Clinical Pain Management

A Practical Guide

Mary E. Lynch, Kenneth D. Craig, Philip H. Peng, Mary E. Lynch, Kenneth D. Craig, Philip W. H. Peng, Mary E. Lynch, Kenneth D. Craig, Philip W. H. Peng

• Publisher: Wiley-Blackwell
• Year: 2011
• Print ISBN: 9781444330694
• eBook ISBN: 9781444329735
• Edition: 1
• Topic: Medicine
• Subtopic: Anesthesiology & Pain Management

Clinical Pain Management takes a practical, interdisciplinary approach to the assessment and management of pain. Concise template chapters serve as a quick reference to physicians, anesthetists and neurologists, as well as other specialists, generalists, and trainees managing pain. Based on the International Association for the Study of Pain's clinical curriculum on the topic, this reference provides to-the-point best-practice guidance in an easy-to-follow layout including tables, bullets, algorithms and guidelines.

Part 1: Basic Understanding of Pain Medicine

Chapter 1

The challenge of pain: a multidimensional phenomenon

Mary Lynch¹, Kenneth D. Craig² & Philip W.H. Peng³

¹ Dalhousie University, Pain Management Unit, Queen Elizabeth II Health Sciences Centre, Halifax, Nova Scotia

² Department of Psychology, University of British Columbia, Vancouver, Canada

³ Department of Anesthesia, Wasser Pain Management Center, Mount Sinai Hospital, University of Toronto, Ontario, Canada

Pain is one of the most challenging problems in medicine and biology. It is a challenge to the sufferer who must often learn to live with pain for which no therapy has been found. It is a challenge to the physician or other health professional who seeks every possible means to help the suffering patient. It is a challenge to the scientist who tries to understand the biological mechanisms that can cause such terrible suffering. It is also a challenge to society, which must find the medical, scientific and financial resources to relieve or prevent pain and suffering as much as possible.

(Melzack & Wall The Challenge of Pain, 1982)

Introduction

The International Association for the Study of Pain (IASP) taxonomy defines pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage” [1]. Pain is divided into two broad categories: acute pain, which is associated with ongoing tissue damage, and chronic pain, which is generally taken to be pain that has persisted for longer periods of time. Many injuries and diseases are capable of instigating acute pain with sources including mechanical tissue damage, inflammation and tissue ischemia. Similarly, chronic pain can be associated with other chronic diseases, terminal illness, or may persist after illness or injury. The point at which chronic pain can be diagnosed may vary with the injury or condition that initiated it; however, for most conditions, pain persisting beyond 3 months is reasonably described as a chronic pain condition. In some cases one can identify a persistent pain condition much earlier, for example, in the case of post-herpetic neuralgia subsequent to an attack of shingles, if pain persists beyond rash healing it indicates a persistent or chronic pain condition is present.

Exponential growth in pain research in the past four decades has increased our understanding regarding underlying mechanisms of the causes of chronic pain, now understood to involve a neural response to tissue injury. In other words, peripheral and central events related to disease or injury can trigger long-lasting changes in peripheral nerves, spinal cord and brain such that the system becomes sensitized and capable of spontaneous activity or of responding to non-noxious stimuli as if painful. By such means, pain can persist beyond the point where normal healing takes place and is often associated with abnormal sensory findings. In consequence, the scientific advances are providing a biological basis for understanding the experience and disabling impact of persistent pain. Table 1.1 presents definitions of pain terms relevant to chronic pain.

Table 1.1 Definitions of pain terms.

Source: Based on Merskey H, Bogduk N, eds. (1994) Classification of Chronic Pain, Descriptions of Chronic Pain Syndromes and Definitions of Pain Terms, 2nd edn. Task Force on Taxonomy, IASP Press, Seattle.

