Misdiagnosis tied to delaying neuroimmunologist visit, MRI
Nausea, vomiting, hiccups without neurological symptoms linked to risk
A longer time from the first symptoms of neuromyelitis optica spectrum disorder (NMOSD) to seeing a neuroimmunology specialist and having an MRI scan is associated with a misdiagnosis, a new study shows.
The risk of misdiagnosis was also higher among those who first presented with persistent nausea, vomiting, or hiccups without any neurological symptoms and who initially tested negative for antibodies against AQP4, the most common target of NMOSD-causing antibodies.
“Our findings not only define important factors for consideration when establishing a differential diagnosis but emphasize the need for further awareness towards NMOSD,” the researchers wrote in the study, “Factors associated with the misdiagnosis of neuromyelitis optica spectrum disorder,” which was published Multiple Sclerosis and Related Disorders.
NMOSD is a rare autoimmune disease that mainly affects the optic nerve, which relays eye-related information to the brain, and the spinal cord. The resulting inflammation leads to vision and muscle control problems, often occurring periodically and followed by periods of remission.
For many patients, the initial symptoms may not be neurological and instead may consist of uncontrollable nausea, vomiting, or hiccups — a condition referred to as area postrema syndrome (APS) and considered a diagnostic criterion of NMOSD.
The symptoms and clinical presentation of NMOSD can make it difficult to differentiate initially from other autoimmune diseases, such as multiple sclerosis (MS). In fact, it ‘s reported that about 30% of people with NMOSD are initially misdiagnosed with MS.
“A prompt and accurate diagnosis is crucial given the underlying [mechanisms] of NMOSD and the accompanying disease course, given the higher risk for disability accumulation following a relapse in comparison to MS,” wrote the researchers who set out to identify factors that may be associated with an NMOSD misdiagnosis.
They retrospectively analyzed data from 199 people with a confirmed NMOSD diagnosis who were treated at one hospital in Dallas, Texas. Most were women (84%), half (50.3%) were white, and 47.2% were Black.
Differences between NMOSD diagnosis, misdiagnosis
Nearly two-thirds of patients (64%) had an initial accurate diagnosis, while 71 (36%) were initially misdiagnosed with other inflammatory diseases, mostly MS (76.4%). People with a misdiagnosis were, on average, younger when their symptoms first presented compared with those who were accurately diagnosed (32.8 vs. 41.1 years).
Misdiagnosed patients were significantly more likely to present with APS alone, without neurological symptoms (32.4% vs. 12.5%) and to initially test negative for anti-AQP4 antibodies (100% vs. 19.3%).
Significantly more people with an accurate diagnosis were tested for AQP4 antibodies (89.1% vs. 30.2%) and significantly less time passed between a negative result and a positive test than in those who were misdiagnosed (mean of 1.5 vs. 3.9 years).
Also, the median time from first symptoms to a first visit to a neuroimmunology specialist was significantly longer for misdiagnosed people than for those with a correct NMOSD diagnosis (4.2 years vs. about six months). A similar result was found for the time from first symptoms to a first MRI scan (median of 4.7 years vs. about 3.5 months).
People with an initial misdiagnosis visited significantly more providers before a neuroimmunology visit (median of 5.5 vs. two) and had significantly more clinic visits or hospitalizations before their correct NMOSD diagnosis (10.5 vs. three), compared with those who were correctly diagnosed. They were also significantly less likely to have received their diagnosis from a neuroimmunologist (15.2% vs. 53.9%).
Results of an NMOSD misdiagnosis
This increased number of providers and healthcare visits “may speak to one of the underlying consequences of the existence of generalized symptoms and misdiagnosis with resulting disease advancement due to the lack of exposure to approved therapies,” the researchers wrote.
Repeating the analyses only on those who were positive for anti-AQP4 antibodies resulted in similar, significant findings between those with an initial incorrect versus a correct diagnosis.
As an interesting finding, the team noted that about one-third (32%) of all patients presented with a rash, mostly on the face and/or extremities (86%).
“The prevalence and location pattern of these rashes may give physicians insight on early disease characteristics that when coupled with more nonspecific symptoms may assist in earlier consideration of NMOSD as a potential diagnosis,” the researchers wrote.
They also noted that strategies for raising awareness of NMOSD are crucially needed and that healthcare providers should have greater access to differential diagnostic tools in their workplace.
“Defined factors can help guide both generalists and specialists in the pursuit of strategies aimed at efficiently diagnosing those with NMOSD such that effective care can be delivered,” they wrote. “Increasing healthcare efficiency may result in a reduction in the use of healthcare resources, exposure to treatments that may be harmful, and will be of benefit in improving psychological recovery.”