Multiple sclerosis: a modern diagnostic algorithm in clinical practice

This article addresses the diagnostic challenges of multiple sclerosis (MS). The criteria for diagnosing this disease are briefly considered in a historical aspect. It is demonstrated that the main principles have remained unchanged throughout time. The diagnosis of MS requires confirmation of the spatial dissemination (DIS) of the demyelinating process, meaning its presence in different regions of the CNS, and to prove the chronic nature of the disease (DIT). Methods for confirming these criteria have improved over time — initially, the basis was only clinical symptoms, then laboratory and technological studies were added, which allowed for faster diagnosis and earlier initiation of treatment.Today we use the diagnostic criteria that were proposed by a team of neurologists led by Professor I. McDonald, revised in 2017. These criteria are not intended for the differential diagnosis of MS but are useful for excluding other possible conditions. The diagnostic algorithm of these criteria is based on the history (number of exacerbations), topical diagnostics (number of lesions in the CNS according to neurological status and topical diagnosis), MRI examination (presence of lesions in different parts of the brain and spinal cord), presence of activity of these lesions according to MRI data (accumulation of contrast agent) and results of cerebrospinal fluid analysis (detection of oligoclonal immunoglobulins of type II or III).The article presents two clinical cases of patients, in whom MS was suspected, but to confirm the diagnosis it was necessary to conduct all necessary studies and perform a full diagnostic algorithm according to the criteria of McDonald, 2017. After these actions, the diagnosis of MS was confirmed in one patient, and in the other it was excluded.At the end of the article, information is provided about the prepared revision of the criteria of McDonald, 2017. At the ECTRIMS 2024 congress, new revised criteria were presented, which had the following additions: it was proposed to include the optic nerve as a fifth topography, add two MRI features ­ the central vein sign (CVS) and the paramagnetic rim lesion (PRL), and include a new diagnostic laboratory marker that has been shown to be accurate for identifying MS — free kappa light chains.