Acute hemorrhage appears hyperdense on computed tomography (CT) scans, with the shape and location of hemorrhage suggesting the underlying pathology. Epidural hematomas are classically lentiform (lens shaped) because of their relationship to arterial injury, with the higher pressure compressing the brain parenchyma (Fig. 73.2). Subdural hematomas are more commonly crescent shaped, with blood from torn veins tracking along the surface of the brain beneath the dura mater (Fig. 73.3). Intraparenchymal hemorrhage can exist as a discrete hematoma or as multiple smaller foci throughout a contused area of brain (Fig. 73.4). In addition to focal areas of hemorrhage, cerebral contusions typically involve cerebral edema, which may progress markedly over a period of several days. Skull fractures may be seen on plain radiographs, but more important is the potential for injury to the underlying brain parenchyma or the existence of intracranial hemorrhage (Fig. 73.5). Subarachnoid hemorrhage appears as hyperdensities within the ventricles, along the falx and tentorium, and around the circle of Willis (Fig. 73.6). One of the most elusive diagnoses is diffuse axonal injury, in which the findings on CT are often much less impressive than the degree of obtundation. Small, punctate hemorrhages along the gray-white interface at the cortical periphery suggest this diagnosis, although the initial scan may be completely normal.

Fig. 73.2 A, Normal head computed tomography (CT) scan at the same level as B. B, Bilateral epidural hematomas on a head CT scan.

Fig. 73.3 A, Normal head computed tomography (CT) scan at the same level as B. B, Large subdural hematoma with a midline shift and compression of the ventricles on a head CT scan.

Fig. 73.4 A, Plain film showing multiple metallic fragments from a shotgun blast involving the eye socket. B, Head computed tomography scan of the same patient showing intracerebral hemorrhage.

Fig. 73.5 Depressed skull fracture with intracerebral air on a head computed tomography scan.

Fig. 73.6 Traumatic subarachnoid hemorrhage on a head computed tomography scan.

Other modalities used to diagnose TBI include magnetic resonance imaging (MRI), functional imaging, brain acoustic monitoring, and bispectral electroencephalography. MRI is superior to CT in identifying cerebral edema and diffuse axonal injury. In addition, analysis sequences allow sensitive detection of acute hemorrhage, particularly in the brainstem and posterior fossa, where CT is less sensitive. However, application of MRI in the management of TBI has been limited because of the lack of uniform availability, the increased time needed for administration and patient isolation during the procedure, and the added challenges of resuscitation and ventilator management within the strong magnetic field. For this reason, MRI is used more commonly in the subacute or chronic phases or in patients whose signs and symptoms are not well explained by the findings on CT. Functional imaging with positron emission tomography, single-photon emission CT, xenon-enhanced CT, and MRI-based imaging may also be useful later in a patient’s course to assess cerebral blood flow and oxygenation, which has prognostic value in predicting functional outcomes but is unlikely to be useful in the acute resuscitation and management of patients with TBI in the ED. Finally, newer modalities such as brain acoustic monitoring and bispectral electroencephalography appear to be useful in the detection of TBI because of prognostic ability rivaling that of CT and the ability to provide continuous data. Future investigations should focus on the utility of these modalities in the ED setting.

Treatment

General

The approach to patients with suspected TBI is directed toward reversal of physiologic derangements and avoidance of secondary insults, early triage to a facility with appropriate resources, and expedited neurosurgical care.

Prehospital Management

Half of all patients who die of TBI do so within the first few hours after their injury.

Prehospital assessment of patients with TBI should include rapid airway evaluation, continuous pulse oxygen saturation monitoring, frequent measurement of blood pressure, determination of GCS scores, and pupillary evaluation.¹ Prehospital intubation should be avoided in patients who are spontaneously breathing and maintaining greater than 90% oxygen saturation.² Prehospital airway management may be necessary in patients with a GCS score lower than 9 or those unable to maintain oxygen saturation greater than 90% with supplemental oxygen. If prehospital endotracheal intubation is performed, confirmation of placement should be done with auscultation and end-tidal capnography. Even mild hyperventilation should be avoided in all cases with the exception of patients who have evidence of herniation or acute neurologic deterioration. Hypotension should be treated with isotonic fluids, although protocols involving prehospital hypertonic saline administration are reasonable for patients with GCS scores lower than 9. Rapid transport is a priority, ideally to a facility with immediately available imaging and neurosurgical care.