases (22/22 [100%]), whereas 11/40 patients (27.5%) Ag-ELISA negative had viable NCC (P < 0.001). Only 1/4 patients (25%) Ag-ELISA positive in class 1 had viable NCC, whereas 1/36 patients (2.8%) Ag-ELISA negative had viable NCC (P = 0.192). In classes 3 and 4, adding Ag-ELISA was not contributory. Combining Ag-ELISA with EITB banding patterns improves discrimination of viable from nonviable NCC, particularly for class 2 responses. Together, these complement neuroimaging more appropriately for the diagnosis of viable NCC.

Brain calcification because of neurocysticercosis: a vast field to be explored

PURPOSE OF REVIEW

Neurocysticercosis is the most common helminthic infection of the central nervous system caused by the larval stage of the pork tapeworm, Taenia solium. Endemic regions include Latin American countries, sub-Saharan Africa, and large regions of Asia, including the Indian subcontinent and is a global health problem. Seizures are the most common manifestation and approximately 30% of adult-onset seizures in endemic regions are attributable to NCC. Calcifications because of neurocysticercosis is the most common finding on imaging in endemic regions and are important seizure foci contributing to the burden of epilepsy.

RECENT FINDINGS

After treatment with antiparasitics for multiple viable parenchymal disease, approximately 38% of cysts that resolved after 6 months of therapy will result in residual calcifications, which represents a significant burden of residual disease. Calcified disease has been referred to as 'inactive disease', but there is accumulating evidence to suggest that calcified granulomas are actually dynamic and substantially contribute to the development and maintenance of seizures.

SUMMARY

Calcified parenchymal neurocysticercosis contributes significantly to the development and maintenance of seizures in endemic regions. Understanding the pathogenesis of the role of calcified NCC in seizure development and risk factors for development of calcifications after treatment is critical to decreasing the burden of symptomatic disease in endemic regions.

Inflammation in neurocysticercosis: clinical relevance and impact on treatment decisions

INTRODUCTION

Neurocysticercosis is caused by the localization of Taenia solium larvae in the central nervous system. The disease remains endemic in most countries of Latin America, Asia and Africa. While major improvements have been made in its diagnosis and treatment, uncertainties persist regarding the clinical implications and treatment of the inflammatory reaction associated with the disease.

AREAS COVERED

In this review, based on PubMed searches, the authors describe the characteristics of the immune-inflammatory response in patients with neurocysticercosis, its clinical implications and the treatment currently administered. The dual role of inflammation (participating in both, the death of the parasite, and the precipitation of serious complications) is discussed. New therapeutic strategies of potential interest are presented.

EXPERT OPINION

Inflammatory reaction is the main pathogenic mechanism associated to neurocysticercosis. Its management is mainly based on corticosteroids administration. This strategy had improved prognostic of patients as it allows for the control of most of the inflammatory complications. On the other side, it might be involved in the persistence of parasites in some patients, despite cysticidal treatment, due to its immunosuppressive properties. New strategies are needed to improve therapeutical management, particularly in the severest presentations.

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.

Intermittent perilesional edema and contrast enhancement in epilepsy with calcified neurocysticercosis may help to identify the seizure focus

Neurocysticercosis is a frequent cause of seizures in endemic countries. It is caused by the larvae of the tapeworm Taenia solium. The larvae once hosted in the cerebral parenchyma evolve into viable cysts, called the vesicular stage (with little or no inflammatory reaction), and may remain at this stage for years, or may enter in an inflammatory-degenerative process (colloidal phase) that ends with calcified nodules. Edema and MRI contrast enhancement associated with these calcifications have been described, suggesting that it may be associated with seizures. However, most of these reports were either cross-sectional case-control series or case reports with a single time point MRI. Therefore, the clinical significance of recurring perilesional edema and contrast enhancement around calcified lesions is still uncertain. Here, we describe repeated MRIs of a patient with calcified neurocysticercosis over 4 years. The seizures were associated with edema and contrast enhancement that disappeared in the seizure-free periods, occurring only around one calcified nodule that coincided with the EEG findings and seizure semiology, although he had three additional calcifications. These findings support the association between pericalcification contrast enhancement and edema with recent seizures. This MRI finding may be a marker to define the epileptogenic focus in epilepsies with calcified neurocysticercosis.

