Validity and prognostic utility of clinical assessment scale for autoimmune encephalitis (CASE) score in children with autoimmune encephalitis

Abstract

Introduction: The clinical assessment scale for autoimmune encephalitis (CASE) is a recently developed and validated scale to rate the severity of autoimmune encephalitis (AE) in adults. But it is yet to be validated in pediatric AE cases.

Methods: In a prospective observational study, we determined the validity and prognostic utility of CASE in the pediatric population with a diagnosis of probable or definite AE. We also determined clinical, neuroimaging, or laboratory-based prognostic factors for favorable clinical outcomes at 3 months after presentation. We used weighted kappa statistics and the intra-class correlation coefficient of individual item scores and total scores for determining inter-observer and intra-observer reliability respectively.

Results: We enrolled a total of 54 patients (28 girls, probable [45%] or definite [55%] AE). Functional status score (FSS), CASE score, and other scores showed significant improvement at the time of discharge and 3-months, as compared to baseline (p < 0.0001). The intra-observer and interobserver reliability of the total scores was excellent (k = 0.94 and 0.95 respectively). CASE was also found to have good internal consistency (Cronbach-α = 0.83). The corrected item-total correlations of all items were >0.40. The correlation between the total CASE score and FSS score at admission, at discharge, and at 3 months was strong (r = 0.90, 0.92, and 0.94, p < 0.001). In multivariate analysis, only seropositivity or definite AE and CASE score at baseline was found to be significant predictive factors for functional status at 3 months (p = 0.03, 0.01).

Conclusion: CASE score can be used for monitoring the severity of pediatric AE patients. It also has prognostic usefulness for predicting functional independence on follow-up.

Keywords: Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis; Autoimmune encephalitis; Autoimmune neurology; Clinical assessment scale for autoimmune encephalitis (CASE) score; Prognosis.