By Pat Anson, Editor

Multiple Sclerosis (MS) is a chronic disease that attacks the body’s central nervous system, causing pain, numbness, difficulty walking, paralysis, loss of vision, and fatigue. Patients diagnosed with MS face enormous physical, emotional and financial challenges coping with a disease that cannot be cured.

Many also discover that they don’t actually have MS.

A new study published in the journal Neurology looks at 110 patients who were incorrectly diagnosed with MS when they actually suffered from more common and treatable conditions such as migraine and fibromyalgia.   

One third of the patients were misdiagnosed for a decade or longer, most took unnecessary and potentially harmful medication to treat a disease they didn't have, and some even participated in clinical trials for experimental MS therapies.

About a third suffered from “unnecessary morbidity” – morbid thoughts of death.

"Misdiagnosis of MS is common; patients may experience common MS symptoms, such as numbness and weakness with a variety of different conditions, many that are more common and less serious than multiple sclerosis," says the study's senior author Brian Weinshenker, MD, a neurologist at Mayo Clinic.

"With the advent of treatments for MS, many physicians feel pushed to reach an early diagnosis, and may be less strict than they should in requiring more specific symptoms or objective neurological findings before making a diagnosis of MS.”

Unlike other chronic illnesses, there is no specific biomarker or blood test for MS. The nerve damage caused by MS is also associated with a wide range of symptoms, many of which are also caused by other conditions such as Lyme disease, lupus, fibromyalgia, and Vitamin B12 deficiency.

Some diagnostic tests for MS, such as magnetic resonance imaging (MRI), can also be misinterpreted.

“Nonspecific MRI abnormalities that can mimic those of MS are very common in healthy individuals, and widespread use of MRI as a diagnostic tool increases the rate of misdiagnosis," said Weinshenker.

The 110 patients included in the study were identified by MS subspecialist neurologists at Mayo Clinic, University of Vermont, Washington University and Oregon Health & Science University.

Twenty two percent of the misdiagnosed patients actually had migraine; 15% had fibromyalgia; 12% had a nonspecific condition flagged by an abnormal MRI; 11% had a conversion or psychogenic disorder; and 6% had neuromyelitis optica spectrum disorder.

"This study suggests significant and long-term unnecessary risks for these patients," said lead author Andrew Solomon, MD, a neurologist at the University of Vermont College of Medicine. "While there may be different reasons for misdiagnoses by subspecialists and nonspecialists, this study suggests that we all make mistakes, and I think we can all do better.”

A previous survey of MS specialists found that more than 95% had seen at least one patient in the past year that was misdiagnosed with MS by another provider.

Some treatments for MS carry serious side effects. One drug, taken by 13 percent of the misdiagnosed patients in the current study, can cause a potentially fatal brain infection. Other patients suffered from the discomfort and inconvenience of daily injections; others experienced side effects from medications or lacked treatment for the conditions they actually had.

There are also enormous financial costs involved. The cost of medications to treat MS in the United States now exceeds $50,000 a year.

"Premature diagnosis of MS should be avoided," says Weinshenker. "When in doubt, physicians often can defer a diagnosis if it is not clear that there is a serious neurological problem or if a patient is stable. Physicians should request a second opinion when they are unsure but concerned that it might be harmful to delay a definitive diagnosis of MS."

Weinshenker and Solomon hope their study will encourage better education of clinicians on the proper use of MS diagnostic criteria and to further studies on how to recognize patients incorrectly diagnosed with MS.