Neurochemical Pathomechanisms in Traumatic Brain Injury

Traumatic brain injury (TBI) has a significant impact on a patient’s cognition, memory, personality, and movement. Understanding the cellular and molecular injuries is of paramount importance in the diagnosis and management of TBI. One must understand the difference between primary and secondary brain injury and the underlying physiology behind each one to effectively care for patients who have suffered a TBI. Although neurosurgeons often focus on the injury that can be seen on imaging, recognizing the underlying molecular and cellular changes associated with these injuries is key. These can occur as a result of the primary injury or as part of a secondary injury. With a primary injury, there is focal or diffuse injury involving neurons, glial cells, or microvasculature, which often leads to clinical symptoms. Secondary injury is often related to hypoxia, ischemia, development of edema, or excitotoxicity. Any of these mechanisms can lead to cell death by way of apoptosis or necrosis. In this chapter, we dive into the molecular and cellular basis for injury in TBI from the perspective of both primary and secondary brain injury.