Association of Patterns of Mild Traumatic Brain Injury with Neurologic Deterioration: Experience at a Level I Trauma Center

Introduction: There are about 2.5 million emergency room visits for traumatic brain injury (TBI) every year and 75%-95% of all TBI patients have mild TBI. Previous studies have suggested that a large proportion of mild TBI patients can be treated in a non-aggressive manner, but they have not differentiated mild TBI as per radiological patterns to help in the selection of these patients. Our study aimed to identify different patterns of mild TBI to determine if certain injuries make patients more prone to neurologic worsening than others, and thus require more intensive monitoring. We also studied the factors associated with neurologic deterioration. Methods: We conducted a retrospective study using an institutional trauma database to identify TBI patients between the years of 2015 and 2016 with admission Glasgow Coma Score (GCS) of 13 to 15, through chart review by the investigators. Radiological and neurological worsening was determined through computed tomography (CT) scan results, GCS scores, and the requirement for neurosurgical intervention. We identified the prevalence of demographic characteristics, radiological patterns, and risk factors. We studied neurologic deterioration (decline in GCS to less than 13 at 48 hours or earlier after admission) and surgical intervention among patients with different radiological patterns of TBI. We further studied the cohort of isolated subdural hematoma (SDH) patients requiring surgery to evaluate the associated risk factors. Results: Out of 374 patients with mild TBI (mean age was 63 years), 59% were male, 77% were Caucasian, the median GCS was 15, majority of patients had isolated SDH (45%), and mixed pattern of hemorrhage (39%); the use of antiplatelet (33%) was the most commonly identified risk factors. Overall 7% of patients were found to have neurologic deterioration (GCS to less than 13) and 9% required surgical intervention at 48 hours or earlier after admission. The most common pattern of TBI requiring surgical intervention was isolated SDH (85%). Among the cohort of patients with isolated SDH, 17% required surgical intervention and 69% of those isolated SDH patients requiring surgery had neurologic deterioration. The most common risk factor in isolated SDH patients requiring surgery was antiplatelet use (34%), anticoagulant use (20%), alcohol abuse (17%), severe renal failure (17%), and thrombocytopenia (7%). Mean size of SDH in patients requiring surgery was 1.6 cm with 0.8 cm of midline shift. Conclusion: This study identified the pattern of mild TBI associated with neurological worsening at our Level I Trauma Center. Among patients with mild TBI, SDH patients seem to be at highest risk for deterioration and requirement for surgery. If these results can be externally validated through a multi-center study, these patients could be selectively identified for aggressive monitoring in the intensive care unit (ICU) and repeat CT scans.