Query: Complex regional pain syndrome

title: Sensory disturbances induced by sensorimotor conflicts are higher in complex regional pain syndrome and fibromyalgia compared to arthritis and healthy people, and positively relate to pain intensity
abstract: Sensorimotor conflicts are well known to induce sensory disturbances. However, explanations as to why patients with chronic pain are more sensitive to sensorimotor conflicts remain elusive. The main objectives of this study were (a) to assess and compare the sensory disturbances induced by sensorimotor conflict in complex regional pain syndrome (n 38) fibromyalgia (n 36) arthritis (n 34) as well as in healthy volunteers (HV) (n 32) (b) to assess whether these disturbances were related to the intensity and duration of pain, or to other clinical variables assessed using questionnaires (abnormalities in sensory perception, depression and anxiety) and (c) to categorize different subgroups of conflict induced sensory disturbances.

title: Dorsal root ganglion stimulation yielded higher treatment success rate for complex regional pain syndrome and causalgia at 3 and 12 months: a randomized comparative trial
abstract: Animal and human studies indicate that electrical stimulation of dorsal root ganglion (DRG) neurons may modulate neuropathic pain signals. ACCURATE, a pivotal, prospective, multicenter, randomized comparative effectiveness trial, was conducted in 152 subjects diagnosed with complex regional pain syndrome or causalgia in the lower extremities. Subjects received neurostimulation of the DRG or dorsal column (spinal cord stimulation, SCS) The primary end point was a composite of safety and efficacy at 3 months, and subjects were assessed through 12 months for long term outcomes and adverse events. The predefined primary composite end point of treatment success was met for subjects with a permanent implant who reported 50% or greater decrease in visual analog scale score from preimplant baseline and who did not report any stimulation related neurological deficits. No subjects reported stimulation related neurological deficits. The percentage of subjects receiving =50% pain relief and treatment success was greater in the DRG arm (81.2% than in the SCS arm (55.7% P 0.001) at 3 months. Device related and serious adverse events were not different between the 2 groups. Dorsal root ganglion stimulation also demonstrated greater improvements in quality of life and psychological disposition. Finally, subjects using DRG stimulation reported less postural variation in paresthesia (P 0.001) and reduced extraneous stimulation in nonpainful areas (P 0.014) indicating DRG stimulation provided more targeted therapy to painful parts of the lower extremities. As the largest prospective, randomized comparative effectiveness trial to date, the results show that DRG stimulation provided a higher rate of treatment success with less postural variation in paresthesia intensity compared to SCS.

title: Correlates and importance of neglect like symptoms in complex regional pain syndrome
abstract: Neglect like symptoms (NLS) are frequently observed in complex regional pain syndrome (CRPS) The clinical meaning of NLS, however, is largely unknown. Therefore, this study sets out to assess the importance of NLS for patient outcome and to explore their clinical correlates. We assessed NLS in a group of 53 patients with CRPS and compared the results to 28 healthy volunteers. To define the origin of the NLS reports, we tested the subjective visual midline, performed a limb laterality recognition test, and quantitative sensory testing. In addition, psychological and pain assessment scales were completed. Tests were analyzed with univariate and multivariate approaches. After 6 months, patients were reassessed and the influence of NLS on pain outcome was determined. Most patients reported NLS in the questionnaire, whereas subjective visual midline and limb laterality recognition test in contrast to previous studies did not reveal perceptual disturbances. Neglect like symptom scores were associated with pain and pain catastrophizing in acute CRPS and anxiety and thermal sensory loss in chronic CRPS. Furthermore, high NLS scores had a negative impact on pain outcome after 6 months. Our results indicate that NLS have a different meaning in acute and chronic CRPS and might be of prognostic value. Possibly, treatment should focus on reducing NLS.

