Neuromyelitis optica Spectrum Disorder (NMOSD)
What is NMOSD?
Neuromyelitis Optic (NMO) was once thought to be a form of multiple sclerosis (MS). NMO has now been defined as a distinct clinical–pathological disorder, although the initial clinical presentation often mimics MS (1). In 2004, Neuromyelitis Opticia (or NMO) was defined by the finding of a positive aquaporin-4 antibody (AQP4-IgG), also known at the NMO antibody. Before the discovery of this antibody, neurologists speculated about whether or not NMO and MS were the same or different disease. It is very clear now however that NMO is a distinct clinical–pathological disorder, although the initial clinical presentation may mimic MS. It is very important to differentiate between these two diseases because they have different treatments.
What are the treatment options?
There are now three new FDA-approved therapies for NMOSD since 2019, including Soliris (eculizumab), Uplizna (inebilizumab-cdon), and Enspryng (satralizumab-mwge). When a patient presents acutely, steroids are commonly used to treat urgently and if the attack is severe often plasma exchange (PLEX) is added. The use of these acute therapies is similar to approaches used in multiple sclerosis. To avoid future attacks or relapses, just like multiple sclerosis, chronic disease modifying therapies are used, although these longer-term disease-modifying treatments are different.