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

Development and validation of a predictive model assessing the risk of seizure recurrence in children with neurocysticercosis

INTRODUCTION

Neurocysticercosis (NCC) is a significant factor contributing to the incidence of seizures in developing countries. While numerous studies have investigated the recurrence of seizures in NCC, their reliability is often limited.

METHODS

We assessed the socio-demographic, clinical, and neuroimaging details of 161 children with seizures caused by NCC. We monitored them for seizure recurrence over a 6-month follow-up period. We divided the children into two groups: those with seizure recurrence and those without. Subsequently, we identified predictive factors associated with seizure recurrence through univariate analysis, followed by multivariate binary logistic regression. We evaluated the prognostic model for discrimination and calibration and then internally validated it using the bootstrap method.

RESULTS

A total of 23 children experienced breakthrough seizures. In multivariate analysis, the presence of epileptiform abnormalities in electroencephalogram (EEG), more than 5 NCC lesions, the presence of perilesional edema greater than 2 cm in maximum dimension, and a cluster of seizures before presentation were significantly associated with seizure recurrence (p < 0.05). These factors were included in the final NEPC (Number of NCC lesions, Epileptiform EEG abnormality, Perilesional edema, and Cluster of seizures) score. The final model exhibited good discrimination (AUC = 89.1 %; 95 % CI=80.5-95.3 %, p < 0.001) and calibration (p = 0.54). A score of 4 appeared to be the optimal threshold for discriminating between individuals with and without seizure recurrence, with sensitivity and specificity values of 85 % and 87 %, respectively. Interrater reliability was very strong between two pediatric neurologists and strong between a pediatric neurologist and a pediatric neurology trainee resident (k = 0.92 and 0.86, respectively).

CONCLUSION

The NEPC score demonstrates good sensitivity and specificity in predicting seizure recurrence in pediatric children with NCC.

Association of ABO blood groups with venous thrombosis recurrence in middle-aged patients: insights from a weighted Cox analysis dedicated to ambispective design

BACKGROUND

In studies of time-to-events, it is common to collect information about events that occurred before the inclusion in a prospective cohort. When the studied risk factors are independent of time, including both pre- and post-inclusion events in the analyses, generally referred to as relying on an ambispective design, increases the statistical power but may lead to a selection bias. In the field of venous thromboembolism (VT), ABO blood groups have been the subject of extensive research due to their substantial effect on VT risk. However, few studies have investigated their effect on the risk of VT recurrence. Motivated by the study of the association of genetically determined ABO blood groups with VT recurrence, we propose a methodology to include pre-inclusion events in the analysis of ambispective studies while avoiding the selection bias due to mortality.

METHODS

This work relies on two independent cohorts of VT patients, the French MARTHA study built on an ambispective design and the Dutch MEGA study built on a standard prospective design. For the analysis of the MARTHA study, a weighted Cox model was developed where weights were defined by the inverse of the survival probability at the time of data collection about the events. Thanks to the collection of information on the vital status of patients, we could estimate the survival probabilities using a delayed-entry Cox model on the death risk. Finally, results obtained in both studies were then meta-analysed.

RESULTS

In the combined sample totalling 2,752 patients including 993 recurrences, the A1 blood group has an increased risk (Hazard Ratio (HR) of 1.18, p = 4.2 × 10^-3) compared with the O1 group, homogeneously in MARTHA and in MEGA. The same trend (HR = 1.19, p = 0.06) was observed for the less frequent A2 group.

CONCLUSION

The proposed methodology increases the power of studies relying on an ambispective design which is frequent in epidemiologic studies about recurrent events. This approach allowed to clarify the association of ABO blood groups with the risk of VT recurrence. Besides, this methodology has an immediate field of application in the context of genome wide association studies.

What Causes Seizures in Neurocysticercosis?

Neurocysticercosis (NCC) is the most prevalent parasitic infection of the central nervous system. It is caused by the presence of larvae of the cestode Taenia solium in the brain. The most common symptom of NCC is seizures, and it is widely considered the world’s leading cause of preventable epilepsy. Despite the prevalence and impact of NCC, a thorough, mechanistic understanding of seizure generation is still lacking. In this review, we address the question “What causes seizures in NCC?” by summarizing and discussing the major theories that seek to explain the seizurogenic and epileptogenic processes in this disorder. In addition, we highlight the potential for recent advances in disease modeling to help accelerate progress in this area.

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.

Comparative Efficacy and Safety of Lacosamide and Oxcarbazepine for Seizure Control in Children with Newly Diagnosed Solitary Neurocysticercosis

BACKGROUND

In newly diagnosed neurocysticercosis (NCC) with seizures, the choice of anti-seizure medication (ASM) seems to be arbitrary due to a lack of comparative studies. Although oxcarbazepine (OXC) is often considered efficacious for focal seizures in NCC, due to adverse effects, newer ASMs like levetiracetam (LCM) and lacosamide are also being explored.

METHODS

This study was performed by case record review of children with newly diagnosed solitary viable parenchymal NCC aged 4-18years who received lacosamide and OXC at least for 12 weeks between August 2019 and April 2021, from a prospective registry of a tertiary care teaching hospital in north India. Seizure control, electroencephalographic abnormalities, resolution of inflammatory granulomas and adverse effects were compared between two arms at 12 and 24 weeks.

