Identifying and Treating Chronic Pain

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.

What is chronic pain?

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.

Causes of chronic pain

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.

What is pain management?

Pain management specialists are physicians who understand the underlying mechanisms of pain and specialize in the evaluation, diagnosis and treatment of a wide variety of pain conditions. Since there can be multiple causes and complications associated with chronic pain, and since not all patients benefit from surgery to alleviate their pain, consulting a pain management doctor may be the most suitable initial step for patients experiencing chronic pain symptoms.

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:

• Spine and joint degenerative conditions
• Slipped and herniated intervertebral discs
• Pain from tendons, ligaments, and muscles
• Complex regional pain syndrome
• Neuropathic pain
• Cancer-related pain

Common pain relieving interventions performed by pain management specialists include:

• Spine procedures directed at herniated discs or facet joints
• Joint injections
• Tendon and ligament injections
• Muscle injections
• Targeted nerve blocks

Examples of injected medications include but are not limited to:

• Cortisone (anti-inflammatory)
• Local anesthetics such as lidocaine
• Regenerative therapies such as platelet rich plasma (PRP)
• Viscosupplementation (synthetic lubricant)

Multimodal pain management

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.2

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.

Posted: 2/7/2018

Authors

Joseph C. Hung, MD
Assistant Attending Physician, Hospital for Special Surgery
Assistant Professor of Anesthesiology, Weill Cornell Medical College

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References

1. IASP Terminology, http://www.iasp-pain.org/Education/Content.aspx?ItemNumber=1698#Pain.
2. Kross E, Berman MG, Mischel W, Smith EE, Wager TD. Social rejection shares somatosensory representations with physical pain. Proc Natl Acad Sci 2011;108(15):6270–5.
3. Hirsh AT, George SZ, Bialosky JE, Robinson ME. Fear of Pain, Pain Catastrophizing, and Acute Pain Perception: Relative Prediction and Timing of Assessment. J Pain 2008;9(9):806–12.
4. Perrot S. Osteoarthritis pain. Best Pract Res Clin Rheumatol 2015;29(1):90–7.
5. Dowell D, Haegerich TM, Chou R. CDC Guideline for Prescribing Opioids for Chronic Pain – United States, 2016. JAMA 2016;315(15):1624.