Validation of proposed diagnostic criteria (the "Budapest Criteria") for Complex Regional Pain Syndrome

Complex regional pain syndrome type I affects brain structure in prefrontal and motor cortex

The complex regional pain syndrome (CRPS) is a rare but debilitating pain disorder that mostly occurs after injuries to the upper limb. A number of studies indicated altered brain function in CRPS, whereas possible influences on brain structure remain poorly investigated. We acquired structural magnetic resonance imaging data from CRPS type I patients and applied voxel-by-voxel statistics to compare white and gray matter brain segments of CRPS patients with matched controls. Patients and controls were statistically compared in two different ways: First, we applied a 2-sample ttest to compare whole brain white and gray matter structure between patients and controls. Second, we aimed to assess structural alterations specifically of the primary somatosensory (S1) and motor cortex (M1) contralateral to the CRPS affected side. To this end, MRI scans of patients with left-sided CRPS (and matched controls) were horizontally flipped before preprocessing and region-of-interest-based group comparison. The unpaired ttest of the "non-flipped" data revealed that CRPS patients presented increased gray matter density in the dorsomedial prefrontal cortex. The same test applied to the "flipped" data showed further increases in gray matter density, not in the S1, but in the M1 contralateral to the CRPS-affected limb which were inversely related to decreased white matter density of the internal capsule within the ipsilateral brain hemisphere. The gray-white matter interaction between motor cortex and internal capsule suggests compensatory mechanisms within the central motor system possibly due to motor dysfunction. Altered gray matter structure in dorsomedial prefrontal cortex may occur in response to emotional processes such as pain-related suffering or elevated analgesic top-down control.

Complex regional pain syndrome is associated with structural abnormalities in pain-related regions of the human brain

Complex regional pain syndrome (CRPS) is a chronic condition that involves significant hyperalgesia of the affected limb, typically accompanied by localized autonomic abnormalities and frequently by motor dysfunction. Although central brain systems are thought to play a role in the development and maintenance of CRPS, these systems have not been well characterized. In this study, we used structural magnetic resonance imaging to characterize differences in gray matter volume between patients with right upper extremity CRPS and matched controls. Analyses were carried out using a whole brain voxel-based morphometry approach. The CRPS group showed decreased gray matter volume in several pain-affect regions, including the dorsal insula, left orbitofrontal cortex, and several aspects of the cingulate cortex. Greater gray matter volume in CRPS patients was seen in the bilateral dorsal putamen and right hypothalamus. Correlation analyses with self-reported pain were then performed on the CRPS group. Pain duration was associated with decreased gray matter in the left dorsolateral prefrontal cortex. Pain intensity was positively correlated with volume in the left posterior hippocampus and left amygdala, and negatively correlated with the bilateral dorsolateral prefrontal cortex. Our findings demonstrate that CRPS is associated with abnormal brain system morphology, particularly pain-related sensory, affect, motor, and autonomic systems.

PERSPECTIVE

This paper presents structural changes in the brains of patients with CRPS, helping us differentiate CRPS from other chronic pain syndromes and furthering our understanding of this challenging disease.

Plasma amino acids changes in complex regional pain syndrome

Complex regional pain syndrome (CRPS) is a severe chronic pain condition that most often develops following trauma. Blood samples were collected from 220 individuals, 160 CRPS subjects, and 60 healthy pain-free controls. Plasma amino acid levels were compared and contrasted between groups. L-Aspartate, L-glutamate, and L-ornithine were significantly increased, whereas L-tryptophan and L-arginine were significantly decreased in CRPS subjects as compared to controls. In addition, the L-kynurenine to L-tryptophan ratio demonstrated a significant increase, whereas the global arginine bioavailability ratio (GABR) was significantly decreased in the CRPS subjects. The CRPS subjects demonstrated a significant correlation between overall pain and the plasma levels of L-glutamate and the L-kynurenine to L-tryptophan ratio. CRPS subjects also showed a correlation between the decrease in plasma L-tryptophan and disease duration. This study shows that CRPS subjects exhibit significant changes in plasma levels of amino acids involved in glutamate receptor activation and in amino acids associated with immune function as compared to healthy pain-free controls. A better understanding of the role plasma amino acids play in the pathophysiology of CRPS may lead to novel treatments for this crippling condition.

Complex regional pain syndrome: more than a peripheral disease

SUMMARY At early stages, complex regional pain syndrome (CRPS) is clinically characterized by damage of peripheral tissues and nerves (edema, activation of osteoblasts, hyperalgesia to blunt pressure). These signs are the result of a dysbalance of pro- and anti-inflammatory cytokines, which normalizes approximately 6 months after the beginning of the disease, independent from clinical outcome. At the same time, evolving clinical signs such as allodynia, cold hyperalgesia, reduced tactile acuity or symptoms of disrupted body representation (e.g., neglect-like syndrome, impaired hand laterality recognition or shift of the body midline) suggest a crucial role of the CNS in the pathophysiology of this pain syndrome. Imaging studies have found a severe but reversible reduction of the cortical hand representation (primary and secondary somatosensory cortices and primary motor cortices). Interestingly however, complex multisensory integration in central association areas are unaffected in CRPS, as patients are capable of integrating artificial body parts or recognize 2D forms despite tactile dysfunction. Furthermore, despite its unilateral clinical manifestation, it has been shown that in CRPS but not in other unilateral neuropathic pain syndromes, alterations in cortical excitability occur bilaterally, both in sensory and motor regions. In conclusion, a more widespread and bilateral pattern of CNS reorganization appears to characterize CRPS, which might be related to dysfunctions in the basal ganglia or in thalamo–cortical structures. Consequently, CRPS treatment should involve not only anti-inflammatory measures and pain therapy, but also the integration of neurorehabilitative training programs.

