A brief review of complex regional pain syndrome and current management

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.

Complex regional pain syndrome: advances in epidemiology, pathophysiology, diagnosis, and treatment

Complex regional pain syndrome (CRPS) is a rare pain disorder that usually occurs in a limb after trauma. The features of this disorder include severe pain and sensory, autonomic, motor, and trophic abnormalities. Research from the past decade has offered new insights into CRPS epidemiology, pathophysiology, diagnosis, and treatment. Early identification of individuals at high risk of CRPS is improving, with several risk factors established and some others identified in prospective studies during the past 5 years. Better understanding of the pathophysiological mechanisms of CRPS has led to its classification as a chronic primary pain disorder, and subtypes of CRPS have been updated. Procedures for diagnosis have also been clarified. Although effective treatment of CRPS remains a challenge, evidence-based integrated management approaches provide new opportunities to improve patient care. Further advances in diagnosis and treatment of CRPS will require coordinated, international multicentre initiatives.

Complex regional pain syndrome: diagnostic challenges and favorable response to prednisolone

Complex regional pain syndrome (CRPS), characterized by severe and disproportionate pain, is a rare and debilitating condition. Due to its rarity, evidence-based treatment guidelines remain limited, creating a challenge for clinicians. We present the case of a 20-year-old female with CRPS type 1 of the right hand. Her pain, initially triggered by a minor trauma, had persisted for three months. The patient demonstrated severe pain, swelling, hyperesthesia, and restricted range of motion. Despite multiple hospital visits, her symptoms did not improve until she was diagnosed with CRPS and treated with oral prednisolone. A dosage of 40 mg daily led to a dramatic response within 10 days. Our report emphasizes the importance of recognizing CRPS and highlights the potential of prednisolone as a treatment option, particularly in resource-limited settings, where more specialized interventions may be unavailable. Further research is essential to establish a stronger evidence base for the use of steroids in CRPS management.

Impact of different CRPS phenotypes and diagnostic criteria on quantitative sensory testing outcomes: systematic review and meta-analysis

OBJECTIVES

This review and meta-analysis evaluated the impact of diagnostic criteria and clinical phenotypes on quantitative sensory testing (QST) outcomes in patients with complex regional pain syndrome (CRPS).

METHODS

Eight databases were searched based on a previously published protocol. Forty studies comparing QST outcomes between CRPS-I vs II, warm vs cold CRPS, upper vs lower limb CRPS, males vs females, or using Budapest vs older IASP criteria were included.

RESULTS

Studies investigating QST differences between CRPS-I vs II (n = 4), between males vs females (n = 2), and between upper and lower limb CRPS (n = 2) showed no significant differences. Four studies compared QST outcomes in warm vs cold CRPS, showing heat hyperalgesia in warm CRPS, with thermal and mechanical sensory loss in cold CRPS. Although CRPS diagnosed using the Budapest criteria (24 studies) vs 1994 IASP criteria (13 studies) showed similar sensory profiles, there was significant heterogeneity and low quality of evidence in the latter.

CONCLUSIONS

Based on the findings of this review, classifying CRPS according to presence or absence of nerve lesion into CRPS-I and II, location (upper or lower limb) or according to sex might not be clinically relevant as all appear to have comparable sensory profiles that might suggest similar underlying mechanisms. In contrast, warm vs cold phenotypes exhibited clear differences in their associated QST sensory profiles. To the extent that differences in underlying mechanisms might lead to differential treatment responsiveness, it appears unlikely that CRPS-I vs II, CRPS location, or patient sex would prove useful in guiding clinical management.

Early versus persistent Complex Regional Pain Syndrome: Is there a difference in patient reported outcomes following rehabilitation?

BACKGROUND

Expert consensus asserts that early treatment of Complex Regional Pain Syndrome (CRPS) leads to better outcomes. Yet no evidence supports this assumption regarding the recognized gold standard of multidisciplinary functional rehabilitation. To address this, we aimed to establish if there is a difference in outcomes between early CRPS (<1 year symptom duration) and persistent CRPS (= >1 year symptom duration) following rehabilitation and whether any gains are maintained at three months.

METHOD

Secondary analysis was conducted on previously collected clinical Patient Reported Outcome Measures (PROMS) data from 218 patients attending a residential multidisciplinary rehabilitation programme. Datasets were categorized into early CRPS (n = 40) or persistent CRPS (n = 178) dependent on symptom duration. Function, pain, self-efficacy, kinesiophobia and psychological health domains were compared using repeated measures analysis of covariance for a two group design for group difference post rehabilitation and at three month follow-up.

RESULTS

Post-rehabilitation, both groups improved in pain, function, kinesiophobia, psychological health and self-efficacy. At three months, the persistent CRPS group maintained improvements in pain and function. This was not achieved in early CRPS.

CONCLUSION

This exploratory study is the first to empirically test the assumption that those with early CRPS have better outcomes following rehabilitation. Our clinical data challenges this, as both early and persistent CRPS groups improved following rehabilitation. Findings indicate that rehabilitation benefits those with CRPS, regardless of symptom duration. However, unlike early CRPS, those with persistent CRPS sustain gains at follow-up. Further prospective exploration is warranted.

SIGNIFICANCE

Expert consensus recommends early treatment for Complex Regional Pain Syndrome, yet there is little empirical evidence to support this. Our findings are the first to challenge this assumption by revealing no difference in outcomes between early and persistent CRPS post-rehabilitation. However, those with persistent CRPS maintain gains after three months, unlike people with early CRPS (symptoms < one year). These findings are relevant to clinical practice as they challenge established assumptions, suggesting a focus on improving early CRPS follow-up outcomes.

Patients With Preexisting Anxiety and Mood Disorders Are More Likely to Develop Complex Regional Pain Syndrome After Fractures

BACKGROUND

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.

QUESTIONS/PURPOSES

(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?

METHODS

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.

RESULTS

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).

CONCLUSION

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 OF EVIDENCE

Level III, therapeutic study.

An update on the pharmacotherapeutic options for complex regional pain syndrome

INTRODUCTION

Complex regional pain syndrome (CRPS) is a rare and painful condition that has a wide range of triggering factors, often traumatic, and can present various clinical manifestations. The lack of knowledge about the underlying mechanisms has led to numerous treatment approaches, both conservative and surgical, which work through different mechanisms of action.

AREAS COVERED

In this review, the authors explore the key aspects of CRPS, including definition, diagnostic criteria, pitfalls, pathogenic hypotheses, and treatment strategies with a focus on pharmacotherapy. The review was based on a comprehensive search of the literature using PubMed, while also considering international guidelines for managing CRPS.

EXPERT OPINION

Based on the available evidence, pharmacological interventions appear to be effective in treating CRPS, especially when they target peripheral mechanisms, specifically nociceptive inflammatory pain, and when administered early in the course of the disease. However, there is still a lack of reliable evidence regarding the effects of drugs on central mechanisms of chronic pain in CRPS. In our expert opinion, drug therapy should be initiated as soon as possible, particularly in warm CRPS patient clusters, to prevent significant functional limitations, psychological distress, and negative impacts on individuals' social and economic well-being.

