MS Diagnostic Criteria Should Be Changed to First Rule Out NMOSD, Study Says

Joana Carvalho, PhD avatar

by Joana Carvalho, PhD |

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NMOSD diagnosis

Diagnostic guidelines for multiple sclerosis (MS) should be amended to first rule out the presence of neuromyelitis optica spectrum disorder (NMOSD), a neurological inflammatory disease that also affects the brain and spinal cord, a study recommends.

The study, “Can a Diagnosis of Multiple Sclerosis Be Made Without Ruling Out Neuromyelitis Optica Spectrum Disorder?,” was published in the journal Multiple Sclerosis and Related Disorders.

MS is a neurodegenerative disorder whose symptoms may be very similar to those of other neurological diseases, including NMOSD. For that reason, and because at this point there is no single test one can take to determine the presence of the disease, getting an accurate diagnosis of MS can be challenging.

Over the years, diagnostic criteria have been established in an attempt to solve this problem. To assess if patients meet the predefined criteria and rule out other disorders that mimic MS, physicians may request patients undergo a series of tests, including magnetic resonance imaging (MRI) scans and spinal fluid analysis.

Nowadays, screening tests for NMOSD, including tests to detect the presence of aquaporin 4 (AQP4), are recommended but not mandatory to establish a diagnosis of MS.

Jagannadha Avasarala, MD, PhD, a neurologist at the Kentucky Neuroscience Institute (KNI) and colleagues now have carried out a study they believe demonstrates that tests should be mandatory to rule out NMOSD before a definitive diagnosis of MS can be made.

In the study, they analyzed data from 319,994 patients who had been diagnosed with MS and had at least one year of uninterrupted health insurance coverage. Patient data was extracted from the Truven Health Analytics (THA) database.

From the 319,994 patients who originally were diagnosed with MS, 2,001 (0.62%) were later diagnosed with NMOSD.

Additionally, when investigators analyzed data from individual patients who were being followed at the University of Kentucky Medical Center, they found that four of the 54 (7.4%) who had been diagnosed initially with MS actually had NMOSD.

“We present 4 illustrative cases that had typical MRI of brain findings consistent with MS but tested positive for NMOSD,” researchers wrote.

Based on these findings, investigators argued that current clinical and radiological criteria seem to be inadequate to distinguish MS from NMOSD. They also noted that if confirmed in larger datasets of patients, these findings indicate that “guidelines to diagnose MS ought to recommend that NMOSD be excluded first despite typical clinical and radiological findings pointing to MS,” the researchers wrote.

Avasarala also noted that the mandatory inclusion of tests to rule out NMOSD is particularly important considering the fact that medications frequently used to treat MS actually may worsen NMOSD.

As an example, the neurologist recalled the case of a 61-year-old woman who visited the UK HealthCare’s Good Samaritan emergency department showing some of the typical symptoms of MS, but ended up being diagnosed with NMOSD.

She had been diagnosed with myasthenia gravis, another autoimmune disease, a few years back and arrived at the hospital complaining of extreme muscle weakness and numbness.

Although symptoms were consistent with a possible diagnosis of MS, screening tests revealed the presence of AQP4 and myelin oligodendrocyte glycoprotein (MOG) antibodies in her blood, confirming the diagnosis of NMOSD and MOG antibody-positive disease.

Avasarala said that, to his knowledge, this was the only reported case of a patient who had three different rare disorders associated with the production of self-reacting antibodies whose symptoms mimicked those of MS.

“Having three different autoimmune processes does complicate the treatment plan. We have to weigh each disease and assess risk for each,” Madison Higgins, said in a university news story Higgins is an advanced practice provider at the KNI, who helped Avasarala develop a treatment plan for this patient.

Together they came up with a treatment plan that consisted of twice monthly infusions of Soliris (eculizumab, the first and only treatment for NMOSD approved by the U.S. Food and Drug Administration), in combination with the medications she already was taking for her myasthenia gravis.

“It is essential to provide an accurate diagnosis and appropriate treatment so that patients can live the lives they planned to. We are fortunate to have the current medications that we do, and it is an extreme disservice to the patient if we don’t provide the accurate diagnosis to allow them maximum benefit from the appropriate treatment regimen,” Higgins said.

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