Prognostic Factors in Complex Regional Pain Syndrome Type 1 Occurring in the Korean Army.

OBJECTIVES: In Korea, patients diagnosed with complex regional pain syndrome (CRPS) in the army are typically discharged from the army; however, the course of the disease after discharge is not known. The purpose of this study was to investigate the course of CRPS that occurred in the army and to identify the influences of various clinical and psychosocial factors immediately before discharge on the disease course. METHODS: Clinical profiles and psychosocial status were collected from the medical records of 16 patients with CRPS type 1 who were discharged during the period between March 2017 and April 2018. The degree of improvement after discharge was assessed by follow-up evaluation through telephone contact. Cox proportional hazards regression was performed to identify clinical and psychosocial predictors for the rate of recovery. RESULTS: The median time to recovery after discharge was 39 weeks (95% confidence interval [CI] = 8.8-69.2 weeks). The sole predictor for time to recovery after discharge was the time period from the onset of pain to discharge. Each one-week increase in the duration of pain experienced in the military was associated with a 18.2% (95% CI = 5.3%-29.5%) reduction in the rate of recovery after discharge (P = 0.007). CONCLUSIONS: Patients who experienced a short period of pain in the military demonstrated a relatively good prognosis after discharge. This may show how prolonged pain in the army could affect the experience of pain from a social point of view, in that it shows the disease course after a change in the social environment.

Graded motor imagery for women at risk for developing type I CRPS following closed treatment of distal radius fractures: a randomized comparative effectiveness trial protocol.

BACKGROUND: Distal radius fractures (DRF) account for nearly one-fifth of all fractures in older adults, and women experience them 5× as often as men. Most DRF occur with low impact injuries to the wrist with an outstretched hand, and are often managed via closed treatment and cast immobilization. Women sustaining a DRF are at risk for upper limb immobility, sensorimotor changes, edema and type I complex regional pain syndrome (CRPS). Since CRPS onset is likely influenced by alterations in the brain's somatosensory region, a rehabilitation intervention, Graded Motor Imagery (GMI), aims to restore cortical representation, including sensory and motor function, of the affected limb. To date, there are no studies on the use of GMI in reducing risk of or preventing the onset of type I CRPS in women with DRF treated with cast immobilization. Due to a higher likelihood of women with this injury developing type I CRPS, it is important to early intervention is needed. METHODS/DESIGN: This article describes a six-week randomized comparative effectiveness trial, where the outcomes of a modified GMI program (mGMI) + standard of care (SOC) group (n = 33) are compared to a SOC only control group (n = 33). Immediately following cast immobilization, both groups participate in four 1-h clinic-based sessions, and a home program for 10 min three times daily until cast removal. Blinded assessments occur within 1 week of cast immobilization (baseline), at three weeks post cast immbolization, cast removal, and at three months post cast removal. The primary outcomes are patient reported wrist/hand function and symptomology on the Patient Rated Wristand Hand Evaluation, McGill Pain Questionnaire, and Budapest CRPS Criteria. The secondary outcomes are grip strength, active range of motion as per goniometry, circumferential edema measurements, and joint position sense. DISCUSSION: This study will investigate the early effects of mGMI + SOC hand therapy compared to SOC alone. We intend to investigate whether an intervention, specifically mGMI, used to treat preexisiting pain and motor dysfunction might also be used to mitigate these problems prior to their onset. If positive effects are observed, mGMI + SOC may be considered for incorporation into early rehabilitation program. TRIAL REGISTRATION: This trial is registered at ClinicalTrials.gov with identifier NCT02957240 (Approval date: April 20, 2017).

Quality of life, functioning and participation of adult patients with an amputation following complex regional pain syndrome I or brachial plexus injury: a scoping review protocol.

INTRODUCTION: This planned scoping review aims to provide insight into current literature regarding perceived quality of life (QoL), functioning and participation of patients with upper limb amputations (ULA) because of therapy-resistant debilitating complex regional pain syndrome type I (CRPS-I) or brachial plexus injury (BPI). It is important to gain insight into these outcomes, so we can properly inform and select patients eligible for amputation. METHODS AND ANALYSIS: Joanna Briggs Institute methodology for scoping reviews, Systematic Reviews and Meta-Analyses Scoping Reviews guidelines and Arksey and O'Malley's framework will be used. Studies regarding adult patients with either BPI or CRPS-I who underwent ULA will be considered for inclusion. Studies should include one or more of the following topics: QoL, functioning or participation and should be written in English, German or Dutch. Searches will be conducted in the Cochrane database, PubMed, EMBASE and Google Scholar. Search strings will be provided by a licenced librarian. All relevant literatures will be considered for inclusion, regardless of published date, in order to give a full scope of available literature. Studies will be selected first by title, then abstract and finally by full article by two reviewers who will discuss after every round. A third reviewer will make final decisions to reach consensus if needed. Data will be presented as brief summaries and in tables using a modified data extraction table. ETHICS AND DISSEMINATION: No ethical approval is required since no original data will be collected. Results will be disseminated through publication in a peer-reviewed journal and presentations at (inter)national conferences.