A review of psychosocial factors in complex regional pain syndrome

Complex regional pain syndrome (CRPS) is a disabling pain condition poorly understood by medical professionals. Because CRPS is particularly enigmatic, and has significant impact on patient function, researchers have examined psychological processes present among patients with this diagnosis. This systematic review examines psychosocial factors associated with CRPS, both predictors and sequelae. Our conclusions are that CRPS is associated with negative outcomes, both psychological (e.g., increased depression and anxiety) and psychosocial (e.g., reduced quality of life, impaired occupational function) in nature. However, research does not reveal support for specific personality or psychopathology predictors of the condition.

A CRPS-IgG-transfer-trauma model reproducing inflammatory and positive sensory signs associated with complex regional pain syndrome

The aetiology of complex regional pain syndrome (CRPS), a highly painful, usually post-traumatic condition affecting the limbs, is unknown, but recent results have suggested an autoimmune contribution. To confirm a role for pathogenic autoantibodies, we established a passive-transfer trauma model. Prior to undergoing incision of hind limb plantar skin and muscle, mice were injected either with serum IgG obtained from chronic CRPS patients or matched healthy volunteers, or with saline. Unilateral hind limb plantar skin and muscle incision was performed to induce typical, mild tissue injury. Mechanical hyperalgesia, paw swelling, heat and cold sensitivity, weight-bearing ability, locomotor activity, motor coordination, paw temperature, and body weight were investigated for 8days. After sacrifice, proinflammatory sensory neuropeptides and cytokines were measured in paw tissues. CRPS patient IgG treatment significantly increased hind limb mechanical hyperalgesia and oedema in the incised paw compared with IgG from healthy subjects or saline. Plantar incision induced a remarkable elevation of substance P immunoreactivity on day 8, which was significantly increased by CRPS-IgG. In this IgG-transfer-trauma model for CRPS, serum IgG from chronic CRPS patients induced clinical and laboratory features resembling the human disease. These results support the hypothesis that autoantibodies may contribute to the pathophysiology of CRPS, and that autoantibody-removing therapies may be effective treatments for long-standing CRPS.

Mirror therapy for Complex Regional Pain Syndrome (CRPS)—A literature review and an illustrative case report

Background and purpose

This case of a 42 year old woman with lower extremity Complex Regional Pain Syndrome (CRPS) after a twisting injury of the ankle, effectively treated with the addition of mirror therapy to a rehabilitation programme, prompted a literature review of both CRPS and mirror therapy. Mirror therapy is a newer adjunct to other forms of pain control and functional restoration for treatment of CRPS as well as other difficult clinical problems. This was a required group project as part of a university based course in chronic pain for healthcare workers.

Materials and methods

The PubMed database up to September 26,2012 was reviewed using four search word groups: “CRPS mirror therapy”, “mirror CRPS”, “reflex sympathetic dystrophy OR Complex Regional Pain Syndrome AND mirror” and “reflex sympathetic dystrophy OR Complex Regional Pain Syndrome AND mirror + RCT”. Nine studies from PubMed met the criteria that this working group had chosen for inclusion in the analysis of mirror therapy as treatment. These references were supplemented by others on CRPS in order to generate an adequate review of both the syndrome CRPS and mirror therapy itself. Some references were specific for mirror therapy in the treatment of CRPS but others described mirror therapy for the treatment of phantom limb pain, brachial plexus avulsion pain, for physical rehabilitation of stroke related paresis and for rehabilitation after hand surgery.

Results

Criteria for the diagnosis of CRPS including the International Association for the Study of Pain criteria and the Budapest criteria are reviewed with an emphasis on the specificity and sensitivity of the various criteria for clinical and research purposes. The signs and symptoms of CRPS are a part of the criteria review.

The main treatment strategy for CRPS is physical rehabilitation for return of function and mirror therapy is one of many possible strategies to aid in this goal.

The patient in this case report had failed many of the adjunctive therapies and rehabilitation had been unsuccessful until the addition of mirror therapy. She then could progress with physical rehabilitation and return to a more normal life. Mirror therapy techniques are briefly described as part of a discussion of its success with relationship to signs and symptoms as well as to the duration of CRPS (and other syndromes). Some discussion of the theories of the central effects of both CRPS and phantom limb pain and how these are affected by mirror therapy is included.

An analysis of the 9 most relevant articles plus a critique of each is present in table form for review.

Conclusions

There appears to be a clear indication for the use of mirror therapy to be included in the multidisciplinary treatment of CRPS types 1 and 2 with a positive effect on both pain and motor function. There is also evidence that mirror therapy can be helpful in other painful conditions such as post stroke pain and phantom limb pain.

Implications

CRPS is often overlooked as an explanation for obscure pain problems. Prompt diagnosis is essential for effective treatment. Mirror therapy is a newer technique, easy to perform and can be a useful adjunct to aid physical rehabilitation and decrease pain in this population. Much further prospective research on mirror therapy in CRPS is ongoing and is needed to systematize the technique, to clarify the effects and to define the place of this therapy in the multidisciplinary management of CRPS.

Evaluation of a prototype tool for communicating body perception disturbances in complex regional pain syndrome

Patients with Complex Regional Pain Syndrome (CRPS) experience distressing changes in body perception. However representing body perception is a challenge. A digital media tool for communicating body perception disturbances was developed. A proof of concept study evaluating the acceptability of the application for patients to communicate their body perception is reported in this methods paper. Thirteen CRPS participants admitted to a 2-week inpatient rehabilitation program used the application in a consultation with a research nurse. Audio recordings were made of the process and a structured questionnaire was administered to capture experiences of using the tool. Participants produced powerful images of disturbances in their body perception. All reported the tool acceptable for communicating their body perception. Participants described the positive impact of now seeing an image they had previously only imagined and could now convey to others. The application has provided a novel way for communicating perceptions that are otherwise difficult to convey.