Neurocysticercosis and Hippocampal Atrophy: MRI Findings and the Evolution of Viable or Calcified Cysts in Patients With Neurocysticercosis

Neurocysticercosis (NC) is the most common parasitic infection of the central nervous system (CNS). Several studies have reported an association between NC and mesial temporal lobe epilepsy (MTLE). We intended to evaluate the frequency of hippocampal atrophy (HA), clinical evolution and imaging findings in patients with calcified neurocysticercotic lesions (CNLs). Methods: One hundred and eighty-one subjects (70 cases and 111 controls) were evaluated for the presence or absence of HA. We assessed the imaging findings, and the evolution of patients with NC treated or not with anthelmintics for NC. Results: Hippocampal volumes were different between cases and controls (p < 0.001). Seventy percent of the cases presented HA. 52.2% of the patients without a history of anthelmintic treatment for NC had reports of epileptic seizures. There was an association between non-treatment and the later occurrence of epileptic seizures (p = 0.006). There was an association between perilesional edema on MRI and the presence of uncontrolled epileptic seizures (p = 0.004). Conclusions: Hippocampal atrophy is frequent in patients with NCC. There was an association between no anthelmintic treatment in the acute phase of NC, perilesional edema, more pronounced hippocampal atrophy, and the occurrence of refractory seizures.

Neurocysticercosis in Children with Seizures: A Cross-Sectional Study

Background

Neurocysticercosis (NCC), a common cause of seizures in children from low and middle income countries (LMICs), if not diagnosed and treated early enough may lead to considerable morbidity and mortality. There is a lack of data on the prevalence of NCC and its clinical characteristics among those with seizure in South-Western Nepal.

Aims and Objectives

To study the prevalence and clinical characteristics of NCC in children with seizures.

Material and Methods

All children admitted to Universal College of Medical Sciences, a tertiary hospital in South-Western Nepal with seizures during 2014–16, were tested for NCC. NCC was diagnosed by neuroimaging [computerized tomography (CT) scan or magnetic resonance imaging (MRI)]. We used logistic regression to test the association between NCC with participants' characteristics and clinical symptoms.

Results

Among 4962 in-patient children, 168 (104 boys and 64 girls) had seizures (138 with generalized tonic clonic seizures (GTCS) and 30 with focal seizures). 43% of children with seizures had CT scan confirmed NCC. The prevalence of NCC in the oldest children (13–16 years) was significantly greater (57.1% versus 15.6%) compared to the youngest (0–4 years) one (p < 0.001). Among 72 children with NCC, the proportions of children with vesicular, calcified, and colloidal stages were 76% (n = 35), 18% (n = 13), and 6% (n = 2), respectively. Children with focal seizures had 13% more NCC compared to those with GTCS but the result was statistically not significant. The adjusted odds of having NCC among 5–8 years, 9–12 years, and 13–16 years children were 6.6 (1.78–24.60), 11.06 (2.74–44.60), and 14.47 (3.13–66.96), respectively, compared to 0–4-year-old children. Reoccurrence of seizures within the first 3 months of taking antiepileptic drug in those with NCC was approximately 3 times higher compared to those without NCC (11% versus 4%, p = 0.084).

Conclusions

This study shows that NCC contributes significantly to higher prevalence of seizures in children in South-Western region of Nepal.

Inflammation is a key risk factor for persistent seizures in neurocysticercosis

Objective

We conducted a retrospective, case-control study of neurocysticercosis patients to ascertain early markers that identify subjects likely to develop treatment-resistant seizures.

Methods

Clinical histories and imaging studies from 38 neurocysticercosis patients who had been followed for 18 months after treatment were evaluated. Both pairwise and multifactorial analyses were conducted to identify factors associated with continued seizures.

Results

Eleven of 38 patients continued to have seizures during the follow-up period. On univariate analysis, the number of neurocysticercosis lesions, number of bands on the baseline neurocysticercosis western blot, edema volumes on follow-up MRI scans, edema volume changes between baseline and follow-up images, and proportion of calcified lesions with perilesional edema were all significantly increased in subjects who had persistent seizures during the 18-month follow-up period. On multivariate analyses using recursive partition and random forest algorithms, variables associated with persistent seizures included: the number of total and calcified lesions, presence of perilesional edema, the rate of change in the lesion and edema volumes from baseline to follow-up, and the number of bands on the neurocysticercosis western blot.

