Is MS the Correct Diagnosis?

Do you ever wonder if your MS diagnosis is right? At times I do, and it seems I am not alone because that was a prime topic at the recent American Academy of Neurology (AAN) annual meeting in Vancouver. The question of how common is the misdiagnosis of MS was tackled by Andrew J. Solomon, MD, Assistant Professor in the Department of Neurological Sciences at the University of Vermont in Burlington.

MS misdiagnosis study

Dr. Solomon kindly shared his presentation slides with me and assisted with my preparation for this article. The study, The Spectrum of Multiple Sclerosis Misdiagnosis in the Era of McDonald Criteria: A Multicenter Study, is currently under peer review for publication and hopefully, we will see the entire results in print in about six months. In the meantime, I want to review his AAN Plenary talk and try to learn more.

Purpose of this study

In our correspondence, Dr. Solomon writes, “The aim was to see if we could collect data on a large group of patients recently determined to have been misdiagnosed with MS over a short time, determine what the correct diagnoses were, understand risks of misdiagnosis, and to apply current diagnostic criteria to potentially help understand causes of misdiagnosis.” In his talk, he told the neurologists present, “We should be thinking, ‘Is this really MS?’ each time we see a new patient rather than simply accepting that diagnosis.”

Identifying people misdiagnosed with MS

The study team used the help of neurologists at the MS centers of the University of Vermont, Oregon Health &a Science University, Washington University, and Mayo Clinic, and over a period of 13 months they identified 110 people who had been misdiagnosed with MS and evaluation they were defined with either ‘definite misdiagnosis’ or ‘probable misdiagnosis.’ The total number of new patients seen during this same time period is unknown so unfortunately, it is impossible to form a view of the prevalence of this problem of misdiagnosis.

The differential diagnosis of MS

This study builds on a previous one from 2012, also led by Dr. Solomon, where 122 neurologists were surveyed and approximately 95% of them reported they had found people misdiagnosed with MS. Dr. Solomon has published a number of journal articles on the question of misdiagnosis and the differential diagnosis of MS.1-3

The 23 doctors involved in this study at the four MS clinics were seeing the patients for the first time and those patients were already diagnosed with MS by another physician. These new patients were not assigned to these doctors because there was a question of their diagnosis but rather they came for an assortment of other reasons such as moving, looking for a new doctor, change of payer coverage, etc., and there were enough 'red flags' to make the clinician take a closer look at the original MS diagnosis.

The complexity of diagnosing multiple sclerosis

Most of us already know how complex a diagnosis of MS might be, especially because there are so many other diseases that can also look and act like multiple sclerosis. The other possibilities – the differential diagnosis – are numerous (over 50 possibilities) so it should come as no surprise that there might be errors in the diagnosis.

The McDonald Criteria

The McDonald Criteria outlines the accepted guidelines for diagnosing multiple sclerosis and it has been updated a number of times to reflect changes in diagnostic tools, particularly the use of MRI data. Generally, the McDonald Criteria requires evidence of MS through dissemination in time and space – in plain language, this means there must be signs of MS damage/activity that has occurred at two or more separate times and in two or more places in the central nervous system and eliminating the possibility that it could be something other than MS.

Misdiagnosis findings

From their group of 110, 33% of the patients had lived with a misdiagnosis of MS for more than 10 years, with an additional 30% in the 3-9 year range. That is a lot of years living with the cloud of MS hanging over you, and for this group they found it was also a lot of years taking a disease modifying treatment (DMT) for a disease they didn’t have. Almost 70% had been on a DMT and a third had been on more than one DMT, and over 30% had been on a DMT for more than 3 years. That’s a lot of injections, pills, and infusions for a disease they did not have, and a lot of unnecessary side effects and financial costs.

Maybe even more troubling is they found 4 patients who had participated in clinical trials for MS drugs who had a definite misdiagnosis. Not only were these patients on a drug for a disease they did not have, they were also used in clinical trial studies to help prove the effectiveness of DMTs for all of us to possibly use.

Where did these misdiagnoses come from?

Where did these misdiagnoses come from? I would have thought that a majority of the misdiagnosed had come from doctors other than neurologists, but surprisingly, a large percentage of the people with the wrong diagnosis had been seen by neurologists who specialize in the treatment of MS (24%) and other neurologists (32%).

What were the real diagnoses?

What was the real diagnosis for these people? The doctors found almost 2/3 of the misdiagnosed could be linked to five other disorders –

  • Migraine alone, or in combination with other diagnoses (22%)
  • Fibromyalgia (15%)
  • Nonspecific or non-localizing neurological symptoms
    w/abnormal MRI (12%)
  • Conversion or psychogenic disorder (11%)
  • Neuromyelitis optica spectrum disorder (6%)

There is a lengthy list of other disorders (remember differential diagnosis) for the remainder, including stroke, mitochondrial disorder, vascular change, neurosarcodoisis, neuropathy, viral meningoencephalitis, and alcohol abuse.

The root problems of misdiagnoses

The problem of misdiagnoses appears rooted in errors of applying the McDonald Criteria according to Dr. Solomon’s study. Almost 65% were a case of not interpreting the demyelinating attack criteria correctly; about half of the misdiagnosis had problems with the historical episode not clearly being disseminated in time. There was also the general problem of accepting a neurological deficiency on an exam that did not have evidence via lesions (MRI), which led to about a 50% error rate. In some cases, the MRI showed lesions but they weren’t in the typical juxtacortical or periventricular location.

Predictably, being wrongly diagnosed with MS led about 30% of the patients to have some other morbidity (medical problem) that could be directly linked to their misdiagnosis. These morbidities included not getting the correct treatment for their disease, and taking the DMTS when not needed.

Study results

The results of this study are unsettling because I personally understand the social, economic, and emotional impact of having a diagnosis of a chronic disease like MS. To know the problem of misdiagnosis is not just isolated incidences and there are more than just an occasional person out there thinking they have MS when they really don’t, is troubling and I hope there will be further study of this problem. The rush to diagnosis by the doctor or the push from the patient to have their illness named must be slowed until all of the pieces fit according to the Macdonald Criteria. To do otherwise can do greater harm than good. For anyone reading this who is not yet diagnosed but believes they have MS - I hope your medical team will be thorough before giving any diagnosis and I hope you will learn more about the diagnosis process.

This study also reinforces the often heard advice we should feel confident in -  if we are diagnosed with MS but it doesn’t feel quite right, it might serve us well to get that second opinion.

Wishing you well,


An excerpt from Dr. Solomon

Excerpted from Dr. Solomon’s plenary address, The Spectrum of Multiple Sclerosis Misdiagnosis in the Era of McDonald Criteria: A Multicenter Study:

“We all know the broad differential diagnosis of MS and a number of rare disorders can mimic MS, but here it was migraine, fibromyalgia, and a number of other disorders that are quite common that mimicked MS and were mistaken for MS. What this means is that the correct diagnosis in many of these cases relies on our clinical skills and critical thinking, not just MRI. The problem is not confined to nonspecialists. MS specialists can also make mistakes.”

“It is important to highlight that our MRI criteria as part of our MS diagnostic criteria, were not developed to differentiate MS from other disorders. The MRI criteria for MS were meant to identify patients at high risk for MS after typical clinical presentations for demyelination,”

“Making a diagnosis of MS is challenging. It is important to acknowledge that. The best way to prevent misdiagnosis may be strict adherence and proper use of our MS diagnostic criteria. In patients with atypical clinical presentations or in patients with nonspecific MRI abnormalities we may need to do more. We may need to monitor longer, do more imaging. That may prevent misdiagnosis in a number of cases.”

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