Children and adolescents with complex regional pain syndrome: more psychologically distressed than other children in pain?

BACKGROUND

Historically, in both adult and pediatric populations, a lack of knowledge regarding complex regional pain syndrome (CRPS) and absence of clear diagnostic criteria have contributed to the view that this is a primarily psychiatric condition.

OBJECTIVE

To test the hypothesis that children with CRPS are more functionally disabled, have more pain and are more psychologically distressed than children with other pain conditions.

METHODS

A total of 101 children evaluated in a tertiary care pediatric pain clinic who met the International Association for the Study of Pain consensus diagnostic criteria for CRPS participated in the present retrospective study. Comparison groups included 103 children with abdominal pain, 291 with headache and 119 with back pain. Children and parents completed self-report questionnaires assessing disability, somatization, pain coping, depression, anxiety and school attendance.

RESULTS

Children with CRPS reported higher pain intensity and more recent onset of pain at the initial tertiary pain clinic evaluation compared with children with other chronic pain conditions. They reported greater functional disability and more somatic symptoms than children with headaches or back pain. Scores on measures of depression and anxiety were within normal limits and similar to those of children in other pain diagnostic groups.

CONCLUSIONS

As a group, clinic-referred children with CRPS may be more functionally impaired and experience more somatic symptoms compared with children with other pain conditions. However, overall psychological functioning as assessed by self-report appears to be similar to that of children with other chronic pain diagnoses. Comprehensive assessment using a biopsychosocial framework is essential to understanding and appropriately treating children with symptoms of CRPS.

Complex regional pain syndrome: a review

Complex regional pain syndrome, formally known as reflex sympathetic dystrophy, is a poorly understood condition that describes a collection of clinical symptoms and signs occurring in the peripheries most commonly after trauma. Pain is the main problem. It is generally out of proportion to the degree of injury and can be unresponsive to narcotics. In addition joint stiffness, temperature and colour changes, and swelling occur. The diagnosis and treatment are challenging for any clinician and a multidisciplinary approach is often necessary with physiotherapy, occupational therapy, and the pain team. The hand surgeon is involved for two reasons, firstly as the upper limb is the most frequently involved, and secondly because the condition may be a complication of the patient's surgery and result in a much prolonged recovery. This review elucidates the recent advances in the knowledge of the aetiology, classification and treatment of this fascinating condition.

Widespread pain in patients with complex regional pain syndrome

OBJECTIVES

Our goal was to ascertain the prevalence of widespread pain in our cohort of patients with complex regional pain syndrome (CRPS).

METHODS

We conducted a retrospective analysis of clinical letters and notes. We assessed data from consecutive patients diagnosed with CRPS according to the Budapest criteria, after a referral to one consultant at a tertiary Pain Medicine referral center.

RESULTS

Between July 2007 and September 2012, 190 patients (149 females) received a diagnosis of CRPS according to the Budapest criteria, and an additional 26 patients received the diagnosis of CRPS NOS (not otherwise specified). The CRPS patients were an average of 44 years of age, and had a median disease duration of 18 months. Before the CRPS incident trigger, a third had already experienced other than everyday pains in the now CRPS-affected limb. Twenty-one patients (11.1%) experienced widespread pain in clinic, which was often not communicated in the referral letters. The types of triggering traumata and frequencies of Budapest signs and symptoms did not differ between patients with or without widespread pain. All patients considered their widespread pain as an important factor affecting their quality of life; for the majority it was of similar severity to the CRPS pain. Additional patients reported CRPS-concomitant regional pains, most commonly headaches/migraines, lower back pain, and irritable bowel syndrome.

DISCUSSION

In this systematic assessment of the incidence of widespread pain in a large cohort of patients with CRPS, important widespread pain affected > 10% of patients. Our data support the inclusion of routine enquiries about additional pains in the clinical assessment of patients with CRPS.

Altered resting-state functional connectivity in complex regional pain syndrome

This study explored the functional connectivity between brain regions implicated in the default mode network, the sensorimotor cortex (S1/M1), and the intraparietal sulcus (IPS/MIP) at rest in patients with complex regional pain syndrome. It also investigated how possible alterations are associated with neuropathic pain. Our group used functional magnetic resonance imaging to investigate functional brain connectivity in 12 complex regional pain syndrome patients in comparison with that in 12 age- and sex-matched healthy controls. Data were analyzed using a seed voxel correlation analysis and an independent component analysis. An analysis of covariance was employed to relate alterations in functional connectivity with clinical symptoms. We found significantly greater reductions in functional default mode network connectivity in patients compared to controls. The functional connectivity maps of S1/M1 and IPS/MIP in patients revealed greater and more diffuse connectivity with other brain regions, mainly with the cingulate cortex, precuneus, thalamus, and prefrontal cortex. In contrast, controls showed greater intraregional connectivity within S1/M1 and IPS/MIP. Furthermore, there was a trend for correlation between alterations in functional connectivity and intensity of neuropathic pain. In our findings, patients with complex regional pain syndrome have substantial spatial alterations in the functional connectivity between brain regions implicated in the resting-state default mode network, S1/M1, and IPS/MIP; these alterations show a trend of correlation with neuropathic pain intensity.

PERSPECTIVE

This article presents spatial alterations in the functional resting-state connectivity of complex regional pain syndrome patients. Our results add further insight into the disease states of CRPS and into the functional architecture of the resting state brains of pain patients in general.