title: Complex regional pain syndrome phenotypic characteristics and potential biomarkers
abstract: Complex regional pain syndrome (CRPS) is a pain condition that usually affects a single limb, often following an injury. The underlying pathophysiology seems to be complex and probably varies between patients. Clinical diagnosis is based on internationally agreed upon criteria, which consider the reported symptoms, presence of signs and exclusion of alternative causes. Research into CRPS biomarkers to support patient stratification and improve diagnostic certainty is an important scientific focus, and recent progress in this area provides an opportunity for an up to date topical review of measurable disease predictive, diagnostic and prognostic parameters. Clinical and biochemical attributes of CRPS that may aid diagnosis and determination of appropriate treatment are delineated. Findings that predict the development of CRPS and support the diagnosis include trauma related factors, neurocognitive peculiarities, psychological markers, and local and systemic changes that indicate activation of the immune system. Analysis of signatures of non coding microRNAs that could predict the treatment response represents a new line of research. Results from the past 5 years of CRPS research indicate that a single marker for CRPS will probably never be found; however, a range of biomarkers might assist in clinical diagnosis and guide prognosis and treatment.

title: Signs and Symptoms in 1,043 Patients with Complex Regional Pain Syndrome.
abstract: Complex regional pain syndrome (CRPS) is a complex pain disorder that can emerge after limb trauma or a lesion in the peripheral nervous system. Typical features include continuing pain, sensory, vasomotor, sudomotor, motor, and trophic changes as well as edema. These signs provide the basis of CRPS diagnosis. A detailed description of the signs, symptoms, and medical history of CRPS could potentially facilitate an earlier and more accurate diagnosis. The aim of this study was to provide such a description, on the basis of epidemiological measures, clinical presentation, and a thorough description of pain sensations. Some signs (eg, differences of skin temperature >1degC) which have been thought to be crucial for diagnosis, were less common than assumed. We identified 11 distinct etiological triggers, which cover more than 99% of the study participants. We developed a weighted score on the basis of the most decisive data, which achieved a sensitivity of .869 and a specificity of .829, compared with .819 and .679 for the Budapest criteria. The weighted diagnostic criteria may help to better aid in distinguishing CRPS from other pain disorders.  This article provides a retrospective epidemiological analysis of 1,043 CRPS patients compared with 421 patients with other pain disorders. The findings could potentially facilitate a more reliable and earlier diagnosis of CRPS, a better differentiation from other pain disorders, and ultimately in a more targeted and effective therapy.

title: The Effect of Ketamine Infusion in the Treatment of Complex Regional Pain Syndrome: a Systemic Review and Meta analysis
abstract: Purpose of ReviewComplex regional pain syndrome (CRPS) is a painful debilitating neurological condition that accounts for approximately 1.2% of adult chronic pain population. Ketamine, an NMDA receptor antagonist, is an anesthetic agent that has been used by some pain specialists for CRPS. There is a growing body of clinical evidence to support the use of ketamine in the treatment of neuropathic pain, especially CRPS. This meta analysis study was aimed to examine the efficacy of ketamine in the treatment of CRPS.Recent FindingsA search of Embase, Pubmed, Web of Knowledge, Cochrane, Clinical Trial.gov, and FDA.gov between Jan 1, 1950, and August 1, 2017, was conducted to evaluate ketamine infusion therapy in the treatment of CRPS. We selected randomized clinical trials or cohort studies for meta analyses. I2 index estimates were calculated to test for variability and heterogeneity across the included studies. The primary outcome is pain relief. The effect of ketamine treatment for complex regional pain syndrome was assessed by 0 10 scale numerical rating pain score. The secondary outcome is the pain relief event rate, which is defined as the percentage of participants who achieved 30% or higher pain relief in each of the qualified studies. Our meta analysis results showed that the Ketamine treatment led to a decreased mean of pain score in comparison to the self controlled baseline (p 0.000001) However, there is a statistical significance of between study heterogeneity. The immediate pain relief event rate was 69% (95% confidence interval (CI) 53% 84% The pain relief event rate at the 1 3 months follow ups was 58% (95% CI 41% 75%.SummaryThe current available studies regarding ketamine infusion for CRPS were reviewed, and meta analyses were conducted to evaluate the efficacy of ketamine infusion in the treatment of CRPS. Our findings suggested that ketamine infusion can provide clinically effective pain relief in short term for less than 3 months. However, because of the high heterogeneity of the included studies and publication bias, additional random controlled trials and standardized multicenter studies are needed to confirm this conclusion. Furthermore, studies are needed to prove long term efficacy of ketamine infusion in the treatment of CRPS.

