Traumatic brain injury

Abstract

There is an increasing incidence of military traumatic brain injury (TBI), and similar injuries are seen in civilians in war zones or terrorist incidents. Indeed, blast-induced mild TBI has been referred to as the signature injury of the conflicts in Iraq and Afghanistan. Assessment involves schemes that are common in civilian practice but, in common with civilian TBI, takes little account of information available from modern imaging (particularly diffusion tensor magnetic resonance imaging) and emerging biomarkers. The efficient logistics of clinical care delivery in the field may have a role in optimizing outcome. Clinical care has much in common with civilian TBI, but intracranial pressure monitoring is not always available, and protocols need to be modified to take account of this. In addition, severe early oedema has led to increasing use of decompressive craniectomy, and blast TBI may be associated with a higher incidence of vasospasm and pseudoaneurysm formation. Visual and/or auditory deficits are common, and there is a significant risk of post-traumatic epilepsy. TBI is rarely an isolated finding in this setting, and persistent post-concussive symptoms are commonly associated with post-traumatic stress disorder and chronic pain, a constellation of findings that has been called the polytrauma clinical triad.

Figure 1.

Worldwide trends in terrorist explosive events from 1999 to 2006. Grey line, incidents; red line, deaths; blue line, injuries.

Figure 2.

TBI hospitalization rates in Operation Enduring Freedom as percentages of total injury rates (redrawn from [37]). All rates expressed as per 10 000 soldier-years. TBI classification by type is based on the Barell matrix [59].

Figure 3.

The ‘polytrauma clinical triad’ in OEF/OIF veterans: incidence of post traumatic stress disorder (PTSD), persistent post-concussive systems (PPCS), and chronic pain in 340 veterans of Operation Enduring Freedom and Operation Iraqi Freedom evaluated at a polytrauma network site in the USA. Only 12 of the 340 veterans were free of all three symptoms. Of the remainder, very few had only symptoms from one of the components of the triad, and 42% had symptoms referable to all three components of the triad. Figure redrawn from data in [90].