The McDonald criteria for MS was first established in 2001 by neurologist Ian McDonald and his team of researcher to diagnose individuals with MS with speed and sensitivity. The criteria include guidelines on Magnetic Resonance Imaging (MRI) evidence, clinical exams and the use of cerebrospinal fluid (fluid found in the brain and spinal cord, collectively called the central nervous system or CNS) to assist with the diagnosis of MS. Since then, it has undergone three separate revisions; the first took place in 2005, the second in 2010 and most recently, in 2017. The International Panel on Diagnosis of MS revised the 2010 McDonald criteria which was presented at the 7th Joint ECTRIMS/ACTRIMS meeting in Paris, France on October 24-28, 2017. The 2017 revisions were spurred by new data/research since the 2010 revision was released and now allow for an earlier and more efficient diagnosis of MS. The new data has lead to: a better understanding of MS including diagnostic strategies with more sensitivity, greater knowledge of conditions that mimic MS (which can result in misdiagnosis) and revised MRI criteria. The 2017 criteria lessen the risk of misdiagnosis, and most importantly, people can be diagnosed earlier and begin treatment right away.
The revisions include both symptomatic and asymptomatic MRI lesions whereas only asymptomatic lesions were applied in the 2010 criteria meaning now all lesions will be counted and considered. Also in the 2010 criteria, evidence of dissemination in time (more than one neurological attack at different points in time) and dissemination in space (lesions on separate areas of the CNS) were required to make a diagnosis of MS. Using the 2017 criteria, a diagnosis of MS in a person with clinically isolated syndrome or CIS, can be made based on evidence of dissemination of space and the presence of at least two oligoclonal bands (OBs) in the cerebrospinal fluid, which indicate inflammation. Presence of the OBs can replace the need for evidence of dissemination in time, allowing for earlier diagnosis and treatment plan. The criteria have further expanded potential lesion areas within the CNS to include cortical (outer most layer of the brain) and optic nerve (transmits visual information from the retina to the brain) lesions. In addition, the 2017 criteria provide more sensitivity for more accurate diagnoses in pediatric, Latin American and Asian patients.