Neuromyelitis Optica Spectrum Disorder in a Chinese Woman with Ocular Myasthenia Gravis: First Reported Case in the Chinese Population

Abstract

Coexisting myasthenia gravis and neuromyelitis optica spectrum disorder was reported as a rare association, with only 26 reported cases in the literature. The authors report the case of a middle-aged Chinese woman with bilateral recurrent optic neuritis and seropositive ocular myasthenia gravis who was subsequently diagnosed with neuromyelitis optica spectrum. She was tested seropositive for the neuromyelitis optica immunoglobulin G (NMO-IgG) and had elevated antinuclear antibody titres, but workup for other autoimmune disorders were negative. She was subsequently prescribed with azathioprine and pyridostigmine, and showed good control of both autoimmune disorders. To the best of the authors' knowledge, this is the first reported case in the literature of a Chinese patient with seropositivity for both anti-acetylcholine receptor and NMO-IgG without a thymic disorder. Testing of NMO-IgG may be considered in patients with optic neuritis with underlying autoimmune disorders even in the absence of transverse myelitis for the detection of associated neuromyelitis optica spectrum disorders.

Coexistence of myasthenia gravis and neuromyelitis optica spectrum disorder: case report in Colombia and literature review

“…However, the coexistence of these two pathologies is evident in some cases where patients never underwent thymectomy. [4][5][6][7][8]10,13,14 or presented NMO before having such surgical procedure done, 4 suggesting that the thymus is not the only responsible factor.…”

“…These anti-AQP4 Abs, also called NMO IgG Abs, are used as a specific test for Neuromyelitis Optica Spectrum Disorders (NMOSD), with a specificity of 99-100% and a sensitivity of 58-91%, though detection rates vary among different laboratory tests, with patients within the NMOSD group being seronegative. 5,6 The prevalence of NMOSD ranges around 3.9 to 10 with an incidence of 0.07 to 0.73 per 100,000 individuals respectively; the difference between women and men is 8-9:1 (1). Higher associations with autoimmune diseases have been reported in seropositive NMOSD patients in up to 25-50% of cases (4), including Systemic Lupus Erythematosus (SLE), Sjögren's syndrome (SS), autoimmune thyroid diseases, and MG (5).…”