FROM THE LANCET NEUROLOGY
Updates to the McDonald criteria for diagnosing multiple sclerosis (MS), first introduced in 2010, should allow initiation of therapy earlier in the time point of disease. The changes expand some of the criteria that can be used for diagnosis of disease.
The McDonald criteria should be applied primarily to patients with a typical clinically isolated syndrome – that is, in whom the probability of MS is high. They are best applied to patients 11 years or older, according to first author Alan J. Thompson, MD, and his colleagues on the International Panel on Diagnosis of Multiple Sclerosis. Their update to the 2010 criteria was published online Dec. 21, 2017, in The Lancet Neurology .
Overall, the panel concluded that the 2010 McDonald criteria were effective, and that the update should be limited to clarification and simplification. They also felt that changes should promote earlier diagnosis while discouraging misdiagnoses.
The changes include:
• Cerebrospinal fluid-specific oligoclonal bands can now be used to diagnose MS in patients with a typical clinically isolated syndrome in whom MRI or clinical signs point to dissemination in space (DIS), and if there is no other, better explanation for clinical signs.
• Symptomatic or asymptomatic MRI lesions can be used in the determination of DIS or dissemination in time (DIT). An exception is MRI lesions in the optic nerve in patients with optic neuritis, due to insufficient evidence. Specifically, the panel notes that DIS “can be demonstrated by one or more T2-hyperintense lesions [symptomatic or asymptomatic] that are characteristic of multiple sclerosis in two or more of four areas of the CNS: periventricular, cortical or juxtacortical, and infratentorial brain regions, and the spinal cord.” DIT is defined by “the simultaneous presence of gadolinium-enhancing and non-enhancing lesions [symptomatic or asymptomatic] at any time or by a new T2-hyperintense or gadolinium-enhancing lesion on follow-up MRI, with reference to a baseline scan, irrespective of the timing of the baseline MRI.”
• In patients experiencing brainstem or spinal cord clinically isolated syndrome, symptomatic lesions are sufficient to determine DIS or DIT.
• Cortical or juxtacortical lesions can be used in determining DIS.
• When MS is diagnosed, physicians should determine disease course (relapsing-remitting, primary progressive, or secondary progressive), whether the disease is active or not, and whether it is progressive, using the clinical history over the previous year.
The update was driven by a range of factors, including ongoing developments in imaging, the performance of the 2010 guidelines in diverse populations, and potential confusion between MS and other conditions with similar imaging characteristics, such as neuromyelitis optica spectrum disorders, which should always be considered because symptoms can overlap with MS. These conditions demand different treatment protocols. In addition, in 2016, the European Magnetic Resonance Imaging in Multiple Sclerosis (MAGNIMS) network suggested changes to the MRI criteria for diagnosing multiple sclerosis.
Updates to the guidelines are hardly finished. The panel called for future examination of optic nerve involvement, diverse populations, advanced imaging techniques, and biomarkers.
Some of the panel members reported financial ties to the pharmaceutical industry.
SOURCE: Thompson A et al., Lancet Neurol. 2017 Dec 21. doi: 10.1016/S1474-4422(17)30470-2
