Whiplash Causes Hypersensitivity to Pain
Chronic whiplash-associated disorder can cause patients a host of problems in addition to neck pain and disability.
A recent study has demonstrated that whiplash victims are also more susceptible to widespread pain and sensitivity to pain stimuli on other body parts far from the original pain source.
Researchers used leg and arm cuffs that were inflated to increase pressure to the deep tissues of the muscles, testing the pain intensity and tolerance for the patients throughout ten minutes of wearing the cuffs. The subjects were women, 25 of whom had whiplash associated disorder, and ten controls who did not.
Patients with whiplash had lower pain thresholds than the control group. The sensitivity to pain was experienced in both the arms and legs of the whiplash victims, extremities far from the neck.
In addition, participants were given a saline injection in their tibialis anterior muscles. The researchers discovered that the whiplash group experienced more pain intensity after the injection than the control group.
Researchers concluded that chronic whiplash-associated disorder led to widespread hyperalgesia, or sensitivity to pain. They suggested that central sensitization may be to blame.
Central sensitization occurs when a trauma such an auto injury starts a chain reaction in a patient's body. Muscle damage and inflammation from the injury sends pain signals to the brain, and the brain reacts by telling the central nervous system that something is wrong. The injured muscles then contract to prevent further injury. The pain centers in the patient's brain become over-stimulated and the patient's entire body can become overly sensitive to pain. The resulting widespread, chronic pain will often affect an auto-injury victim in the arms, legs, hands, and feet, sources spread far away from the original source of the injury. Central sensitization can harm an auto injury-victim's quality of life and ability to work.
Lemming D, et al. Widespread pain hypersensitivity and facilitated temporal summation of deep tissue pain in whiplash associated disorder: an explorative study of women. Journal of Rehabilitation Medicine 2012; 44(8): 648-57. doi: 10.2340/16501977-1006.