Evaluating the Association of Calcified Neurocysticercosis and Mesial Temporal Lobe Epilepsy With Hippocampal Sclerosis in a Large Cohort of Patients With Epilepsy

Abstract

BackgroundNeurocysticercosis (NCC) is a parasitic infection of the central nervous system that has been associated with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). However, this association has not been completely established.ObjectiveTo evaluate the prevalence of calcified NCC (cNCC), its characteristics and a possible association between cNCC and MTLE-HS in a cohort of 731 patients with epilepsy.MethodsWe review clinical, EEG and neuroimaging findings of 731 patients with epilepsy. From these, 659 had CT-scans and 441 patients had complete neuroimaging with CT-scans and MRI. In these patients, we review the prevalence and characteristic of epilepsy in cNCC and in MTLE-HS patients.ResultsForty-two (6.4%) of the 659 patients studied with CT-scans had cNCC. cNCC lesions were more frequent in women than in men (n = 33–78.6% vs. n = 09–21.4%, respectively; OR = 3.64;(95%CI = 1.71–7.69); p < 0.001). cNCC was more often in patients who developed epilepsy later in life, in older patients, in patients who had a longer history of epilepsy, and in those with a lower educational level. MTLE–HS was observed in 93 (21.1%) of 441 patients that had complete neuroimaging, and 25 (26.9%) of these 93 patients also had cNCC. Calcified NCC was observed in only 17 (4.9%) of the remaining 348 patients that had other types of epilepsy rather than MTLE-HS. Thus, in our cohort, cNCC was more frequently associated with MTLE-HS than with other forms of epilepsy, O.R. = 11.90;(95%CI = 6.10–23.26); p < 0.0001).ConclusionsAs expected, in some patients the epilepsy was directly related to cNCC lesional zone, although this was observed in a surprisingly lower number of patients. Also, cNCC lesions were observed in other forms of epilepsy, a finding that could occur only by chance, with epilepsy probably being not related to cNCC at all. In this cohort, cNCC was very commonly associated with MTLE-HS, an observation in agreement with the hypothesis that NCC can contribute to or directly cause MTLE-HS in many patients. Given the broad world prevalence of NCC and the relatively few studies in this field, our findings add more data suggesting a possible and intriguing frequent interplay between NCC and MTLE-HS, two of the most common causes of focal epilepsy worldwide.

Current Role of Surgery in the Treatment of Neurocysticercosis

“…Debate persists whether the nature of this association is causal or casual. Many studies have investigated the relationship between NCC and hippocampus sclerosis and there are doubts whether hippocampus sclerosis results from recurrent seizures from local or distant focus or from chronic recurrent inflammation [ 95 , 96 , 97 ]. For example, status epilepticus from a distant lesion could lead to hippocampus injury; NCC can induce gliosis surrounding the hippocampus causing damage to it; antibodies against NCC could have a cross-reaction against hippocampal cells; the hippocampus being a highly sensitive structure of the brain, can be damaged secondary to systemic conditions (such as febrile seizures) [ 98 , 99 , 100 , 101 ].…”

Neurocysticercosis: A Review into Treatment Options, Indications, and Their Efficacy

“…However, the question of a causal link between mesial temporal sclerosis with NC exists, and further evidence is needed to support these conclusions. 48 The most used drugs are carbamazepine, phenytoin, phenobarbital and valproic acid. There is no evidence that treatment should be different from other epilepsy causes.…”

“…However, the question of a causal link between mesial temporal sclerosis with NC exists, and further evidence is needed to support these conclusions. 48 …”

“…Many authors argue that this association is merely a casual relationship, while others point to causal factors determining MTLE-HS in patients with NC. 48 , 63 Besides, MTLE-HS can be a differential diagnosis in patients with seizures non-concordant with NC localization. Despite this discussion, it seems clear that mesial temporal lobe surgery is an effective option for drug-resistant seizures, providing long-term seizure control and cessation of anti-epileptic drugs.…”

New animal models of neurocysticercosis can help understand epileptogenesis in neuroinfection

“…Even if located distant from the hippocampus. Whether this is due to subclinical seizure activity or inflammatory mediators is not yet known (Singh et al, 2013 ; Del Brutto et al, 2021 ; Secchi et al, 2022 ).…”