Prevalence and predisposing factors of post-stroke complex regional pain syndrome: Retrospective case-control study

INTRODUCTION

Poststroke complex regional pain syndrome (CRPS) is an important complication in stroke survivors. The identification of factors associated with post-stroke CRPS is important for preventive measures and early diagnosis.

METHODS

A total of 141 first-ever stroke survivors in the subacute stage were retrospectively analyzed. Demographic data, diagnosis time, duration of hospitalization, location of brain lesion, etiology, comorbidities, and blood test findings were investigated. Clinical data included Medical Research Council (MRC) grade, Fugl-Meyer assessment (FMA), National Institute for Health Stroke Scale (NIHSS), Berg Balance Scale (BBS).

RESULTS

Among 141 patients with subacute stroke, 22 were diagnosed with CRPS, with a prevalence of 15.6 %. The mean time to diagnosis was 38.6 (±16.5) days. The prevalence according to the degree of paralysis was 33.3 % in MRC grades 0 and 1, 8.6 % in grade 2, and 0 % in grade 3 or higher. The incidence rates within 1 month after stroke were 1.42 % and 22.47 % between 1 and 3 months after stroke, respectively. The independent risk factors for CRPS were hospitalization duration and FMA, NIHSS, and BBS scores. The sensitivity and specificity of the NIHSS score for predicting post-stroke CRPS were 86.4 % and 59.7 %, respectively, with an optimal cutoff value of 7.5.

CONCLUSIONS

CRPS of the affected upper limb in stroke patients is associated with stroke severity, including paralysis, and the incidence increases over time during the subacute phase. Additionally, having sufficient strength to move through a full range of motion against gravity had a protective effect against CRPS.

Resting-state Electroencephalography Microstates Correlate with Pain Intensity in Patients with Complex Regional Pain Syndrome

Objective: Severe pain and other symptoms in complex regional pain syndrome (CRPS), such as allodynia and hyperalgesia, are associated with abnormal resting-state brain network activity. No studies to date have examined resting-state brain networks in CRPS patients using electroencephalography (EEG), which can clarify the temporal dynamics of brain networks. Methods: We conducted microstate analysis using resting-state EEG signals to prospectively reveal direct correlations with pain intensity in CRPS patients (n = 17). Five microstate topographies were fitted back to individual CRPS patients' EEG data, and temporal microstate measures were subsequently calculated. Results: Our results revealed five distinct microstates, termed microstates A to E, from resting EEG data in patients with CRPS. Microstates C, D and E were significantly correlated with pain intensity before pain treatment. Particularly, microstates D and E were significantly improved together with pain alleviation after pain treatment. As microstates D and E in the present study have previously been related to attentional networks and the default mode network, improvement in these networks might be related to pain relief in CRPS patients. Conclusions: The functional alterations of these brain networks affected the pain intensity of CRPS patients. Therefore, EEG microstate analyses may be used to identify surrogate markers for pain intensity.

Experiences of diagnosis and treatment for upper limb Complex Regional Pain Syndrome: a qualitative analysis

INTRODUCTION

Complex Regional Pain Syndrome (CRPS) most frequently affects the upper limb, with high associated disability. Delays to diagnosis and appropriate treatment can adversely impact prognosis and quality of life, but little is known about the healthcare experiences of people with CRPS. This study aimed to explore lived experiences of diagnosis and treatment for people with upper limb CRPS.

METHODS

Participants were recruited through online support groups and multiple public and private healthcare settings in the Greater Wellington Region, New Zealand. Semi-structured interviews were conducted with participants who had experienced upper limb CRPS for more than three months and less than three years. Interviews were transcribed verbatim and analysed using reflexive thematic analysis.

RESULTS

Thirteen participants (11 female, 2 male) aged between 43 and 68 years were interviewed. Duration of CRPS ranged from 7 months to 2.5 years. Five themes were identified. Participants initially engaged in healthcare out of a desire to return to being the person they were before having CRPS. Three interacting experiences epitomised the overall healthcare experience: (1) not knowing what is going on, (2) not being taken seriously, and (3) healthcare as adding another layer of load. Meanwhile, participants used multiple approaches in an attempt to not let CRPS stop them from continuing to live their lives.

CONCLUSIONS

Participants in this study felt that credible information, validation, and simplification from healthcare providers and systems would support their process of navigating towards a meaningful life and self-concept in the presence of CRPS.

COVID-19 Vaccination-related Complex Regional Pain Syndrome Masquerading as Erythromelalgia: A Case Report

Abstract is missing (Short communication)

Complex regional pain syndrome following vascular access creation for hemodialysis

Pain and swelling of a limb following creation of arterio-venous fistula (AVF) are often attributable to vascular disorders like venous hypertension or limb ischaemia. Here we report the case of a 70-years old man who developed pain and swelling of upper limb distal to the AVF during second post-operative week due to a complex regional pain syndrome (CRPS). CRPS is characterized by pain that is disproportionate to the invoking injury, autonomic dysfunction, trophic changes and functional impairment of affected limb. Hyperalgesia and allodynia are pain patterns characteristic of CRPS. CRPS has been reported rarely following AVF creation surgery. Prompt diagnosis of CRPS is important to avoid misdiagnosis of vascular disorders and for implementation of right therapeutic strategy.

Interpretation and content validity of the items of the Hamilton inventory to evaluate outcomes in Persian-speaking patients with complex regional pain syndrome: A cognitive interview approach

BACKGROUND

The Hamilton Inventory for complex regional pain syndrome (CRPS) is a multidisciplinary assessment tool to evaluate signs and symptoms in patients with CRPS, developed in the English language.

PURPOSE

This study aims to translate and cross-culturally adapt this tool for Persian-speaking patients with CRPS. Furthermore, this study aimed to understand how 1) Persian-speaking experts and patients interpret and calibrate responses to items on the Hamilton Inventory and 2) compensatory strategies that might affect responses.

STUDY DESIGN

A cross sectional study with cognitive interview method.

METHODS

Ten health care providers and 10 patients with CRPS were interviewed using cognitive interviewing techniques (talk-aloud, semi-structured interview probes). All interviews were recorded and transcribed verbatim. A directed content analysis was done to analyze the interviews using a previously established framework.

RESULTS

Overall, the items on the Hamilton Inventory were well received by participants. Areas, where questions were unclear to some participants were recorded and categorized into five themes: Clarity and Comprehension (100%) in item 1 from the health professional tool and (65%) from the eleven items of the patient-reported tool. Perspective modifiers of culture influenced the calibrations of items "I feel my condition has negatively affected my relationships." (12%) and "My symptoms affect my comfort level with intimacy." (20%) from the patient-reported tool.

CONCLUSION

The findings of this study demonstrate that there is no need for substantive changes to the items of the Hamilton Inventory, as they tend to be understood by Persian-speaking experts and patients with CRPS.