title: Complex Regional Pain Syndrome Practical Diagnostic and Treatment Guidelines
abstract: 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 highquality evidence to guide therapy is lacking.  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.  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.

title: Heartbeat enhanced immersive virtual reality to treat complex regional pain syndrome
abstract: To develop and test a new immersive digital technology for complex regional pain syndrome (CRPS) that combines principles from mirror therapy and immersive virtual reality and the latest research from multisensory body processing.  In this crossover double blind study, 24 patients with CRPS and 24 age and sex matched healthy controls were immersed in a virtual environment and shown a virtual depiction of their affected limb that was flashing in synchrony (or in asynchrony in the control condition) with their own online detected heartbeat (heartbeat enhanced virtual reality [HEVR] The primary outcome measures for pain reduction were subjective pain ratings, force strength, and heart rate variability (HRV) Results HEVR reduced pain ratings, improved motor limb function, and modulated a physiologic pain marker (HRV) These significant improvements were reliable and highly selective, absent in control HEVR conditions, not observed in healthy controls, and obtained without the application of tactile stimulation (or movement) of the painful limb, using a readily available biological signal (the heartbeat) that is most often not consciously perceived (thus preventing placebo effects)  Next to these specific and well controlled analgesic effects, immersive HEVR allows the application of prolonged and repeated doses of digital therapy, enables the automatized integration with existing pain treatments, and avoids application of painful bodily cues while minimizing the active involvement of the patient and therapist. Classification of evidence This study provides Class III evidence that HEVR reduces pain and increases force strength in patients with CRPS.

title: Autoinflammatory and autoimmune contributions to complex regional pain syndrome
abstract: Complex regional pain syndrome (CRPS) is a highly enigmatic syndrome typically developing after injury or surgery to a limb. Severe pain and disability are common among those with chronic forms of this condition. Accumulating evidence suggests that CRPS may involve both autoinflammatory and autoimmune components. In this review article, evidence for dysfunction of both the innate and adaptive immune systems in CRPS is presented. Findings from human studies in which cytokines and other inflammatory mediators were measured in the skin of affected limbs are discussed. Additional results from studies of mediator levels in animal models are evaluated in this context. Similarly, the evidence from human, animal, and translational studies of the production of autoantibodies and the potential targets of those antibodies is reviewed. Compelling evidence of autoinflammation in skin and muscle of the affected limb has been collected from CRPS patients and laboratory animals. Cytokines including IL 1b, IL 6, TNFa, and others are reliably identified during the acute phases of the syndrome. More recently, autoimmune contributions have been suggested by the discovery of self directed pain promoting IgG and IgM antibodies in CRPS patients and model animals. Both the autoimmune and the autoinflammatory components of CRPS appear to be regulated by neuropeptide containing peripheral nerve fibers and the sympathetic nervous system. While CRPS displays a complex neuroimmunological pathogenesis, therapeutic interventions could be designed targeting autoinflammation, autoimmunity, or the neural support for these phenomena.

title: Are you better? A multi centre study of patient defined recovery from Complex Regional Pain Syndrome
abstract: Complex Regional Pain Syndrome (CRPS) symptoms can significantly differ between patients, fluctuate over time, disappear or persist. This leads to problems in defining recovery and in evaluating the efficacy of therapeutic interventions.