Page 13 - DECISION-MAKING IN SEVERE TRAUMATIC BRAIN INJURY PATIENT OUTCOME, HOSPITAL COSTS, AND RESEARCH PRACTICE

Worldwide, an estimated fifty to sixty-nine million people a year sustain a traumatic 1 brain injury (TBI). 1,2 The all-cause, all-severity global yearly incidence of TBI is
estimated at 939 cases per 100,000 people, of which an estimated 5.48 million people (73/100,000) suffer severe TBI (s-TBI). 2 In Europe, there are an estimated 2.5 million
new cases of TBI each year. 1 Numbers from The Netherlands show almost 35.000 annual emergency department visits. 3 The most common causes of TBI are road traffic accidents and falls. 1 In recent years, the number of falls is increasing, especially in the elderly. 1,3-7 The medical consequences of TBI are substantial and range from symptoms like headache and fatigue to severe disabilities and even death. 7-11 The high occurrence and acute and chronic consequences of TBI contribute to the substantial healthcare- and socioeconomic burden and cause harm to patients, proxies and societies. 1
Diagnosis and classification
TBI is defined as ‘an alteration in brain function, or other evidence of brain pathology, caused by an external force’. 12 It can be diagnosed and classified by using trauma mechanism, clinical severity, presence of structural damage on neuroimaging, and prognostic risk. 13 Clinical severity is the most frequently used classification method and usually indicated by the level of consciousness as represented by the Glasgow Coma Scale. 1,14,15 The combined sum score (3 to 15) of the eye (1-4), verbal (1-5) and motor (1-6) components is used to categorize patients in three severity groups: severe TBI (GCS 3-8), moderate TBI (GCS 9-12), and mild TBI (GCS 13-15). These severity groups account for an estimated 8%, 11% and 81% of all TBI patients respectively. 2
Although these TBI severity groups are frequently used in clinical practice and research, the clinical presentation of patients within these categories remains highly variable. 16 Variability in TBI is very common and complicates diagnosis, classification and clinical practice. It is the result of differences in patient characteristics, or particulars of trauma, such as type, intensity, direction, and duration of the external forces, but also by uncertainties related to the complexity of the brain. 1,13 Many aspects of the pathophysiological mechanisms of TBI are still unknown. The mechanism of TBI can be best understood by distinguishing primary and secondary brain injury. 1,13,17
Primary and secondary brain injury
Primary brain injury occurs at the time of the initial injury and causes diffuse or localized brain tissue destruction and areas of intracerebral or extracerebral haemorrhage. Primary injury is irreversible by definition and therefore unsuitable
General introduction
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