SUMMARY: Moderate TBI materially increases the severity of and death-rate from other injuries. TBI interferes with the body's adjustment to hemorrhage, and is thereby exacerbated.
Head injury is the most important single factor contributing to mortality and morbidity after accidental injury (1).
Although only one-fifth of trauma patients who reach hospital have suffered Traumatic Brain Injury (TBI), it is one of the injuries in nearly two-thirds of those who subsequently die (2).
Practice PointTraumatic Brain Injury interferes with the healing of other injuries |
Obviously some of these subsequent deaths are caused by severe TBI alone. However, even moderate TBI, when combined with non-brain injuries, has a detrimental effect on survival.
Again, because this cumulative effect is greatest in the 26-40 year age group, it may be that alcohol and recreational drugs are part of the explanation.
Nevertheless, there is growing empirical evidence that TBI also impairs the body's response to other injuries.
In particular, TBI has an adverse effect on the physiological processes that compensate after acute hemorrhage (3, 4). By unknown means, neurotrauma impairs the body's mechanisms for maintaining blood pressure and blood flow to vital organs.
In consequence, hemorrhagic shock combined with TBI causes a secondary injury to the brain: even when blood and fluid loss has been corrected, delivery and use of oxygen by the brain remains impaired.
Practice PointThe severity and prognosis of Traumatic Brain Injury are worsened by bodily hemorrhage |
This empirical research is in its early stages, and it is not yet known to what degree the impairment of physiological responses by concurrent TBI might also adversely affect the healing of soft tissue injuries.
SUMMARY: PTSD complicates MTBI more commonly than was previously realised. MTBI and PTSD each worsen the prognosis of the other.
In the 4 years since we last reviewed the proposition that these two conditions are generally mutually exclusive, empirical research has shown the concurrence to be far from rare.
New evidence suggests that PTSD occurs in 1 or 2 out of every 6 Mild Traumatic Brain Injury (MTBI) victims (5, 6).
In particular, following MVA, PTSD is as common in those with MTBI as in those without brain injury (5, 7).
Practice PointPTSD is sufficiently common after MTBI that claimant counsel should routinely request psychiatric assessment |
However, the pattern of PTSD is different. Fewer MTBI victims report fear and helplessness (8), perhaps because they were unaware, or not fully aware, of some aspects of the trauma.
In contrast, intrusive symptoms are initially less common (9) but later more common(8) in the MTBI population.
Since stresses that follow trauma can compound maladjustment (10, 11), it may be that cumulative problems following MTBI progressively amplify anxiety and result in increased intrusions.
Practice PointIf both PTSD and MTBI have been diagnosed, medical expert opinion should address the medical research literature on their interaction |
Conversely, PTSD exacerbates many of the symptoms of MTBI, notably concentration deficits, dizziness, fatigue, headaches, sensitivity to sound and visual disturbances.
SUMMARY: The factors determining success in Return to Work after MTBI in a Motor Vehicle Accident are still being determined. Social support and sense of control in the employment environment are powerful determinants. Formal rehabilitation may be counterproductive.
Between 80% (12) and 88% (13, 14) of previously employed victims of MVA who suffer MTBI eventually return to work. What distinguishes those who do not?
Some of the non-returners, of course, have additional injuries that have a greater impact on employability than the problems arising from the brain injury.
Practice PointSocial, economic and employment factors are more important in prognosis than MTBI features or cognitive impairment |
However, secondary effects of isolated MTBI also interfere with recovery.
Because of their irritability or their difficulties following conversations (15), MTBI clients may withdraw from those social relationships considered critical to maximum recovery (16).
Cognitive deficits may become evident only after return to school or work. (17).
Similarly, many MTBI victims are unable to return to pre-injury levels of employment(12, 13, 14, 18) and thereby suffer loss of income, satisfaction and self-esteem.
Certain characteristics that distinguish patients with isolated MTBI who do not return to work have been identified(18, 19, 20, 21):
Practice PointKnown adverse prognostic factors:1. Young age 2. Not married 3. Lack of family support 4. Low socioeconomic status 5. Preinjury employment
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Of particular interest to personal injury counsel, admission to a rehabilitation facility may not have a beneficial effect on Return to Work(18), perhaps because the frequent interaction with health-care professionals signifies dependence and a continuing sick role (22).
Conversely, failure to Return to Work may have an adverse effect on cognitive abilities because clients are missing the stimulation and structure of the work environment(12).
Other factors remain to be researched.
Copyright © 2008 Electronic Handbook of Legal Medicine