By Ulrike W. Kaunzner, MD
Assistant Professor of Clinical Neurology, Weill Cornell Medical College
SYNOPSIS: A recent prospective study showed that including the optic nerve as an additional topographic area in multiple sclerosis diagnostic decision-making improves sensitivity and diagnostic performance compared to the McDonald 2017 criteria: 92.5% sensitivity of the modified criteria vs. 88.2% of the current criteria.
SOURCE: Vidal-Jordana A, Rovira A, Calderon W, et al. Adding the optic nerve in multiple sclerosis diagnostic criteria. Neurology 2024;102:e200805.
Optic neuritis (ON), inflammation of the optic nerve, is one of the most common manifestations of multiple sclerosis (MS). ON presents as the initial symptom in about 30% of newly diagnosed MS patients and occurs in up to 70% of MS patients throughout their disease course. Despite being an important clinical presentation in MS patients, ON is not included in the last McDonald criteria from 2017 for establishing dissemination of lesions in space.
Investigators from five different MAGNIMS (European Magnetic Resonance Imaging for Multiple Sclerosis) sites have evaluated the value of ON and associated imaging findings in a prospective study. The overall goal of Vidal-Jordana et al was to determine the effect of including optic nerve lesions in the diagnostic McDonald criteria, and to evaluate the sensitivity of three tests in detecting optic nerve injury: optic nerve magnetic resonance imaging (MRI), optical coherence tomography (OCT), and visual evoked potentials (VEP).
They evaluated 157 patients with a first clinical event or clinical isolated syndrome (CIS) indicative of MS. Out of this cohort, 60 patients (60/157, 38.2%) presented with ON, which was confirmed with at least two of three tests: MRI, OCT, or VEP. During the 28 months of follow-up time, 71% of patients were diagnosed with MS by a subsequent clinical or imaging event. Among the different optic nerve testing modalities, 40% of patients had an abnormal optic nerve MRI, 33% of patients had changes in their OCT retinal nerve fiber layer, 18% of patients had changes in their OCT ganglion cell and inner plexiform layer, and 38% of patients had a finding on VEP.
Allowing ON assessment to fulfill dissemination in space requirements for the McDonald 2017 criteria increased sensitivity for MS minimally (91.8% vs. 88.2%) and decreased specificity slightly (71.1% vs. 82.2%). Sensitivity for predicting a new T2 or second relapse was higher with ON assessment (87.7% vs. 80.8%), and specificity of including ON assessment was similarly low (39.0% with ON assessment, 43.9% without ON assessment). In addition, it was suggested that it is not necessary to assess the presence of optic nerve lesions in all patients. In those patients for whom an MS diagnosis using the current McDonald criteria is not possible, the optic nerve should be assessed.
COMMENTARY
This is an important study, since the addition of the optic nerve to the diagnostic MS criteria has been a point of discussion for a long time. Prior studies have indicated that adding the optic nerve may have a diagnostic benefit, and some of these studies have been using objective measures. The current study is prospective and assesses the currently available modalities for evaluating the optic nerve. The addition of the optic nerve as a fifth area improves sensitivity and diagnostic performance compared to the McDonald 2017 criteria: 92.5% sensitivity of the modified criteria vs. 88.2% of the current 2017 criteria.
It is important to highlight that ON can be the result of other diseases, such as rheumatological disorders, or other neuro-inflammatory diseases, such as neuromyelitis optica (NMO) or anti-myelin oligodendrocyte glycoprotein (MOG) disorders. The differential diagnoses are broad and need to be thoroughly evaluated. However, the inclusion of ON into the new diagnostic MS criteria could improve the ability to detect cases of MS early and could facilitate early treatment decisions. The McDonald Criteria committee had its last meeting in December 2023, and it will be notable to see if the committee recommends that the optic nerve be included as an additional structure for dissemination in space.
