This chapter will examine traumatic brain injury (TBI) in the contexts of rehabilitation outcomes, systemic medical manifestations, and complications. The natural history of TBI will be reviewed in addition to multiple factors that may affect outcome. Additionally appropriate outcome measures will be analyzed. Common medical complications that occur during the rehabilitation of the TBI population will also be discussed. Finally, common issues in the medical management of TBI, including difficulties in diagnosis, provision of care, and research issues, will be reviewed.
The natural history of TBI is broadly characterized by an initial period of impaired consciousness, followed by a period of post-traumatic confusion/amnesia and finally a period of recovery of function. Most patients with mild traumatic brain injury recover within weeks to months without intervention, but approximately 15% of patients may still have symptoms at 1 year.1 Prognostic indicators of TBI include patient demographics (age, gender, prior TBI), initial injury details (initial severity, coma length, Glasgow Coma Scale [GCS], injury etiology), and rehabilitation course (length, timing, and intensity of rehabilitation). Outcome measures are divided into several domains, such as movement, cognition, and function.
PATIENT FACTORS AFFECTING OUTCOME
Studies have demonstrated that older patients have worse outcomes than younger patients, likely secondary to decreased capacity for neuroplasticity in the aged brain and increased number of comorbidities (e.g., cardiovascular to cerebrovascular disease). Additionally, older TBI victims generally have been found to have higher rates of mortality.2 Older age at the time of injury has been shown to be associated with poorer performance in multiple cognitive domains.).3 Some studies also suggest that patients afflicted with TBI are more likely to develop neurodegenerative disorders such as Alzheimer's disease.4 Mild TBI patients afflicted with post-traumatic stress disorder (PTSD) or depression have been found to have higher rates of comorbidities with related physical health problems.5 An example includes soldiers deployed in Iraq with PTSD and depression; when followed for 3 to 4 months after return home, this cohort reported higher rates of physical health problems (self-report of poor general health, missed workdays, and headache) for 3 to 4 months. When adjusted for covariates, interestingly only headache remained statistically significant.
Hypoxia and hypotension are independently associated with significant increases in morbidity and mortality from severe head injury. Hypotension is profoundly detrimental, occurring in 34.6% of these patients, and is associated with a 150% increase in mortality.6 Severe trauma to an extracranial organ system is the primary etiology of hypotension-induced brain injury in this population. Hypoxia and hypotension are common and lead to detrimental secondary brain insults in patients with direct traumatic brain injury. Hypotension in particular was found to be a major determinant of outcome in severe TBI.
Patients involved in motor vehicle accidents (MVAs) typically ...