When It's Not Multiple Sclerosis

Background: The diagnosis of multiple sclerosis is a process that involves evaluation of the patient history, examination, and imaging in addition to several other ancillary steps. Room for error in this process may lead to misdiagnosis. Recent literature on misdiagnosis focuses either on case reports or surveys of multiple MS specialists and estimates misdiagnosis rates at 5-10%. We evaluated the referrals to our tertiary care sub-specialty multiple sclerosis clinic in an effort to understand the types of and reasons for these errors. 

Objectives: To identify the incidence of misdiagnosis of multiple sclerosis and any patterns or common mistakes that lead to these errors.

Methods: All new consults seen in a sub-specialty multiple sclerosis clinic from July – December 2016 were evaluated and categorized by initial diagnosis, category of disease, and more likely diagnosis after appropriate workup was completed.  93 new patient consults were completed in this time.  

Results: 33/93 new patients referred to our clinic did not meet diagnostic criteria for multiple sclerosis or were felt to have a more likely alternate diagnosis.  3 of these non-multiple sclerosis patients were on disease modifying therapy to treat MS.  The most common alternate diagnoses were spine spondylosis, migraine, and white matter ischemic disease. The ancillary tests most likely to help differentiate MS from alternate diagnoses are recent imaging of the entire central nervous system and lumbar puncture.

Conclusions: This review highlights the importance of careful evaluation of a patient’s presentation prior to diagnosing multiple sclerosis and on receiving a referral for treatment options. Neurologists, and MS specialists especially, should re-evaluate an existing MS diagnosis rather than taking it at face value. Diseases misdiagnosed as MS vary but, concordant with previous studies that evaluated reasons for misdiagnosis, include spine disease, migraines, and cerebrovascular ischemic disease.

Research made possible by fellowship grant from the National Multiple Sclerosis Society and unrestricted educational grant from Biogen.