Limited research suggests that there may be Warm complex regional pain syndrome (CRPS) and Cold CRPS subtypes, with inflammatory mechanisms contributing most strongly to the former. This study for ...the first time used an unbiased statistical pattern recognition technique to evaluate whether distinct Warm vs Cold CRPS subtypes can be discerned in the clinical population. An international, multisite study was conducted using standardized procedures to evaluate signs and symptoms in 152 patients with clinical CRPS at baseline, with 3-month follow-up evaluations in 112 of these patients. Two-step cluster analysis using automated cluster selection identified a 2-cluster solution as optimal. Results revealed a Warm CRPS patient cluster characterized by a warm, red, edematous, and sweaty extremity and a Cold CRPS patient cluster characterized by a cold, blue, and less edematous extremity. Median pain duration was significantly (P < 0.001) shorter in the Warm CRPS (4.7 months) than in the Cold CRPS subtype (20 months), with pain intensity comparable. A derived total inflammatory score was significantly (P < 0.001) elevated in the Warm CRPS group (compared with Cold CRPS) at baseline but diminished significantly (P < 0.001) over the follow-up period, whereas this score did not diminish in the Cold CRPS group (time × subtype interaction: P < 0.001). Results support the existence of a Warm CRPS subtype common in patients with acute (<6 months) CRPS and a relatively distinct Cold CRPS subtype most common in chronic CRPS. The pattern of clinical features suggests that inflammatory mechanisms contribute most prominently to the Warm CRPS subtype but that these mechanisms diminish substantially during the first year postinjury.
There have been many articles highlighting differences and similarities between complex regional pain syndrome (CRPS) and functional neurological disorders (FND) but until now the discussions have ...often been adversarial with an erroneous focus on malingering and a view of FND as ‘all in the mind’. However, understanding of the nature, frequency and treatment of FND has changed dramatically in the last 10–15 years. FND is no longer assumed to be only the result of ‘conversion’ of psychological conflict but is understood as a complex interplay between physiological stimulus, expectation, learning and attention mediated through a Bayesian framework, with biopsychosocial predisposing, triggering and perpetuating inputs. Building on this new ‘whole brain’ perspective of FND, we reframe the debate about the ‘psychological versus physical’ basis of CRPS. We recognise how CRPS research may inform mechanistic understanding of FND and conversely, how advances in FND, especially treatment, have implications for improving understanding and management of CRPS.
Objective
This is the fourth edition of diagnostic and treatment guidelines for complex regional pain syndrome (CRPS; aka reflex sympathetic dystrophy).
Methods
Expert practitioners in each ...discipline traditionally utilized in the treatment of CRPS systematically reviewed the available and relevant literature; due to the paucity of levels 1 and 2 studies, less rigorous, preliminary research reports were included. The literature review was supplemented with knowledge gained from extensive empirical clinical experience, particularly in areas where high‐quality evidence to guide therapy is lacking.
Results
The research quality, clinical relevance, and “state of the art” of diagnostic criteria or treatment modalities are discussed, sometimes in considerable detail with an eye to the expert practitioner in each therapeutic area. Levels of evidence are mentioned when available, so that the practitioner can better assess and analyze the modality under discussion, and if desired, to personally consider the citations. Tables provide details on characteristics of studies in different subject domains described in the literature.
Conclusions
In the humanitarian spirit of making the most of all current thinking in the area, balanced by a careful case‐by‐case analysis of the risk/cost vs benefit analysis, the authors offer these “practical” guidelines.
Complex regional pain syndrome (CRPS) is a multifactorial condition that may affect patients who sustain a fracture in the upper and lower extremities. Prior investigations have formed a foundation ...for exploring a possible association between psychiatric disorders and the development of CRPS; however, current studies are conflicted regarding the existence and temporality of a relationship between psychiatric disorders and the potential development of CRPS.
(1) Are patients with preexisting anxiety and mood disorders (AMDs) at increased risk of receiving a diagnosis of CRPS after upper or lower extremity fractures? (2) Are patients with preexisting AMDs at increased risk of being diagnosed with CRPS after surgical fixation of their fracture?
A large, retrospective cohort study was conducted using the TriNetX electronic medical record platform, which contains data from more than 100 million patients. This platform gathers data from healthcare organizations in the United States and Europe and collects comprehensive data over time that includes temporality rather than simply the binary presence or absence of conditions. The cohort included 760,595 patients older than 18 years with upper or lower extremity fractures between 2003 and 2022. Included patients had a minimum 1-year follow-up. We defined AMDs as any diagnosis of anxiety, depressive episode or disorder, a manic episode, or bipolar disorder. Patients with polytrauma or concurrent upper and lower extremity fractures were excluded to reduce confounders. CRPS I diagnosis was identified via International Classification of Diseases, Tenth Edition codes. Propensity score matching was performed to balance cohorts based on age, gender, and race. Hazard ratios and Aalen-Johansen cumulative incidence curves for the diagnosis of CRPS were calculated for patients with and without AMD diagnoses before sustaining a fracture. A subanalysis was performed in which we examined individuals in the upper and lower extremity fracture cohorts who underwent surgical treatment.
Patients with preexisting AMDs were at a higher risk of experiencing CRPS I than patients without AMDs were (upper extremity: HR 1.8 95% CI 1.7 to 1.9; p < 0.01, lower extremity: HR 2.2 95% CI 2.0 to 2.3; p < 0.01). Similarly, patients with preexisting AMDs were at higher risk of experiencing CRPS I after fracture fixation than patients without AMDs were (upper extremity: HR 1.3 95% CI 1.2 to 1.5; p < 0.01, lower extremity: HR 2.3 95% CI 2.1 to 2.5; p < 0.01).
