Chapter 25: Chronic Pain

LEARNING OBJECTIVES

1. Assess the impact of chronic pain on individuals and society.

2. Clarify terminology associated with nociception, pain, and chronic pain.

3. Compare and contrast nociceptive and neuropathic pain and central sensitization.

4. Apply the International Classification of Functioning, Disability, and Health (ICF) model to chronic pain.

5. Explain the pathophysiological processes underlying chronic pain, including immune, endocrine, and autonomic system involvement and neuroplastic changes that occur.

6. Propose risk factors associated with chronic pain.

7. Describe methods for obtaining a thorough, biopsychosocial history from patients.

8. Contrast various outcome measures for examining chronic pain and its impact on activity and participation.

9. Describe tests and measures appropriate for examining individuals with chronic pain.

10. Relate examination findings to evaluation and prognosis for individuals with chronic pain.

11. Describe appropriate physical therapy interventions for individuals with chronic pain.

12. Summarize medical management of chronic pain.

13. Discuss complementary and alternative medicine approaches to managing chronic pain.

Pain is the most common reason why people visit health care providers and physical therapists. Chronic pain affects from 25¹ to 116 million Americans,^2,3 accounting for up to 20% of all primary care visits in the United States;^4,5 low back pain (LBP) is the second most common reason for physician visits.⁶ Chronic pain affects more people than diabetes, heart disease, and cancer combined.³ Studies show that 36.6% of American adults have reported being often troubled by pain, and one-third of those report that this pain is disabling.^7,8 Chronic pain is more prevalent among women and people with lower socioeconomic status.^1,8 Spinal pain, headache, and arthritis are the most common types of chronic pain: LBP affects 28%, headache and migraine affect 16%, neck pain affects 15%, and combined peripheral joint pain affects 30% of Americans.^5,9 Other conditions such as stroke, spinal cord injury (SCI), diabetes, multiple sclerosis (MS), HIV/AIDS, amputation, Parkinson’s disease, cancer, chemotherapy or radiation for cancer, and a variety of other conditions can also lead to chronic pain.¹⁰

Chronic pain exacts a huge toll in medical care, lost workdays, and compromised quality of life. In the United States, the national economic cost of chronic pain is estimated at $560 billion to $635 billion per year with $261 billion to $386 billion per year of that due to direct medical costs.^2,11 Lost productivity due to pain costs $297 billion to $336 billion per year.² Quality of life is severely compromised for people with chronic pain, often rated even lower than among people dying of cancer.¹²

This chapter will focus on chronic pain most likely to present for physical therapy intervention. It is not the goal of this chapter to address cancer or visceral pain, even though those are growing specialty areas within physical therapy. Recent advances in pain physiology are presented as a foundation for understanding common chronic pain conditions and the appropriate interventions ...