Prevalence of Orthostatic Autonomic Dysregulation in Pediatric Concussion.

Importance: Pediatric concussion can affect the autonomic nervous system. Understanding the prevalence and characteristics of physiological autonomic dysregulation (AD) and symptom provocation following concussion is crucial for optimizing recovery and developing targeted interventions. Objectives: To determine the prevalence of AD and symptom provocation upon postural change and to (1) explore the overlap between AD and symptom provocation, (2) apply adult orthostatic tachycardia criteria (heart rate [HR] ≥30 bpm) to this pediatric population, (3) explore associations of demographic and injury characteristics with AD and symptom provocation, and (4) characterize AD presentation and identify the predominant orthostatic sign. Design, Setting, and Participants: This retrospective cohort study used electronic medical record review of clinical data at tertiary care concussion clinics that operate as a learning health system in Canada. Patients aged 5 to younger than 18 years who presented to those clinics within 45 days of a diagnosed concussion between August 2022 and January 2024 were included. Analysis was conducted from April to October 2024. Exposure: Diagnosis of concussion. Main Outcomes and Measures: Primary outcomes were AD presence (defined as the presence of either a decrease in systolic BP [≥20 mm Hg], decrease in diastolic BP [≥10 mm Hg], or increase in HR [≥40 bpm]), and symptom provocation (new or worsening). HR, blood pressure (BP), and symptoms were measured after a 2-minute supine rest and 1 minute of unsupported standing. Results: Of 764 eligible patients, 451 (231 female [51.22%]; 129 [28.60%] aged 5-11 years and 322 [71.40%] aged 12 to <18 years) were included; objective AD was identified in 45 patients (9.98%; 95% CI, 7.54%-13.09%), primarily by HR changes (22 of 45 patients [48.89%]). When applying adult tachycardia criteria, AD prevalence was 23.73% (95% CI, 20.03%-27.88%). Orthostatic symptom provocation occurred in 103 of 445 patients (23.15%; 95% CI, 19.47%-27.28%). Among 134 patients with either AD or symptom provocation, 12 (8.96%) exhibited both. Patients with AD had higher rates of neurodevelopmental disorders than patients without AD (15 of 45 patients [33.33%] vs 75 of 406 patients [18.47%]; P = .02), while symptom provocation was associated with female sex (63 of 103 patients [61.17%] vs 166 of 342 patients [48.54%]; P = .03), preexisting mental health disorders (28 of 103 patients [27.18%] vs 45 of 342 patients [13.16%]; P < .001), higher concussion symptom burden (median [IQR] symptom intensity score, 46.00 [16.00-67.00] vs 21.00 [6.00-46.00]; P < .001), and status of posttraumatic amnesia at injury (22 of 103 patients with posttraumatic amnesia [22.68%] vs 63 of 342 patients without [18.92%]; P = .009). Conclusions and Relevance: In this cohort study of children and adolescents with concussion, approximately 1 in 10 exhibited AD and 1 in 4 exhibited symptom provocation. The observed low concordance between physiological AD and symptom provocation, along with their distinct clinical profiles, might suggest these represent separate phenomena in pediatric concussion; future research should explore whether incorporating both measures into clinical assessments enhances understanding of concussion and informs targeted interventions to optimize recovery.