A 50 Year-Old Woman with A Delayed Diagnosis of Neuromyelitis Optica Spectrum Disorder: The Clinical Course and Serial Neuroimaging Findings.

Purpose: Neuromyelitis optica (NMO) spectrum disorder and multiple sclerosis (MS) have similar clinical presentations which may make a diagnostic difficulty, especially when the data of aquaporin-4 (AQP4) antibody is not available. We reported the diagnostic and therapeutic dilemma of a woman with a delayed diagnosis of NMO spectrum disorder for more than 20 years.

Case report: The patient was a 51 years old woman who suffered from several episodes of relapsing and remission of limbs weakness, visual impairment and gait disturbance since 29 years old. She was diagnosed as a case of MS and received treatment accordingly. Treatment with the use of Rebif was started since 2008-2012, and was then shifted to Fingolimod due to several minor attacks were still noted during this period. Serum AQP4-IgG was checked before the use of Fingolimod by using Enzyme-linked immunosorbent assay (ELISA) and the result showed sero-negative for this Ab. However, occasional minor attacks were still noted. In May 2018, severe relapsing developed and brain magnetic resonance imaging (MRI) showed marked progression of the brain lesion. Initially, progressive multifocal leukoencephalopathy was suspected, but both cerebrospinal fluid and serologic study for John Cunningham virus (JCV) were negative. AQP4-IgG was rechecked by using cell-based assay (CBA), and the result showed positive finding. Thereafter, her therapy was changed to NMO spectrum disorder regimen.

Conclusion: It is worthwhile to recheck the serum AQP4-IgG if the initial study showed negative result by using ELISA since CBA has higher sensitivity than previous study method.