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Timely information and insights into the world of evidence-based medicine as it applies to IMEs and other health-related services across Canada. Your feeback and suggestions are welcome.

Part 1: Chronic Pain

Separating Chronic Pain from Injury and Illness: Challenges In Diagnosis

Pain - the nerve impulses used by the body to communicate problems, injuries, or sickness to the brain - is an invaluable tool to be used when diagnosing a medical issue. When that tool short circuits, however, and continues long past the point where the original trigger has resolved, or when it appears seemingly unlinked to any specific injury and refuses to go away, it crosses over into a medical condition of its own called 'chronic pain.' This term is most commonly applied to pain that lasts for six months or more, with the American Medical Association recognizing 'chronic pain syndrome' in 19871.

Any chronic pain diagnosis requires patience and diligence. One of the primary challenges facing an assessor is that each individual processes pain differently, as what may be a high level of pain for one person may be experienced as minor discomfort to another2. There several different pain scales that can be used to assess the level of pain being experienced, including the Wong-Baker scale, the Brief Pain Inventory (BPI), a simple numerical scale, or asking a patient to describe the feeling in plain language3. When and how often the pain occurs, and whether there are activities that make it worse, or that alleviate it, is also useful information that can gathered in conversation with the patient, or by asking them to keep a pain journal that logs their experiences.

Seeking a cause for the pain is often the focus for general practitioners when a patient presents with this type of complaint. This is an effort that can require multiple visits before the realization that the pain itself may be separate or adjacent to any specific injuries or existing medical conditions. This last point is a crucial one, because it is important to investigate any other possible medical condition associated with the pain that has presented before reaching a diagnosis of chronic pain. As a result, physical and neurological exams, blood work, and imaging scans are often necessary, which can add weeks or even months to the assessment process4.

It's here that another of chronic pain's more difficult aspects comes to the fore: it's entirely possible for pain associated with a medical issue discovered during any of the above-listed examinations to be labelled chronic, which means that the condition can exist alongside another, yet require its own management plan separate from that of its trigger. It's also possible for chronic pain to be linked to a past medical problem, injury, or illness that had been considered resolved, or even to present itself absent any other symptoms, issues, or problems.

The variety of potential triggers, medical conditions, injuries, and presentations of chronic pain often require a lengthy diagnostic process compared to other types of illnesses. By focusing on the duration of the pain, its location, and it's severity, and by linking it to or ruling out a specific triggering medical condition or injury, past or present, it's possible to confidently make a chronic pain diagnosis and formulate a treatment and management plan.

  1. US Department of Health and Human Services, Social Security Administration Office of Disability. Report of the Commission on the Evaluation of Pain. SSA Pub. No. 64-031 1987;23.
  2. NIH. Chronic Pain: Symptoms, Diagnosis, & Treatment. NIH Medline Plus 2011;6(1):5-6.
  3. Canadian Physiotherapy Association. Pain Assessment. https://physiotherapy.ca/pain-assessment  (accessed April 22, 2018).
  4. Brunton, Stephen. Approach to assessment and diagnosis of chronic pain. The Journal of Family Practice 2004;53:S3-10.