Dual diagnosis of myasthenia gravis and neuromyelitis optica-spectrum disorder.

TitleDual diagnosis of myasthenia gravis and neuromyelitis optica-spectrum disorder.
Publication TypeJournal Article
AuthorsLavy L, Wundes A, Distad B, Johnson S
JournalInternational Journal of MS Care

Background: Central nervous system (CNS) demyelinating diseases such as neuromyelitis optica (NMO) and longitudinally extensive transverse myelitis (LETM) have been rarely reported in patients with myasthenia gravis (MG). The presence of NMO-IgG antibodies is emerging as an important diagnostic feature of NMO-spectrum disorders and appears to be predictive of relapse. We report the case of a thymectomized patient with MG who developed LETM associated with NMO-IgG seropositivity and positive antinuclear antibodies (ANA) in order to highlight the coexistence of autoimmunity with NMO-spectrum disorders. Methods: Case presentation and literature review. Discussion: A 59-year-old woman was diagnosed with MG at age 42 years with positive acetylcholine receptor binding antibodies. At age 42 years, she underwent thymectomy and treatment with prednisone until age 55 years, when she switched to azathioprine. At age 58 years, she tapered off azathioprine. Seven months later, she developed burning chest pain, ascending parethesias, and weakness in the legs and abdomen. Cervical magnetic resonance imaging (MRI) showed T2 hyperintensity extending from C6 to T2. MRI brain and visual evoked potentials were normal. NMO-IgG antibodies and ANA titers were positive. Neurologic examination revealed a sensory level in the upper thorax. She was started on oral steroids and azathioprine. Patients with MG may be predisposed to the development of other autoimmune diseases such as LETM and NMO due to dysregulation of B-cell autoimmunity, possibly exacerbated by thymectomy via a breakdown in self-tolerance, as previously proposed by Gotkine et al. MG patients with LETM and seropositive NMO-IgG fall into the category of patients with NMO-spectrum disorders and appear susceptible to developing autoantibodies such as ANA. Such laboratory evidence of autoimmunity is frequently found in NMO-spectrum disorders, although often without clinical manifestations. The case and relevant literature will be presented.


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