Differential diagnosis of MS

Abstract

Diagnostic criteria for MS rely on the demonstration of CNS disease in space and time and in reasonable exclusion of other causes. Since McDonald 2001, in patients with a first attack, MRI may provide evidence of diagnosis for dissemination in space and time. The 2010 McDonald criteria selected the Magnims criteria for dissemination in space (DIS). DIS is defined as the presence of ≥1 asymptomatic T2 lesion(s) in at least two of four locations considered characteristic for MS in previous MRI criteria: juxtacortical, periventricular, infratentorial and spinal cord. These criteria simplify the previous Barkhof criteria and highlight the importance of lesion location for MS diagnosis. Moreover, this new definition relies on T2 lesions only. Non-inclusion of gadolinium enhancing lesions seems appropriate since enhancing lesions per se provide information on disease activity and not on dissemination in space. For demonstration of dissemination in time (DIT), an MRI performed at any time demonstrating DIS and showing at least one or more asymptomatic gadolinium enhancing and non-enhancing lesions(s) (this being used as evidence for DIT) would be sufficient to diagnose MS. Although many studies have already shown the importance of CSF study in the diagnosis and differential diagnosis of MS, the presence of oligoclonal bands has not been included in the diagnosis algorithm. These criteria have been adapted to other populations such as patients with primary progressive MS or patients with paediatric MS. An overview of the past diagnostic criteria will also be performed as well as new directions for the future will be considered (intracortical lesions, 3 T MRI, other). One of the problems of the diagnosis of MS is that we should rule out other conditions and this is not always an easy task. Clinical cases to illustrate differential diagnoses will be presented.