Pain acceptance-based coping in complex regional pain syndrome Type I: daily relations with pain intensity, activity, and mood.

This study aimed to examine the temporal patterning of pain acceptance-based coping, activity, and mood in patients with complex regional pain syndrome Type I (CRPS-I), by using a daily diary method. A total of 30 patients with CRPS-I seeking treatment in a tertiary pain management center located in Seoul, Korea participated in the study. Multilevel random effects analyses indicated that (a) engagement in pain acceptance-based coping was significantly associated with lower same-day pain and negative mood and greater same-day activity and positive mood; (b) pain acceptance-based coping predicted increases in activity on the following day; (c) greater pain intensity was significantly associated with lower same-day pain acceptance-based coping and activity and greater same-day negative mood; and (d) pain intensity did not predict pain acceptance-based coping, activity, or mood on the following day. These findings suggest that patients with CRPS-I may benefit from responding to pain with acceptance. Further study and eventual application of this process in CRPS-I may improve upon the success of current approaches to this problem.

Algodystrophy in children and adolescents: a review.

Algodystrophy occurs in children significantly less frequently than in adults. Symptomatology, course, responsiveness to treatment and prognosis of the pediatric disease is also different from the "adult" form. This paper presents substantial peculiarities of pediatric algodystrophy: it occurs after relatively minor trauma, involves lower limb more frequently than upper limb and presents with pain, paleness and coldness of the skin in the affected part, as well as with serious functional impairment. Diagnosis of the condition is based on clinical grounds and no imaging is necessary to confirm the diagnosis. Psychological distress is suspected in the development of the disease in children and adolescents, but there is no definitive evidence supporting this view. Treatment of pediatric algodystrophy should be complex and consist of physical therapy, psychotherapy, pain therapy and, in selected cases, sympathetic and somatic blocks. The literature emphasizes very poor knowledge of algodystrophy in the pediatric community.

Anxious personality is a risk factor for developing complex regional pain syndrome type I.

The aim of this study was to investigate the role of psychological factors in the development of complex regional pain syndrome (CRPS) type I following the fracture of the distal radius. Fifty patients (average age 57.70 ± 13.43 years) with a distal radius fracture were enrolled in the present study. All of the patients were treated by closed reduction and cast immobilization. The Toronto Alexithymia Scale-20, Anxiety Sensitivity Index, State-Trait Anxiety Inventory, and Beck Depression Inventory were used to determine the patients' psychological features 2 days after the fracture. The patients were followed for 2 months after cast immobilization was completed using the International Association for the Study of Pain criteria to diagnose CRPS type I. CRPS type I developed in 13 (26%) patients of the 32 (34.4%) female patients and 18 (11.1%) male patients. The risk of CRPS type I was significantly increased in patients with high trait anxiety scores (P = 0.038). The results show that, after fracturing the distal radius, patients who have an anxious personality have a higher risk of developing CRPS type I. Following these patients closely for the development of CRPS type I may be advantageous for early preventative and therapeutic interventions.

Evidence based guidelines for complex regional pain syndrome type 1.

BACKGROUND: Treatment of complex regional pain syndrome type I (CRPS-I) is subject to discussion. The purpose of this study was to develop multidisciplinary guidelines for treatment of CRPS-I. METHOD: A multidisciplinary task force graded literature evaluating treatment effects for CRPS-I according to their strength of evidence, published between 1980 to June 2005. Treatment recommendations based on the literature findings were formulated and formally approved by all Dutch professional associations involved in CRPS-I treatment. RESULTS: For pain treatment, the WHO analgesic ladder is advised with the exception of strong opioids. For neuropathic pain, anticonvulsants and tricyclic antidepressants may be considered. For inflammatory symptoms, free-radical scavengers (dimethylsulphoxide or acetylcysteine) are advised. To promote peripheral blood flow, vasodilatory medication may be considered. Percutaneous sympathetic blockades may be used to increase blood flow in case vasodilatory medication has insufficient effect. To decrease functional limitations, standardised physiotherapy and occupational therapy are advised. To prevent the occurrence of CRPS-I after wrist fractures, vitamin C is recommended. Adequate perioperative analgesia, limitation of operating time, limited use of tourniquet, and use of regional anaesthetic techniques are recommended for secondary prevention of CRPS-I. CONCLUSIONS: Based on the literature identified and the extent of evidence found for therapeutic interventions for CRPS-I, we conclude that further research is needed into each of the therapeutic modalities discussed in the guidelines.