The complex regional pain syndrome: Diagnosis and management strategies

Complex regional pain syndrome (CRPS) is a chronic disease that affects a limb following an injury or trauma. The CRPS associated with symptoms, including severe pain, swelling, as well as changes in skin color and temperature. Treatment of CRPS requires a multidisciplinary approach, with a focus on personalized treatment plans and addressing psychological factors. This review provides an overview of updates in the diagnosis and treatment of CRPS. There are clinical criteria for diagnosing CRPS, including persistent pain and swelling. The CRPS can also be diagnosed with imaging and laboratory tests. Novel insights into treatment approaches for CRPS have been gained from advances in understanding its pathophysiology. Treatment of CRPS includes both pharmacological and non-pharmacological interventions. The latest guidelines for CRPS treatment emphasize the importance of early diagnosis and intervention, personalized treatment plans, and addressing psychological factors in managing CRPS.

Chronic Pain Syndromes: Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) is a chronic pain condition characterized by intense pain, usually in a body region that has experienced trauma, and autonomic and inflammatory features. It most commonly develops after an arm or leg injury. Patients typically present with extreme hyperalgesia and/or allodynia. The Budapest Criteria are used to make this clinical diagnosis. Prompt diagnosis and aggressive management are critical because long-term outcomes are improved when treatment is initiated soon after symptom onset. The primary management options are rehabilitation and physical therapy, including such approaches as progressive tactile stimulation, normalization of movement to prevent limited range of motion, and others. No drugs are approved by the Food and Drug Administration (FDA) for CRPS management, but some evidence supports the use of drugs used to manage other types of neuropathic pain (eg, gabapentin, tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors). Nonsteroidal anti-inflammatory drugs also are used, and corticosteroids, bisphosphonates, ketamine, and other drugs can be helpful, particularly for early-stage CRPS. When pain severity prevents patients from participating in rehabilitation, referral to a pain specialist is warranted for consideration of procedural interventions, including sympathetic nerve blockade and spinal cord stimulation.

Diagnosis and Outcomes of 225 Consecutive Cases of Complex Regional Pain Syndrome of the Hand

BACKGROUND

The lack of specific tests and potential diagnostic inaccuracy may be behind the stunning figures of complex regional pain syndrome (CRPS) cases. The author tested the hypothesis that patients diagnosed with CRPS at referral could be assigned to recognized conditions and treated accordingly.

METHODS

From January of 2018 to April of 2021, 225 consecutive patients attended the author's office having been diagnosed with and treated for CRPS for an average of 16 ± 26 months. There were 180 women and 45 men; no patient was excluded.

RESULTS

All patients could be allocated in named conditions: 79 had a wrong diagnosis; seven had a true causalgia; 16 were dystonic-psychogenic hands; 20 presented a flare reaction; and 90 had an "irritative" carpal tunnel syndrome. The remaining 13 patients had a miscellany of symptoms within a substandard management setting. Surgery was offered to 175 with a correctable cause; 50 (20 of whom had a tangible cause responsible for their pain) declined, and their outcome is unknown. The remaining 125 were operated on and tracked for an average of 20 ± 9 months. In the operated group, pain dropped 7.5 ± 2.2 points ( P < 0.0001) on a numerical rating scale of 0 to 10. Disabilities of the Arm, Shoulder, and Hand questionnaire scores fell from 80 to 16 ( P < 0.0001). Patients who were operated on rated their satisfaction on a scale of 0 to 10 as 8.9 ± 1.9.

CONCLUSIONS

Unlike with CRPS, all patients in this series had a true, diagnosable condition explaining their clinical picture. Most patients who agreed to be operated on had a favorable outcome.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Optimising management of complex regional pain syndrome to improve clinical outcomes throughout the therapy care pathway in England: Protocol for a qualitative interview and observational study with patients and clinicians

INTRODUCTION

Complex Regional Pain Syndrome (CRPS) is a disabling and distressing chronic pain condition characterised by a range of sensory, motor, autonomic and trophic symptoms. Guidelines recommend early referral for therapies that promote movement of the painful limb. However, evidence suggests a lack of defined therapy pathways for CRPS.

AIMS

The current study aims to explore CRPS therapy management in centres of excellence in England, and outside of these settings, to understand what facilitates and hinders best practice. The overall aim is to develop a draft stratified package of care to expedite patient access to optimal CRPS therapy across the management pathway.

METHODS AND ANALYSIS

Semi-structured interviews will be conducted with therapists working in CRPS centres of excellence and with therapists in other settings. Observations of therapy interventions in CRPS centres of excellence and interviews with patients who have received this care, will also help to identify potential key care package components. Interview data will be analysed using thematic analysis, mapped to the Theoretical Domains Framework (TDF), and Intervention Mapping Adapt (IMA) framework. Observations will be described and documented using the TDF headings.

CONCLUSION

A triangulation protocol for qualitative health research will be used to integrate all data. Online stakeholder events will be held using consensus methods to agree a draft package of care for future implementation following further refinement, testing and evaluation.

CLINICAL TRIAL REGISTRATION

The trial was registered with ISRCTN registry on 24 February 2022 (ISRCTN16917807).

Clinical results of lumbar sympathetic blocks in lower limb complex regional pain syndrome using infrared thermography as a support tool

AIM

To describe the clinical outcomes for a group of complex regional pain syndrome patients using infrared thermography as an intraprocedural support tool when undertaking fluoroscopy-guided lumbar sympathetic blocks.

SUBJECTS

27 patients with lower limb complex regional pain syndrome accompanied by severe pain and persistent functional impairment.

METHODS

A series of three fluoroscopic-guided lumbar sympathetic blocks with local anesthetic and corticoids using infrared thermography as an intraprocedural support tool were performed. Clinical variables were collected at baseline, prior to each block, and one, three, and six months after blocks in a standardized checklist assessing each of the clinical categories of complex regional pain syndrome stipulated in the Budapest criteria.

RESULTS

23.75% of the blocks required more than one chance to achieve the desired thermal pattern and therefore to be considered as successful. A decrease in pain measured on a visual analogic scale was observed at all time points compared to pre-blockade data, but only 37% of the cases were categorized as responders, representing a ≥ 30% decrease in VAS, with the disappearance of pain at rest. An improvement of most of the clinical variables recorded was observed, such as tingling, edema, perception of thermal asymmetry, difference in coloring and sweating. There was a significant decrease of neuropathic pain and improvement of functional limitation. Logistic regression analysis showed the main variable to explain the probability of being a responder was immobilization time (odds ratio of 0.89).

CONCLUSION

A series of fluoroscopy-guided lumbar sympathetic blocks controlled by infrared thermography in the treatment of lower limb CRPS showed a responder rate of 37%.

Complex Regional Pain Syndrome: Evidence-Based Advances in Concepts and Treatments

PURPOSE OF REVIEW

This review presents the most current information about the epidemiology of complex regional pain syndrome (CRPS), classification and diagnostic criteria, childhood CRPS, subtypes, pathophysiology, conventional and less conventional treatments, and preventive strategies.

