Abstract

Neuromyelitis optica spectrum disorder (NMOSD) is a demyelinating disorder of the central nervous system that is distinct from multiple sclerosis and is primarily characterized by recurrent episodes of optic neuritis (ON) and/or longitudinal extensive transverse myelitis (LETM). The presence of aquaporin antibodies (AQP4-ab) in the serum and/or cerebrospinal fluid (CSF) is a highly specific biomarker for diagnosis, although repeated testing may be necessary to confirm its presence. Here, we report on a case of a 15-year-old African American female diagnosed with NMOSD following two recurrent brainstem events, which consistently tested seronegative for AQP4-ab for five years and maintained a stable clinical and magnetic resonance imaging (MRI) status. The patient was treated with mycophenolate mofetil (MMF) therapy for five years and remained without relapse by MRI. At that point therapy was discontinued. Repeat surveillance testing six months after discontinuation revealed high positive titers of AQP4-ab, despite the patient being asymptomatic. Patient ultimately presented with altered mental status, and subcutaneous nodules were noted, prompting a rheumatological evaluation, which was consistent with a diagnosis of systemic lupus erythematosus (SLE). Intense immunosuppression therapy provided full clinical and MRI recovery. Our case outlines the importance of monitoring AQP-4 antibody seropositivity in patients with a high clinical suspicion, despite initial negative tests results. This case also challenges the often-provided recommendation for therapy interruption after 5 years of clinical remission and demonstrates the possibility of development of other autoimmune disorders like SLE in conjunction with NMOSD.

Authors and Affiliations