RESULTS

Total 31 (8.3 ± 4.7 years, 19 boys) and 72 (8.6 ± 4.2 years, 43 boys) completed at least 12 weeks follow-up in LCM and OXC groups, out of which 2 and 51 completed at least 24 weeks follow-up in LCM and OXC groups, respectively. The occurrence of breakthrough seizure was comparable in both arms at 12 and 24 weeks (1/31 and 2/22 in lacosamide group vs. 2/72 and 4/51 in OXC group, p = 0.66 and 0.59, respectively). Patients receiving OXC had more frequent treatment-emergent adverse events (p = 0.0001) and four patients required discontinuation due to severe adverse events (SAEs), while none in the lacosamide group had SAEs.

CONCLUSIONS

Lacosamide appears to be efficacious and safe for achieving seizure freedom in patients with solitary viable parenchymal neurocysticercosis.

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.

Epilepsy outcomes and hippocampal volumes in children with multiple parenchymal neurocysticercoses

Background:

We aimed to study the radiological and epilepsy outcomes of children with multiple neurocysticercosis (NCC) and the relationship with hippocampus volume.

Study Design:

Observational study.

Materials and Methods:

Children between 5 and 18 years of age with NCC lesions and completed more than 2-year follow-up were enrolled. Magnetic resonance imaging (MRI) brain with a predefined protocol was done as per clinical indication, and bilateral hippocampi volume was measured with a region of interest-based manual method. Proportion of children who had radiological resolution of lesions, proportion of children who were seizure-free for at least 3 months after antiepileptic drugs withdrawal, and mean hippocampi volume were calculated.

Results:

During the study period, 229 children followed up in pediatric NCC clinic were enrolled, the mean age was 10.5 ± 3 years, and 129 (56%) were boys. A total of 159 (65%) children had single-lesion NCC, and 79 (35%) had multiple lesion (> 2) NCC. Resolution of lesions was seen in 8% children with multiple NCC, significantly less as compared to the single NCC group (8% vs. 27%, P = 0.006). Multiple-lesion NCC group had a higher rate of calcification as compared to children with a single lesion (66% vs. 47%, P = 0.008). Twenty-nine (37%) children with multiple-lesion NCC were seizure free for at least 3 months after antiepileptic drug withdrawal. Mean combined hippocampal volume in children with single-lesion NCC was 2.96 (0.62) mL and multiple-lesion NCC was 2.88(0.43) mL.

Conclusion:

Children with multiple-lesion NCC have lower resolution, and higher calcification during follow-up in comparison to single-lesion NCC. Frequency of children who remained seizure-free 3-month post AED withdrawal was similar in single- and multiple-lesion groups.

A prospective cohort study to assess the frequency and risk factors for calcification in single lesion parenchymal neurocysticercosis

BACKGROUND

Calcified neurocysticercosis (NCC) predisposes patients to an enduring state of epilepsy. The predictors for calcification in parenchymal neurocysticercosis are not well defined.

METHOD

In this prospective cohort study, consecutive children with single-lesion parenchymal NCC were enrolled and followed up for one year. All patients were investigated with brain 3 T-MRI and electroimmunotransfer blot (EITB). Clinical follow-ups were performed every 3 months. Radiology was repeated at the 6-month and one-year follow-ups. The proportion of calcified lesions at one year and the predictors of calcification were studied.

RESULT

During the study period from June 2013 to December 2015, 93 children with single lesion parenchymal NCC were enrolled. At presentation, 90 % of the lesions were in the colloidal stage, and 71 % of the lesions had moderate to severe perilesional oedema. All children had 6 months of follow-up, and 86 (92.5 %) had one year of follow-up. Seizure recurrence was present in 13 (14 %) children. Follow-up radiology at one year showed lesion resolution in 51 (59 %) lesions and calcification in 28 (32.5 %) lesions. Children with calcified lesions during follow-up had a higher odds of seizure recurrences {OR, 95 % CI 3.6(2.3-5.6)}. The presence at baseline of diffusion restriction {OR, 95% CI 2.9 (1.01-8.8)}, scolex or wall calcification in the T2 Star weighted angiography MRI images {OR, 95% CI 3.7 (1.7-8.2)} and >10 mm size of the lesion {OR, 95 % CI 2.4 (1.2-5.01)} predicted lesion calcification.

CONCLUSION

Children with calcification of the parenchymal NCC lesions have a higher risk for seizure recurrence during follow-up. The presence of diffusion restriction, calcified nidus in the colloidal nodular stage, and >10 mm size of the lesion at baseline predicted calcification of the lesion during follow-up.

Microsurgical Treatment of Epilepsy with Parenchymal Neurocysticercosis

Parenchymal neurocysticercosis is the most common form of neurocysticercosis in the central nervous system (CNS), which mainly causes epilepsy and usually responses well to routine medications. However, there are appreciable cases of relapses refractory to medical treatment. We investigated microsurgical treatment of epilepsy with parenchymal neurocysticercosis. Nine cases of epilepsy caused by parenchymal neurocysticercosis from 2002 to 2018 were analyzed retrospectively. Cysts in 7 cases were completely removed. No case died of operation and no new dysfunction of the nervous system was observed after surgery. Among the other 9 cases, 8 cases became seizure-free or controlled by medicine according to the postoperative follow-up for 6 months to 9 years. One case was lost for follow-up. It was suggested that epilepsy with parenchymal neurocysticercosis can usually be controlled after routine medications. However, surgery is still indicated in some cases and careful microsurgery is associated with satisfactory clinical outcomes in appropriately selected cases.