Development and Validation of a Comprehensive Acute Encephalitis Syndrome Severity Score in Children with Acute Encephalitis Syndrome

Background and aims: No comprehensive scoring system is currently available to predict functional neurological outcomes in children with acute encephalitis syndrome (AES).We therefore developed and validated a score specifically tailored for these children. Patients and methods:We developed the comprehensive acute encephalitis syndrome severity score (CAESS), which consists of five items Glasgow Coma Scale (GCS), focal deficit, status epilepticus, features of raised intracranial pressure (ICP), and pediatric logistic organ dysfunction-2 (PELOD-2) score selected after reviewing published literature.The content validity was assessed through the content validity index (CVI) and content validity ratio (CVR).The model's fit was examined using confirmatory factor analysis (CFA).Functional outcome was determined as good or poor at 6 months, based on the pediatric cerebral performance category (PCPC) score.Construct validity was established by correlating CAESS scores with the functional status scale (FSS), the intelligence quotient (IQ), and the gross motor function measure (GMFM-88).Results: Comprehensive acute encephalitis syndrome severity score was evaluated in 159 children with AES; 114 (71%) had favorable outcomes at 6 months.Inter-rater reliability was good to excellent across items intraclass correlation coefficient (ICC) range 0.82-0.94;kappa 0.80-0.92.Internal consistency was good (Cronbach's alpha = 0.80).Content validity was also good (I-CVI 0.9-1.0;CVR 0.8-1.0).Confirmatory factor analysis supported a unidimensional structure, demonstrating good model fit Tucker-Lewis index (TLI) = 0.98, comparative fit index (CFI) = 0.99, and root mean square error of approximation (RMSEA) = 0.05.Comprehensive acute encephalitis syndrome severity score demonstrated strong discriminant validity (AUC = 0.91).At a cut-off 6, CAESS showed sensitivity of 88.9%, specificity of 84.2%, and a Youden index of 0.73.Strong correlations were observed with FSS (r = 0.82), PCPC (r = 0.84), GMFM-88 (r = -0.83),IQ (r = -0.71),and pediatric quality of life inventory (PedsQL TM ) score (r = -0.74). Conclusion:The CAESS score may be a valid and reliable tool for predicting functional outcomes in children with acute encephalitis syndrome.However, given the absence of internal split-sample validation and external validation in an independent population, further prospective studies with robust internal validation and external replication are required before it can be recommended for routine clinical use.