A recent study found that nearly 18 percent of patients diagnosed with multiple sclerosis before being referred to two major Los Angeles medical centers for treatment actually had been misdiagnosed with the autoimmune disease.

The study by researchers at the Cedars-Sinai Multiple Sclerosis and Neuroimmunology Center; UCLA; and the University of Vermont analyzed the cases of 241 patients who had been diagnosed by other physicians and then referred to the Cedars-Sinai or UCLA MS clinics during the course of a year. Investigators sought to determine how many patients were misdiagnosed with MS, and identify common characteristics among those who had been misdiagnosed.

The investigators found that many patients who came to the medical centers with a previous diagnosis of MS did not fulfill the criteria for that diagnosis. The patients spent an average of four years being treated for MS before receiving a correct diagnosis.

The most common correct diagnosis was migrane (16 percent), followed by radiologically isolated syndrome, a condition in which patients do not experience symptoms of MS even though their imaging tests look similar to those of MS patients. Other correct diagnoses included spondylopathy (a disorder of the vertebrae) and neuropathy (nerve damage).

Among those misdiagnosed, 72 percent had been prescribed MS treatments. Forty-eight percent of these patients received therapies that carry a known risk of developing progressive multifocal leukoencephalopathy, a serious disease in the white matter of the brain, caused by viral infection. Investigators estimated that the unnecessary treatments identified in this study alone cost almost $10 million.

According to Dr. Ben Thrower, MS Focus senior medical advisor, “The results of this study are alarming. There is a balance between the need to get MS diagnosed quickly with the need to get it diagnosed accurately. Misdiagnosing MS and starting a treatment needlessly is problematic on two fronts. Some of the available MS therapies can have significant side effects. In addition, a misdiagnosis may delay treatment of the true underlying condition. The diagnosis of MS has always depended upon the right clinical story, the right findings on examination and the right findings on testing such as MRI and spinal fluid examination. All other explanations need to be ruled out. Hopefully, we can find that right balance between diagnostic speed and accuracy so that fewer people are misdiagnosed.”

The investigators hope that the results of this study will help improve diagnostic procedures and help prevent future MS misdiagnoses.

The study will be published in the May issue of the journal Multiple Sclerosis and Related Disorders.