Chronic pain is defined as reoccurring or persistent pain lasting more than 3 months.[1] It continues past normal healing times and therefore does not have the same function as acute pain.[2] Acute pain serves to signal the body that there is a threat so the body can avoid future danger. Chronic pain, on the other hand, does not serve this purpose.[3] The International Association for the Study of Pain (IASP) defines pain as "An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage".[4] Chronic pain is considered a syndrome because of the associated symptoms that develop in those experiencing chronic pain.[5] Chronic pain affects approximately 20% of people and accounts for 15–20% of visits to a physician.[2]
Pain can be categorized according to its location, cause, or the anatomical system which it affects. Pain can also defy these classifications, making it difficult to classify chronic pain. The newest standard for classifying chronic pain was created for the ICD-11. To create this classification system the IASP collaborated with the World Health Organization to form the Task Force for the Classification of Chronic Pain. The IASP Task Force was made up of pain experts.[2] This task force developed a new model to classify chronic pain for the ICD-11. This new classification system emphasized the cause of pain, underlying mechanisms, body sites, and the biopsychosocial model of chronic pain.[2] This classification system differentiates chronic primary pain from chronic secondary pain, incorporates already existing diagnosis, and further characterizes chronic pain syndromes. The ICD-11 category for chronic pain includes the most common types of chronic pain, chronic primary pain, chronic cancer pain, chronic posttraumatic and postsurgical pain, chronic neuropathic pain, chronic secondary headache and orofacial pain, chronic secondary visceral pain, and chronic secondary musculoskeletal pain. There can also be significant overlap between the categories.[6] The ICD-11 also has an "other" subcategory for each category of pain, such as "other specified chronic cancer pain" or "other specified chronic neuropathic pain", to include chronic pain that does not fit into other categories. [7]
- ^ Treede et al. 2015, p. 1004.
- ^ a b c d Treede et al. 2015, p. 1003.
- ^ Clunie et al. 2018, p. 623.
- ^ Raja et al. 2020, p. 1976.
- ^ Mostoufi 2020, p. 533.
- ^ Treede et al. 2019, p. 20.
- ^ Treede et al. 2019, p. 25.