Allodynia	Pain due to a stimulus that does not normally provoke pain
Anesthesia dolorosa	Pain in a region that is anesthetic dolorosa
Dysesthesia	An unpleasant abnormal sensation, whether spontaneous or evoked
Hyperalgesia	An increased response to a stimulus that is normally painful
Hyperpathia	A painful syndrome characterized by an abnormally painful reaction to a stimulus, especially a repetitive stimulus as well as an increased threshold
Neuropathic	Pain initiated or caused by a primary pain lesion or dysfunction in the nervous system
Nociceptor	A receptor preferentially sensitive to a noxious stimulus or to a stimulus that would become noxious if prolonged
Pain	An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage
Paresthesia	An abnormal sensation, whether spontaneous or evoked (use dysesthesia when the abnormal sensation is unpleasant)

Traditionally, clinicians have conceptualized chronic pain as a symptom of disease or injury. Treatment was focused on addressing the underlying cause with the expectation that the pain would then resolve. It was thought that the pain itself could not kill. We now know that the opposite is true. Pain persists beyond injury and there is mounting evidence that “pain can kill.” In addition to contributing to ongoing suffering, disability and diminished life quality, it has been demonstrated that uncontrolled pain compromises immune function, promotes tumor growth and can compromise healing with an increase in morbidity and mortality following surgery [2,3], as well as a decrease in the quality of recovery [4]. Clinical studies suggest that prolonged untreated pain suffered early in life may have long-lasting effects on the individual patterns of stress hormone responses. These effects may extend to persistent changes in nociceptive processing with implications for pain experienced later in life [5]. Chronic pain is associated with the poorest health-related quality of life when compared with other chronic diseases such as emphysema, heart failure or depression and has been found to double the risk of death by suicide compared to controls [6]. Often chronic pain causes more suffering and disability than the injury or illness that caused it in the first place [7]. The condition has major implications not only for those directly suffering, but also family and loved ones become enmeshed in the suffering person’s challenges, the work place suffers through loss of productive employees, the community is deprived of active citizens and the economic costs of caring for those suffering from chronic pain are dramatic.

Chronic pain is an escalating public health problem which remains neglected. Alarming figures demonstrate that more than 50% of patients still suffer severe intolerable pain after surgery and trauma [8]. Inadequately treated acute pain puts people at higher risk of developing chronic pain. For example, intensity of acute postoperative pain correlates with the development of persistent postoperative pain, which is now known to be a major and under-recognized health problem. The prevalence of chronic pain subsequent to surgery has been found in 10–50% of patients following many commonly performed surgical procedures and in 2–10% this pain can be severe [9].

The epidemiology of chronic pain has been examined in high-quality surveys of general populations from several countries which have demonstrated that the prevalence of chronic pain is at least 18–20% [10–12]. These rates will increase with the aging of the population. In addition to the human suffering inflicted by pain there is also a large economic toll. Pain accounts for over 20% of doctor visits and 10% of drug sales and costs developed countries $1 trillion each year [13].

Chronic pain has many characteristics of a disease epidemic that is silent yet growing; hence addressing it is imperative. It must be recognized as a multidimensional phenomenon involving biopsychosocial aspects. Daniel Carr, in a recent IASP Clinical Updates, expressed it most succinctly: “The remarkable restorative capacity of the body after common injury … is turned upside down (and) hyperalgesia, disuse atrophy, contractures, immobility, fear-avoidance, helplessness, depression, anxiety, catastrophizing, social isolation, and stigmatization are the norm” [14].

Such is the experience and challenge of chronic pain and it is up to current and future generations of clinicians to relieve or prevent pain and suffering as much as possible. The challenges must be confronted at biological, psychological and social levels. Not only is a better understanding needed, but reforms of caregiving systems that address medical, psychological and health service delivery must be undertaken.

References

1 Merskey H, Bogduk N. (1994) Classification of Chronic Pain. IASP Press, Seattle.

2 Liebeskind JC. (1991) Pain can kill. Pain 44:3–4.

3 Page GG. (2005) Acute pain and immune impairment. IASP Pain Clinical Updates XIII (March 2005):1–4.

4 Wu CL, Rowlingson AJ, Partin AW et al. (2005) Correlation of postoperative pain to quality of recovery in the immediate postoperative period. Reg Anesth Pain Med 30:516–22.

5 Finley GA, Franck LS, Grunau RE et al. (2005) Why children’s pain matters. IASP Pain Clinical Updates XIII(4):1–6.

6 Tang N, Crane C. (2006) Suicidality in chronic pain: review of the prevalence, risk factors and psychological links. Psychol Med 36:575–86.