RECENT FINDINGS

CRPS is a painful disorder with multifactorial pathophysiology. The data describe sensitization of the central and peripheral nervous systems, inflammation, possible genetic factors, sympatho-afferent coupling, autoimmunity, and mental health factors as contributors to the syndrome. In addition to conventional subtypes (type I and type II), cluster analyses have uncovered other proposed subtypes. Prevalence of CRPS is approximately 1.2%, female gender is consistently associated with a higher risk of development, and substantial physical, emotional, and financial costs can result from the syndrome. Children with CRPS seem to benefit from multifaceted physical therapy leading to a high percentage of symptom-free patients. The best available evidence along with standard clinical practice supports pharmacological agents, physical and occupational therapy, sympathetic blocks for engaging physical restoration, steroids for acute CRPS, neuromodulation, ketamine, and intrathecal baclofen as therapeutic approaches. There are many emerging treatments that can be considered as a part of individualized, patient-centered care. Vitamin C may be preventive. CRPS can lead to progressively painful sensory and vascular changes, edema, limb weakness, and trophic disturbances, all of which substantially erode healthy living. Despite some progress in research, more comprehensive basic science investigation is needed to clarify the molecular mechanisms of the disease so that targeted treatments can be developed for better outcomes. Incorporating a variety of standard therapies with different modes of action may offer the most effective analgesia. Introducing less conventional approaches may also be helpful when traditional treatments fail to provide sufficient improvement.

Central sensitization in CRPS patients with widespread pain: a cross-sectional study

OBJECTIVE

Widespread pain hypersensitivity and enhanced temporal summation of pain (TSP) are commonly reported in patients with complex regional pain syndrome (CRPS) and discussed as proxies for central sensitization. This study aimed to directly relate such signs of neuronal hyperexcitability to the pain phenotype of CRPS patients.

METHODS

Twenty-one CRPS patients and 20 healthy controls (HC) were recruited. The pain phenotype including spatial pain extent (assessed in % body surface) and intensity were assessed and related to widespread pain hypersensitivity, TSP, and psychological factors. Quantitative sensory testing (QST) was performed in the affected, the contralateral and a remote (control) area.

RESULTS

CRPS patients showed decreased pressure pain thresholds in all tested areas (affected: t(34)  = 4.98, P < .001, contralateral: t(35) = 3.19, P = .005, control: t(31) = 2.65, P = .012). Additionally, patients showed increased TSP in the affected area (F(3,111) = 4.57, P = .009) compared to HC. TSP was even more enhanced in patients with a high compared to a low spatial pain extent (F(3,51) = 5.67, P = .008), suggesting pronounced spinal sensitization in patients with extended pain patterns. Furthermore, the spatial pain extent positively correlated with the Bath Body Perception Disturbance Scale (ρ = 0.491; P = .048).

CONCLUSIONS

Overall, we provide evidence that the pain phenotype in CRPS, that is, spatial pain extent, might be related to sensitization mechanism within the central nociceptive system. This study points towards central neuronal excitability as a potential therapeutic target in patients with more widespread CRPS.

Management of complex regional pain syndrome in trauma and orthopaedic surgery-a systematic review

INTRODUCTION

Complex regional pain syndrome (CRPS) is a neurological pain disorder that is challenging to diagnose and manage, resulting in increased morbidity and costs. It most commonly occurs following traumatic injury, such as a fracture, crush injury or surgery. Recent research has evaluated the efficacy of treatments which have contradicted previous hypotheses. This systematic review summarizes these findings to improve clinician's decision-making.

SOURCES OF DATA

A comprehensive search of PubMed, MEDLINE and Embase databases from inception through January 2021 was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two reviewers independently screened relevant articles discussing the management of CRPS in adult trauma patients. All prospective and retrospective studies, non-randomized comparison studies and case series were considered for inclusion. Data extraction was performed by populating a predefined data abstraction sheet.

AREAS OF AGREEMENT

There is strong evidence to suggest the efficacy of prompt physiotherapy, lidocaine, ketamine, bisphosphonates, sympathectomy and brachial plexus blocks in the management of CRPS.

AREAS OF CONTROVERSY

The latest evidence suggests that vitamin C has no significant role to play in the treatment or prevention of CRPS.

GROWING POINTS

A multidisciplinary team approach and early diagnosis are imperative for successful treatment of CRPS. The Budapest criteria and the British Orthopaedic Association Standards for Trauma and Orthopaedics (BOAST) guidelines should be used when diagnosing CRPS. There is currently no clear evidence of superiority in any treatment.

AREAS TIMELY FOR DEVELOPING RESEARCH

There are few high-quality studies that inform the best treatment modalities for CRPS. Though emerging treatments show promise, further research is needed.

Amputation for Complex Regional Pain Syndrome: Meta-Analysis and Validation of a Histopathology Scoring System

OBJECTIVE

Pathology can provide crucial insights into the etiology of disease. The goal of this review is to evaluate the rigor of histopathology reports of Complex Regional Pain Syndrome (CRPS).

METHODS

A systematic search of multiple databases identified papers that described amputation for CRPS with pathology findings. Control pathology articles were randomly chosen from the same journals. Landmark articles in Surgical Pathology were previously identified. Papers were categorized by the use of histology: Anatomic (microscopic description), Diagnostic (binary result), and Substrate (special studies only). A novel Histopathology Score assigned 1 point for each of 10 History elements and 15 Pathology elements. All articles were scored and analyzed by appropriate statistics.

RESULTS

The search identified 22 CRPS, 50 Control and 50 Landmark articles. Multivariable analysis of the Pathology Score showed a significantly higher score for Anatomic vs Non-Anatomic papers (Incidence Rate Ratio (IRR) 1.54, P < .001) and Landmark vs CRPS articles (IRR 1.39, P value .003). CRPS papers reported some elements infrequently: diagnostic criteria (31.8%), routine stain (50%), any clinic-pathologic correlation (40.9%), and sample size >2 (27.3%).

CONCLUSIONS

The Pathology Score is a useful quality assessment tool to evaluate studies. As expected, Anatomic papers scored significantly higher than Non-Anatomic papers. CRPS papers had small sample sizes (median 1) and infrequent reporting of diagnostic criteria, routine stain, any clinical pathologic correlation. These particular elements are crucial for analyzing and reviewing pathologic features. The analysis explains why it is quite difficult to write a meaningful systematic review of CRPS histology at this time.

Delphi study to define core clinical outcomes for inclusion in a complex regional pain syndrome international research registry and data bank

ABSTRACT

Complex regional pain syndrome (CRPS) clinical trials have historically captured a diverse range of outcomes. A minimum set of CRPS patient-reported outcomes has been agreed for inclusion in a future CRPS international clinical research registry and data bank. This study aimed to identify a complementary set of core clinical outcomes. Clinicians and researchers from the international CRPS community informed the content of a 2-round electronic Delphi study. Participation was invited from members of the International Association for the Study of Pain CRPS Special Interest Group and the International Research Consortium for CRPS. In round 1, participants rated the relevance of 59 clinical outcomes in relation to the question "What is the clinical presentation and course of CRPS, and what factors influence it?" (1 = not relevant and 9 = highly relevant). In round 2, participants rerated each outcome in the light of the round 1 median scores. The criterion for consensus was median score ≥7, agreed by 75% of respondents. The core study team considered the feasibility of data collection of each identified outcome in agreeing final selections. Sixty respondents completed both survey rounds, with responses broadly consistent across professions. Nine outcomes met the consensus criterion. Final outcomes recommended for inclusion in the core clinical set were record of medications, presence of posttraumatic stress disorder, extent of allodynia, and skin temperature difference between limbs. Study findings provide robust recommendations for core clinical outcome data fields in the future CPRS international clinical research registry. Alongside patient-reported outcomes, these data will enable a better understanding of CRPS.

