Development of a severity score for CRPS

Abstract

The clinical diagnosis of Complex Regional Pain Syndrome (CRPS) is a dichotomous (yes/no) categorization necessary for clinical decision-making. However, such dichotomous diagnostic categories do not convey an individual's subtle and temporal gradations in severity of the condition, and have poor statistical power when used as an outcome measure in research. This study evaluated the validity and potential utility of a continuous type score to index severity of CRPS. Psychometric and medical evaluations were conducted in 114 CRPS patients and 41 non-CRPS neuropathic pain patients. Based on the presence/absence of 17 clinically-assessed signs and symptoms of CRPS, an overall CRPS Severity Score (CSS) was derived. The CSS discriminated well between CRPS and non-CRPS patients (p<.001), and displayed strong associations with dichotomous CRPS diagnoses using both IASP diagnostic criteria (Eta=0.69) and proposed revised criteria (Eta=0.77-0.88). Higher CSS was associated with significantly higher clinical pain intensity, distress, and functional impairments, as well as greater bilateral temperature asymmetry and thermal perception abnormalities (p's<.05). In an archival prospective dataset, increases in anxiety and depression from pre-surgical baseline to 4 weeks post-knee arthroplasty were found to predict significantly higher CSS at 6- and 12-month follow-up (p's<.05). Results indicate the CSS corresponds with and complements currently accepted dichotomous diagnostic criteria for CRPS, and support its validity as an index of CRPS severity. Its utility as an outcome measure in research studies is also suggested, with potential statistical advantages over dichotomous diagnostic criteria.

Complex regional pain syndrome

“…In older patients undergoing total knee arthroplasty (n=77), greater increases in the extent of depressive symptoms from before surgery to one month after surgery predicted greater severity of CRPS symptoms at six month and 12 month follow-up. 96 Similar effects were seen for early increases in anxiety after surgery as that the greater the intensity of early pain and the longer a CRPS-like presentation persists, the more likely it is to be CRPS rather than delayed normal healing.…”

“…109 110 The ischemic reperfusion injury animal model described previously that reproduces many features of CRPS type I activates this oxidative stress pathway, 35 37 and pharmacological interventions that reduce oxidative stress a predictor of the severity of CRPS at six months. 96 In addition, preoperative anxiety significantly predicted the presence of a CRPS-like syndrome at one month after surgery, but not at three or six month follow-up. 97 Similarly, in patients with an upper extremity fracture (n=50), higher anxiety (but not depression) two days after fracture predicted significantly higher risk of a diagnosis of CRPS at two to four month follow-up.…”

“…Box 2 | Possible mechanisms involved in complex regional pain syndrome Nerve injury [31][32][33][34] Ischemic reperfusion injury or oxidative stress [35][36][37][38][39][40] Central sensitization [41][42][43] Peripheral sensitization 44 45 Altered sympathetic nervous system function or sympathoafferent coupling [46][47][48][49][50][51][52] Inflammatory and immune related factors Brain changes [78][79][80][81][82][83][84][85][86][87][88][89] Genetic factors [90][91][92] Psychological factors and disuse [93][94][95][96][97][98][99][100][101][102][103] deep tissues after injury have also been suggested as triggers for the onset of CRPS. …”

The Role of Pain Coping and Kinesiophobia in Patients With Complex Regional Pain Syndrome Type 1 of the Legs

“…This score counts the presence of 8 symptoms and 9 signs for a maximum score of 17, with higher scores reflecting more severe CRPS. 24 Patients also completed the McGill Pain Questionnaire (MPQ), 25 Questionnaire on Walking 26 and Rising, 27 the SF-36, 28 Tampa Scale for Kinesiophobia (TSK), 29 and Pain Coping Inventory (PCI). 14 The MPQ is a valid and reliable instrument that includes 20 categories of words that evaluate various aspects of pain.…”

Mast Cells

“…URING the last century, we have heard numerous hypotheses about the pathophysiology of the clinical conundrum complex regional pain syndrome (CRPS), 1 which has an incidence of 2-5% after limb fractures. 2 We have read about sympathetic disturbances, 3 sympathonociceptive coupling, 4 spinal changes, 5 CRPS personality, 6 and malingering.…”