Long Term Misdiagnosis of Neuromyelitis Optica Spectrum Disorder Patients with Multiple Sclerosis

Abstract

Abstract Background Neuromyelitis optica spectrum disorders (NMOSD) and multiple sclerosis (MS) are inflammatory diseases of the central nervous system. Due to their many shared presentations, NMOSD misdiagnosis as MS is a rather common medical misconduct. Few studies have focused on the reasons for these misdiagnoses and how they were corrected in the end. Methods In this study, we report 10 cases of long-term NMOSD misdiagnosis as MS. We reviewed patients' medical records and collected their clinical, radiographic and laboratory data. Also, reasons for the misdiagnoses and how NMOSD diagnosis was confirmed were investigated. Results Nine patients (90%) were female and one was male (10%) with a mean age of 42.88 ± 7.09. Mean EDSS at onset was 1.44 ± 0.39 and 6 patients (60%) were NMO-IgG positive. All brain MRIs at onset had periventricular lesions which fulfilled MS diagnosis. However, periventricular lesions were reduced in 5 patients by the time of NMOSD diagnosis and no longer fulfilled MS diagnostic criteria. Only 2 patients had spinal lesions at onset one of which was a long extending transverse myelitis (LETM). Moreover, new LETM lesions were observed in the spinal MRI of 7 patients at the time of NMOSD diagnosis which led to the diagnosis; either alone or along with the confirmation of autoantibody seropositivity. In 3 patients, NMO-IgG seropositivity in the absence of LETM, led to NMOSD confirmation. Conclusion In order to further avoid misdiagnoses, we suggest to carefully follow the patients with uncertain diagnoses and check several times for NMO-IgG and other autoantibodies reported in NMOSD.