Updated McDonald Criteria for MS Diagnosis Are Out: Q&A with the Revision Co-Chair

The 2010 McDonald criteria for diagnosis of multiple sclerosis (MS), the specialty standard in research and clinical practice, were recently revised by the International Panel on Diagnosis of Multiple Sclerosis. Jeffrey Cohen, MD, of Cleveland Clinic’s Mellen Center for Multiple Sclerosis Treatment and Research, co-chaired the international panel, and chaired the International Advisory Committee on Clinical Trials in MS for the past six years. Last October, he presented an overview of the revised criteria at the 7th joint ECTRIMS-ACTRIMS meeting in Paris, and now the criteria have been published in full by Lancet Neurology.

Consult QD recently interviewed Dr. Cohen (shown with a patient above) on key features of the 2017 revisions of the McDonald criteria.

Q: Can you outline the main changes?

Dr. Cohen: The most significant revision is that cerebrospinal fluid (CSF) results can now be used to diagnose MS under appropriate clinical circumstances. The old criteria required demonstrating that patients had lesions disseminated in space and time clinically or by MRI. The new criteria allow for a diagnosis to be made in a patient with a single attack and confirmation of dissemination in space based on clinical or MRI evidence if the CSF is positive for two or more oligoclonal bands.

The other revisions are really refinements:

• Symptomatic lesions can now be used to demonstrate dissemination in space or in time (or both). Previously, this was felt to be “double counting,” but new data support allowing such lesions to help make the diagnosis.
• Cortical lesions can now be used to demonstrate dissemination in space; they are now regarded as diagnostically equivalent to juxtacortical lesions. New imaging techniques are better able to identify such lesions.
• The panel recommended that a provisional disease course be specified as soon as the diagnosis is made — active or not, progressive or not — and periodically reevaluated based on accumulated information. Such categorization, starting at the initial diagnosis, can have important implications for treatment.

Q: Can you let us in on any controversies or unresolved issues?

Dr. Cohen: Several other potential revisions were debated, but we ended up opting against those changes because of insufficient data. The most contentious issue surrounded incorporating optic nerve involvement into the criteria. While optic nerve involvement is an important feature of MS, diagnostic sensitivity and specificity of MRI, visual evoked potentials and optical coherence tomography to demonstrate optic nerve lesions and inform the diagnostic criteria were deemed insufficient. This area was identified as a high priority for future research.

Another controversy concerned the number of periventricular lesions required to fulfill MRI criteria for dissemination in space. The 2001 and 2005 McDonald criteria required three or more lesions, and the 2010 McDonald criteria reduced the requirement to one. We considered changing back the required number because a single periventricular lesion is not uncommon in older people and those with vascular disease, including migraines. But changing it back would have reduced sensitivity and only modestly increased specificity.

One other interesting area is “radiologically isolated syndrome” — that is, patients without clinical manifestations of MS but with incidental radiological findings suggestive of it. Many of these patients go on to develop MS and may benefit from early treatment, but without more data, we could not recommend changing the current diagnostic criteria.

Q: The McDonald criteria were first published in 2001 and revised in 2005 and 2010. What prompted the current update?

Dr. Cohen: New data have emerged since the last revision, including from studies conducted in more diverse populations. The new information goes beyond the North American and western European adults that the 2010 criteria were mostly based on. Additional studies were reviewed from Asia, the Middle East and Latin America, as well as in children. In general, the data support the applicability of the 2010 McDonald criteria in these diverse populations.

However, for children younger than 11 years old, special care in diagnosis is needed, as the likelihood of MS is low.

Q: Can you share any overall principles that emerged during the panel’s discussions?

Dr. Cohen: The panel decided early on to only make changes that were supported by reasonable evidence rather than based solely on “expert opinion.” We weren’t set on making major changes, but rather on simplifying and clarifying the 2010 criteria.

The issue of misdiagnosis was always at the forefront of our discussions. We want patients to have prompt access to appropriate therapies, but we don’t want to get the diagnosis wrong and expose patients to potent anti-inflammatory drugs unnecessarily. Efficiency in diagnosis must be balanced with caution.

The McDonald criteria cannot be viewed as a simple checklist. Ultimately, diagnosis requires expertise. I would urge physicians not to rush to judgment and to obtain more information if the diagnosis is uncertain.