Molecular and clinical markers of pain relief in complex regional pain syndrome: An observational study

BACKGROUND

Complex regional pain syndrome (CRPS) is marked by disproportionate pain after trauma. Whilst the long-term outcome is crucial to patients, predictors or biomarkers of the course of pain or CRPS symptoms are still lacking. In particular, microRNAs, such as miR-223, decreased in CRPS, have been described only in cross-sectional studies.

METHODS

In this study, we characterised CRPS patients over a course of 2.5 years of standard treatment. The patient underwent clinical examination including pain measurement, symptom questionnaires, quantitative sensory testing (QST) and blood sampling. Exosomal microRNA levels were measured via qPCR. After follow-up, patients were stratified into 'pain relief' (mean pain reduced by ≥2 numeric rating scale) or 'persistence' (mean pain unchanged or worsened). The primary outcome was miR-223 and miR-939 expression, secondary outcomes were differences in clinical parameters between groups and time points.

RESULTS

Thirty-nine patients were included, 33 of whom qualified for stratification. Overall, patients reported lower pain and improved clinical characteristics after 2.5 years, but no significant changes in QST or miR-223 and miR-939 expression levels. 16 patients met the criteria for pain relief. This was associated with stable exosomal miR-223 expression, whilst levels further decreased in pain persistence. Clinically, pain relief was marked by shorter disease duration and correlated positively with high initial pain.

CONCLUSION

We identified progressively reduced miR-223 as a putative biomarker of chronic CRPS pain. Clinically, this study underlines the importance of early diagnosis and treatment showing that high initial pain does not predict an unfavourable outcome. Finally, pain relief and recovery of sensory disturbances seem independent processes.

Comparison of Epidemiological Data of Complex Regional Pain Syndrome (CRPS) Patients in Relation to Disease Severity-A Retrospective Single-Center Study

A retrospective data analysis of 159 complex regional pain syndrome (CRPS) patients (n = 116 women, 73.0%, mean age 60.9 ± 14.4 years; n = 43 men, 27.0%, mean age 52.3 ± 16.7 years) was performed from 2009 to 2020. The right side was affected in 74 patients (46.5%), the left in 84 patients (52.8%), and 1 patient (0.7%) developed a bilateral CRPS. Data were analyzed for the frequency and distribution of symptoms. The number of reduction maneuvers and the number of Budapest criteria were compared in relation to the severity of CRPS. Hand and wrist (n = 107, 67.3%), followed by foot and ankle (n = 36, 22.6%) and other locations (n = 16, 10.1%) were mainly affected by CRPS. The main causes included direct trauma (n = 120, 75.5%), surgery without previous trauma (n = 25, 15.7%), other causes (n = 9, 5.7%), and spontaneous development (n = 3, 1.9%); there was also missing documentation (n = 2, 1.3%). The most common symptoms were difference in temperature (n = 156, 98.1%), limitation of movement (n = 149, 93.7%), and swelling (n = 146, 91.8%). There was no correlation between the number of reduction maneuvers and the number of Budapest criteria. In summary, patients with the following constellation are at increased risk of CRPS: a female, over 60 years old, who has fallen and has sustained a fracture in the hand or wrist with persistent pain and has been immobilized with a cast for approx. 4 weeks.

Assessment of body perception disturbances in complex regional pain syndrome: A systematic review using the COSMIN guideline

OBJECTIVE

To conduct a systematic review to identify which tools are being used to assess body perception disturbances in Complex Regional Pain Syndrome (CRPS) and to provide an evidence-based recommendation in the selection of an assessment tool, based on measurement properties.

DATABASES AND DATA TREATMENT

Five electronic databases (EMBASE, Pubmed, PsycInfo, Science Direct and Web of Science) were searched for English or French written articles, with no time restrictions. All original articles using a body perception assessment tool with adult patients with CRPS were selected, regardless of their design (controlled trials, single case, qualitative study). Two investigators screened abstracts, selected full articles and extracted data independently.

RESULTS

Thirty-eight full-text papers were obtained and three main methods to evaluate body perception disturbances were identified: The Bath Body Perception Disturbance Scale, the Neglect-like Symptoms questionnaire adapted from Galer and the patient's body perception description. No full psychometric assessments were found. The Limb Laterality Recognition Task was also used in conjunction with another method.

CONCLUSIONS

Three main assessment methods for CRPS body perception disturbances are currently used. Full psychometric evaluation has not been completed for any of the assessment methods. As a consequence, we could not fully apply the COSMIN guideline. To date, there is no agreement concerning the use of a specific questionnaire or scale. The results indicate a need for further research such as psychometric properties of these questionnaires.

SIGNIFICANCE

This systematic review identified body perception disturbances assessment methods and their the psychometric properties in order to provide help and guidance to researchers and clinicians to investigate those clinical features.

Preoperative Predictors of Complex Regional Pain Syndrome Outcomes in the 6 Months Following Total Knee Arthroplasty

This prospective observational study evaluated preoperative predictors of complex regional pain syndrome (CRPS) outcomes in the 6 months following total knee arthroplasty (TKA). Participants were n = 110 osteoarthritis patients (64.5% female) undergoing unilateral TKA with no prior CRPS history. Domains of negative affect (depression, anxiety, catastrophizing), pain (intensity, widespread pain, temporal summation of pain [TSP]), pain interference, sleep disturbance, and pro-inflammatory status (tumor necrosis factor-alpha [TNF-a]) were assessed preoperatively. CRPS outcomes at 6-week and 6-month follow-up included the continuous CRPS Severity Score (CSS) and dichotomous CRPS diagnoses (2012 IASP criteria). At 6 months, 12.7% of participants met CRPS criteria, exhibiting a "warm CRPS" phenotype. Six-week CSS scores were predicted by greater preoperative depression, anxiety, catastrophizing, TSP, pain intensity, sleep disturbance, and TNF-a (P's < .05). Provisional CRPS diagnosis at 6 weeks was predicted by higher preoperative TSP, sleep disturbance, and TNF-a (P's < .05). CSS scores at 6 months were predicted by more widespread and intense preoperative pain, and higher preoperative TSP, pain interference, and TNF-a (P's < .01). CRPS diagnosis at 6 months was predicted only by more widespread and intense pain preoperatively (P's < .05). Risk for CRPS following TKA appears to involve preoperative central sensitization and inflammatory mechanisms. Preoperative negative affect is unlikely to directly influence long-term CRPS risk. PERSPECTIVE: This article identifies preoperative predictors of CRPS features at 6 months following total knee arthroplasty, including more widespread pain and higher pain intensity, temporal summation of pain, pain interference, and tumor necrosis factor-alpha levels. Findings suggest the importance of central sensitization and inflammatory mechanisms in CRPS risk following tissue trauma.