Neuroinflammation, neuroautoimmunity, and the co-morbidities of complex regional pain syndrome

Complex Regional Pain Syndrome (CRPS) is associated with non-dermatomal patterns of pain, unusual movement disorders, and somatovisceral dysfunctions. These symptoms are viewed by some neurologists and psychiatrists as being psychogenic in origin. Recent evidence, however, suggests that an autoimmune attack on self-antigens found in the peripheral and central nervous system may underlie a number of CRPS symptoms. From both animal and human studies, evidence is accumulating that neuroinflammation can spread, either anterograde or retrograde, via axonal projections in the CNS, thereby establishing neuroinflammatory tracks and secondary neuroinflammatory foci within the neuraxis. These findings suggest that neuroinflammatory lesions, as well as their associated functional consequences, should be evaluated during the differential diagnosis of non-dermatomal pain presentations, atypical movement disorders, as well as other "medically unexplained symptoms", which are often attributed to psychogenic illness.

Complex regional pain syndrome of the knee - a case report

Background

Persistent unexplained pain around the knee can be a perplexing problem. Reports of complex regional pain syndrome involving primarily knee have been published, yet complex regional pain syndrome of the knee is infrequently included in differential diagnosis of pain out of proportion.

Case presentation

A 54 year old female presented to the physiotherapy outpatient department with complains of severe anterior knee pain and stiffness, persisting for more than 2 months post arthroscopic medial plical excision. The patient met the criteria for establishing a probable diagnosis of complex regional pain syndrome (CRPS) knee. Pressure algometre, goniometric measurements and knee outcome survey activities of daily living scale were used to document any changes. This patient was managed for a period of four sessions using graded desensitization therapy, TENS and mobilisation with feedback. Patient showed marked improvement in range of movement (ROM), hypersensitivity, pain and function.

Conclusion

Meticulous examination, early diagnosis and prompt treatment resulted in a quick improvement in the patient’s condition.

Reliability of infrared thermometric measurements of skin temperature in the hand

STUDY DESIGN

Clinical measurement study.

INTRODUCTION

Skin temperature asymmetries (STAs) are used in the diagnosis of complex regional pain syndrome (CRPS), but little evidence exists for reliability of the equipment and methods.

PURPOSE

This study examined the reliability of an inexpensive infrared (IR) thermometer and measurement points in the hand for the study of STA.

METHODS

ST was measured three times at five points on both hands with an IR thermometer by two raters in 20 volunteers (12 normals and 8 CRPS).

RESULTS

ST measurement results using IR thermometers support inter-rater reliability: intraclass correlation coefficient (ICC) estimate for single measures 0.80; all ST measurement points were also highly reliable (ICC single measures, 0.83-0.91).

CONCLUSIONS

The equipment demonstrated excellent reliability, with little difference in the reliability of the five measurement sites. These preliminary findings support their use in future CRPS research.

LEVEL OF EVIDENCE

Not applicable.

Primary somatosensory cortex function in complex regional pain syndrome: a systematic review and meta-analysis

That complex regional pain syndrome (CRPS) is associated with functional reorganization in the primary somatosensory cortex (S1) is widely accepted and seldom questioned. Despite more than a decade of research, there has been no systematic review of the CRPS literature concerning the changes in S1 function, and therefore the extent of these changes is unclear. Here we conduct a systematic review and meta-analysis to quantify the spatial and temporal aspects of S1 function in CRPS. A comprehensive search strategy identified functional neuroimaging studies of S1 in CRPS. We adhered to a rigorous systematic review protocol when extracting data and appraising risk of bias. Outcomes were grouped into spatial representation; activation levels, including disinhibition; peak latency of activation; and glucose metabolism. Meta-analysis was conducted where possible. Fifteen studies were included, all investigating upper-extremity CRPS. In patients with CRPS, the S1 spatial representation of the affected hand is smaller than that of the unaffected hand and that of non-CRPS controls; however, this evidence comes from only a few studies. There is no difference in activation, disinhibition, or latency of peripherally evoked S1 responses in CRPS. The risk of bias was high across studies, mainly from unclear sampling methods and unblinded analysis of outcomes.

PERSPECTIVE

The evidence for a difference in function of the primary somatosensory cortex in CRPS compared with controls is clouded by high risk of bias and conflicting results, but reduced representation size seems consistent.

Gardner-Diamond syndrome associated with complex regional pain syndrome

BACKGROUND

Gardner-Diamond syndrome (GDS) is also known as psychogenic purpura, autoerythrocyte sensitization syndrome and painful bruising syndrome.

MAIN OBSERVATION

This is a case report of 27-year-old woman who presented with unexplained bruising and intramuscular hematomas after a seven year history of complex regional pain syndrome. Her evaluation consisted of hematological studies, skin and muscle biopsy; it failed to reveal an underlying coagulopathy, vasculitis or other demonstrable cause. In the absence of any other etiology, she was diagnosed as Gardner-Diamond syndrome.

CONCLUSIONS

This patient is unique because of intramuscular hematomas and the association of Complex regional pain syndrome with Gardner-Diamond syndrome.

Diagnosis of partial complex regional pain syndrome type 1 of the hand: retrospective study of 16 cases and literature review

Background

The partial form of the complex regional pain syndrome of the hand type 1 (CRPS 1), involving only 1 to 3 fingers, is a rare condition first described in 1972. The aim of the study is to define more precisely the diagnosis workup and the prognosis of this clinical entity.

Methods

Retrospective study of CRPS1 partial form observed during five years in a rehabilitation ward. Application of The Budapest criteria, evaluation of radiological exams, therapeutic results and vocational outcomes. Comparison with cases from literature review.

