Diagnosing MS Using the McDonald Criteria
James Bowen, MD, Medical Director, Multiple Sclerosis Center
Swedish Neuroscience Institute, Seattle, WA
Criteria for the diagnosis of MS have been based on diagnosis by "lesions" in space and over time. The first set of criteria was known as the Schumacher Criteria. These were followed by the Poser Criteria. The best and most current set of criteria for diagnosing MS is the McDonald Criteria. The McDonald Criteria were developed in April 2001 by an international panel in association with the National MS Society of America, modified in 2005, and revised in 2010.
The primary goal of the McDonald Criteria is to enable the diagnosis of MS sooner and to permit earlier treatment of MS. For clinical research trials, it is important to ensure that those without a definite diagnosis of MS are not enrolled. The bottom line is that there have to be 2 attacks in time and at 2 locations. You can get the locations in time either by clinical attacks or by MRI changes over time. You can get the 2 locations in the nervous system either by clinical attacks or by MRI criteria.
The requirement for at least 2 attacks in time is needed to assure that the condition is not due to a one-time event such as a viral infection. This requirement can be met by having 2 clinical attacks (for example, two different episodes of optic neuritis). If there is only one clinical attack, then changes on serial MRIs can be used to document the second event. MRI changes could be a new T2/FLAIR lesion or a newly enhancing lesion. A new enhancing lesion must be ≥ 3 months after the onset of the initial clinical event and at a site different from the initial event. A new T2/FLAIR lesion must be ≥ 30 days after the event.
The requirement for lesions in at least 2 locations within the central nervous system assures that single-site pathologies are not misdiagnosed (for example, recurrent spinal cord events due to a disc). This requirement can be met by having 2 clinical locations (for example, optic neuritis and transverse myelitis). If there are not two clinical locations, then changes on the MRI can be used instead. MRI findings use the criteria developed by Barkof, et al. They are listed in detail in the links.
Finally, the criteria require that no better explanation be present. This is often the most difficult portion of the criteria. It assures that patients are not misdiagnosed due to other diseases (for example, a patient with ocular migraine and cervical myelopathy due to disc disease).
In the VA, the vast majority of veterans have already been diagnosed—often in the military or in the private sector. The basis for the diagnosis needs to be reviewed in light of the criteria AND documented either by inclusion of the ACTUAL reports or at least by detailed note.
Veterans presenting with symptoms of MS should be diagnosed using the McDonald Criteria. Diagnosis should only be done by a knowledgeable physician (usually a neurologist or rehabilitation medicine MD with experience working with MS patients). Diagnosis should not be made simply by an MRI scan of the brain or spinal cord.
Polman, C. H., et al.. (2011), Diagnostic criteria for multiple sclerosis: 2010 Revisions to the McDonald criteria. Annals of Neurology, 69: 292–302. doi: 10.1002/ana.22366
Link to results of a study comparing the McDonald to the Poser Criteria.
Link to Diagnostic Criteria for MS: 2005 Revisions to the “McDonald” Criteria. Annals of Neurology (2005) 58:840-846.
Last Updated: March 2011