Clinical and paraclinical profile of neuromyelitis optic spectrum disorder in a peruvian cohort

Background: Neuromyelitis Optica Spectrum Disorders (NMOSD) is an autoimmune, inflammatory disorder of the Central Nervous System that typically involves the spinal cord and the optic nerves. Recently, the clinical and radiological spectrum of NMOSD has been increasing in Latin America. In Peru, there have only been a few clinical reports on NMOSD published. For this reason, we aimed to assess the clinical and paraclinical characteristics of patients with NMOSD from a tertiary-level neurological center in Lima-Peru. Methods: This is a descriptive study. We assessed medical reports of patients with NMOSD based on the 2015 diagnostic criteria attended in a goverment institute (Instituto Nacional de Ciencias Neurologicas) from Peru between 2013-2019. Those patients who met diagnostic criteria were selected and analyzed. We analyzed continuous data among groups (AQP4-IgG seropositive and AQP4-IgG seronegative/unknow). Results: We identified 58 clinical records that met the selection criteria and were included in the study. The highest percentage of patients (53%) were born in the north of Peru (from parallel 0°01’48’’S – 6°56’38’’S). NMOSD were more prevalent in women (86%), the male:female ratio was 1:6, the mean age at diagnosis was 50 years. AQP4-IgG antibodies were tested in (63.8%), 62% of whom were seropositive and 38% seronegative. The frequency of EO-NMO and LO-NMO was 34.8% and 65.2% in AQP4-IgG seropositive patients, respectively. Unknown AQP4-IgG was found 21 patients. In LO-NMOSD group, AQP4-IgG seropositive was found in a higher percentage. Optic neuritis was the first clinical event at 40% . In the patients who presented myelitis as the first clinical event, 18.2% were AQP4-IgG seropositive, while only 4.8% was found in the rest of the patients. 17% had other associated autoimmune diseases and 16% had anti-nuclear antibodies. 79% of patients had low vitamin D-25(OH) levels (<30ng/ml). Orbit MRI showed unilateral optic neuritis in 46.6%. Spinal cord MRIs showed extensive longitudinal myelitis in 52% of patients and the thoracic segment was the most frequently affected (47%). Conclusions: In the present study of a peruvian NMOSD cohort, we found a higher frequency of unilateral optic neuritis cases, and a higher percentage of AQP4-IgG seropositive patients among those older than 50.