Canadian surveillance study of complex regional pain syndrome in children

ABSTRACT

This study describes the minimum incidence of pediatric complex regional pain syndrome (CRPS), clinical features, and treatments recommended by pediatricians and pain clinics in Canada. Participants in the Canadian Paediatric Surveillance Program reported new cases of CRPS aged 2 to 18 years monthly and completed a detailed case reporting questionnaire from September 2017 to August 2019. Descriptive analysis was completed, and the annual incidence of CRPS by sex and age groupings was estimated. A total of 198 cases were reported to the Canadian Paediatric Surveillance Program, and 168 (84.8%) met the case definition. The minimum Canadian incidence of CRPS is estimated at 1.14/100,000 (95% confidence interval 0.93-1.35/100,000) children per year. Incidence was highest among girls 12 years and older (3.10, 95% confidence interval 2.76-3.44/100,000). The mean age of CRPS diagnosis was 12.2 years (SD = 2.4), with the mean time from symptom onset to diagnosis of 5.6 months (SD = 9.9) and no known inciting event for 19.6% of cases. Most cases had lower limb involvement (79.8%). Nonsteroidal anti-inflammatory drugs (82.7%) and acetaminophen (66.0%) were prescribed more commonly than antiepileptic drugs (52.3%) and antidepressants (32.0%). Referrals most commonly included physical therapy (83.3%) and multidisciplinary pain clinics (72.6%); a small number of patients withdrew from treatment because of pain exacerbation (5.3%). Pain education was recommended for only 65.6% of cases. Treatment variability highlights the need for empiric data to support treatment of pediatric CRPS and development of treatment consensus guidelines.

Osteo-Cutaneous Trophic Changes in Complex Regional Pain Syndrome and their Reversal with Steroids

BACKGROUND

Complex regional pain syndrome (CRPS) is a chronic pain condition characterized by autonomic and inflammatory features. There is paucity of data regarding sustained benefits of any treatment modality. We aimed to document the effect of steroids in CRPS on long-term basis.

MATERIALS AND METHODS

We came across five patients of CRPS in Out Patient clinics of super-speciality Institutes in North India. All five cases fulfilled the Budapest criteria for the diagnosis of CRPS. All of them received prednisolone and were prospectively followed up for 2 years. Treatment outcome was carefully recorded in all affected modalities.

RESULTS

All five cases were found to have excruciating neuropathic pain in defined regions along with cutaneous manifestations. Osseous changes in the form of surface erosion of underlying bones in four cases and marked marrow edema leading to considerable increase in bone thickness in one case were noted. All these features improved considerably following steroid therapy. Bone marrow edema and bone resorption showed improvement on serial imaging.

CONCLUSION

Apart from pain relief, steroids therapy is capable of reversing the osteo-cutaneous autonomic changes of CRPS type I.

First case report of Pacinian corpuscle hyperplasia following complex regional pain syndrome

Pacinian disorders are exceedingly rare, and the exact pathogenesis is still unknown. The most common symptoms are pain, sensory changes, and a visible or palpable mass, and diagnosis is usually made by pathological examination after the excision of the painful nodule. In this case report, we present the case of a 49-year-old male with Pacinian corpuscle hyperplasia located on the metacarpophalangeal joint, emerging at the same hand of the patient two years after the treatment due to complex regional pain syndrome (CRPS). To the best of our knowledge, this is the first case report revealing the association of CRPS with hyperplasia of Pacinian corpuscles.

OUP accepted manuscript

There have been some modest recent advancements in the research of Complex Regional Pain Syndrome, yet the amount and quality of the work in this complicated multifactorial disease remains low (with some notable exceptions; e.g., the recent work on the dorsal root ganglion stimulation). The semi-systematic (though in some cases narrative) approach to review is necessary so that we might treat our patients while waiting for “better research.” This semi-systematic review was conducted by experts in the field, (deliberately) some of whom are promising young researchers supplemented by the experience of “elder statesman” researchers, who all mention the system they have used to examine the literature. What we found is generally low- to medium-quality research with small numbers of subjects; however, there are some recent exceptions to this. The primary reason for this paucity of research is the fact that this is a rare disease, and it is very difficult to acquire a sufficient sample size for statistical significance using traditional statistical approaches. Several larger trials have failed, probably due to using the broad general diagnostic criteria (the “Budapest” criteria) in a multifactorial/multi-mechanism disease. Responsive subsets can often be identified in these larger trials, but not sufficient to achieve statistically significant results in the general diagnostic grouping. This being the case the authors have necessarily included data from less compelling protocols, including trials such as case series and even in some instances case reports/empirical information. In the humanitarian spirit of treating our often desperate patients with this rare syndrome, without great evidence, we must take what data we can find (as in this work) and tailor a treatment regime for each patient.

Complex regional pain syndrome type II caused by iatrogenic lateral dorsal cutaneous nerve injury: A case report

RATIONALE

Complex regional pain syndrome (CRPS) is a painful condition classified as type I or II depending on the absence or presence of nerve injury, respectively. Injury to the lateral dorsal cutaneous nerve (LDCN), a branch of the sural nerve, is a rare occurrence observed after a sprain or procedures conducted on the lateral side of the ankle.

PATIENT CONCERNS

A 38-year-old female, who had undergone prolotherapy for a sprain in the lateral side of the left ankle 3 months ago, presented with persistent causalgia and dysesthesia around the injection site.

DIAGNOSIS

An electrodiagnostic study was conducted, which confirmed that the patient had peripheral neuropathy of the left LDCN. Considering the digital infrared thermal imaging and three-phase bone scan findings and the clinical presentation, the condition was diagnosed as CRPS type II due to iatrogenic LDCN injury according to the Budapest diagnostic criteria for CRPS.

INTERVENTIONS

The patient was treated with steroid pulse therapy, physical therapy, and transcutaneous electrical nerve stimulation, as well as nonsteroidal anti-inflammatory drugs, pregabalin, and tricyclic antidepressants.

OUTCOMES

After 1 month of treatment, allodynia of the left foot persisted, but the pain reduced from 6 points to 3 points on the numeric rating scale. Partial recovery of amplitude and conduction velocity was confirmed in the follow-up electrodiagnostic study.

LESSONS

LDCN injury should be considered in patients who complain of persistent lateral ankle and foot paresthesia or pain after sprain or procedures performed on the lateral side of the ankle. Early diagnosis and treatment can lead to a good prognosis when the LDCN injury has progressed to CRPS.

Associated Neurotrophic Keratopathy in Complex Regional Pain Syndrome

PURPOSE

To report a case of neurotrophic keratopathy (NK) in a patient with complex regional pain syndrome (CRPS) with ipsilateral facial involvement.

METHODS

Case report.

RESULTS

An 18-year old woman with a 5-year history of CRPS type I, a systemic disorder with a neuropathic component with associated limb and right facial involvement, presented with an insidious onset of blurred vision and pain in the right eye. Ocular examination revealed decreased corneal sensation, as measured by Cochet-Bonnet testing, associated with recurrent epithelial defects and whorl-like superficial corneal epitheliopathy. NK was suspected and confirmed by in vivo confocal microscopy (IVCM), which revealed rarefaction of the subbasal nerve plexus in the affected eye. To enhance corneal nerve health, plasma rich in growth factors drops were used. Persistence of NK prompted a superficial keratectomy with placement of an amniotic membrane graft and a course of cenegermin 0.002% (Oxervate; Dompé Farmaceutici SpA, Italy) in the postoperative period. This combination therapy resulted in successful epithelial closure and vision improvement after 8 weeks of therapy with no recurrence of disease for 11 months. Importantly, at that final visit, IVCM demonstrated growth of corneal nerves for the first time in this patient.

