Diagnosis

2024 McDonald Criteria: applying the new diagnostic framework in clinical practice

The 2024 McDonald Criteria broaden the diagnostic framework for Multiple Sclerosis while maintaining a case-based approach. By integrating clinical findings, cerebrospinal fluid biomarkers, optic nerve assessment and selected MRI markers, the revised criteria may support earlier diagnosis while reducing unnecessary testing.

The 2024 revision of the McDonald Criteria introduces several important changes designed to support earlier and more accurate diagnosis of Multiple Sclerosis (MS).

Mario Habek reviews how the revised criteria can be applied in clinical practice, including the incorporation of Radiologically Isolated Syndrome (RIS), the optic nerve as a fifth topography, kappa free light chains in cerebrospinal fluid analysis, and new MRI markers such as the central vein sign and paramagnetic rim lesions.

Key Insights from the Lecture:

Radiologically Isolated Syndrome can now meet diagnostic criteria for Multiple Sclerosis in selected situations, including when dissemination in space and time are demonstrated.
The optic nerve is now included as a fifth topography for demonstrating dissemination in space.
Optic nerve involvement can be assessed clinically or through MRI, visual evoked potentials and optical coherence tomography (OCT).
In some patients with typical symptoms and involvement of four out of five central nervous system topographies, dissemination in time is no longer required for diagnosis.
Kappa free light chains can support cerebrospinal fluid assessment and may be used alongside or instead of oligoclonal bands in the diagnostic framework discussed during the session.
The central vein sign and paramagnetic rim lesions can help increase diagnostic specificity, particularly when differentiating MS from mimics.
These advanced MRI markers are not required in every patient and should be used selectively when additional diagnostic information is needed.
Additional considerations are required in older patients, pediatric cases and people with primary progressive Multiple Sclerosis.
In primary progressive MS, two spinal cord lesions may contribute to demonstrating dissemination in space.
The revised framework encourages clinicians to select the most appropriate diagnostic tests for each individual case rather than applying every available investigation routinely.