On the relationship between calcified neurocysticercosis and epilepsy in an endemic village: A large‐scale, computed tomography–based population study in rural Ecuador

Abstract

SUMMARY Objective Using a large-scale population-based study, we aimed to assess prevalence and patterns of presentation of neurocysticercosis (NCC) and its relationship with epilepsy in community-dwellers aged ≥20 years living in Atahualpa (rural Ecuador). Methods In a three-phase epidemiological study, individuals with suspected seizures were identified during a door-to-door survey and an interview (Phase I). Then, neurologists evaluated suspected cases and randomly selected negative persons to estimate epilepsy prevalence (Phase II). In Phase III, all participants were offered non-contrast CT for identifying NCC cases. The independent association between NCC (exposure) and epilepsy (outcome) was assessed by the use of multivariate logistic regression models adjusted for age, sex, level of education and alcohol intake. CT findings were subsequently compared to archived brain MRIs in a sizable subgroup of participants. Results Of 1,604 villagers aged ≥20 years, 1,462 (91%) were enrolled. Forty-one persons with epilepsy (PWE) were identified, for a crude prevalence of epilepsy of 28 per 1,000 population (95% C.I.: 20.7 – 38.2). A head CT was performed in 1,228 (84%) out of 1,462 participants, including 39 of 41 PWE. CT showed lesions consistent with calcified parenchymal brain cysticerci in 118 (9.6%) cases (95% C.I.: 8.1% – 11.4%). No patient had other forms of NCC. Nine of 39 PWE, as opposed to 109 of 1,189 participants without epilepsy, had NCC (23.1% versus 9.2%, p=0.004). This difference persisted in the adjusted logistic regression model (OR: 3.04; 95% C.I.: 1.35 – 6.81; p=0.007). Significance This large CT-based study demonstrates that PWE had three times the odds of having NCC than those without epilepsy, providing robust epidemiological evidence favoring the relationship between NCC and epilepsy.

Exploring the complex associations over time among albendazole treatment, cyst evolution, and seizure outcomes in neurocysticercosis

“…The ILAE defines epilepsy as “at least two unprovoked (or reflex) seizures occurring greater than 24 hours apart.” As we have shown, NC has a complex clinical course, which might make it difficult to categorize all cases into the current proposed classification of the ILAE Commission, but if the seizures resolve when the cysts resolve, then it seems appropriate to define the seizure as being acute symptomatic. Some studies have tried to determine the association between NC and epilepsy by means of cross‐sectional studies . Unfortunately, cross‐sectional studies cannot answer the question about NC as a cause of epilepsy, because temporality cannot be determined.…”

“…Some studies have tried to determine the association between NC and epilepsy by means of cross-sectional studies. 34,35 Unfortunately, cross-sectional studies cannot answer the question about NC as a cause of epilepsy, because temporality cannot be determined. Prospective studies enrolling participants with new onset NC-related seizures are necessary to assess the proportion of individuals with NC who develop epilepsy.…”

Supratentorial arachnoid cysts and seizures/epilepsy: A population study in community dwellers aged ≥20 years

“…Atahualpa is a rural Ecuadorian village, where previous epidemiologic studies on seizures/epilepsy have been conducted . Inhabitants are homogeneous regarding race/ethnicity (Amerindians), socioeconomic status, and lifestyle .…”

“…Atahualpa is a rural Ecuadorian village, where previous epidemiologic studies on seizures/epilepsy have been conducted. 10,11 Inhabitants are homogeneous regarding race/ethnicity (Amerindians), socioeconomic status, and lifestyle. 12 The study followed the recommendations of the standards of reporting of neurologic disorders (STROND) guidelines, 13 and was approved by the institutional review board of Hospital-Clínica Kennedy, Guayaquil, Ecuador (FWA 00006867).…”

Announcements

“…In addition, most of the arguments mentioned in the letter to disparage our findings (cysticercotic lesions as innocent bystanders, potential dual pathology) were already addressed in the discussion section of our paper. 5 Neurocysticercosis experts believe that more research on the association between neurocysticercosis and epilepsy is needed. [6][7][8] Even the results of a recent systematic review and meta-analysis strongly suggest that additional information on this topic is desirable.…”