Fibromyalgia: An Environmental Scan

Table of Contents


4.1 Chronic Pain

4.1.1 Overview

Chronic pain develops over time and is considered when pain persists three months or more in duration. It is often assumed, incorrectly that the difference between the designation of either ‘acute’ or ‘chronic’ is the duration of pain. In fact, the true difference lies in whether or not physiological function returns to normal. In some cases, chronic pain can persist for different reasons beyond what originally created the chronic pain situation initially. In many instances, chronic pain syndromes are triggered by a trauma, injury or a disease. An issue, such as the extent of a trauma or augmentation in the body’s nervous system in response to the adversity creates the situation through which the body does not return to normal processes. Ultimately, physical and chemical changes take place within the body whereby chronic pain is experienced on a physical level even after the origin (if determined) of the pain is gone. In other words, the body does not have the ability to return to previous levels of homeostasis causing an on-going situation of constant or recurring chronic pain (Gatchel et al. 2007). Common chronic non-malignant pain is seen in conditions such as multiple sclerosis, chronic post-surgical pain, trigeminal neuralgia and fibromyalgia to name a few. Perhaps the most familiar chronic pain is musculoskeletal, which is sometimes referred to as mechanical chronic pain and includes osteoarthritis, rheumatoid arthritis, osteoporosis, different traumas, various injuries and other conditions.  Common areas of the body affected by chronic pain are the back, neck, chest, ribs and knee. Malignant pain stemming from various forms of cancer is beyond the scope of this report, thus the following discussion regarding chronic pain refers to non-malignant conditions (See Appendix E for a comprehensive list of pain conditions).

Historically, the research and classification of chronic pain was focused on sensory characteristics. More recently, both researchers and clinicians have broadened the scope of chronic pain to include cognitive processes, affective influence, behavioural factors and the over-riding influence of stress that affect homeostasis within the body. Estimates suggest that globally up to 20% of people suffer with chronic pain (H Breivik et al. 2005). In Canada, the National Population Survey (NPS) from 1994-95 estimated overall prevalence rates of chronic pain of 15% and 20% of the population for men and women respectively and also noted that the prevalence for chronic pain increased with age (with the exception of migraine headaches) (Tunks, Crook, and Weir 2008) . Similarly, a cross-sectional survey of 46,000 study participants conducted across 15 European countries found that 20% of the general population reports chronic pain, which is similar to other current global estimates (H. Breivik et al. 2006). The epidemiology of chronic pain produces wide estimates of prevalence in the population. Various reasons exist to explain the variations and are attributed to: the definition of chronic pain used in epidemiologic and other studies (e.g., general medical condition or pain disorder), the specific methodology used to identify cases, and the particular type of data used to produce the estimates such as self-report methods versus census data, to highlight a few.

In medicine, the biopsychological method to understanding disease involves an approach where biological, psychological and social factors all significantly impact disease. Despite numerous aspects of chronic pain disorders remaining elusive to researchers and clinicians, the biopsychological approach is well recognized as a way to provide a framework in both understanding and treating various chronic pain disorders. It is precisely the interaction of physical, emotional and social factors that can enable or exacerbate symptoms.  Furthermore, the culmination of various factors may also contribute to the on-going nature of chronic pain (Gatchel et al. 2007). Concerning the biological, recent research has examined the association between genetics and chronic pain. Simply put, an overexpression or absence of a gene can produce functional changes within the body. The components and activities within the nervous system involved in pain transmission can be affected by changes in gene expression or the augmentation of pain pathways (Gatchel et al. 2007), albeit no one gene is known to cause any specific CP disorder.

Changes to the pain processing pathways in the central nervous system or extensive tissue damage and scarring from injury can create chronic pain states that are difficult to diagnose, treat and subsequently manage. In some conditions, the severity of the pain is without explanation, in other words there is no identifiable trauma or injury to explain an individual’s suffering. Furthermore, other variables such as the environment, physical and emotional stress levels and an individual’s coping mechanisms can affect the perseverance and amount of pain experienced. Thus, chronic pain leads to a significant burden of illness for individuals, their families and society as a whole. Particular studies have demonstrated that over half the individuals suffering with chronic pain reported an interference with work, over 80% stated they also had a co-morbid condition and both the chronic pain and psychological distress accounted for increased health care utilization (Tunks et al. 2008).

The treatment and subsequent response by an individual to treatment of chronic pain is much different that acute pain. Determining both the severity of chronic pain and effective treatments are difficult to estimate. On the other hand, acute pain has an unambiguous cause such as a trauma or other pathology. The treatment of acute pain is informed by gold-standard protocols. Conversely, “[m]any chronic pain conditions lack a defined cause, are more difficult to diagnose, and are often associated with mood effects…” (Wallace and Daniel J Clauw 2005). Chronic pain treatment often does not address the pathological cause and pain often continues or returns when treatment is finished.

The focus of treatment for chronic pain is: finding the shortest pathway to reducing pain, maintenance of pain reduction for the patient, cost effectiveness for the patient (as many treatments are third party providers), the improvement on quality of life, the improvement of physical function, the impact on anxiety and mood, reducing the effect of drug side effects and a consideration of the risk-benefit of treatment for pain reduction. The underlying cause of chronic pain should be treated where possible and oral medication is a cornerstone of chronic pain treatment. Importantly and emphasized by the World Health Organization (WHO) is that there must be an emphasis on individual plan of care and that treatment approaches for chronic pain must be combined with psychological support in order to realize efficacy in reducing pain.

Various studies conducted over the past 10 years cite that individuals from all geographical areas experience undue suffering with chronic pain even though various treatments exist to relieve such pain. Importantly, a majority of the older adult population and up to one in five adults suffer with various forms of chronic pain despite effective medications (H Breivik et al. 2005). One reason for this situation is the stigma that is associated with opioid use. Many issues such as prescription abuse, addiction problems and the scrutiny of clinicians prescribing opioid medication and particularly strong opioids has resulted in low(er) prescribing patterns despite empirical evidence documenting their efficacy in treating and managing long-term chronic pain (Castro-Lopez, J. et al. 2005). Clinicians have issues to address such as the dependency surrounding opioids use, tolerance development to medication and how to supervise the patient.

Research suggests that 40%–50% of chronic pain patients also suffer from depressive disorders (Banks & Kerns, 1996; Dersh, Gatchel, Mayer, Polatin, & Temple, 2006; Romano & Turner, 1985). Epidemiologic studies have shown a statistically significant association between chronic pain and depression even though the causal order is unknown. Specifically, work done on chronic musculoskeletal pain disorders suggests that the chronic pain in fact causes the depression (Marcus, 2009). Similarly, the episode of depression onset is often stated as occurring after the onset of a particular pain disorder. Conversely, research in other patient populations has shown that previous bouts of depression were found among patients before their chronic pain disorder manifested. Despite conflicting results and the unknown nature of the causal relations between depression and CP, it is widely accepted that conditions involving pain and psychological aspects have a reciprocal impact on illness and disease (Gatchel et al. 2007).

The diagnosis, treatment and management of chronic pain are complex. Individuals must understand their condition, know the impact of lifestyle choices and develop effective coping strategies; this requires education both for clinicians and patients alike, which we cannot assume either group has from the outset. The loss of productivity and daily activity due to chronic pain is extensive. An individual’s constant management and living with chronic pain has a significant impact on one’s quality of life. Common activities such as socializing, exercising, performing at work, daily activities and getting quality rest and sleep are impacted by chronic pain. Over time, this can lead to depression, feelings of social isolation and loss of personal self-esteem. Importantly, depression is the most frequent psychological reaction to chronic pain (Taylor 2007).