March 11, 2011 — The International Panel on the Diagnosis of Multiple Sclerosis (MS) has revised the McDonald Criteria for diagnosing the disease.
"The 2010 revisions to the McDonald Criteria will in some instances allow a more rapid diagnosis of MS, with equivalent or improved specificity and/or sensitivity compared with past criteria and will in many instances clarify and simplify the diagnostic process with fewer required MRI [magnetic resonance imaging] examinations," the panel states.
The McDonald Criteria, named for the chair of the original panel, the late neurologist W. Ian McDonald, MB, ChB, PhD, were originally issued in 2001 and updated in 2005. New data generated since 2005 led the panel to reconvene in May 2010 in Dublin, Ireland, to refine the criteria.
The revised criteria were published online March 8 in Annals of Neurology, just ahead of National MS Awareness Week (March 14-20). They are available online.
Corresponding author is Chris H. Polman MD, PhD, from the Department of Neurology at VU Medical Center, Amsterdam, the Netherlands.
What's Changed?
"One of the most dramatic changes is that for the very first time we are going to use a diagnostic criteria that will allow some patients to be diagnosed at the time of their first symptoms, whereas previously we always had to wait for new disease to develop," National MS Society Chief Medical Officer Aaron Miller, MD, noted in a telephone interview with Medscape Medical News. Dr. Miller is a professor of neurology and medical director of the MS Center at Mount Sinai Medical Center in New York City. He was not on the panel.
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| Dr. Aaron Miller |
Previous iterations of the McDonald Criteria, as well as the latest revision, include recommendations on using MRI to demonstrate dissemination of disease in time and space. The revisions, Dr. Miller noted, are based largely on the work of the MAGNIMS (European Magnetic Resonance Imaging in MS) group that has shown benefits of using a simplified MRI scheme to demonstrate this. They state the following:
Dissemination in time can be demonstrated by a new T2 or gadolinium-enhancing lesion on a follow-up MRI, with reference to a baseline scan, regardless of when the baseline MRI was obtained. The earlier versions specified that the reference scan be performed at least 30 days after the initial clinical event; this is no longer a requirement.
Dissemination in space can be demonstrated with at least 1 T2 lesion in at least 2 of 4 areas of the central nervous system: periventricular, juxtacortical, infratentorial, or spinal cord. These lesions need not be gadolinium enhanced.
"This is a much simpler MRI schema to use," Dr. Miller said. "Now we have the possibility that a patient who presents with a CIS [clinically isolated syndrome] who has a brain MRI that shows both gadolinium-enhancing lesions and other T2-hyperintense lesions could be diagnosed at that point as having MS.
"In the previous iteration of the McDonald Criteria or its predecessor," he explained, "we always had to wait for new disease activity to occur; now the presumption is that when you have gadolinium-enhanced activity and other nonenhancing lesions that the nonenhancing lesions occurred sometime in the past and the gadolinium-enhancing lesions are occurring currently and so you meet dissemination in time."
Primary-Progressive MS Less Clear
The revised McDonald Criteria also state that primary-progressive MS may be diagnosed in subjects with the following: 1 year of disease progression (determined retrospectively or prospectively) plus at least 2 of the following 3 criteria: dissemination in space in the brain based on at least 1 T2 lesion in periventricular, juxtacortical, or infratentorial regions; dissemination in space in the spinal cord based on at least 2 T2 lesions; or positive cerebrospinal fluid findings.
"Even though there has been some modification of the criteria for primary-progressive MS," Dr. Miller noted, "this, in particular, still remains less clear-cut than for relapsing-remitting disease. And all of this emphasizes the importance of developing biomarkers and understanding primary-progressive disease better, which are among the critical areas of research that the National MS Society is supporting."
There is also a new emphasis in the revised criteria that they only be applied to individuals who present with a CIS suggestive of MS or those who have symptoms consistent with a central nervous system inflammatory demyelinating disease, the panel notes.
The panel also considered how well the diagnostic criteria can be applied to children and Asian and Latin American populations. "The McDonald Criteria were developed with data gathered largely from adult Caucasian European and North American populations, and their applicability has been questioned for other populations, particularly pediatric cases, Asians, and Latin Americans," the panel notes.
The panel concluded that the revised criteria apply to most of these populations but that there are some situations in which further considerations and tests would be recommended to properly diagnose MS in these groups. These situations are fully spelled out in the report.
The Basics Still Apply
Making an accurate diagnosis of MS can be challenging; there is no single diagnostic test. In general, the panel reminds clinicians that it's a matter of ruling out other possible causes of neurologic symptoms suggestive of MS by obtaining a careful patient history, clinical examination, a variety of laboratory tests, and MRI scans.
These basic tenets remain in the revised McDonald Criteria, the panel emphasizes. "The requirement remains that there must be no better explanation than MS for the clinical and laboratory findings — other possible diagnoses must be considered and excluded," the National MS Society adds in a prepared statement.
"There remains a need for further testing in prospective and retrospective datasets of many of these criteria, especially in populations of patients typical of those seen in general neurology practices, both to further assess their value and utility and to provide suggestions for further refinements in the future," the panel notes.
The panel was supported by the US National MS Society and the European Committee for Treatment and Research in Multiple Sclerosis, the MS International Federation, and MS Ireland. A complete list of potential conflicts of interest for panel members can be found in the original article.
Ann Neurol. 2011;69:292-302. Published online March 8, 2011.
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