Andrew Atkinson considers IASP’s recently published amendments to the Budapest Criteria for the diagnosis of CRPS.
With no medical tests for Complex Regional Pain Syndrome (CRPS), a clinical diagnosis is based entirely upon an accepted set of guidelines. At their conference in 2004, the International Association for the Study of Pain (IASP) adopted a new set of guidelines, superseding those in place for a decade. As the hosting city for the conference, the Budapest Criteria were born. They differentiate between ‘signs’, which are seen or felt by the clinician carrying out the examination and ‘symptoms’, which the patient reports. You will find the Budapest Criteria summarised in an earlier article, so I have not repeated them here.
Valencia consensus-based adaptation
With advances in medical science over the following decade and a half, the Budapest Criteria were long overdue an overhaul. Consequently, in 2019, the IASP CRPS Special Interest Group convened a workshop in Valencia “to review perceived ambiguities in the diagnostic text and issues identified in applying these criteria in both the research and clinical contexts.” Their conclusions were reported recently in the IASP journal, PAIN.
Following the review, a consensus was reached regarding updates to the assessment instructions for CRPS and the associated text. Crucially, however, “the wording of the diagnostic criteria themselves was not altered so as to avoid invalidating the criteria.” So, the Budapest Criteria survive but now incorporate “the Valencia consensus-based adaptation” – which admittedly does not readily trip off the tongue!
The following are just some of the changes recommended:
- There is a recognition that the parent classification of CRPS as a “focal or segmental autonomic disorder” is “a mistake based on the historic misunderstanding of CRPS as primarily an autonomic disorder.” It’s therefore proposed that the parent classification be changed to “chronic primary pain”.
- The group have clarified that the diagnostic signs of CRPS Type II “must extend beyond any identified injured nerve territory” and it should “not be classed as a neuropathic pain condition”, acknowledging that the “diagnostic signs of CRPS I (without discrete nerve damage) and II are identical.”
- A third CRPS subtype has been introduced – “CRPS with Remission of Some Features” for patients who were previously documented as having fully met the CRPS criteria but who currently display CRPS features insufficient to fully meet the diagnostic criteria. They have also modified the description of the current diagnostic label CRPS Not Otherwise Specified (NOS) to minimise any confusion with using this latter term. The term “CRPS-NOS” in the current IASP criteria “has been retained exclusively for application to patients who have never been documented to fulfil the new IASP CRPS criteria” rather than for patients who no longer meet the CRPS criteria.
- “Warm/cold CRPS and early/persistent CRPS are overlapping presentations that are clinically observed” but there is “not…sufficient evidence yet to create formal CRPS subgroups according to these features.”
- “All patients should be asked systematically about all symptoms listed in the criteria at each formal diagnostic evaluation, even if they have not previously reported certain symptoms. This is recommended because CRPS signs and symptoms are clinically observed to fluctuate over time.”
- “For evaluating possible spreading of CRPS beyond a single limb, the full diagnostic criteria must be applied to each limb individually…[The] extension of pain alone to other limbs, which is not unusual, in the absence of other CRPS features is not formally considered to be spreading CRPS.”
- “Hyperalgesia…is a clinical observation in which a painful stimulus evokes more pain than it normally would.” The group have recommended “standard testing for hyperalgesia by comparing the response to a single pinprick applied in the center of the most affected region to the response to an identical pinprick at the corresponding location on the unaffected limb, or an equivalent control site in the case of bilateral CRPS. The test is positive if reported pain is more intense or lasts longer on the affected limb.”
- “Stimuli used in clinical allodynia assessment can include light touch, vibration, cool or warm temperature, deep tissue or joint pressure in the affected area, or joint movement. Only one of these is required to confirm whether allodynia is present or absent.”
- “Temperature asymmetry is assessed in the affected area and compared with the corresponding area on the contralateral extremity, or a suitable control site in the case of bilateral CRPS. Such asymmetry should be obvious to the touch of the dorsum of the hand of the examiner.” [our emphasis]
- The clinician should specify the nature of “obvious colour asymmetry of a regional nature (i.e. hand, foot, knee, or larger region).”