Neuromyelitis Optica (Devic's Disease)

Neuromyelitis optica spectrum disorder (NMOSD), formerly known as Devic's disease, is a severe autoimmune central nervous system demyelinating disease distinct from multiple sclerosis. AQP4-IgG (aquaporin-4) antibody is positive in approximately 70-80% of cases; MOG-IgG is positive in some seronegative cases.

It is characterised by classical optic neuritis (often bilateral and severe) and longitudinally extensive transverse myelitis (LETM, lesion ≥3 vertebral segments) attacks. Other typical attack patterns: area postrema syndrome (intractable vomiting, hiccups), brainstem syndrome, diencephalic syndrome (narcolepsy-like) and cerebral syndrome.

Diagnostic criteria (2015 IPND): typical clinical attack + AQP4-IgG positivity = NMOSD diagnosis; in seronegative cases, two core clinical findings and additional MRI criteria are required. Acute attack treatment: high-dose intravenous methylprednisolone, plasmapheresis. Long-term immunosuppression: rituximab, eculizumab (anti-C5), inebilizumab (anti-CD19), satralizumab (anti-IL-6R) and azathioprine. Disability accumulates rapidly when untreated.