McDonald criteria

The McDonald criteria are diagnostic criteria for multiple sclerosis (MS). These criteria are named after neurologist W. Ian McDonald who directed an international panel in association with the National Multiple Sclerosis Society (NMSS) of America and recommended revised diagnostic criteria for MS in April 2001. These new criteria intended to replace the Poser criteria and the older Schumacher criteria. They have undergone revisions in 2005, 2010 and 2017.Two of the following:and nonenhancing lesions at any time; or A new T2 and/or gadolinium-enhancing lesion(s) on follow-up MRI, irrespective of its timing with reference to a baseline scan; orAwait a second clinical attack. For DIS:1 or more T2 lesion in at least 2 of 4 MS-typical regions of the CNS(periventricular, juxtacortical, infratentorial, or spinal cord); orAwait a second clinical attack implicating a different CNS site; andFor DIT:Simultaneous presence of asymptomatic gadolinium-enhancingand nonenhancing lesions at any time; orA new T2 and/or gadolinium-enhancing lesion(s) on follow-up MRI,irrespective of its timing with reference to a baseline scan; orAwait a second clinical attack.two or three of the following:1. Evidence for DIS in the brain based on 1 or more T2 lesions in theMS-characteristic (periventricular, juxtacortical, or infratentorial) regions 2. Evidence for DIS in the spinal cord based on 2 or more T2lesions in the cord 3. Positive CSF (isoelectric focusing evidence of oligoclonal bandsand/or elevated IgG index) The McDonald criteria are diagnostic criteria for multiple sclerosis (MS). These criteria are named after neurologist W. Ian McDonald who directed an international panel in association with the National Multiple Sclerosis Society (NMSS) of America and recommended revised diagnostic criteria for MS in April 2001. These new criteria intended to replace the Poser criteria and the older Schumacher criteria. They have undergone revisions in 2005, 2010 and 2017. They maintain the Poser requirement to demonstrate 'dissemination of lesions in space and time' (DIS and DIT) but they discourage the previously used Poser terms such as 'clinically definite' and 'probable MS', and propose as diagnostic either 'MS', 'possible MS', or 'not MS'. The McDonald criteria maintained a scheme for diagnosing MS based solely on clinical grounds but also proposed for the first time that when clinical evidence is lacking, magnetic resonance imaging (MRI) findings can serve as surrogates for dissemination in space (DIS) and/or time (DIT) to diagnose MS. The criteria try to prove the existence of demyelinating lesions, by image or by their effects, showing that they occur in different areas of the nervous system (DIS) and that they accumulate over time (DIT). The McDonald criteria facilitate the diagnosis of MS in patients who present with their first demyelinating attack and significantly increase the sensitivity for diagnosing MS without compromising the specificity. The McDonald criteria for the diagnosis of multiple sclerosis were revised first in 2005 to clarify exactly what is meant by an 'attack', 'dissemination' and a 'positive MRI', etc. Later they were revised again in 2017. McDonald criteria are the standard clinical case definition for MS and the 2010 version is regarded as the gold standard test for MS diagnosis. They discourage the previously used terms such as 'clinically definite' and 'probable MS', and propose as diagnostic variants like 'MS', 'possible MS', or 'not MS', though these terms chage between revisions. As of 2017 revision The term ‘possible MS’ was added for people with a typical clinically isolated syndrome who did not meet the criteria. Pathology is generally regarded as the gold standard in defining different forms of inflammatory demyelinating diseases. Specificity of the McDonald criteria is low due to the fact that the nature of the lesions is not considered, but only their dissemination. None of the criteria are MS-specific. In order to reduce false positives, McDonald et al. propose that their criteria should be applied only after any other disease has been ruled out. In 2008 a consensus was developed for differential diagnosis. Another criticism of the McDonald criteria is that the definition of 'lesions typical of MS' is unclear; a 2013 review identified the following characteristics: specific cell morphology shown by hematoxylin, demyelination shown by Luxol fast blue, macrophage appearance by KiM1P or CD68, damage to the axons shown by Bielschowsky stain, astrocytopathy shown by glial fibrillary acidic protein, and different lymphocyte subtypes, reacting to CD3, CD4, CD8, CD20 and CD138.