Misdiagnosis could be more common than expected among patients with neuromyelitis optica spectrum disorder (NMOSD), according to a study recently published in the Multiple Sclerosis Journal.

“In addition, misdiagnosis might be a problem of knowledge or experience, considering that NMOSD is a rare and complex disease,” the authors wrote.

This retrospective study included 469 patients previously diagnosed with NMOSD from centers in 6 different countries in Latin America: Argentina, Chile, Colombia, Ecuador, Paraguay, and Venezuela. A total of 12% of the participants received an initial misdiagnosis. 

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Most misdiagnosed patients were women (78%) and of mixed ethnicity (58%). Mean age was 37.5 years. Most cases (n=205) were from Argentina, with 14.63% of the misdiagnosis cases, followed by Colombia, Venezuela, Ecuador, Paraguay, and Chile, with 88, 64, 44, 41, and 27 cases, and 14.77%, 6.25%, 6.81%, 4.87%, and 14.81% of the misdiagnosis cases, respectively. 

The most common incorrect diagnosis was multiple sclerosis in 66.1% of the cases, followed by clinically isolated syndrome in 17.9% of the cases, cerebrovascular disease and chronic relapsing inflammatory optic neuropathy each in 3.6% of cases, and migraine, sarcoidosis, optic neuropathy, glaucoma and tumor in 0.2% cases each. 

In 33% of the misdiagnosed cases, an NMOSD or myasthenia gravis specialist determined the incorrect characterization, and more than half (57%) of the patients required 2 or more neurology consults before receiving the correct diagnosis. 

The rather high incidence of NMOSD misdiagnosis in Latin America could be explained by the potentially varying differential diagnosis among regions, and the fact that most publications regarding this disease are from Europe, Asia, and North America, the authors noted.

“Our findings justify further investigation utilizing correct methodologies to identify knowledge gaps for key aspects (clinical and radiological) of the NMOSD and MS diagnostic criteria in clinical practice to implement appropriate educational interventions,” the researchers concluded. 


Carnero E, Lopez P, Criniti J, et al. Frequency of NMOSD misdiagnosis in a cohort from Latin America: impact and evaluation of different contributors. Mult Scler J. Published online December 1, 2022. doi:10.1177/13524585221136259