For anyone who has treated patients who had whiplash injuries they know that the pain associated with whiplash is somehow different from other types of neck pain. In the hundreds of patients I have treated who were suffering from a whiplash injury, a disproportionately high number seem to develop chronic unremitting pain. Another characteristic of whiplash injury is that the original pain associated with a neck injury often spreads to nearby regions of the shoulders, arms or even down to the mid-back. In many whiplash patients, the pain unfortunately too often spreads throughout the body, leading to a condition known as chronic widespread pain syndrome.
Because whiplash injuries often involve litigation, many doctors and particularly defense attorneys, have attributed this chronic unrelenting pain associated with whiplash to the fact that patients often seek financial gain through litigation.
In my own practice, I have seen patients who continue to experience neck and widespread pain many years after their court case was settled and they received a settlement payment. This observation argues against litigation as the reason people develop long-term and widespread pain so often after whiplash injury.
There is growing evidence in the scientific literature that supports the idea that whiplash is in the unique type of injury and that a significant number of people who have sustained this type of injury will go on to develop long-lasting pain which spreads well beyond the original injury in the neck.
Researchers publishing in the medical journal Pain looked at nearly 1000 patients who were involved with motor vehicle accidents and sustained a whiplash injury. They compared those patients who are involved litigation versus patients with whiplash who were not involved in litigation. The authors of this study concluded that persistent pain after motor vehicle accident is common even in those patients not involved in litigation. Their findings suggest that some physiological abnormality is likely responsible for the common finding of persistent widespread pain following whiplash injuries that is unrelated to litigation.
Other researchers publishing in the journal Disability Rehabilitation looked at over 700 patients suffering from posttraumatic neck pain. They found the nearly twice as many females versus male whiplash victims reported chronic widespread pain. They conclude that the high-frequency of regional and widespread pain among patients with persistent neck pain after trauma requires a multidisciplinary approach to treatment. What these findings suggest is that traditional treatments for whiplash injuries often failed to correct the underlying problem and leave a significant number of patients, particularly women, at risk for the development of chronic widespread pain symptoms.
The significant number of patients who develop chronic painful symptoms that often spread to the adjacent regions of the body or to the entire body itself following injury to the neck suggests that whiplash trauma involves more than the muscles and joints of the neck itself. In fact, it suggests that patients that develop long-standing and widespread pain following a whiplash injury may actually have alterations in brain function.
To explain how altered brain function may lead to chronic and widespread pain, we need to delve into the neurological circuits that normally process pain and injury.
Think about the last time you stubbed your toe; there was an initial intense pain which quickly converts to a more achy and less intense set of symptoms. This is because at the moment of the initial impact, certain circuits that tell the brain the body has been injured are activated. The circuits from the periphery, in our example the toe, ascend into the spinal cord up to the brain itself. When the signal reaches the brain you become aware that you damaged your toe. However that is not the end of the story. Shortly after you become aware that you have injured your toe, another neurological circuit is activated. This circuit descends from the brain back to the spinal cord and its purpose is to dampen or shut off the ascending pain signals.
This is a simplified example that explains why the intense pain of stubbing your toe soon becomes a more achy, throbbing sensation which while unpleasant, is much different than the original painful experience.
The bright idea here is that there is ascending “on-switch” for pain which sends pain signals from the body to the brain that also activates the descending pain “off- switch” to the spinal cord. This is how pain signaling in its simplest form is supposed to work.
Patients that develop long-standing chronic pain that doesn’t respond well to most forms of care, are believed to have impaired descending circuits that fails to turn off the pain signals traveling from the body to the brain.
If this failure of ascending inhibition of pain signals is severe, it can spill over into adjacent parts of the spinal cord and thus cause pain sensations in parts of the body that were not originally injured.
Researchers publishing a review of literature in the journal Pain Physician looked at studies specifically addressing the issue of brain abnormalities in chronic pain states including patients suffering from whiplash. What they found was that patients suffering from chronic neck pain from whatever cause had brain abnormalities associated with pain processing. The researchers also found these abnormalities in pain processing were more evident in patients suffering from whiplash injury.
Thus the available research suggests that chronic pain and particularly chronic pain following a whiplash injury result from an abnormal signal processing in the brain rather than the neck, muscles, joints, and ligaments originally injured at the time of the whiplash injury. This argues for a different type of treatment than those commonly used to treat chronic post-whiplash pain.
Another group of researchers publishing in the Scandinavian Journal of Pain, use d a special type of MRI scan to study the pain processing circuits in the brains of patients suffering from chronic pain associated with whiplash injury. They furthermore took blood samples of these patients and tested for biomarkers of inflammation in the blood.
They found elevated levels of inflammatory markers in about one of 3 chronic whiplash sufferers. They further found pain processing signal abnormalities, particularly related to the application of cold, in the pain processing circuits of chronic whiplash patients.
There is a model of chronic pain called the Thermo-regulatory Disinhibition model of central pain. In this model (which is beyond the scope of this article) abnormalities in the peripheral pathways that deal with the ability to properly process cold sensations such as an ice bag applied to the skin, are associated with increased activity in those circuits related to pain processing.
In a nutshell, the ability to feel cold sensation suppresses the ability to feel pain at the brain level, therefore anything that alters the ability to process cold stimuli enhances the body’s processing of painful stimuli. Taken to the extreme, loss of ability to process cold signaling will lead to intense pain which is generated at the brain level. This is a common finding after a patient has a stroke or spinal cord injury.
It provides a model however, which helps to explain why a substantial number of whiplash patients go on to develop chronic widespread pain. It also provides a treatment option, based on restoring normal cold sensation processing, which could have the effect of reducing pain signaling going to the brain.
This is a novel approach to the treatment of chronic pain following whiplash injury and represents a brain-based method to treat pain in the body that often fails to respond to traditional methods of rehabilitation.
There are a number of means and methods available to attempt to restore normal cold signal processing that have been found to be abnormal in patients suffering from chronic whiplash signs and symptoms. The restoration of cold signaling in the brain can directly attenuate the brain’s processing of painful stimuli.
These methods of treating pain through modulation of cold processing circuits in the brain, offer the first true breakthrough in chronic whiplash pain management in years. They are an exciting development for patients suffering from chronic widespread post-whiplash pain.