Traumatic brain injury is primary and secondary. Primary injury is due to the direct impact of the trauma, while secondary is due to hypoxia leading to a cascade of events set off by ischemia/reperfusion. The focus of management is prevention and treatment of secondary injury.
Severity of brain injury is assessed both clinically and radiologically. A Glasgow Coma Scale (normal range 3-15) of 13 to 15 is considered mild brain injury, 9 to 12 moderate, and 3 to 8 severe brain injury. The Marshall score using head computed tomography (CT) is also used to predict severity.
The CT scan is the fastest and most widely used initial imaging modality available for skull and brain parenchymal lesions. CT angiography and perfusion studies further help to characterize vascular/perfusion deficits.
Preventing and treating hypoxia and hypotension to prevent hypoxia and adequate perfusion is of utmost importance.
Patients with risk factors for spinal cord injury should be handled with care in the field and their spine stabilized with rigid cervical collars on a board with straps.
TRAUMATIC BRAIN INJURY
Traumatic brain injury (TBI) is the leading cause of death in the early decades of life. The estimated number of deaths is 50,000 with 40% of survivors with disability after the injury.1 The estimated incidence is 17.5 to 24.6 deaths per 100,000 population.2,3 Men are more likely to suffer TBI compared to women and the majority of injuries are due to falls.
In TBI injuries are classified as primary and secondary. Primary injury (Table 50–1) happens at the time of impact and secondary injury occurs later due to oxygen deprivation to the brain and the cascade of events set off by ischemia and reperfusion leading to further injury. The target of management focuses more on prevention and treatment of secondary brain injury.
++ Table Graphic Jump Location Table 50–1Primary brain injury. ||Download (.pdf) Table 50–1 Primary brain injury.
|Primary Injury (Direct Impact) |
Depressed skull fracture
|Diffuse axonal injury |
In primary injury, depending upon the mechanism of trauma, fractures of the skull can be open or closed, depressed or nondepressed, and linear or comminuted. Most of these fractures are evident on clinical exam but radiography is required for accurate diagnosis. Both plain skull X-ray and computed tomography (CT) scan can be used for skull fractures, although plain radiologic films are better for linear calvarial fractures tangential to the axial plane. Multislice CT, alternatively, can delineate skull fractures better than plain CT scans. Fractures can result in neurologic deficits related to underlying brain injury, cerebral spinal fluid (CSF) leak (suggesting dural laceration) such as otorrhea or rhinorrhea, pituitary gland shearing injuries, and cranial nerve (CN) injuries. Depending on ...