Results

132 patients were hospitalized with the diagnosis of CRPS type 1 of the hand. 16 partial forms were isolated: 11 men, 5 women with a mean age of 43 years. Among these patients, 14 (88%) met The Budapest criteria and the two remaining cases were diagnosed by using the three phase bone scintigraphy. Only moderate improvement was obtained in the majority of the patients. At the maximal time of follow-up (4 to 9 years), 50% of the patients hadn’t returned to work. From the literature review, 19 cases were eligible for clinical comparisons. The main differences between our series and the literature were: more men involved, later diagnosis and worst prognosis in term of return to work.

Conclusions

This is the largest series of consecutive partial form of CRPS. The Budapest criteria are sufficient for the diagnosis in 88% of cases. As in complete form of CRPS1 of the hand, three phase bone scintigraphy should only be used in doubtful cases in the first six months of the illness. Partial form of CRPS1 of the hand is rare and its prevalence remains unknown. Long term prognosis (4 to 9 years) is poor in our series, 50% of patients didn’t returned to work.

Coping with chronic complex regional pain syndrome: advice from patients for patients

OBJECTIVE

To explore what advice people currently living with chronic complex regional pain syndrome would offer to another person coming to terms with a diagnosis of chronic complex regional pain syndrome.

METHODS

Semi-structured interviews with 21 adults (5 male) living with chronic complex regional pain syndrome who had completed a complex regional pain syndrome rehabilitation programme were conducted.

RESULTS

Effectively self-managing complex regional pain syndrome required individuals to play an active role. This could only be achieved if they felt they had sufficient control. Means of attaining control involved attaining a level of acceptance, becoming well-informed and accessing the right kind of support. The advice offered by patients for patients largely reflected that offered by healthcare professionals. One area where there was a conflict concerned sleep hygiene.

CONCLUSIONS

Our study provides support both for the argument put forward by Redman that without appropriate preparation and support, self-management is ineffective, and that by Skuladottir and Hallsdottir that the main challenge of the chronic pain trajectory is that of retaining a sense of control. The clinical implications of this are discussed.

Rehabilitation of complex regional pain syndrome: evidence based or trial and error?

SUMMARY Complex regional pain syndrome (CRPS), a relatively rare condition, is commonly diagnosed late and has no known cause or cure. There is a limited evidence base for therapeutic interventions and the majority of patients make a spontaneous recovery. The florid signs and symptoms of early CRPS are diminished and altered in the more persistent treatment-resistant form. New signs and symptoms, not listed in diagnostic criteria, begin to emerge that can confuse both the patient and clinician, and lead to questioning of the diagnosis. Trying to implement timely and evidence-based rehabilitation techniques within the above scenario is a significant challenge. This article will discuss those challenges and consider recent clinical and research advances that have sought to address some of these problems in CRPS type I.

Establishing a relationship between bacteria in the human gut and complex regional pain syndrome

Complex Regional Pain Syndrome (CRPS) is a serious and painful condition involving the peripheral and central nervous systems. Full comprehension of the disorder's pathophysiology remains incomplete, but research implicates the immune system as a contributor to chronic pain. Because of the impact gastrointestinal bacteria have in the development and behavior of the immune system, this study compares the GI microbial communities of 16 participants with CRPS (5 of whom have intestinal discomforts) and 16 healthy controls using 454 sequencing technology. CRPS subjects were found to have significantly less diversity than their healthy counterparts. Statistical analysis of the phylogenetic classifications revealed significantly increased levels of Proteobacteria and decreased levels of Firmicutes in CRPS subjects. Clustering analysis showed significant separation between healthy controls and CRPS subjects. These results support the hypothesis that the GI microbial communities of CRPS participants differ from those of their healthy counterparts. These variations may hold the key to understanding how CRPS develops and provide information that could yield a potential treatment.

Spinal cord stimulation as treatment for complex regional pain syndrome should be considered earlier than last resort therapy

BACKGROUND

Spinal cord stimulation (SCS), by virtue of its historically described up-front costs and level of invasiveness, has been relegated by several complex regional pain syndrome (CRPS) treatment algorithms to a therapy of last resort. Newer information regarding safety, cost, and efficacy leads us to believe that SCS for the treatment of CRPS should be implemented earlier in a treatment algorithm using a more comprehensive approach.

METHODS

We reviewed the literature on pain care algorithmic thinking and applied the safety, appropriateness, fiscal or cost neutrality, and efficacy (S.A.F.E.) principles to establish an appropriate position for SCS in an algorithm of pain care.

RESULTS AND CONCLUSION

Based on literature-contingent considerations of safety, efficacy, cost efficacy, and cost neutrality, we conclude that SCS should not be considered a therapy of last resort for CRPS but rather should be applied earlier (e.g., three months) as soon as more conservative therapies have failed.

Complex regional pain syndrome in children: asking the right questions

BACKGROUND

Complex regional pain syndrome (CRPS) is a painful disorder without a known unifying mechanism. There are little data on which to base evaluation and treatment decisions, and what data are available come from studies involving adults; however, even that literature is relatively sparse. Developing robust research for CRPS in children is essential for the progress toward optimal treatment.

OBJECTIVES

To determine potential avenues of research in pediatric CRPS based on a review of the literature. Areas of concern include diagnostic criteria, peripheral mechanisms, central nervous system mechanisms, the role of the autonomic nervous system, possible risk factors, options for prevention and potential avenues of treatment.

METHODS

A literature review was performed and the results applied to form the hypotheses posited in the form of research questions.

