Introduction: The present study aims to explore the factors influencing spinal clinically isolated syndrome (CIS) conversion to multiple sclerosis (MS).
Material and methods: Sixty-one patients diagnosed with spinal CIS from January 2010 to November 2020 were divided into a non-progressing (CIS) group with 27 patients, and a conversion to MS (MS) group with 34 patients, based on whether they had converted to MS. The clinical presentation at onset, the Expanded Disability Status Scale (EDSS) before and after steroid therapy, the results of magnetic resonance imaging (MRI), the oligoclonal bands in cerebrospinal fluid (CSF-OCB), and the evoked potentials (EPs) were retrospectively analysed.
Results: Differences in gender and age were not statistically significant between the MS and CIS groups. The median time to relapse was 12 months for the MS group, with an upper quartile of 23.7 months, and 91.2% of patients relapsed within three years. In univariate analysis, patients with CIS beginning with sensory symptoms had a lower level of progression to MS (OR = 0.311). Patients with Kurtzke Functional Systems Scores (FSSs) of pyramidal functions ≥ 2 (OR = 3.582) and positive CSF-OCB (OR = 5.208) quickly progressed to MS. There was no significant difference between the two groups in terms of spinal cord lesions < 3 vertebral segments, gadolinium enhancing lesions, or abnormal EPs. The difference in the EDSS scores before and after steroid therapy was higher in the MS group than in the CIS group (p = 0.001). Differences of ≥ 1.5 in the EDSS scores before and after steroid therapy were risk factors for CIS conversion to MS (OR = 9.333).
Conclusions: Patients with spinal CIS with pure sensory abnormalities at onset were less likely to convert to MS (OR = 0.311), and the risk factors were, in order of risk, the difference in EDSS score before and after steroid therapy (≥ 1.5; OR = 9.333), positive CSF-OCB (OR = 5.208), and those with an FSS of the pyramidal functions score ≥ 2; OR = 3.582). The present study serves as a simple 'first step'. Any potential predictors identified should be validated via future prospective studies.
Keywords: CSF-OCB; EDSS before and after steroid therapy; multiple sclerosis; spinal clinically isolated syndrome.