Chapter 1

Introduction to pain

Anita M. Unruh, Jenny Strong and Hubert van Griensven

The authors express their gratitude to Drs Allen Finley and Paula Forgeron for reviewing sections pertaining to the roles of members of the team.

OVERVIEW

Pain is a serious and often debilitating problem for people who live with it, their families and our society. Yet pain is a common occurrence in all of life. As an early warning system of possible harm, pain alerts the person experiencing it of danger and the need to withdraw from the situation. Pain is frequently associated with the bumps and bruises of childhood, health procedures and unintentional injuries, as well as illnesses and diseases that may occur over a normal lifespan. Despite its association with injury and disease, pain is a subjective symptom that cannot be objectively measured in the way that temperature can be measured with a thermometer. That subjectivity is part of its presenting challenge. Many other factors aside from pain, such as age, gender, underlying disability, and social or cultural contexts, shape how we communicate about pain to others. For all of these reasons, pain is an intensely personal experience with biological, psychological and social components, existing where a person says it exists and when a person says it exists (McCaffery & Beebe 1989).

This book was initially written in 2002 as a textbook for occupational therapists and physiotherapists who are involved in caring for and treating people who live with pain. In this revised book, we have prepared an interprofessional text on pain for students in any health profession. In this chapter, we will briefly examine what pain is, the experience of the person confronted with ongoing pain, the healthcare team that is involved in pain management, and the roles and responsibilities of health professionals within this team. To prepare, go to Reflective exercise 1.1, and complete the questions.

Reflective exercise 1.1

Gather some blank white paper and a set of coloured markers. Think about a pain experience that you have had in the past 3 weeks. The pain can be minor or more troublesome.

◆ What caused the pain?

◆ Was it familiar or something unexpected?

◆ Were you alone or with others?

◆ How did being alone or being with others affect how you felt and what you did about the pain?

◆ What factors affected whether you were concerned about the pain or saw it as of no great consequence?

◆ What did you do to make the pain better? Was it effective?

On the paper, draw a picture of your pain. If we could see it what would it look like?

The International Association for the Study of Pain (IASP) defined pain as, ‘an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage’ (Merskey & Bogduk 1994, p. 210). This definition highlights the duality of pain as a physiological and psychological experience. It is a physiological event within the body that is dependent on subjective recognition, that is, without psychological awareness pain cannot exist. The definition also highlights several other important aspects of the pain experience. Pain is usually perceived as a warning signal of actual or potential tissue damage. Nevertheless, pain can occur in the absence of tissue damage, even though the experience may be described by the individual as if damage had occurred. The assumption that pain is linked with tissue damage is protective, reflexive and ingrained biologically, psychologically and socially in human nature. It is thus a very strongly held and deeply embedded assumption, which is difficult to break when pain persists in the absence of treatable tissue pathology.

Acute pain usually stops long before healing is completed, a process that may take a few days or a few weeks (Loeser & Melzack 1999). Chronic pain is often considered as pain that persists for more than 3–6 months. Pain may be present and persistent for many reasons, as detailed further in Chapters 5 and 6. The IASP definition of chronic pain is:

‘A persistent pain that is not amenable, as a rule, to treatments based upon specific remedies, or to the routine methods of pain control such as non-narcotic analgesics.’

(Merskey & Bogduk 1994, p. xii)

Loeser & Melzack (1999, p. 1609) concluded:

‘It is not the duration of pain that distinguishes acute from chronic pain but, more importantly, the inability of the body to restore its physiological functions to normal homeostatic levels.’

These distinctions between acute and chronic pain have important implications for pain assessment and intervention. Acute pain signals tissue damage, but chronic pain that is not associated with disease is markedly disassociated from tissue damage and may be out of proportion to any initiating pathology or tissue damage.

Pain is a highly subjective experience. The best measure of pain is a reliable and valid self-report measure of pain (see Chapter 7) for persons who can provide self-report, and validated behavioural measures of pain for individuals who are unable to self-report. While such measures provide important information about pain, many people who live with chronic pain, if not most, confront at some time disbelief and doubt from health professionals, family, friends or colleagues due to the subjectivity of pain and its invisibility to an observer.