RESULTS AND CONCLUSIONS

CRPS is a complicated entity that is more than a painful sensory condition. There is evidence for peripheral inflammatory and neurological changes, and reorganization in both sensory and motor cortexes. In addition, a significant motor component is frequently observed and there appear to be tangible risk factors. Many of these pieces of evidence suggest options for prevention, treatment and monitoring progress and outcome. Most of the data are derived from adult studies and need to be replicated in children. Furthermore, there may be factors unique to pediatrics due to developmental changes in neuroplasticity as well as somatic, endocrinological and emotional growth. Some of these developmental factors may shed light on the adult condition.

[Please don't hurt me!: a plea against invasive procedures in children and adolescents with complex regional pain syndrome (CRPS)]

BACKGROUND

Complex regional pain syndrome (CRPS; formerly known as Morbus Sudeck/reflex dystrophy) is diagnosed in children and adolescents, but the clinical presentation is often atypical. Unfortunately, potentially harmful, invasive treatments are used in pediatric patients.

PATIENTS AND METHODS

A retrospective chart study of pediatric chronic pain patients with CRPS was performed.

RESULTS

Over the course of 6 years, 37 (35 girls) children and adolescents took part in a multidisciplinary chronic pain inpatient program. At admission, patients took on average 4.4 (range 1-10) different medications and 29 different pharmaceuticals were used overall. Prior to admission, invasive pain treatments were performed without success in 16 of the children (43%). At least 13 children received two or more invasive treatments. Although sympathetic blocks were most prevalent, operations and regional anesthesia were also used.

CONCLUSION

Despite a lack of evidence for invasive procedures, these continue to be used in children and adolescents with CRPS, who later respond positively to conventional treatment. The English full-text version of this article is available at SpringerLink (under "Supplemental").

Morphological macrovascular alterations in complex regional pain syndrome type I demonstrated by increased intima-media thickness

Background

Although intima-media thickness (IMT) was increased in several inflammatory diseases, studies investigating whether the inflammatory processes lead to macrovascular alteration with increased IMT in complex regional pain syndrome (CRPS) lack.

Methods

Using ultrasound (high-resolution B-mode), we compared bilaterally the IMT of the common carotid artery (CCA-IMT), the radial artery (RA-IMT), the brachial artery (BRA-IMT) and the quotient Q_RA/CCA, in CRPS type I (n=17), peripheral nerve injury (PNI, n=17) and pain-free controls (PFC, n=22, matched to CRPS by gender, age and traditional cardiovascular risk factors). Statistics: Spearman’s correlation, paired t-test, ANOVA (p<0.05).

Results

Compared to PFC, RA-IMT were significantly increased in both patient groups bilaterally (mean±standard deviation, CRPS affected side vs. PFC dominant side: 0.32±0.08 mm vs. 0.19±0.08 mm, p<0.001; PNI affected side vs. PFC dominant side: 0.27±0.09 mm vs. 0.19±0.08 mm, p< 0.05; CRPS non-affected side vs. PFC non-dominant side: 0.30±0.10 mm vs. 0.19±0.09 mm, p<0.001; PNI non-affected side vs. PFC non-dominant side: 0.25±0.10 mm vs. 0.19±0.09 mm, p<0.05) and Q_RA/CCA (CRPS affected-side vs. PFC dominant side: 0.49±0.12 vs. 0.30±0.11, p<0.001; PNI affected side vs. PFC dominant side: 0.41±0.10 vs. 0.30±0.11, p<0.05; CRPS non-affected side vs. PFC non-dominant side: 0.43±0.19 vs. 0.30±0.13, p<0.001; PNI non-affected side vs. PFC non-dominant side: 0.39±0.14 vs. 0.30±0.13, p<0.05), and BRA-IMT - only on the affected side in CRPS (CRPS: 0.42±0.06 mm vs. PFC: 0.35±0.08 mm; p<0.05). In CRPS, Q_RA/CCA was significantly higher on the affected side compared to PNI (p<0.05). However, only CRPS displayed within-group side-to-side differences with a significantly increased RA-IMT and Q_RA/CCA on the affected side (p<0.05). The CCA-IMT was comparable between all groups and sides.

Conclusions

The increased IMT of peripheral arteries in CRPS suggests ongoing inflammatory process. Until now, only endothelial dysfunction has been reported. The presented morphological macrovascular alterations might explain the treatment resistance of some CRPS patients.

Complex regional pain syndrome: practical diagnostic and treatment guidelines, 4th edition

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.

[Pronounced symptom deterioration in complex regional pain syndrome type II after isolated application of a highly concentrated capsaicin patch. A case report]

Topical 8 % capsaicin is an established therapeutic option for the treatment of peripheral neuropathic pain. In accordance with the internationally accepted definition, complex regional pain syndrome (CRPS) type II is a form of neuropathic pain so that capsaicin plasters represent a treatment option. However, for the treatment of CRPS it is recommended that painful stimuli should be avoided but capsaicin induces a strong nociceptive stimulation and so its use is at present controversial. We report on the course of such an application in a patient who developed CRPS type II with intractable neuropathic pain after hallux surgery. As a result of a single treatment with capsaicin a pronounced recurrence developed with central nervous symptoms.

