Abstracts

Rationale: Recent studies have suggested an association between hippocampal sclerosis (HS) and neurocysticercosis (NC). The finding of calcified brain lesions suggestive of inactive cysticercosis in patients with epilepsy and HS may represent an incidental finding. Isolated case reports have shown emergence of HS after resolution of active NC lesions and case series have suggested an increased prevalence of HS in NC. These studies were not controlled for possible confounding factors. We evaluated the association of HS and NC in a case-control study, controlling for possible confounders. Methods: Patients attending a tertiary referral epilepsy clinic in a large teaching hospital were randomly selected to participate in the study if they presented one of the following types of etiologies: hippocampal sclerosis (HS), focal symptomatic (FS), nonlesional extratemporal focal epilepsy (NLF) and idiopathic generalized epilepsy (IGE). After collecting clinical, treatment, epidemiological and demographic data, all patients were invited to undergo a head CT. Brain scans were analyzed by a neuroradiologist, blinded to patients data who noted the presence of calcified lesions suggestive of inactive NC. The frequency of calcified lesions, as well as all other data, was compared between the four groups, by univariate analysis and followed by multivariate analysis. Results: From 173 patients agreeing to participate the study, 127 were submitted to a head CT. Patients who underwent the head CT were older and had a longer epilepsy duration, in comparison with who did not showed for the head CT, but did not differ with the others parameters, including group. HS group showed a higher prevalence of calcified lesions than the other groups (15/55 or 27.3% X 5/72 or 6.9%; p=0.002). The multivariate analysis revealed that the finding of HS was an independent predictor of the presence of calcified lesions at the head CT (p=0.047, OR=3.2), as well as age>39.5 years (p=0.049; OR=3.4) and previous contact with pigs (p=0.023; OR=4.1). Comparing HS patients with and without NC there was not difference regarding occurrence of an initial precipitating insult (i.e. febrile seizure). Conclusions: Although it is not possible to establish a cause-effect relationship, we observed an independent relation between hippocampal sclerosis and presence of calcified lesions suggesting inactive NC, controlling for confounders such as socioeconomic status and contact with pigs. The mechanisms involved in this association should be further clarified.