Acute concussion symptom severity and delayed symptom resolution.

BACKGROUND AND OBJECTIVES Up to 30% of children who have concussion initially evaluated in the emergency department (ED) display delayed symptom resolution (DSR). Greater initial symptom severity may be an easily quantifiable predictor of DSR. We hypothesized that greater symptom severity immediately after injury increases the risk for DSR. METHODS We conducted a prospective longitudinal cohort study of children 8 to 18 years old presenting to the ED with concussion. Acute symptom severity was assessed using a graded symptom inventory. Presence of DSR was assessed 1 month later. Graded symptom inventory scores were tested for association with DSR by sensitivity analysis. We conducted a similar analysis for post-concussion syndrome (PCS) as defined by the International Statistical Classification of Diseases and Related Health Problems, 10th revision. Potential symptoms characteristic of DSR were explored by using hierarchical cluster analysis. RESULTS We enrolled 234 subjects; 179 (76%) completed follow-up. Thirty-eight subjects (21%) experienced DSR. Initial symptom severity was not significantly associated with DSR 1 month after concussion. A total of 22 subjects (12%) had PCS. Scores >10 (possible range, 0-28) were associated with an increased risk for PCS (RR, 3.1; 95% confidence interval 1.2-8.0). Three of 6 of the most characteristic symptoms of DSR were also most characteristic of early symptom resolution. However, cognitive symptoms were more characteristic of subjects reporting DSR. CONCLUSIONS Greater symptom severity measured at ED presentation does not predict DSR but is associated with PCS. Risk stratification therefore depends on how the persistent symptoms are defined. Cognitive symptoms may warrant particular attention in future study. Follow-up is recommended for all patients after ED evaluation of concussion to monitor for DSR.