Has your doctor ever asked you to rate your pain on a scale of 1 to 10?
If so, then you can probably appreciate that pain is a very subjective experience. For that reason defining, calculating, and treating it can be tricky.
An added layer is that there exist different types of pain. Bumped, bruised, or scraped, most have us have likely experienced acute pain.
We usually associate this type of pain with tissue damage, disease, or inflammation.1 If the primary cause is resolved, then the acute pain resolves too. But what about the times pain doesn’t go away?
Chronic pain
Chronic pain is pain that persists after the normal expected healing time and can even exist without tissue damage. We can also consider pain chronic if it lasts more than three months.1
Chronic pain affects up to 30% of individuals worldwide and severely impacts quality of life for those affected.2 In fact, it is a leading cause of disability and is correlated with reduced life expectancy.2
Categories of chronic pain
There are three categories of chronic pain:
- Nociceptive
- Nociplastic
- Neuropathic
Nociceptive pain is caused by tissue damage and is the most common form of chronic pain. Some examples could be arthritis, burns, or ulcers.
Nociplastic pain occurs due to abnormal processing of pain. Fibromyalgia and irritable bowel syndrome.
Neuropathic pain is due to a disease or injury that affects nerve cells (neurons). This can be neurons as part of the central nervous system (neurons that sense things or that you use to consciously do things) or the peripheral nervous system (neurons that control involuntary responses, glands, etc). It can account for up to 25% of chronic pain, examples of neuropathic pain include diabetic neuropathy and spinal cord injury.
How is chronic pain diagnosed?
Well, it may be surprising, but the doctor will just ask you to rate your pain on a scale. There is as yet no objective measure to determine the severity of pain, but to get a better sense of the situation, they will likely ask:
- Where the pain is
- How often it occurs
- What is your medical and surgical history
- What is its impact on your life
Groups with higher rates of chronic pain2
These include:
- Women
- Military veterans
- Those from lower socioeconomic backgrounds
- Those suffering from depression and/or anxiety or PTSD
Treatments
Chronic pain is complex. A treatment focused on the precise mechanism causing the pain would be best, but in practice, the cause of pain is often hard to pinpoint.
The goal, therefore is often to identify how best to manage the individual’s chronic pain symptoms and to improve their quality of life.
Chronic pain is a dynamic phenomenon exacerbated by social and psychological factors.1,2 As such, guidelines, such as those from the US Department of Health and Human Services, have suggested a multidisciplinary and personalized, biopsychosocial approach to treatment.2
Treatments can include:
- Restorative therapies (physical therapy/exercise)
- Pharmacotherapies
- Procedural interventions
- Behavioural treatments
Clinicians should tailor these approaches to the individual.
Exercise and physiotherapy
Physical exercise is a recommended self-management strategy. No strong evidence proves that one type of exercise is more beneficial than another, but it is important to focus on the patient’s needs.
Some examples are strength training for back pain or low-level aerobic exercise for fibromyalgia.
While generally not prescribed in isolation, the anti-inflammatory effects of physical activity are well documented.4
Regular exercise can reduce systemic inflammation. It does this by decreasing the levels of pro-inflammatory cytokines (a substance secreted by cells that can impact other cells) in circulation. This then has a trickle-down effect of reducing chronic pain.4
However, for this to be effective, consistency is key.
Cognitive Behavioural Therapy (CBT)
CBT is a common psychologically based intervention for chronic pain. It’s not the way to go for everyone but can be helpful for those who are motivated.
Its focus is to change negative, or maladaptive, ways of thinking on an individual basis. It encourages the patient to identify unhelpful thoughts, especially those that can turn into negative behaviors that may worsen their symptoms, such as the impact of anxiety and depression.1
Non-opioid Medicines
This can include analgesics, anti-epileptic drugs, topical and oral non-steroidal anti-inflammatory drugs (NSAIDs), and muscle relaxants. Many may be first-line medications.
Opioids
Although used more frequently in the past, opioids are no longer a first-line treatment for chronic pain. They can be very effective for managing chronic pain but also come with risks.
Prolonged opioid use carries the risk of misuse, abuse, and addiction, especially for those who are under 30, have a prior history of substance abuse, experience psychological stress or trauma, or have an unclear cause of chronic pain.
For example, the use of codeine for longer than 180 days can increase the risk of cardiovascular events.1
Additional, but less common risks of prolonged opioid therapy include immunosuppression, osteoporosis, reduced fertility, sexual dysfunction, and an increased risk of heart attacks.
Surgical interventions
Surgical interventions are most common for joint and spine-related pain and includes procedures such as spine decompression and neurostimulation.
This is an invasive, and potentially irreversible step, doctors will rule out all other pharmacological and physiological treatments.1
Stimulation procedures
These include spinal cord stimulation (SCS) and deep brain stimulation (DBS). SCS and DBS are invasive procedures that implant an electric signal-generating medical device with the goal of inhibiting pain.1
For electrical stimulation without implanting a medical device, clinicians might use a method called transcutaneous electrical nerve stimulation (TENS) and percutaneous electrical nerve stimulation (PENS).
TENS works through electrodes placed on the skin to stimulate the nerve fibres in the location of the pain.
Research indicates that TENS may work by either blocking the transmission of pain or reducing the perception of pain.1 It is most helpful for localized pain.
PENS, on the other hand, involves thin needle electrodes that go through the skin and target specific nerve clusters.5 While not a lot of solid research on TENS/PENS has been published, it does seem to work for some people.
The future of chronic pain treatments
Regenerative therapies: This would involve using stem cells to repair or replace injured tissue. Scientists hope that this method will avoid many of the side effects that come with current approaches to pain management.
Mechanisms of Pain: Investigation into the switch from acute to chronic pain and how it can be prevented.
Biomarkers: Researchers are also developing ways to measure pain objectively, using biomarkers. A simple blood test would significantly help with diagnosis and treatment.
Conclusion
Chronic pain is a multidimensional condition that can’t be diagnosed or treated through one standard method.
The current recommendation is to use an interdisciplinary approach and consider the biological, social, and psychological aspects that contribute to chronic pain, and adopt personalized therapeutic interventions.
As the research continues, physicians may have more tools to help provide patients with relief and improved quality of life.
References
- Hylands-White N, Duarte RV, Raphael JH. An overview of treatment approaches for chronic pain management. Rheumatol Int. 2017;37(1):29-42. doi:10.1007/s00296-016-3481-8
- Cohen SP, Vase L, Hooten WM. Chronic pain: an update on burden, best practices, and new advances. The Lancet. 2021;397(10289):2082-2097. doi:10.1016/S0140-6736(21)00393-7
- Chronic Pain: What You Need To Know. National Center for Complementary and Integrative Health. National Institute of Health. US Department of Health and Human Services. Accessed September 11, 2023. https://www.nccih.nih.gov/health/chronic-pain-what-you-need-to-know
- Borisovskaya A, Chmelik E, Karnik A. Exercise and Chronic Pain. In: Xiao J, ed. Physical Exercise for Human Health. Advances in Experimental Medicine and Biology. Springer; 2020:233-253. doi:10.1007/978-981-15-1792-1_16
- Specialists P and S. Nerve Stimulation Devices for Chronic Pain. Pain & Spine Specialists Maryland and Pennsylvania. Published June 9, 2023. Accessed September 25, 2023. https://painandspinespecialists.com/nerve-stimulation-devices-for-chronic-pain/
