Modern diagnosis and treatment of multiple sclerosis: advances, challenges, and future directions.

The diagnosis and treatment of multiple sclerosis (MS) remain an evolving challenge in modern neurology. Recent advances are reflected in the 2024 revision of the McDonald criteria, which aim to facilitate earlier, more accurate and biologically informed diagnosis of MS. Key updates include expansion of dissemination in space to incorporate the optic nerve, integration of relapsing and progressive onset MS within a unified diagnostic framework, provision for diagnosis in selected asymptomatic individuals, dispensing with the requirement for dissemination of time in certain situations and incorporation of more specific imaging biomarkers. These include specific radiological features such as the central vein sign and paramagnetic rim lesions, visual pathway assessments using optical coherence tomography, magnetic resonance imaging and visual evoked potentials. Furthermore, oligoclonal bands and kappa free light chain index are now acknowledged as alternative cerebrospinal fluid biomarkers of intrathecal immunoglobulin synthesis. These revisions acknowledge the evolving understanding of MS biology alongside the substantial advances in disease modifying therapies. This review uses the 2024 McDonald criteria as an overarching framework to synthesise and contextualise the recent developments in MS diagnosis and treatment, highlighting their clinical implications, current limitations and future directions.