McDonald criteria


Your diagnosis of multiple sclerosis may have been made using the McDonald criteria. This is a tool for clinicians to ensure that they provide an accurate diagnosis of MS as early as possible, and guide them to the tests they should arrange for you in order to be sure.

The first set of criteria were published in 2001 by a team led by Prof Ian McDonald. They have been extensively revised several times, most recently in 2017. The revisions are made by a panel of MS experts who look at the most up-to-date research on how MS appears and progresses in patients.

Consultant neurologist, Dr Gemma Maxwell, sums up the McDonald criteria

The 2017 revisions to the McDonald Criteria

The newest revisions will not change your diagnosis of MS, but they may allow a doctor to give a diagnosis of MS to someone earlier in their own disease course. This could mean that a patient gets access to the right treatment sooner. 

The key requirement for a diagnosis of MS is evidence of damage to the central nervous system that is disseminated in time and space. This means showing that damage has occurred at different dates (Dissemination in time, or DIT) and to different parts (Dissemination in space, or DIS) of the central nervous system. This distinguishes MS from other neurological conditions.

The McDonald criteria use MRI evidence extensively and suggest that an MRI scan is made for everyone in whom an MS diagnosis is possible. Lesions may be found even in someone with few or no clinical symptoms, which would be evidence for DIS.

The presence of oligoclonal bands in the spinal fluid is also a good marker for MS. It shows that there has been disease activity in the past, and so can be used as evidence of DIT.

What evidence is needed to be able to diagnose MS?

Evidence needed to secure an MS diagnosis
What evidence for MS does the patient already have? What additional data is needed for an MS diagnosis?
Two or more relapses AND EITHER objective clinical evidence of two or more lesions OR objective clinical evidence of one lesion together with reasonable historical evidence of a previous relapse None

Two or more relapses; objective clinical evidence of one lesion

(shows DIT)

Dissemination in space shown by:

One or more MRI detected lesions typical of MS OR A further relapse showing damage to another part of the CNS

One relapse; objective clinical evidence of two or more lesions

(shows DIS)

Dissemination in time shown by:

Oligoclonal bands OR MRI evidence of a new lesion since a previous scan OR A further relapse

One attack/relapse; objective clinical evidence of one lesion (known as 'clinically isolated syndrome')

Dissemination in space shown by:

One or more MRI detected lesions typical of MS OR A further relapse showing activity in another part of the CNS Dissemination in time shown by: Oligoclonal bands OR MRI showing new lesions since a previous scan OR A further relapse

Insidious neurological progression suggestive of multiple sclerosis (typical for primary progressive MS) Continued progression for one year (from previous symptoms or by ongoing observation) plus any two of: One or more MRI detected lesions in the brain typical of MS, Two or more MRI detected lesions in the spinal cord, Oligoclonal bands in the spinal fluid

 

So, if you visit your doctor with a neurological symptom that suggests a potential first MS event (CIS), you could therefore have an MRI scan and lumbar puncture. If these tests show lesions in the central nervous system and oligoclonal bands in your spinal fluid, a diagnosis of MS could be made immediately. You would not need to wait for another attack or relapse before starting treatment.

A diagnosis of MS is most secure if there is more than one kind of evidence. Misdiagnosing MS could put patients at risk from the side-effects of MS drugs unnecessarily. Clinicians still need to use their judgement, particularly when diagnosing MS in children or population groups where MS is uncommon.

Find out more

References
Thompson AJ, et al.
Diagnosis of multiple sclerosis: 2017 revisions of the McDonald criteria.
Lancet Neurology 2018 Feb;17(2):162-173
Summary (link is external)
Polman CH, et al.
Diagnostic criteria for multiple sclerosis: 2010 Revisions to the McDonald criteria.
Annals of Neurology 2011;69(2):292-302.
Full article (link is external)
On this page