Awareness of the relationship between AMDs and CRPS I will direct future research about the development of this condition and associated neurologic changes. Additionally, surgeons can address AMDs perioperatively and arrange for the treatment of these AMDs with psychiatrists, neurologists, or social work, as appropriate. Accordingly, patients with AMDs should also be made aware of the inherent risk of CRPS I after an upper or lower extremity fracture to comprehensively educate and care for this at-risk patient population.
Level III, therapeutic study.
Background
Complex regional pain syndrome is a painful and disabling post‐traumatic primary pain disorder. Acute and chronic complex regional pain syndrome (CRPS) are major clinical challenges. In ...Europe, progress is hampered by significant heterogeneity in clinical practice. We sought to establish standards for the diagnosis and management of CRPS.
Methods
The European Pain Federation established a pan‐European task force of experts in CRPS who followed a four‐stage consensus challenge process to produce mandatory quality standards worded as grammatically imperative (must‐do) statements.
Results
We developed 17 standards in 8 areas of care. There are 2 standards in diagnosis, 1 in multidisciplinary care, 1 in assessment, 3 for care pathways, 1 in information and education, 4 in pain management, 3 in physical rehabilitation and 2 on distress management. The standards are presented and summarized, and their generation and consequences were discussed. Also presented are domains of practice for which no agreement on a standard could be reached. Areas of research needed to improve the validity and uptake of these standards are discussed.
Conclusion
The European Pain Federation task force present 17 standards of the diagnosis and management of CRPS for use in Europe. These are considered achievable for most countries and aspirational for a minority of countries depending on their healthcare resource and structures.
Significance
This position statement summarizes expert opinion on acceptable standards for CRPS care in Europe.
The mechanisms underlying complex regional pain syndrome (CRPS) have been increasingly studied over the past decade. Classically, this painful and disabling disorder was considered to emerge from ...pathology of the central nervous system. However, the involvement of additional peripheral disease mechanisms is likely, and recently these mechanisms have also attracted scientific attention. The present article provides an overview of the current understandings regarding pathology of the autonomic and somatic nervous system in CRPS, as well as the roles of neurogenic inflammation, hypoxia, and the contribution of psychological factors. Potential connections between the separate disease mechanisms will be discussed. Additionally, currently known risk factors for CRPS will be addressed. Insight into risk factors is of relevance as it facilitates early diagnosis and tailored treatment. Moreover, it may provide clues for further unraveling of the pathogenesis and etiology of CRPS.
Complex Regional Pain Syndrome (CRPS), a chronic pain condition, develops mainly after limb trauma and severely inhibits function. While early diagnosis is essential, factors for CRPS onset are ...elusive. Therefore, identifying those at risk is crucial. Sensory modulation dysfunction (SMD), affects the capacity to regulate responses to sensory input in a graded and adaptive manner and was found associated with hyperalgesia in otherwise healthy individuals, suggestive of altered pain processing.
To test SMD as a potential risk factor for CRPS.
In this cross-sectional study, forty-four individuals with CRPS (29.9±11 years, 27 men) and 204 healthy controls (27.4±3.7 years, 105 men) completed the Sensory Responsiveness Questionnaire-Intensity Scale (SRQ-IS). A physician conducted the CRPS Severity Score (CSS), testing individuals with CRPS.
Thirty-four percent of the individuals with CRPS and twelve percent of the healthy individuals were identified to have SMD (χ2 (1) = 11.95; p<0.001). Logistic regression modeling revealed that the risk of CRPS is 2.68 and 8.21 times higher in individuals with sensory over- and sensory under-responsiveness, respectively, compared to non-SMD individuals (p = 0.03 and p = 0.01, respectively).
SMD, particularly sensory under-responsiveness, might serve as a potential risk factor for CRPS and therefore screening for SMD is recommended. This study provides the risk index probability clinical tool a simple evaluation to be applied by clinicians in order to identify those at risk for CRPS immediately after injury. Further research is needed.
Complex regional pain syndrome (CRPS) is a debilitating chronic pain condition that, although exceedingly rare, carries a significant burden for the affected patient population. The complex and ...ambiguous pathophysiology of this condition further complicates clinical management and therapeutic interventions. Furthermore, being a diagnosis of exclusion requires a diligent workup to ensure an accurate diagnosis and subsequent targeted management. The development of the Budapest diagnostic criteria helped to consolidate existing definitions of CRPS but extensive work remains in identifying the underlying pathways. Currently, two distinct types are identified by the presence (CRPS type 1) or absence (CRPS type 2) of neuronal injury. Current management directed at this disease is broad and growing, ranging from non-invasive modalities such as physical and psychological therapy to more invasive techniques such as dorsal root ganglion stimulation and potentially amputation. Ideal therapeutic interventions are multimodal in nature to address the likely multifactorial pathological development of CRPS. Regardless, a significant need remains for continued studies to elucidate the pathways involved in developing CRPS as well as more robust clinical trials for various treatment modalities.
Summary A complex regional pain syndrome (CRPS)—multiple system dysfunction, severe and often chronic pain, and disability—can be triggered by a minor injury, a fact that has fascinated scientists ...and perplexed clinicians for decades. However, substantial advances across several medical disciplines have recently improved our understanding of CRPS. Compelling evidence implicates biological pathways that underlie aberrant inflammation, vasomotor dysfunction, and maladaptive neuroplasticity in the clinical features of CRPS. Collectively, the evidence points to CRPS being a multifactorial disorder that is associated with an aberrant host response to tissue injury. Variation in susceptibility to perturbed regulation of any of the underlying biological pathways probably accounts for the clinical heterogeneity of CRPS.