Intractable Epilepsy associated with Neurocysticercosis: Perilesional Epileptogenic Features

ABSTRACT

BACKGROUND: Neurocysticercosis (NCC) is the most common parasitic disease of the CNS and seizures are the most frequent clinical manifestations of it. Although the medical treatment of NCC is effective, epilepsy surgery is still needed to treat refractory seizures. We investigated five cases with refractory seizures due to NCC to verify perilesional epileptogenic changes in NCC. METHOD: We included 5 intractable epilepsy patients who had epilepsy surgery and pathologically proven cysticercosis although serological tests were negative. A routine EEG and brain MRI were performed in all patients. Video scalp-EEG monitorings were done in 5 patients, including an invasive-EEG monitoring in one. We analyzed the relationships between semiology, brain MRI, interictal, and ictal EEG findings, pathologic features and surgical outcomes. RESULTS: All patients had abdominal or psychic aura, evolving into automotor seizure and then secondarily generalized tonic clonic seizures. Two patients often had only the aura. In brain MRI, four patients had showed NCC lesions in the mesial temporal area, and one had it in the basal occipital area. Hippocampal atrophy was also detected in 3 patients. Irritative and ictal onset zones on an EEG were located around the lesions. Pathologic findings confirmed hippocampal sclerosis in 3 patients and coritcal dyslamination and many single heterotopic neurons in the temporal lobe in 1 patient. Surgical outcomes showed 3 patients in class IA, 1 in class IC, and 1 in class IIB by Engel classification. CONCLUSIONS: Epileptic foci could be formed focally around the NCC lesion and hippocampal sclerosis frequently accompanied when the lesion was located near the mesial temporal structures. After verifying epileptic foci and lesion, epilepsy surgery had good surgical outcome.