Neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) are two different autoimmune disorders that share several similarities. Both disorders attack the central nervous system (CNS) and have some of the same symptoms, such as blurry vision, numbness, tingling, and limb weakness. In fact, the disorders are so similar that 42.5% of patients with NMOSD with available data were initially misdiagnosed with MS in a retrospective study.
In contrast to MS, relapse recovery is poorer in NMOSD, and the potential for irreversible damage from attacks is high. Thus, it is vital that health care providers accurately diagnose NMOSD so that they can provide proper individualized treatment.
Here are some differences in presentation that can support the right course of action:
NMOSD usually occurs in women who are older than patients with MS
While the median age of onset for MS is 29 years old, the median age of a patient with NMOSD is 39 years old. Additionally, the female to male ratio in MS is 2:1, but in NMOSD, the ratio is 9:1 .
Initial NMOSD symptoms are often severe gastrointestinal (GI) issues
Uncontrollable hiccups, nausea, and vomiting for weeks are typically among the first signs of NMOSD. These severe and constant GI issues affect a patient’s ability to conduct their daily activities. Such symptoms are rare with MS.
NMOSD damage clusters in the central nervous system
While MS damages the entire CNS, NMOSD primarily damages the optic nerves, spinal cord, and sometimes the brain and brainstem.
NMOSD spinal cord lesions are longer
Patients with NMOSD have lesions on their spinal cords that are longer than lesions found in patients with MS. These lesions will often reach along several areas of the spinal cord.
Vision damage is often more severe and can occur in both eyes with NMOSD
With MS, vision difficulties usually happen in just one eye, and most patients recover. In contrast, NMOSD often affects the part of the brain where the two optic nerves connect, leading to potential vision impairment in both eyes. Moreover, patients with NMOSD can develop blurry vision, washed-out color vision, and visual field defects, and have a much higher likelihood of developing temporary or permanent vision loss .
Sources: NMOSD VS MS. (2019). Every Attack Matters. https://everyattackmatters.com/nmosd-vs-ms
 Barone, J. (2020, November 17). Eight important ways NMOSD is different from MS. HealthCentral. https://www.healthcentral.com/article/how-nmosd-differs-from-ms