Interpretation

Measures of both inflammation and disease burden are key risk factors for persistent seizures despite anticonvulsant treatments in patients with neurocysticercosis. Inflammation is therefore a potentially modifiable risk factor for the frequently seen severe seizure disorders in patients with neurocysticercosis.

Disease Centered Around Calcified Taenia solium Granuloma

Taenia solium (the pork tapeworm) is present in most developing countries, where it is a frequent cause of seizures and other neurological disease. Parasitic larvae invade the human brain, establish, and eventually resolve, leaving a calcified scar. While these lesions are common in endemic regions, and most of these are clinically silent, a proportion of individuals with calcified cysticerci develop seizures from these lesions, and 30-65% of these cases are associated with perilesional edema (PE), likely due to host inflammation. This manuscript summarizes the importance, characteristics, natural history, and potential prevention and treatments of symptomatic calcified neurocysticercosis (NCC).

Neurocysticercosis in pregnancy: maternal and fetal outcomes

Neurocysticercosis (NCC) is a parasitic infection with the larvae of Taenia solium from contaminated pork. It is a leading cause of seizures in the developing world. Symptoms may be secondary to live or degenerating cysts, or previous infection causing calcification or gliosis. Diagnosis is based on clinical presentation, radiological confirmation of intracranial lesions and immunological testing. Management involves symptom control with antiepileptics and antiparasitic agents. Few cases have been described of maternal NCC during pregnancy. We describe a 25-year-old female presenting to a London hospital with secondary generalized seizures. MRI of the brain confirmed a calcified lesion in the right parietal lobe, and she gave a corroborative history of NCC during her childhood in India. She was stabilized initially on antiepileptics, but during her pregnancy presented with breakthrough seizures and radiological evidence of NCC reactivation. She was managed symptomatically with antiepileptics and completed the pregnancy to term with no fetal complications.

Update on Cysticercosis Epileptogenesis: the Role of the Hippocampus

Neurocysticercosis (NCC) is the most common helminthic infection of the nervous system and a frequent cause of reactive seizures and epilepsy worldwide. In many cases, multiple episodes of focal seizures related to an identifiable parenchymal brain cyst (and likely attributable to local damage) continue for years after the cyst resolves. However, cases where seizure semiology, interictal EEG abnormalities, and parasites location do not correlate raise concerns about the causal relationship between NCC and either reactive seizures or epilepsy, as well as the epileptogenic potential of parasites. Neurosurgical series of patients with intractable epilepsy and cross-sectional population-based studies have shown a robust association between NCC and hippocampal sclerosis (HS), which might contribute to the above-referred inconsistencies. Current information does not allow to define whether in patients with NCC, HS could result from recurrent seizure activity from a local or distant focus or from chronic recurrent inflammation. In either case, HS may become the pathological substrate of subsequent mesial temporal lobe epilepsy (MTLE). Longitudinal clinical- and population-based cohort studies are needed to evaluate the causal relationship between NCC and HS and to characterize this association with the occurrence of MTLE. If a cause-and-effect relationship between NCC and HS is demonstrated, NCC patients could be assessed to examine neuronal mechanisms of hippocampal epileptogenesis in comparison with animal models, to identify biomarkers of hippocampal epileptogenesis, and to develop novel interventions to prevent epilepsy in NCC and perhaps in other forms of acquired epilepsy.

Neurocysticercosis

Neurocysticercosis is the commonest parasitic disease of the nervous system in humans, and constitutes a major public health problem for most of the developing world. The clinical manifestations of Neurocysticercosis (NCC) largely depend on number of lesions, site, and host immune response against the parasite. Diagnosis is mainly based upon neuro imaging studies and is supported by antibody/antigen detection in the serum and occasionally the cerebrospinal fluid. Randomized controlled trials evaluating the clinical benefit of treatment with cysticidal agents have shown hastened resolution of lesions in most, and reduced seizure recurrence in some studies. Outcome is favourable in single lesion parenchymal NCC but is guarded in multiple lesion and extra parenchymal NCC.

Neurocysticercosis: A natural human model of epileptogenesis

OBJECTIVE

To develop a better understanding of mechanisms of seizures and long-term epileptogenesis using neurocysticercosis.

METHODS

A workshop was held bringing together experts in epilepsy and epileptogenesis and neurocysticercosis.

