After studying this chapter, the student should be able to:
Explain the distinction between primary and secondary brain injury.
Define intracranial pressure (ICP) and cerebral perfusion pressure (CPP), and understand the relationship between the 2 pressures.
Discuss the Monro-Kellie doctrine and its implications for management of intracranial hypertension.
Understand the diagnosis of concussion, or postconcussive syndrome, and discuss return-to-play criteria for injured athletes.
Understand the clinical features of acute spinal cord injury (SCI), including spinal shock and neurogenic shock.
Traumatic brain injury (TBI) is a global health problem and one that has generated increasing public attention over the past several years. Overall, the most common cause of TBI in civilian populations is motor vehicle collision; falls constitute the second largest category, followed by self-inflicted injuries and assault. In the United States, approximately 1.4 million individuals sustain TBIs each year. Of those, approximately 235,000 require hospitalization, and 50,000 result in death. TBI can result in significant long-term motor, cognitive, and behavioral impairment; >3 million TBI survivors in the United States are living with chronic disabilities as a result of their injuries. Because traumatic injuries often affect patients who are young and otherwise healthy, it is a costly disease: The estimated annual costs of TBI, including lost productivity, exceed $76 billion.
Similarly, traumatic injury to the spinal cord can have devastating, life-long effects. Trauma is the leading cause of acute myelopathy in the United States, resulting in about 54 cases per 1 million people annually. The prevalence of spinal cord injury (SCI) in the United States is estimated at approximately 250,000 individuals. As with TBI, SCI often affects young adults: The average age of victims, according to the National Spinal Cord Injury Database, is 40.2 years. However, the rate of SCIs in the elderly has been increasing, largely related to falls. Unsurprisingly, the sequelae of SCI depend on the location and extent of the injury, with complete cervical cord lesions resulting in the most severe deficits. Unfortunately, this is not an uncommon scenario. Nationally, 30.1% of SCI patients at discharge demonstrate incomplete quadriplegia; 25.6% have complete paraplegia; 20.4% have complete quadriplegia; and 18.5% have incomplete paraplegia. Less than 1% of SCI patients recover full neurologic function at the time of hospital discharge.
Traumatic brain injury is a broad term used to describe the diverse pathologic changes that may occur when the cranium is subjected to external forces. The specific injuries sustained by an individual can vary widely depending on the mechanism of the insult; for example, the magnitude, duration, and orientation of the force applied to the cranium have a significant impact on the nature of the resulting lesion(s). Due to the heterogeneous nature of TBI, a variety of classification schemes have arisen. TBI can be classified according to mechanism of ...