International panel revises ‘McDonald Criteria’ for diagnosing multiple sclerosis

Mar 10, 2011

An international panel has revised and simplified the "McDonald Criteria" commonly used to diagnose multiple sclerosis, incorporating new data that should speed the diagnosis without compromising accuracy. The International Panel on Diagnosis of MS, organized and supported by the National Multiple Sclerosis Society and the European Committee for Treatment and Research in Multiple Sclerosis, was chaired by Chris H Polman MD PhD (Free University of Amsterdam). Full details are available in the free-access paper published in the February 2011 issue of Annals of Neurology.

"Treating MS early and effectively is likely our best way to prevent permanent damage to the nervous system, so speeding the diagnosis of MS without compromising accuracy is a key goal," stated National Multiple Sclerosis Society Chief Medical Officer Aaron Miller MD, Professor of Neurology and Medical Director of the Multiple Sclerosis Center at Mount Sinai Medical Center in New York City. "These updated diagnostic criteria appear to achieve this goal."

The National MS Society has developed materials to help neurologists understand and apply the 2010 revised diagnostic criteria in practice. These include plans to produce pocket cards summarizing the new criteria.

Determining if an individual has multiple sclerosis can be difficult because there is no single test that can accurately determine the diagnosis. Generally the process of diagnosis involves obtaining evidence from patient history, clinical examination, a variety of laboratory tests, and MRI scans, all intended to rule out other possible causes of disease and to gather data consistent with a diagnosis of multiple sclerosis.

The newly revised 2010 McDonald Criteria incorporate updated information on using MRI as a tool for speeding diagnosis.

The McDonald Criteria for Diagnosis of MS were originally published in 2001. They were named for the chair of the original panel, the late neurologist W Ian McDonald MB ChB PhD. Dr. Polman chaired the panels responsible for the 2005 and 2010 revisions. The previous versions have been the subject of extensive debate and testing. A significant body of new information about the utility of the Criteria has been published. The International Panel reconvened in May 2010 in Dublin to consider these new data and to develop consensus for revising and updating the McDonald Criteria, with an eye toward speeding and easing diagnosis without compromising accuracy.

The diagnosis of multiple sclerosis is a partly subjective process, and is best made by an expert who is familiar with the disease and who can interpret imaging and laboratory evidence that can supplement the clinical diagnostic process. The requirement remains that there must be no better explanation than multiple sclerosis for the clinical and laboratory findings – other possible diagnoses must be considered and excluded.

The key to an multiple sclerosis diagnosis has been, and remains, the objective demonstration of dissemination of typical disease signs and symptoms in time and space. The 2010 revisions maintain this requirement, but offer several ways of using imaging to determine dissemination. It remains the case that while the use of paraclinical and laboratory examination can speed a multiple sclerosis diagnosis, a solid diagnosis can be made on clinical grounds alone.

No single test can provide adequate information to support a multiple sclerosis diagnosis. Therefore, supportive and confirmatory paraclinical examinations – including analysis of lesions by MRI, of cerebrospinal fluid, and sometimes of evoked potentials – are still important in helping to confirm a multiple sclerosis diagnosis.

There is new emphasis that the McDonald Criteria should only be applied to those who present with a clinically isolated syndrome suggestive of multiple sclerosis, or who have symptoms consistent with a central nervous system inflammatory demyelinating disease. The panel also considered how well the Criteria can be applied to specific populations such as pediatric multiple sclerosis and Asian and Latin American populations. They concluded that the 2010 Revised Criteria would apply to the majority of these populations, but the paper describes specific situations in which further considerations and tests would be recommended to properly diagnose multiple sclerosis in these groups.

In past versions of the McDonald Criteria, guidelines were presented for using MRI to demonstrate dissemination of disease in time and space, based on earlier studies. For the 2010 Revised Criteria, published recommendations from the European MAGNIMS multicenter collaboration have been incorporated. These indicate that:

• 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. (Previous versions had 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 out of 4 areas of the central nervous system: periventricular, juxtacortical, infratentorial, or spinal cord. These lesions need not be gadolinium enhanced.

In the case of diagnosing primary-progressive multiple sclerosis, aspects of the previous criteria remain, but the MAGNIMS recommendations for demonstrating dissemination in space were incorporated to harmonize with other 2010 updates. As shown in Table 1, diagnosing primary-progressive multiple sclerosis requires 1 year of disease progression (determined retrospectively or prospectively), plus at least 2 out of these 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.

While the International Panel has provided revised and simplified criteria for multiple sclerosis diagnosis, recommendations for further testing of the Criteria are made as well, to bolster the scientific evidence supporting the 2010 recommendations.

The 2010 Revisions to the McDonald Diagnostic Criteria for MS should speed and make easier and more certain the diagnosis of multiple sclerosis. As with the original Criteria, these need prospective study, and it is expected that additional research will result in further refinements.

Source: News Release
National Multiple Sclerosis Society
March 9, 2011