RESULTS

Human neurocysticercosis and parallel animal models offer a unique opportunity to understand basic mechanisms of seizures. Inflammatory responses to degenerating forms and later-stage calcified parasite granulomas are associated with seizures and epilepsy. Other mechanisms may also be involved in epileptogenesis.

SIGNIFICANCE

Naturally occurring brain infections with neurocysticercosis offer a unique opportunity to develop treatments for one of the world's most common causes of epilepsy and for the development of more general antiepileptogenic treatments. Key advantages stem from the time course in which an acute seizure heralds a start of the epileptogenic process, and radiographic changes of calcification and perilesional edema provide biomarkers of a chronic epileptic state.

Calcified neurocysticercosis associates with hippocampal atrophy: a population-based study

Calcified neurocysticercosis has been associated with hippocampal atrophy in patients with refractory epilepsy, but the relevance of this association in the population at large is unknown. We assessed calcified cysticerci and its association with hippocampal atrophy in elderly persons living in Atahualpa, an Ecuadorian village endemic for neurocysticercosis. All Atahualpa residents ≥ 60 years of age were invited to undergo computed tomography/magnetic resonance imaging for neurocysticercosis detection. Twenty-eight (11%) out of 248 enrolled persons had calcified cysticerci (case-patients) and were matched 1:1 by age, sex, and years of education to individuals without neurocysticercosis on computed tomography/magnetic resonance imaging (controls). Four case-patients and none of the controls had epilepsy (P = 0.134). Cognitive performance was similar across both groups. The Scheltens' medial temporal atrophy scale was used for hippocampal rating in case-patients and matched controls without neurocysticercosis. Mean score in the Scheltens' scale was higher in case-patients than in controls (P < 0.001). Atrophic hippocampi were noticed in 19 case-patients and five controls (P = 0.003). Atrophy was bilateral in 11 case-patients and unilateral in eight. All case-patients with unilateral hippocampal atrophy had at least one ipsilateral calcification. This study shows an association between calcified cysticerci and hippocampal atrophy and raises the possibility of an inflammation-mediated hippocampal damage as the responsible mechanism for these findings.

Neurocysticercosis: an update

Neurocysticercosis (NCC) is the most common helminthic disease of the nervous system in humans and a major cause of acquired epilepsy worldwide. The presentation of the disease is dependent on both the immunological response of the host against the parasite as well as the location of the encysted organisms within the central nervous system (CNS). The principles of management utilized for intraparenchymal disease cannot be applied to extraparenchymal NCC. An advance in management of intraparenchymal NCC, the most common form encountered by physicians, is the use of both albendazole and praziquantel as a treatment strategy. Patients with subarachnoid NCC (SANCC) require months of treatment with both an antiparasitic agent and steroids to avoid complications such as hydrocephalus and vascular events during treatment. The determinants of successful treatment in SANCC have not been established, but response to therapy can be determined by evaluating several endpoints related to disease evolution including radiographic changes, serum antigen, and CSF antigen. Intraventricular NCC is primarily a surgical disease and data supports minimally invasive endoscopic removal of cysts in many of these patients. NCC is increasingly recognized in non-endemic countries due to increased immigration making it important for physicians to become familiar with the management of this disease.

Neglected parasitic infections in the United States: cysticercosis

Cysticercosis is a potentially fatal and preventable neglected parasitic infection caused by the larval form of Taenia solium. Patients with symptomatic disease usually have signs and symptoms of neurocysticercosis, which commonly manifest as seizures or increased intracranial pressure. Although there are many persons living in the United States who emigrated from highly disease-endemic countries and there are foci of autochthonous transmission of the parasite in the United States, little is known about burden and epidemiology of the disease in this country. In addition, despite advances in the diagnosis and management of neurocysticercosis, there remain many unanswered questions. Improving our understanding and management of neurocysticercosis in the United States will require improved surveillance or focused prospective studies in appropriate areas and allocation of resources towards answering some of the key questions discussed in this report.