Parents' perspective of their journey caring for a child with chronic neuropathic pain

When a child has chronic pain, it affects the parents. Their response and how it is factored into their lives and family function was the phenomenon of interest that drove this study. The available literature was sparse, especially when the pain etiology was neuropathic. The purpose of this study was to describe the parents' perception of the pain journey from the initial occurrence of their child's pain through the labyrinth of treatment options to successful outcome, to gain a better understanding of parental beliefs about pain, and to learn how parental attitudes and behaviors relate to children's response to treatment for chronic pain. Qualitative descriptive design was used to better understand the phenomenon from those who were the experts because they had experienced it. Parents whose child was enrolled in a pain rehabilitation program participated in open-ended interviews. The children/adolescents were 8-18 years old and diagnosed with complex regional pain syndrome or a related chronic pain condition. During data immersion, the investigators uncovered the pervasive underlying themes of suffering and disempowerment. In addition, the multiple meaning elements were grouped into three categories and supportive subcategories labeled as follows: parent distress, with subcategories schism in parenting, searching, and disabled parenting; and lack of control, with the subcategories family/community, fear, and empowerment. The voices of parents were heard in their description of the exhausting and difficult journey in search of pain relief for their child. Their comments provided insight into how they defined the child's pain and their related parental role.

Treatment of complex regional pain syndrome type I with neridronate: a randomized, double-blind, placebo-controlled study

OBJECTIVE

Complex regional pain syndrome type I (CRPS-I) is a severely disabling pain syndrome for which no definite treatment has been established. The aim of this multi-centre, randomized, double-blind placebo-controlled trial was to test the efficacy of the amino-bisphosphonate neridronate in patients with CRP-I.

METHODS

Eighty-two patients with CRP-I at either hand or foot were randomly assigned to i.v. infusion of 100 mg neridronate given four times over 10 days or placebo. After 50 days the former placebo patients were given open label the same regimen of neridronate.

RESULTS

Within the first 20 days, visual analogue scale (VAS) score decreased significantly more in the neridronate group. In the following 20 days, VAS remained unchanged in the placebo group and further decreased in the active group by 46.5 mm (95% CI -52.5, -40.5) vs 22.6 mm (95% CI -28.8, -16.3) for placebo group (P < 0.0001). Significant improvements vs placebo were observed also for a number of other indices of pain and quality of life. During the open-extension phase in the formerly placebo group the results of treatment were superimposable on those seen during the blind phase in the active group. A year later none of the patients was referring symptoms linked to CRPS-I.

CONCLUSION

In patients with acute CRPS-I, four i.v. infusions of neridronate 100 mg are associated with clinically relevant and persistent benefits. These results provide conclusive evidence that the use of bisphosphonates, at appropriate doses, is the treatment of choice for CRPS-I.

TRIAL REGISTRATION

EU Clinical Trials Register, https://www.clinicaltrialsregister.eu/, 2007-003372-18.

Efficacy of ultrasonography guided stellate ganglion blockade in the stroke patients with complex regional pain syndrome

Objective

To compare the efficacy of ultrasonography guided stellate ganglion block (US-SGB) with that of blind SGB in management of the stroke patients with complex regional pain syndrome (CRPS) type 1.

Method

Forty-two patients with post-stroke CRPS were randomly assigned to either US-guided SGB (22 patients) or blind SGB group (20 patients). The mean age of US-guided SGB and blind SGB groups was 61.3±5.6 years and 59.1±4.5 years. We performed two blockades at 7-day intervals on the affected side of patients with CRPS. Pain intensity, using a visual analog score (VAS), score of CRPS clinical severity, and the amounts of affected hand swelling with a hand volumeter were assessed before, 2 weeks and 4 weeks after treatment.

Results

In both groups, VAS and the amount of hand swelling were significantly decreased after 2 weeks and after 4 weeks. Between two groups, VAS difference of US-guided SGB group and that of blind SGB group were 2.61±1.09, 1.88±0.62 at 2 weeks and 3.67±1.03, 3.13±0.62 at 4 weeks, respectively. US-guided SGB group showed more significant improvement in mean change of VAS compared to the blind SGB group (p-value<0.05).

Conclusion

Both US-guided SGB and blind SGB techniques were effective in relieving pain in subacute stroke patients with CRPS. US-guided SGB was better in pain relief but has no advantages in reduction of hand swelling in this study.

Imaging and clinical evidence of sensorimotor problems in CRPS: utilizing novel treatment approaches

Inflammation and altered autonomic function are diagnostic signs and symptoms of Complex Regional Pain Syndrome. In the acute stages these are commonly at their most florid accompanied by severe pain and reduced function. Understandably this has directed research towards potential peripheral drivers for the causal mechanisms of this condition. In particular this is now focused on the inflammatory process and the potential role of autoantibodies. More subtle changes also occur in terms of altered tactile processing within the affected limb, disturbances in body perception and motor planning problems that become more evident as the condition progresses. Through careful clinical observation and neuro-imaging techniques, these changes are now thought to be associated with altered cortical processing that includes reorganisation of both the motor and sensory maps. Furthermore, there appears to be a close relationship between the intensity of pain experienced and the extent of cortical re-organisation. This increased knowledge around the peripheral and central mechanisms that may be operating in CRPS has been used to inform novel therapeutic approaches. We discuss here the presenting signs and symptoms of CRPS, with particular focus on sensory and motor changes and consider which mechanisms may drive these changes. Finally, we consider the emerging therapeutic options designed to correct these aberrant mechanisms.

A case of pain, motor impairment, and swelling of the arm after acute herpes zoster infection

Complex regional pain syndrome (CRPS) and postherpetic neuralgia (PHN) represent neuropathic pain syndromes that may appear with similar clinical signs and symptoms. Medical history and clinical distribution of symptoms and signs (PHN typically at the thorax; CRPS typically at the limbs) is obvious in most cases, helping to discriminate between both disorders. Here, we present a patient suffering from CRPS II following PHN of one upper extremity. This case demonstrates that both etiology and part of the body affected by a neuropathy influence the pain phenotype.

