Nasr, Zahra

Background: Epstein–Barr virus (EBV) is a key environmental risk factor for multiple sclerosis (MS), and tonsils and adenoids serve as a primary viral reservoir. This study investigates the potential role of adenotonsillectomy in pediatric-onset multiple sclerosis (POMS) risk and relapse rate. Objectives: POMS participants and controls were recruited from 16 pediatric MS clinics between 1 November 2011 and 1 July 2017. Clinical and demographic information, including history of adenotonsillectomy, EBV serostatus, and HLA-DRB1*15:01:01 status, were collected. Multivariable logistic regression assessed the association between adenotonsillectomy and MS risk. In addition, negative binomial regression offset by follow-up time was used to assess the relationship between adenotonsillectomy and relapse rate in POMS participants with available follow-up data. Results: The case-control analysis included 359 POMS participants and 560 pediatric controls. Individuals with a history of adenotonsillectomy had a 63% increased odds of MS (adjusted odds ratio (OR) = 1.63, 95% confidence interval (CI) = 1.01–2.64, p = 0.046). Among the 239 POMS participants with available follow-up data, adenotonsillectomy was associated with a twofold increase in annualized relapse rate (adjusted incidence rate ratio (IRR) = 2.00, 95% CI = 1.15–3.48, p = 0.013). Conclusions: Prior adenotonsillectomy was associated with increased risk of MS and greater relapse rate in pediatric patients, suggesting a potential interplay between EBV, immune regulation, and MS pathogenesis.

AbstractObjectiveMultiple Sclerosis (MS) is often accompanied by myelopathy, which may be associated with progressive worsening. A specific finding of MS‐associated myelopathy is McArdle sign, wherein neck flexion is associated with prominent increased limb weakness relative to that detected with neck extension. In this study, we characterized neuromotor control properties of finger extensors in association with the McArdle sign.MethodsA custom‐built device was utilized to monitor torque production of the wrist extensors with simultaneous recording of surface electromyography of the extensor digitorum. The electromyography was decomposed and analyzed via both linear and nominal regressions.ResultsLinear regressions demonstrated a strong difference between groups for MS from healthy controls and other myelopathies for motor unit action potential amplitude and average firing rate (p < 0.001). Further, linear regression demonstrated good correlations of neuromotor variables to mechanical torque output (0.24 ≤ R2 ≤ 0.76). Nominal regression distinguished MS from healthy controls with an AUC of 0.87, specificity of 0.97, and sensitivity of 0.64. Nominal regression of MS from other myelopathies demonstrated an AUC of 0.88, specificity of 0.85, and sensitivity of 0.79.InterpretationThese data demonstrate the neuromotor control factors that largely determine muscle force production change with the observation of McArdle sign; these neuromotor control factors can differentiate MS from both healthy controls and other myelopathy conditions.