Characteristics of Devic's disease (neuromyelitis optica) in Mexico

Objective To report clinical and epidemiological data of Devic's disease in Mexico. Design Retrospective study of hospital case records. Setting The medical records were those of the National Institute for Neurology and Neurosurgery (INNN), a tertiary care referral center in Mexico City. Patients There were 424 medical histories available for review among 561 discharges with diagnoses of multiple sclerosis (MS), neuromyelitis optica (NMO), or equivalents. 390 met the diagnostic criteria of MS and 34 the NMO criteria. Main outcome measures We recorded clinical signs, visual acuities, and the Expanded Disability Status Scale (EDSS) at the initial diagnostic admission and during follow-up. All patients had examination of cerebrospinal fluid (CSF) at diagnosis; head and spine magnetic resonance imaging (MRI) were performed at diagnosis and at follow-up. Results All 34 patients were Mexican Mestizos, who comprise 79% of the residents of Mexico City. There were 23 monophasic and I I relapsing cases. Intervals between initial and defining events for the 8 ON and 12 myelitis onsets were 17 and 24 months (means) and 15 and 17 months (medians), respectively. Mean follow-up from onset was 70.2 months and 42.9 months from diagnostic examination. No patient showed improvement in EDSS scores. Visual loss was severe. Conclusion A provisional prevalence rate of about I per 100,000 population for NMO in Mexican Mestizos might be offered. The disease seems more severe in our population than in other recent series.