Pain is defined by the International Association for the Study of Pain (IASP) as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage."1
This definition by its complex nature suggests that the pain experience has multiple dimensions and is not necessarily associated with known injury or damage to the body. When most people think about pain, they are most likely thinking of acute pain. Acute pain typically begins suddenly and in most cases is caused by injury or damage to the body. The source is easily located and the intensity of pain usually increases in relation to the severity of the pain trigger. A common example is the pain a patient feels following surgery.
When pain persists beyond the typical healing period (typically six months), it may be labeled as chronic pain. In comparison to acute pain, chronic pain often has no known origin or behaves independently from the initial causative event (injury) over time.
A major difference between chronic pain and acute pain is that chronic pain serves no useful or protective function. When we burn our hand on a stove, the resulting acute pain tells our body to pull back in order to prevent further injury. But when pain persists for months after surgery, it does not usually serve any helpful purpose. Rather, chronic pain instead tends to negatively interfere with meaningful rehabilitation, mood, and quality of life. Chronic pain can be considered a disease by itself.
There are many theories as to what causes chronic pain. One theory suggests that in some individuals, the nerves that transmit pain become increasingly sensitized with repeated activation. In this scenario, stimuli that normally do not cause discomfort (such as light touch) can become increasingly painful.
The emotional component of the pain experience is also an often neglected and contributing factor. Some research has shown that emotional suffering and physical pain activate the same regions of the brain.2 And other research has shown that existing fear of pain is a strong predictor of reported pain in response to a painful trigger.3
The difference between types of pain is not always clear. For example, osteoarthritis is a common pain condition resulting from the wear and tear on our joints over time. While this certainly qualifies as “chronic pain” in terms of duration, related pain symptoms are not typically continuous and instead follow a waxing and waning course.4 And so patients with pain conditions that linger, but are not always or continuously painful, may be confused when trying to label their underlying issue as chronic.
Since there could be multiple causes and complications associated with chronic pain, patients seeking treatment should be evaluated by specialists who are capable of treating a wide variety of pain conditions. Not all patients benefit from surgery to alleviate their pain, so physicians who understand the underlying mechanisms of pain and specialize in the evaluation, diagnosis and treatment of pain conditions may be the most suitable initial step for patients experiencing chronic pain symptoms. These specialized physicians are known as pain management specialists.
Pain Medicine interventions have the potential to not only provide therapeutic pain relief but may also offer substantial diagnostic value. That is, if accurately directing pain medication to an anatomic structure does not provide any benefit, then that particular body part is likely not causing pain symptoms. As it can be difficult to set apart age-related degenerative changes seen on imaging from true pain generators, interventional pain procedures can often provide more useful diagnostic information than radiographs.
Frequently treated conditions include:
Common pain relieving interventions performed by pain management specialists include:
Examples of injected medications include but are not limited to:
While opioid medication remains an invaluable tool in managing acute or postsurgical pain, any benefits from long-term use of these medications have yet to be definitely determined from high quality research studies. However, we do know that long-term use of opioid medications increases the chance of getting into a motor vehicle accident, enhances the risk for both fatal and nonfatal overdose, depresses the immune system's protective functions, and alters hormone levels including testosterone.5
Chronic pain responds best when treated using a multidisciplinary approach. Depending on the condition, a pain management specialist may initiate multiple treatments including rehabilitation and physical therapy, pain psychology to teach pain coping and distraction techniques, non-opioid medication therapy, and interventional pain relieving procedures.