Revisions to criteria used in the diagnosis of MS

Experts have recommended changes to the widely used 2010 McDonald criteria for the diagnosis of MS.1,2 The revisions, published in The Lancet Neurology, are intended to facilitate early and accurate diagnosis of MS and reduce the likelihood of misdiagnosis.

The earlier MS is diagnosed, the sooner treatment to minimize disease activity can be initiated. When making a diagnosis of MS, neurologists consider evidence from clinical assessments and magnetic resonance imaging (MRI) brain scans. The 2010 McDonald criteria allow a diagnosis of MS to be made in a person who has had just one relapse if there is MRI evidence for the development of lesions – areas of intense damage – in multiple brain regions (dissemination in space) and the development of new lesions over time (dissemination in time).

Recent technological advances and new data related to the diagnosis of MS have prompted the re-examination of the 2010 McDonald criteria. An international group of MS experts, including MS neurologists, imaging specialists and experts in diagnostic laboratory tests, considered relevant published and unpublished data on the diagnosis of MS and reviewed the 2010 McDonald criteria. Despite consensus among the experts that the 2010 McDonald criteria performed well, several evidence-based revisions were proposed and agreed.

Detection of antibodies in the spinal fluid

Antibodies, which are made by the immune system to fight infection, mistakenly attack tissue in the brain, spinal cord and optic nerve in people with MS. Consequently, the level of antibodies in the fluid that surrounds the brain and spinal cord (cerebrospinal fluid, CSF) is higher in a person with MS than in a person without the disease.

Antibodies can be detected by a laboratory technique called electrophoresis; antibodies of similar sizes group together forming visible ‘bands’. Recent data show that the presence in the CSF (but not in the blood) of oligoclonal bands – two or more ‘bands’ of different sized antibodies – is a predictor for the risk of a second relapse in MS, after accounting for confounding factors. Therefore, the experts recommended the following: for a person who has experienced just one relapse, the presence of CSF-specific oligoclonal bands could substitute for MRI evidence of dissemination of lesions in time, allowing an MS diagnosis to be reached in some people who were not diagnosable with the 2010 McDonald criteria (Figure).

Figure. Simplified 2017 McDonald criteria for the diagnosis of MS (excluding primary progressive MS)  

 

 

 

 

 

 

 

 

 

Lesions

The experts reached consensus that most symptomatic lesions – areas of damage detected by MRI that are thought to be the cause of particular symptoms – can now be used as evidence for dissemination in space or time. Moreover, lesions in the cerebral cortex (the outer layer of the brain) can be used, in addition to juxtacortical lesions (areas of damage that extend into the cortex of the brain), to show dissemination in space. This revision was made in response to improvements in techniques to identify lesions in the cortex; however, the experts noted that these lesions may not currently be detectable by standard MRI.

 

The authors highlighted the role of clinicians with MS-related expertise in optimal diagnosis of the disease. They also suggested topics for future research which might lead to further refinements of the criteria. In their words, the goal is “to make a rapid and accurate diagnosis of MS to allow appropriate management…keeping fully in mind the potential dangers of misdiagnosis”.

 

References

  1. Polman CH, Reingold SC, Banwell B, et al. Diagnostic criteria for multiple sclerosis: 2010 revisions to the McDonald Criteria. Ann Neurol. 2011;69:292–302; doi: 10.1002/ana.22366.
  2. Thompson AJ, Banwell BL, Barkhof F, et al. Diagnosis of multiple sclerosis: 2017 revisions of the McDonald criteria. Lancet Neurol. 2018;17:162–73; doi:10.1016/S1474-4422(17)30470-2.

 


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