CONCLUSIONS

This is the first case report of NK occurring in the context of CRPS, a neuropathy with ipsilateral facial pain involvement. IVCM was important in the diagnosis of NK, which responded successfully to ocular surface treatments focused on nerve health stimulation that ultimately resulted in corneal nerve growth.

Complex Regional Pain Syndrome in Athletes: Scoping Review

Background and Objectives: Complex regional pain syndrome (CRPS) is a chronic condition characterized by disproportionate regional pain, usually affecting distal limbs, that follows trauma or surgery. Athletes may develop CRPS because of exposure to traumatic or overuse injuries. The aim of the present study is to review the available literature about CRPS type 1 in athletes. Materials and Methods: We searched two online databases (PubMed and Web of Science), selecting papers aiming at investigating CRPS type 1 (algodystrophy) in athletes. The analysis of databases was made considering original articles published until 30 June 2021, written in English. Results: Fifteen papers (12 case reports, 3 case series) were selected for a total of 20 clinical cases (15 females, 5 males), aged between 10 and 46 years (mean age 18.4 ± 9.8 standard deviation years). Patients included practiced different types of sport (soccer, athletics, gymnastics, basketball). The most involved anatomical sites were lower limbs, and time to diagnosis ranged from 2 days to 4 years. The most used treatments were pharmacological and physical therapies, but sometimes invasive approaches, as regional nerve, or lumbar sympathetic blocks, were provided. The main assessed outcomes were return to activity and pain. Conclusions: Our review suggests a higher prevalence of CRPS type 1 in younger people and in lower limbs than in general population but confirms the higher prevalence in females. However, the number of studies addressing CRPS in athletes is limited, as well as the number of involved patients, considering that only few and heterogeneous case reports were published about this topic. Moreover, the high prevalence of old studies (only 5 available studies in the last 10 years) might have influenced the choice of both assessment tools and management strategies. Despite these limitations, athletes showing disproportionate pain after sport-related injury should be promptly evaluated and treated through a multidimensional approach to avoid long-term consequences of algodystrophy.

Skin Temperature Assessment During Lumbar Sympathetic Blocks by Infrared Thermography

Complex Regional Pain Syndrome (CRPS) is a pain disorder that can be triggered by injuries or surgery affecting most often limbs. Its multifaceted pathophysiology makes its diagnosis and treatment a challenging work. To reduce pain, patients diagnosed with CRPS commonly undergo sympathetic blocks which involves the injection of a local anesthetic drug around the nerves. Currently, this procedure is guided by fluoroscopy which occasionally is considered as little accurate. For this reason, the use of infrared thermography as a technique of support has been considered.In this work, thermal images of feet soles in patients with lower limbs CRPS undergoing lumbar sympathetic blocks were recorded and evaluated. The images were analyzed by means of a computer-aided intuitive software tool developed using MATLAB. This tool provides the possibility of editing regions of interest, extracting the most important information of these regions and exporting the results data to an Excel file.Clinical Relevance- The final purpose of this work is to value the potential of infrared thermography and the analysis of its images as an intraoperatory technique of support in lumbar sympathetic blocks in patients with lower limbs CRPS.

Development of a Screening Tool for Pediatric Neuropathic Pain and Complex Regional Pain Syndrome: Pediatric PainSCAN

OBJECTIVE

Neuropathic pain (NP) and complex regional pain syndrome (CRPS) in children can result in significant disability and emotional distress. Early assessment and treatment could potentially improve pain, function, quality of life, and reduce costs to the health care system. Currently, there are no screening tools for pediatric NP and CRPS. This research aimed to develop and establish the content validity of a screening tool for pediatric NP and CRPS using a phased approach.

MATERIALS AND METHODS

Phase I surveyed clinical experts using a modified Delphi procedure to elicit disease concepts for inclusion. In phase II, a consensus conference including clinicians, researchers, and people with lived experience, informed the initial item pool. Consensus for item inclusion was achieved using a nominal group technique for voting. Phase III used iterative rounds of cognitive interviews with children aged 8 to 18 years with CRPS or NP to evaluate the tool's comprehensiveness and individual item relevance and comprehensibility. Descriptive statistics were used to describe participant characteristics. Content analysis was used to analyze patient interviews.

RESULTS

Phase I (n=50) generated an initial item pool (22 items). Phase II generated a comprehensive item pool (50 items), after which an initial version of the screening tool was drafted. Following phase III (n=26) after item revision and elimination, 37 items remained.

DISCUSSION

The Pediatric PainSCAN is a novel screening tool that has undergone rigorous development and content validity testing. Further research is needed to conduct item reduction, determine scoring, and test additional measurement properties.

Complex Regional Pain Syndrome Evolving to Full-Blown Fibromyalgia: A Proposal of Common Mechanisms

BACKGROUND

Spread of complex regional pain syndrome (CRPS) outside the affected limb is a well-recognized phenomenon; nevertheless, the actual evolution from CRPS to fibromyalgia is poorly documented. Similar mechanisms have been recently put forward to explain the development of CRPS and fibromyalgia including dorsal root ganglia (DRG) hyperexcitability and small fiber neuropathy.

OBJECTIVES

The aims of this study were to describe 3 cases with typical CRPS evolving to full-blown fibromyalgia and to discuss the potential pathogenetic mechanisms linking these debilitating illnesses.

METHODS

This was a review of medical records and PubMed search on the relationship between CRPS-fibromyalgia with DRG and small nerve fiber neuropathy.

RESULTS

Our 3 cases displayed over time orderly evolution from CRPS to fibromyalgia. Dorsal root ganglion hyperexcitability and small fiber neuropathy have been recently demonstrated in CRPS and in fibromyalgia. Dorsal root ganglia contain the small nerve fiber cell bodies surrounded by glial cells. After trauma, DRG perineuronal glial cells produce diverse proinflammatory mediators. Macrophages, lymphocytes, and satellite glial cells may drive the immune response to more rostrally and caudally located DRG and other spinal cord sites. Dorsal root ganglion metabolic changes may lead to small nerve fiber degeneration. This mechanism may explain the development of widespread pain and autonomic dysfunction.

CONCLUSIONS

Clinicians should be aware that CRPS can evolve to full-blown fibromyalgia. Spreading of neuroinflammation through DRG glial cell activation could theoretically explain the transformation from regional to generalized complex pain syndrome.

Too Much Sitting: A Serious 21st Century Health Risk

While weekly moderate-to-vigorous physical activity (MVPA) is considered a well-established key determinant for regulating weight and reducing risks of obesity and associated noncommunicable diseases, MVPA alone may not be enough to offset excessive sitting time. This integrative literature review aims to advance the discussion about sedentary behavior as a significant independent health risk for obesity and associated noncommunicable diseases, to increase awareness, to synthesize important evidence on sedentary behavior and a number of negative health outcomes, and to present the application of a whole-day approach to physical activity as a feasible strategy to promote health.

Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) is a rare, chronic pain disorder. It is challenging for patients and physicians because it leads to significant morbidity due to chronic pain that may last for years. CRPS typically develops four to six weeks after direct trauma, such as an injury or surgery, and causes pain that is out of proportion to the inciting injury. It is associated with multiple physiologic mechanisms, affecting skin texture or localized sensory, motor, sudomotor, and vasomotor pathways. The diagnosis is made clinically using standardized diagnostic criteria. Ancillary testing is not necessary for the diagnosis of CRPS but can be useful to rule out alternative diagnoses. There are two types of CRPS, type 1 and type 2, although treatment is the same for both. There is no single proven treatment modality for CRPS, and there have been no large randomized controlled studies of CRPS treatments. Most treatments are based on studies of their use for other types of neuropathic pain. The mainstay of treatment is to improve function of the affected body part and to decrease pain; therefore, treatment requires multiple modalities, including medications, behavioral health interventions, and referral to a pain specialist.

Complex Regional Pain Syndrome: The Importance of Early Diagnosis

Complex regional pain syndrome (CRPS) is a potentially life-altering, neuropathic pain condition that often affects an extremity in response to surgery or even minor trauma. The pain is often disproportionate to the injury sustained or the surgical procedure performed-and it has been described as excruciating and unbearable. CRPS can result in irreversible, disabling changes in the affected limb. In some cases it has resulted in amputation or severe psychological issues. However, CRPS outcomes are generally more successful with early detection and treatment. This article presents an overview of CRPS and discusses the critical role nurses can play in recognizing the condition early, assisting with treatment, and providing psychological support.

Quantitative Analysis of Real-Time Infrared Thermography for the Assessment of Lumbar Sympathetic Blocks: A Preliminary Study

Lumbar sympathetic blocks (LSBs) are commonly performed to treat pain ailments in the lower limbs. LSBs involve injecting local anesthetic around the nerves. The injection is guided by fluoroscopy which is sometimes considered to be insufficiently accurate. The main aim was to analyze the plantar foot skin temperature data acquired while performing LSBs in patients with complex regional pain syndrome (CRPS) affecting the lower limbs. Forty-four LSBs for treating lower limb CRPS in 13 patients were assessed. Pain medicine physicians visualized the infrared thermography (IRT) video in real time and classified the performance depending on the observed thermal changes within the first 4 min. Thirty-two percent of the cases did not register temperature variations after lidocaine was injected, requiring the needle to be relocated. Differences between moments are indicated using the 95% confidence intervals of the differences (CI 95%), the Cohen effect size (ES) and the significance (p value). In successful cases, after injecting lidocaine, increases at minute 7 for the mean (CI 95% (1.4, 2.1 °C), p < 0.001 and ES = 0.5), at minute 5 for maximum temperature (CI 95% (2.3, 3.3 °C), p < 0.001 and ES = 0.6) and at minute 6 for SD (CI 95% (0.2, 0.3 °C), p < 0.001 and ES = 0.5) were observed. The results of our preliminary study showed that the measurement of skin temperature in real time by infrared thermography is valuable for assessing the success of lumbar sympathetic blocks.

Screening and diagnostic tools for complex regional pain syndrome: a systematic review

ABSTRACT

Complex regional pain syndrome (CRPS) is a severely painful condition that presents with a constellation of symptoms. The understanding of the pathophysiology of CRPS has evolved over time, as have the diagnostic criteria. Our primary objective was to identify screening and diagnostic tools for CRPS and summarize their feasibility, measurement properties, and study quality. A secondary objective was to identify screening and diagnostic tools used for CRPS in pediatric populations (0-21 years of age). A systematic review of English articles in electronic databases (PsycINFO, MEDLINE, Embase, CINAHL, CENTRAL, and Web of Science) was conducted with the aid of a librarian in November 2018 and updated in July 2020. Studies were included if the tool was a screening or diagnostic tool, the tool included self-report or physical examination, and the primary objective of the study was to evaluate the measurement properties or feasibility of use. For each study, data were extracted for quality indicators using the QUADAS-2 tool. No screening tools were identified. Four diagnostic tools were identified: the Veldman criteria, International Association for the Study of Pain criteria, Budapest Criteria, and Budapest Research Criteria. There are no diagnostic tools validated for use in pediatric CRPS. Because there are no extant screening tools for CRPS, all people with suspected disease should undergo rapid diagnostic assessment by a clinician. For adults, the Budapest Criteria are the preferred diagnostic tool. Future research is recommended to develop a diagnostic tool for pediatric populations and screening tools for both pediatric and adults.

The Role of FLIR ONE Thermography in Complex Regional Pain Syndrome: A Case Series

ABSTRACT

Complex regional pain syndrome remains a debated syndrome characterized by symptoms and signs, including pain, sensory disturbances, thermal asymmetry, edema, and motor impairments. Thermography is a tool that assesses skin surface temperature distribution. Current literature focuses on the role of thermography for diagnostic purposes; however, its role in monitoring the response to treatment in complex regional pain syndrome is unclear. We present a case series of four patients with complex regional pain syndrome where a FLIR ONE thermal imaging camera (FLIR Systems, Inc, Wilsonville, OR) was used to assist in the diagnosis of complex regional pain syndrome, capture the effects of diagnostic nerve blocks to evaluate a peripheral nerve contribution to complex regional pain syndrome, as well as monitor and assess treatment efficacy with prednisone and surgery. Four patients were screened by clinical assessment to meet the Budapest Criteria. The thermal images revealed improvement in the temperature distribution after therapeutic intervention. We also noted temporary but immediate changes on thermal imaging with diagnostic nerve blocks. Our cases suggest that the FLIR ONE thermal imaging camera has the potential to be an accessible monitoring tool to assist in diagnosis and assess treatment efficacy in complex regional pain syndrome over time.

Clinical overlap of functional neurologic symptom disorder and complex regional pain syndrome in pediatrics: A case report

This case study documents a 13-year-old female who presented to our intensive inpatient chronic pain rehabilitation program with complex regional pain syndrome (CRPS) of her left leg, which was significantly interfering with her normal daily functioning. She participated in a full day of traditional interdisciplinary therapies, including physical and occupational therapy for 3 hours daily. As assistive equipment was altered or weaned her physical mobility, balance, and tremors worsened and/or increased. As she began advancing her legs more independently (versus requiring physical assist), she demonstrated more variable functional strength and stability, inconsistent balance reactions, and a more unsteady gait pattern. The team was treating her according to her incoming CRPS diagnosis; however, as treatment progressed, her physical and psychological presentation seemed more aligned with diagnostic criteria of functional neurologic symptom disorder (FND). Staff then treated according to the FND diagnosis resulting in successful long-term outcomes. The clinical impact from this case study includes highlighting the commonalities between CPRS and FND clinically, discussing treatment suggestions depending on the diagnosis, and emphasizing key components of family/patient education.