Abstracts

In areas where neurocysticercosis (NCC) is endemic, chronic calcified neurocysticercosis (cNCC) is frequently observed in patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS). Considering that both disorders have been associated with recurrent seizures or cognitive impairment, there is some concern about whether temporal lobectomy is effective for seizure control in MTLE-HS patients who also exhibits radiological findings of cNCC and if surgical procedure is cognitively safe in these circumstances. Retrospective analysis of pre- and post-surgical clinical and neuropsychological data of a cohort of 178 consecutive MTLE-HS patients submitted to temporal lobectomy, comparing results according to the presence or absence of radiological evidence of cNCC. cNCC was observed in 71 (37.2%) patients with MTLE-HS, being significantly more common in women. This prevalence was far higher than expected for our population. During pre-surgical evaluation, patients with MTLE-HS plus cNCC presented a baseline cognitive impairment, that was not further accentuated by temporal lobectomy. Long-term seizure control was not affected by cNCC. cNCC is highly prevalent among MTLE-HS patients living in endemic areas, perhaps indicating a possible cause-effect relationship. Seizures are common in active NCC but might vanish after lesions calcify. Thus, when MTLE-HS-cNCC patients go for investigation, many might have old and already silent cNCC lesions with seizures initiating only in the mesial temporal lobe, making difficult a prompt association between both pathologies. When cNCC is not longer an epileptogenic zone, it is unnecessary to remove it, a concept in line with our findings indicating that cNCC is not a risk factor for poor surgical outcome when seizures are proved to originate in MTL in these patients. Moreover, cNCC is not a risk factor for cognitive decline after temporal lobectomy as well. Thus, we conclude that at least in some patients, NCC might cause or contribute to MTLE-HS development early in life. In spite of this, when seizure are proved to originate from MTL, temporal lobectomy is effective for seizure control and can be safely performed. Because we observed a high prevalence of cNCC in MTLE-HS patients, we believe this study might be relevant for therapeutic decisions in a large number of patients worldwide. (Supported by FAPESP.)