Study objective: To determine the prevalence of abnormal computed tomography (CT) scans and define high-risk clinical variables in patients with mild head injury.
Design: Retrospective descriptive study of patients with Glasgow Coma Scale (GCS) scores of 13 or greater who presented to the emergency department with blunt head trauma and who underwent cranial CT.
Setting: Level I trauma center, university ED.
Results: During the 15-month study period, 1,448 patients underwent CT scanning for mild head injury. Abnormalities resulting from the trauma were found in 119 (8.2%), and 11 patients (.76%) required neurosurgical intervention. Patients with higher GCS scores had a greater chance of having a solitary CT abnormality (P = .004). Bicyclists and pedestrians struck by cars were more likely than others to sustain intracranial injury. High-risk clinical variables included the presence of cranial soft-tissue injury, a focal neurologic deficit, signs of basilar skull fracture and age older than 60 years. A strategy using those variables had a sensitivity of 91.6% and a specificity of 46.2% for detecting a CT abnormality. None of the patients missed by this strategy required medical or neurosurgical management for the CT finding.
Conclusion: Abnormalities on CT scans in patients with mild head trauma are fairly common, although the need for neurosurgical intervention is rare. Clinical decision rules can be used to identify those patients with more serious intracranial pathology. Such strategies should be validated prospectively in various ED settings.