Mild traumatic brain injury (MTBI) is a common result of falls and motor vehicle crashes. A few patients with MTBI have a serious injury, while many more have some neurologic symptoms for days to months after the injury. The American Congress of Rehabilitation Medicine has defined MTBI as requiring at least one of the following factors: (1) a period of loss of consciousness (LOC) of less than 30 minutes and a Glasgow Coma Scale (GCS) score of 13 to 15 after resolution of LOC; (2) any memory loss of the event immediately before or after the accident that continues for no more than 24 hours; or (3) any altered mental status at the time of the accident. This definition of MTBI is broad and contributes to the difficulty of interpreting the MTBI literature. Because the GCS score is commonly used to grade brain-injury severity, a diagnosis of MTBI usually means a post-trauma score of 13 or greater. Probably the best way to estimate the severity of head trauma is to measure serial GCS scores hourly over three to four hours; a decline in GCS indicates a patient who may need neurosurgical intervention. The challenge of early identification of the patient requiring neurosurgical intervention remains. Jagoda and associates developed a clinical policy for neuroimaging and decision-making for patients presenting with MTBI in emergency departments.

Concentrating on patients over age 15 years who presented with a GCS of 15 within 24 hours after blunt trauma, a literature search was used to answer these questions: (1) is there a role for plain radiographs? (2) which patients should have an early noncontrast computed tomographic (CT) scan of the head? and (3) can patients with a normal head CT scan be discharged safely?

Although radiographic demonstration of a skull fracture increases the likelihood of an intracranial lesion, it has a low sensitivity for the diagnosis of intracranial hemorrhage, giving plain radiographs limited clinical value. Based on the data, skull films are not recommended in the evaluation of MTBI.

Based on multiple studies of the use of non-contrast CT scanning to evaluate patients with MTBI, a head CT scan is not indicated for patients who do not have headache, vomiting, age greater than 60 years, drug or alcohol intoxication, deficits in short-term memory, physical evidence of trauma above the clavicle, or seizure.

Literature examining the post-trauma natural history of MTBIs supports the recommendation that patients who present six hours after injury and have a normal clinical evaluation and a normal CT scan can safely be discharged from the emergency department. Patients can be discharged earlier if there will be a responsible person present to observe them.

The authors conclude that their recommendations about management of patients with MTBI, as noted in the accompanying table, are somewhat limited because of inconsistencies of definitions and outcome measurements. More studies are needed to look at how to recognize potentially detrimental postconcussive syndrome and determine the proper role of magnetic resonance imaging and other neuroimaging modalities.