Classifying Chronic Pain Using APS’s Taxonomy

Classifying Chronic Pain Using the American Pain Society’s Taxonomy – Helen Fosam, PhD – November 07, 2016

a systematic review identified several psychosocial variables that contribute to the transition from acute to chronic pain.

These factors, considered to have a greater influence than biomedical and social variables, include

  • previous traumatic experience in childhood,
  • challenges and distress in daily life, [living with constant pain is in itself a distressing challenge – zyp]
  • coping behavior, [I suspect they mean “avoiding pain”, in which they take a normal evolved behavior designed for survival and turn it into a cause of our own pain -zyp]
  • anxiety, depression [almost all patients with pain that has lasted for years eventually fall into these states -zyp]
  • work dissatisfaction.

In addition, catastrophizing, beliefs, and suppressing or ignoring pain as a coping strategy can

  • worsen the pain experience,
  • affect the response to analgesic medications, and
  • increase the risk of chronicity of acute pain.

Yet, suppressing and ignoring is exactly what we are advised to do with chronic pain.

AAPT recognizes and incorporates psychosocial concepts and processes in its assessment of chronic pain. A significant advance from the core diagnostic criteria currently used for numerous pain conditions (dimension 1), the AAPT also provides dimensions on which to categorize common features and comorbidities of chronic pain (dimensions 2 and 3), as well as detailing the consequences (dimension 4) and the contributory mechanisms (dimension 5).

These dimensions, individually and collectively, are variables that can provide assessment of the risk for developing a chronic pain condition from acute pain, the severity of pain-related consequences such as disability, and the success or failure of various pain treatments.

Additional evidence highlighting the influence of psychosocial factors as mediators and moderators of chronic pain is necessary, in order to better design treatments.

Indeed, I would like to see additional evidence that it’s not my broken body that’s causing all kinds of pinching and aching pain, but rather my “psychosocial” attitude.

With a very clear mechanical reason for my pain (defective and loose connective tissue), I demand PROOF that MY pain is NOT physical.

The AAPT classification system is a positive contribution to improving the management of chronic pain, as it enables the assessment of the multidimensional contributors to the pain experience by incorporating the psychosocial influences.

The complexity and individual variability of the chronic pain experience highlights the need for a comprehensive approach to its assessment. A variety of approaches have been used to develop diagnostic criteria for chronic pain, however, current approaches to chronic pain classification, and on which the diagnostic criteria are based, lack an evidence-based taxonomy.

My experience so far is that there is very little evidence-base for any cause or cure for chronic pain.

It is essential that a treatment strategy is designed to improve not only physical function, but also affect improvement in the psychosocial domains, such as catastrophizing, self-efficacy, depression, and improved coping skills.

This approach must be individualized so that a highly distressed and challenged individual with chronic pain may require more specific psychological expertise, compared to an individual with less severe psychosocial problems.

Especially for chronic pain, treatment absolutely must be individualized. Any particular standard dose would be wrong for almost everyone. You can’t treat a patient like the “average patient” because such a person does not exist.

It’s like weighing hundreds of dogs and finding that the size of the “average dog” is 37.1415926535 pounds: you may never find an individual dog of that weight.

An empirically based pain classification system that recognizes individual differences as well as the significant influence of biopsychosocial domains in the pain experience, can serve to inform policy, clarify prognosis, guide treatment decisions, and overall, improve pain management.

You cannot concurrently standardize (classify) and individualize (variation) anything. The more they insist that pain is psychosocially individualized, the less sensible any kind of standardization seems.

Summary and Clinical Applicability

In partnership with the American Pain Society, an evidence-based chronic pain classification system – the ACTTION-American Pain Society Pain Taxonomy (AAPT) was developed to address the need for evidence-based diagnostic criteria for the major chronic pain conditions.

The AAPT is an evidence-based multidimensional chronic pain classification system that incorporates psychosocial concepts and processes in the assessment of chronic pain.

The improved classification of chronic pain offers opportunity to broaden and enhance therapeutic interventions that may include more effective blending of psychological intervention with a biomedical approach to chronic pain management.

For an explanation of how the ful AAPT was developed and what criteria it tries to measure, see this full-text PMC article:
The ACTTION-American Pain Society Pain Taxonomy (AAPT): An Evidence-Based and Multi-Dimensional Approach to Classifying Chronic Pain Conditions
This document has several tables which give an outline of the taxonomy:

Table 1

Characteristics of an Ideal Diagnostic System

Characteristic Description
Biologically Plausible The diagnostic system must be consistent with the biological processes underlying the signs and symptoms that characterize the disorders of interest.
Exhaustive The diagnostic system must encompass all clinical disorders within the domain of interest.
Mutually Exclusive The diagnostic system must encode each disorder once and only once.
Reliable The diagnostic system must be applicable with a high degree of consistency across time and between diagnosticians.
Clinically Useful The diagnostic system must be useful in the clinical setting, guiding prognosis and therapy.
Simple The diagnostic system must be both straightforward and efficient enough for practical use.

Table 2

Organization of Chronic Pain Disorders to be Included in the AAPT.*

Peripheral & Central Nervous Systems
  – Peripheral Neuropathic Pain
  – Central Neuropathic Pain
Musculoskeletal Pain System
  – Osteoarthritis
  – Other Arthritides (e.g. Rheumatoid Arthritis, Gout, Connective Tissue Diseases)
  – Musculoskeletal Low Back Pain
  – Myofascial Pain, Chronic Widespread Pain, and Fibromyalgia
  – Other Predominantly Musculoskeletal Pain
Orofacial & Head Pain System
  – Headache Disorders*
  – Temporomandibular Disorders
  – Other Orofacial Pain
Visceral, Pelvic & Urogenital Pain
  – Visceral Pain: Abdominal, Pelvic, and Urogenital Pain
Disease-Associated Pains Not Classified Elsewhere
  -E.g. Pain associated with active cancer, with sickle cell disease, or with Lyme disease.

Table 3

The Dimensions Comprising the AAPT.

Dimension Description
Dimension 1: Core Diagnostic Criteria Includes symptoms and signs required for diagnosis of the disorder (e.g. periauricular pain, palpation sensitivity, joint sounds in the case of TMD). Also includes diagnostic tests and differential diagnosis considerations.
Dimension 2: Common Features Provides additional information regarding the disorder, including common pain characteristics (e.g. location, temporal qualities, descriptors), non-pain features (numbness, fatigue), and the epidemiology of the disorder. These features are helpful in describing the disorder but are not used as part of the diagnosis.
Dimension 3: Common Medical Comorbidities Includes medical diagnoses that co-occur with high frequency with the pain disorder. For example, diabetes mellitus is often comorbid with osteoarthritis, and major depression is comorbid with many chronic pain disorders.
Dimension 4: Neurobiological, Psychosocial and Functional Consequences Includes information regarding neurobiological and psychosocial consequences of chronic pain, as well as the functional impact of the pain disorder. Examples include, allostatic load, sleep quality, mood/affect, coping resources, physical function, and pain-related interference with daily activities
Dimension 5: Putative Neurobiological and Psychosocial Mechanisms, Risk Factors & Protective Factors Includes putative neurobiological and psychosocial mechanisms contributing to the pain disorder, including potential risk factors and protective factors.

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