Evaluation of the 2015 diagnostic criteria for neuromyelitis optica spectrum disorder.

Abstract

To evaluate the application of the 2015 International Panel for NMO Diagnosis (IPND) criteria to consecutive cases of neuromyelitis optica spectrum disorder (NMOSD) in a large cohort of individuals with CNS inflammatory diseases. In total, 594 patients with CNS inflammatory diseases were included. Rigorous confirmation of the patients' aquaporin-4 immunoglobulin G antibodies (AQP4-IgG) status throughout the disease duration (mean 9.2 ± 5.7 years) using repeated assays, including ELISA and cell-based assay, was performed. A total of 252 patients fulfilled the IPND criteria (AQP4-IgG positive: 226 [90%], AQP4-IgG negative: 26 [10%]). Of these, 136 (54%) patients met the 2006 neuromyelitis optica criteria. When we assumed an unknown AQP4-IgG status in the confirmed NMOSD group with AQP4-IgG, 162 of 226 (72%) patients with AQP4-IgG were classified as having NMOSD by the IPND criteria. The majority of patients were diagnosed with NMOSD within 2 years of onset (73%) or after a second attack (72%). Acute myelitis (83%) and optic neuritis (65%) were the most common clinical features throughout the disease duration. Optic neuritis (42%) was the most common initial manifestation, followed by acute myelitis (38%) and area postrema syndrome (14%). The IPND criteria well-reflected the broader clinical spectrum of NMOSD and markedly improved the diagnostic yield compared to the previous criteria, even in patients with an unknown AQP4-IgG status.