Most have some familiarity with the immediate consequences of a common injury. A back or shoulder strain, for instance, will produce pain in those areas. Less well known, however, is how one injury can lead to the development of a completely unrelated disease process.
Take, for example, a traumatic brain injury. Most would readily associate this type of injury with memory loss, and perhaps difficulty in cognitive functioning. However, traumatic brain injury gives rise to a host of potential complications, including an increased risk of Alzheimer’s disease, Parkinson’s disease—even bipolar disorder.1
A hip fracture one would associate with pain and limitation of motion in that specific region. Actually those with hip fractures have an increased risk of suffering chronic widespread bodily pain.2
Many readily associate phantom pain and physical disability with those who have suffered an amputation of a limb. But amputees also have an increased risk of morbidity and mortality from cardiovascular disease.3
These are three examples of “hidden injuries”—complications that arise as a consequence of an initial injury. Like any complex, interrelated system, the human body, once having sustained an injury, is more susceptible to developing later afflictions. Perhaps this is due to trauma-induced weakness or pathology, or perhaps it’s a byproduct of the body’s healing response, or both, but in any event these later complications can at times be worse than the initial injury itself. This explains why many injuries remain undervalued—all that’s considered are the initial symptoms, not the long-term consequences.
Researchers, some might suggest, should be directing more attention to this area. For if it can be determined why these complications arise following an injury, this knowledge could then be used to treat the complication itself. Amputees have a higher risk of cardiovascular disease—but why? Is this simply due to lack of mobility? Or does a change in the coronary arteries take place? It would seem amputees should have the same rate of coronary artery disease as others. The fact that they don’t implies there are physiologic changes occurring following an amputation that remain undiscovered and unrecognized.
“Any fact becomes important when it’s connected to another,” wrote Umberto Eco in Foucault’s Pendulum. The body’s response to an injury remains uncharted territory, a maddeningly complex entanglement researchers in medicine should systematically seek to disentangle. In the future perhaps the secret to achieving breakthroughs will be to focus on consequence rather than cause.
1See, e.g., Perry, et al., Association of traumatic brain injury with subsequent neurological and psychiatric disease: a meta-analysis, J Neurosurg. 2016 Feb;124(2):511-26 (“Analyses of individual diagnoses revealed higher odds of Alzheimer’s disease, Parkinson’s disease, mild cognitive impairment, depression, mixed affective disorders, and bipolar disorder in individuals with previous TBI as compared to those without TBI.”).
2See, e.g., Walker-Bone, et al., Chronic widespread bodily pain is increased among individuals with history of fracture: findings from UK Biobank, Arch Osteoporos. 2016;11:1 (“In this cross-sectional analysis, previous fracture is associated with an increased likelihood of chronic widespread bodily pain, particularly with hip fractures in women, and spine fractures in both sexes.”).
3See, e.g., Naschitz, et al., Why traumatic leg amputees are at increased risk for cardiovascular diseases, QJM. 2008 Apr;101(4):251-9 (“Post-traumatic lower limb amputees have an increased morbidity and mortality from cardiovascular disease.”).
