Antistreptolysin O Titers, Symptom Burden, and Multidimesional Correlates in Children with Suspected Streptococcal-Associated Neuropsychiatric Presentations: An Observational Cohort Study

Pediatric acute-onset neuropsychiatric presentations occurring in the context of prior streptococcal exposure remain clinically important but diagnostically inconclusive, particularly at the interface between PANS and PANDAS. This observational cohort study examined whether serological, psychometric, and electroencephalographic findings converged within a clinically selected pediatric psychiatric sample. Children and adolescents presenting with acute-onset or abruptly worsened neuropsychiatric symptoms and a history suggestive of prior streptococcal exposure were recruited over a 12-month period through inpatient and outpatient child psychiatric services. Of 154 screened cases, 96 with analyzable baseline data were retained and stratified by ASO status. Symptom burden was quantified using the Pediatric Acute-onset Neuropsychiatric Syndrome 31-Item Symptom Rating Scale (PANS-31) and examined in relation to ASO titers, time since the last reported streptococcal infection, EEG findings, and selected developmental and clinical-history variables. Higher ASO values were strongly associated with greater PANS-31 symptom burden, whereas a shorter interval since the last reported streptococcal infection was associated with both higher ASO titers and higher symptom scores. PANS-31 showed good total-scale internal consistency and meaningful domain-level convergence with age-appropriate CSI-4 and ASI-4 domains. These findings do not support a disease-specific biomarker model, but suggest that higher antistreptococcal serology, more recent streptococcal exposure, and greater neuropsychiatric burden may cluster within a more clearly expressed clinical phenotype in a real-world psychiatric environment.