Effect of immunomodulating medications in complex regional pain syndrome: a systematic review

BACKGROUND

Different mechanisms are involved in a complex network of interactions resulting in the painful and impairing disorder, complex regional pain syndrome (CRPS). There is convincing evidence that inflammation plays a pivotal role in the pathophysiology of CRPS. Immunomodulating medication reduces the manifestation of inflammation by acting on the mediators of inflammation. Therefore, as inflammation is involved in the pathophysiology of CRPS, immunomodulating medication in CRPS patients may prove beneficial.

OBJECTIVES

To describe the current empirical evidence for the efficacy of administering the most commonly used immunomodulating medication (ie, glucocorticoids, tumor necrosis factor-α antagonists, thalidomide, bisphosphonates, and immunoglobulins) in CRPS patients.

METHODS

PubMed was searched for original articles that investigated CRPS and the use of one of the abovementioned immunomodulating agents.

RESULTS

The search yielded 39 relevant articles: from these, information on study design, sample size, duration of disease, type and route of medication, primary outcome measures, and results was examined.

DISCUSSION

Theoretically, the use of immunomodulating medication could counteract the ongoing inflammation and might be an important step in improving a disabled hand or foot, leading to further recovery. However, more high-quality intervention studies are needed.

Is there a correlation between symptoms and bone scintigraphic findings in patients with complex regional pain syndrome?

BACKGROUND

Complex regional pain syndrome (CRPS) is characterized by pain in combination with sensory, vasomotor, sudomotor, trophic and motor abnormalities. The diagnosis of CRPS is based primarily on clinical criteria and the presence of distinct signs and symptoms. The role of bone scintigraphy in the diagnosis of these patients has been limited by its variable sensitivity. In this study, we aim to look if the presence of specific symptoms or symptom subgroups in patients with clinically diagnosed CRPS correlates with scintigraphic findings in bone scan.

MATERIALS AND METHODS

We retrospectively reviewed clinical records of patients referred for bone scintigraphy with the clinical diagnosis of CRPS during the period December 2006 until February 2011. Patients were classified into 4 distinct subgroups according to the presence of specific symptoms namely sensory subgroup, sudomotor and/or edema subgroup, vasomotor subgroup and finally motor and/or trophic changes subgroup. We looked specifically for the correlation between these specific symptoms and scintigraphic bone findings.

RESULTS

37 patients were referred for bone scintigraphy with the clinical diagnosis of CRPS and were enrolled in the study. The presence of vasomotor symptoms and (motor and/or trophic changes) was significantly higher in patients with positive bone scintigraphy (P value 0.0133, 0.018 respectively). There was no other statistically significant correlation between the presence of specific symptoms or symptom subgroups on one hand and the result of bone scintigraphy on the other hand.

CONCLUSIONS

The probability of positive bone scintigraphy increased significantly in patients with vasomotor symptoms and in patients with motor and/or trophic changes. This may contribute to the reported variability of the diagnostic performance of bone scintigraphy in CRPS patients.

Genetic HLA associations in complex regional pain syndrome with and without dystonia

We previously showed evidence for a genetic association of the human leukocyte antigen (HLA) system and complex regional pain syndrome (CRPS) with dystonia. Involvement of the HLA system suggests that CRPS has a genetic component with perturbed regulation of inflammation and neuroplasticity as possible disease mechanisms. However, it is at present unclear whether the observed association with HLA-B62 and HLA-DQ8 in CRPS patients with dystonia also holds true for patients without dystonia. Therefore, we tested the possible association with HLA-B62 and HLA-DQ8 in a clinically homogeneous group of 131 CRPS patients without dystonia. In addition, we investigated the possible association with other alleles of the HLA-A, HLA-B, HLA-C, HLA-DR, and HLA-DQ loci. We showed an increased prevalence of HLA-DQ8 (molecularly typed as HLA-DQB1*03:02; OR = 1.65 [95% CI 1.12-2.42], P = .014) in CRPS without dystonia, whereas no association was observed for HLA-B62 (molecularly typed as HLA-B*15:01; OR = 1.22 [95% CI .78-1.92], P = .458). Our data suggest that CRPS with and CRPS without dystonia may be genetically different, but overlapping, disease entities because only HLA-DQ8 is associated with both. The findings also indicate that distinct biological pathways may play a role in both CRPS subtypes.

PERSPECTIVE

This study is the first to replicate a specific HLA region conferring genetic risk for the development of CRPS. Moreover, associations of HLA-DQ8 with both CRPS with and CRPS without dystonia, and HLA-B62 only with CRPS with dystonia, suggest that these disease entities may be genetically different, but overlapping.

Complex regional pain syndrome following spine surgery: clinical and prognostic implications

BACKGROUND

Complex regional pain syndrome (CRPS) has been reported following spinal surgery, but its frequency after spinal surgery is unknown. The aim of this study was to determine the frequency of spinal surgery preceding CRPS and to examine these patients regarding the course of the disease and prognostic factors.

METHODS

We examined 35 CRPS patients regarding the symptoms and signs of CRPS, the type of CRPS (I or II), the origin and grade of the disease, the type of surgeries prior to CRPS onset, the course of the disease, and the therapies following diagnosis of CRPS.

RESULTS

In 6 patients, CRPS began during the postoperative course (lumbar spine surgery, n = 5; cervical spine surgery, n = 1). Four of these patients suffered from CRPS II. The course of the disease in the 6 patients was not different from that of patients with CRPS of other origins. First symptoms of CRPS could be observed 1-14 days after surgery.

CONCLUSIONS

CRPS is a rare complication after spinal surgery, but spinal surgery precedes the onset of CRPS of the lower limb in almost one-third of the cases. The first typical symptoms of CRPS emerge within 2 weeks after spinal surgery.