Over-Diagnosing of Multiple Sclerosis : The Potential Pitfalls of the 2010 McDonald Criteria
With the revised 2010 McDonald criteria, the diagnosis of Multiple Sclerosis is too frequently being assigned to individuals who do not have the disease. In this day and age of efficacious, yet often toxic therapies, this is a potentially serious issue. The following provides a brief overview of the principal factors underlying this diagnostic shortcoming.
Physicians currently apply the McDonald criteria to patients presenting with any type of neurological symptoms, even though it is clearly stated within the publication that these criteria should only be used in patients that present with symptoms characteristic of multiple sclerosis: optic neuritis, partial myelitis and brainstem syndromes. By doing so, they misapply the sensitivity and specificity of the McDonald criteria and increase the likelihood of a false positive diagnostic.
Secondly, the criteria combines clinical and radiological information but does nothing to confirm the biology of the disease. This once again creates a propensity for false positive MS diagnostics. Multiple Sclerosis is a chronic progressive inflammatory disease of the central nervous system. With the advent of ever more sensitive MRI’s, physicians need a process which confirms the inflammatory nature of the lesions they are detecting.
The presence of cerebrospinal fluid (CSF), oligoclonal bands (OB) and elevated IgG index was once part of the diagnostic criteria. Though nonspecific, their presence confirms the inflammatory nature of the disease. An argument can be made that CSF OB should be reinstated as part of the diagnostic criteria of MS and that CSF OB negative MS is either a false negative or another disease altogether.
Dr. François Jacques
Director of the Multiple Sclerosis clinic