Clinical characteristics of the late-onset epilepsy in Mexico to the beginning of the new millennium: 455 cases

Introduction. Epilepsy is a multifactorial disorder, and several factors can modify its prevalence in different regions. Among these, local culture, public health policies and survival rate can be cited. Alongside, the cause of epilepsy may be different according to time and geographic registries. In Mexico, neurocysticercosis remains a leading cause of seizures. Nonetheless, lifestyle changes and the increase in life expectancy have fostered the incidence of stroke. Both diseases are the main underlying disorders causing epilepsy in Mexico. Lately, their respective incidence is being reversed, and therefore their role is gradually interchanging. Objectives. To describe and assess the epidemiological and clinical features of a sample of Mexican patients with late-onset seizures. Material and methods. A group of 455 patients aged over 20 years old was recruited from ten different centers nationwide. The study included patients with onset of epilepsy from year 2000 on, and clinical features of seizures were recorded for every patient, electroencephalogram (EEG) and brain computed tomography (CT) were performed. Results. No gender-related differences were observed. Age distribution was as follows: the highest incidence occurred in the third decade of life and 18% of the patients were aged above 60 years old. Generalized seizures were recorded in 49% of the patients. Pharmacological management used a single drug in 83% of the patients and the most frequently used drug was diphenylhydantoine (PHT) and the second was carbamazepine (CBZ). Abnormal electro-encephalographic findings were recoded in 66% of the cases. Concerning etiologies, the first cause was neurocysticerosis in 21% of the cases, followed by stroke in 17% of them. No cause could be found in 49% of the patients. These findings slightly differ from those of other centers in developed countries. Conclusions. In the last decades, the societal changes in the country have greatly influence the shift in the underlying causes of late-onset seizures. Even if neurocysticercosis stands still as the first cause, its frequency has declined by more than 50% while the increase of stroke incidence has boosted its etiological role and their difference is now statistically non-significant.