Evans blue staining reveals vascular leakage associated with focal areas of host-parasite interaction in brains of pigs infected with Taenia solium

Cysticidal drug treatment of viable Taenia solium brain parenchymal cysts leads to an acute pericystic host inflammatory response and blood brain barrier breakdown (BBB), commonly resulting in seizures. Naturally infected pigs, untreated or treated one time with praziquantel were sacrificed at 48 hr and 120 hr following the injection of Evans blue (EB) to assess the effect of treatment on larval parasites and surrounding tissue. Examination of harvested non encapsulated muscle cysts unexpectedly revealed one or more small, focal round region(s) of Evans blue dye infiltration (REBI) on the surface of otherwise non dye-stained muscle cysts. Histopathological analysis of REBI revealed focal areas of eosinophil-rich inflammatory infiltrates that migrated from the capsule into the tegument and internal structures of the parasite. In addition some encapsulated brain cysts, in which the presence of REBI could not be directly assessed, showed histopathology identical to that of the REBI. Muscle cysts with REBI were more frequent in pigs that had received praziquantel (6.6% of 3736 cysts; n = 6 pigs) than in those that were untreated (0.2% of 3172 cysts; n = 2 pigs). Similar results were found in the brain, where 20.7% of 29 cysts showed histopathology identical to muscle REBI cysts in praziquantel-treated pigs compared to the 4.3% of 47 cysts in untreated pigs. Closer examination of REBI infiltrates showed that EB was taken up only by eosinophils, a major component of the cellular infiltrates, which likely explains persistence of EB in the REBI. REBI likely represent early damaging host responses to T. solium cysts and highlight the focal nature of this initial host response and the importance of eosinophils at sites of host-parasite interaction. These findings suggest new avenues for immunomodulation to reduce inflammatory side effects of anthelmintic therapy.

Calcified neurocysticercus, perilesional edema, and histologic inflammation

Abstract. Here, we present the second report of the histopathology of a Taenia solium calcification giving rise to perilesional edema. This has important implications, because if perilesional edema lesions are inflammatory in character, immunosuppressive or anti-inflammatory medications, not just antiepileptic drugs alone, may be useful to prevent or treat recurring episodes in such patients.

PET reveals inflammation around calcified Taenia solium granulomas with perilesional edema

OBJECTIVE

Neurocysticercosis, an infection with the larval form of the tapeworm, Taeniasolium, is the cause of 29% of epilepsy in endemic regions. Epilepsy in this population is mostly associated with calcified granulomas; at the time of seizure recurrence 50% of those with calcifications demonstrate transient surrounding perilesional edema. Whether edema is consequence of the seizure, or a result of host inflammation directed against parasite antigens or other processes is unknown. To investigate whether perilesional edema is due to inflammation, we imaged a marker of neuroinflammation, translocater protein (TSPO), using positron emission tomography (PET) and the selective ligand (11)C-PBR28.

METHODS

In nine patients with perilesional edema, degenerating cyst or both, PET findings were compared to the corresponding magnetic resonance images. Degenerating cysts were also studied because unlike perilesional edema, degenerating cysts are known to have inflammation. In three of the nine patients, changes in (11)C-PBR28 binding were also studied over time. (11)C-PBR28 binding was compared to the contralateral un-affected region.

RESULTS

(11)C-PBR28 binding increased by a mean of 13% in perilesional edema or degenerating cysts (P = 0.0005, n = 13 in nine patients). Among these 13 lesions, perilesional edema (n=10) showed a slightly smaller increase of 10% compared to the contralateral side (P = 0.005) than the three degenerating cysts. In five lesions with perilesional edema in which repeated measurements of (11)C-PBR28 binding were done, increased binding lasted for 2-9 months.

CONCLUSIONS

Increased TSPO in perilesional edema indicates an inflammatory etiology. The long duration of increased TSPO binding after resolution of the original perilesional edema and the pattern of periodic episodes is consistent with intermittent exacerbation from a continued baseline presence of low level inflammation. Novel anti-inflammatory measures may be useful in the prevention or treatment of seizures in this population.

Corticosteroid withdrawal precipitates perilesional edema around calcified Taenia solium cysts

Calcified Taenia solium granulomas are the focus of repeated episodes of perilesional edema and seizures in 50% of persons with calcifications, history of seizures, and a positive serology for cysticercosis. The pathophysiology is unclear but recent studies suggest the edema is caused by inflammation. We report two new cases and four other published cases where cessation of corticosteroids appeared to result in recurrence or new appearance of perilesional edema around calcifications. This suggests that perilesional edema is an immune-mediated phenomenon.