7 Melzack R, Wall PD. (1988) The Challenge of Pain. Penguin Books, London.

8 Bond M, Breivik H, Niv D. (2004) Global day against pain, new declaration. http://www. painreliefhumanright.com

9 Kehlet H, Jensen TS, Woolf CJ. (2006) Persistent postsurgical pain: risk factors and prevention. Lancet 367:1618–25.

10 Lynch ME, Schopflocher D, Taenzer P et al. (2009) Research funding for pain in Canada. Pain Res Manag 14(2):113–15.

11 Blyth FM, March LM, Brnabic AJ et al. (2001) Chronic pain in Australia: a prevalence study. Pain 89(2–3):127–34.

12 Eriksen J, Jensen MK, Sjogren P et al. (2003) Epidemiology of chronic non-malignant pain in Denmark. Pain 106(3):221–8.

13 Max MB, Stewart WF. (2008) The molecular epidemiology of pain: a new discipline for drug discovery. Nat Rev Drug Discov 7:647–58.

14 Carr DB. (2009) What does pain hurt? IASP Pain Clinical Updates XVII(3):1–6.

Chapter 2

Epidemiology and economics of chronic and recurrent pain

Dennis C. Turk & Brian R. Theodore

Department of Anesthesiology & Pain Medicine, University of Washington, Seattle, USA

Introduction

Pain is among the most common symptoms leading patients to consult a physician in the USA [1]. Data from the National Health Interview Survey [2] indicates that during the 3 months prior to the inventory 15% of adults had experienced a migraine or severe headache, 15% had experienced pain in the neck area, 27% in the lower back and 4% in the jaw. Extrapolating to the adult US population these percentages would translate to 31,066,000 for migraine, 28,401,000 head neck pain, 52,325,000 for low back pain and 9,535,000 for jaw pain. The National Center for Health Statistics estimates that about 25% of the US population has chronic or recurrent pain, and 40% state that the pain has a moderate or severe degrading impact on their lives [3].

Chronic and recurrent pain has not only significant health consequences, but also personal, economic and societal implications. It impacts on quality of life, productivity, healthcare utilization and has both direct and indirect costs. This chapter provides a summary of the prevalence of some of the most common chronic and recurrent pain disorders and describes their economic impact.

Epidemiology of Chronic and Recurrent Pain

In a review of 15 epidemiological studies from industrialized nations, Verhaak et al. [4] noted that the point prevalence for chronic non-cancer pain (CNCP) in an adult population ranges 2–40%, with a median of 15%. Similar rates were reported from studies documenting the prevalence of CNCP in epidemiological studies conducted in lower income nations, with a point prevalence of approximately 18% [5]. The adolescent population also reports a prevalence ranging 1–15% [6]. As noted in these reviews, the wide range in the prevalence rate of CNCP is influenced by various factors, including the population sampled (e.g. community vs. primary care), the definition of CNCP by duration (e.g. >1 month, >3 months, >6 months), the type of methodology used in the epidemiological study (e.g. mail-in survey, telephone survey, physical exam), the phrasing of questions included, the focus on the various parts of the body being surveyed and response rates.

Musculoskeletal Pain

Among musculoskeletal locations, the most commonly afflicted region is the lower back. Epidemiological surveys in the USA report a prevalence rate of 25% for low back pain any time during a 3-month period [3], 19% prevalence rate for chronic low back pain during a 12-month period [7] and a lifetime prevalence rate of 29.5% [7]. Similar findings have been reported in other industrialized nations, with prevalence rates for chronic low back pain ranging 13–28% [6]. Over 13 million Americans are permanently disabled by back pain [8]. Low back pain is also the most common of chronic pain conditions reported by adolescents, with prevalence rates ranging 8–44% [6]. Recent reports based on data contained in a large national survey estimated that 46.4 million Americans (21% of the population) had self-reported doctor-diagnosed arthritis [9] and 30.1 million have had neck pain in the past 3 months [10]. The US Centers for Di...

Table of contents

• Cover
• Dedication
• Title page
• Copyright page
• List of contributors
• Foreword
• Part 1: Basic Understanding of Pain Medicine
• Part 2: Assessment of Pain
• Part 3: Management
• Part 4: Pharmacotherapy
• Part 5: Interventional
• Part 6: Physical Therapy and Rehabilitation
• Part 7: Psychological
• Part 8: Complementary Therapies
• Part 9: Specific Clinical States
• Part 10: Special Populations
• Index