Generalization of exposure in vivo in Complex Regional Pain Syndrome type I.

Exposure in vivo has been found successful in reducing pain-related fear, disability, and experienced pain in chronic pain patients. Despite the success of exposure treatment, experimental studies show that extinction learning is fragile, raising doubts whether extinction of pain-related fear generalizes to new threatening activities after treatment. This study examined whether a particular exposure treatment, in which patients are exposed to a variety of activities (Multiple Exposure condition), promotes generalization of extinction to new threatening situations, compared to an exposure treatment in which subjects are repeatedly exposed to the same set of activities (Repeated Exposure condition). Generalization tests were combined with randomized replicated single case experimental designs (N = 8). Included were patients with Complex Regional Pain Syndrome type I reporting elevated levels of pain-related fear. The Multiple Exposure treatment condition consisted of at least 15 activities to which patients were exposed once. The Repeated Exposure treatment condition exposed patients to only three activities during five sessions each. Generalization was tested by exposing patients to new fearful activities post-treatment and 6-months follow-up. Patients from both conditions performed equally well at both generalization tests. Daily measures showed that the Multiple Exposure condition is preferred to reduce fear of movement/(re)injury, pain catastrophizing and pain experience.

Can the outcome of spinal cord stimulation in chronic complex regional pain syndrome type I patients be predicted by catastrophizing thoughts?

BACKGROUND: In this study, we examined whether pain catastrophizing is a predictor of spinal cord stimulation (SCS) outcome in patients with complex regional pain syndrome type I (CRPS-I). METHODS: Participants in this prospective cohort study were 32 patients with chronic CRPS-I, who received permanent SCS after a positive response to test stimulation. Baseline assessment was performed before test stimulation and included questions on demographic variables, disease information, pain intensity, pain catastrophizing, and health-related quality of life (QOL). Follow-up assessment was performed 9 mo after final implantation and included pain intensity, global perceived effect (GPE), and QOL. Successful SCS outcome was defined as a reduction of pain intensity of at least 50% on a visual analog scale or "much improved" or "total pain relief" on GPE. RESULTS: After 9 months, 38% of the patients had a successful outcome in reduced pain intensity and 53% of the patients in GPE. In addition, improvements were apparent on several of the domains of QOL. However, no evidence was found for the predictive value of pain catastrophizing on the efficacy of SCS in reduction of pain intensity, GPE, or QOL. CONCLUSIONS: This study showed that the efficacy of SCS in reduction of pain intensity, GPE, and QOL in a well-defined chronic CRPS-I population was not predicted by pain catastrophizing. Therefore, we conclude that a high level of pain catastrophizing in patients with CRPS-I is not a contraindication for SCS treatment.

Clinical Features of Pediatric Complex Regional Pain Syndrome: A 5-Year Retrospective Chart Review.

OBJECTIVES: Complex regional pain syndrome (CRPS) is a painful condition of a limb characterized by a constellation of symptoms. Little is known about the clinical features of pediatric CRPS, with fewer than a dozen studies published to date. The aim of this study was to explore the clinical course of pediatric CRPS, with emphasis on clinical features and disease outcomes. A secondary aim was to discern differences in clinical features of pediatric CRPS with and without related movement disorders, and between children who had a favorable and unfavorable outcome. MATERIALS AND METHODS: We carried out a retrospective chart review of children with CRPS who presented to a pediatric Chronic Pain Clinic in Canada over a 5-year period (2012 to 2016). RESULTS: The study identified 59 children with CRPS (mean age: 12.7±2.5; 74.6% female; 72.9% lower extremity). In total, 87% (n=48) of children experienced complete resolution or significant improvement of CRPS, with a relapse rate of 15%. Overall, 25% (n=15) had a CRPS-related movement disorder. There were no differences in the clinical features of pediatric CRPS with or without related movement disorders. Children who experienced a favorable outcome had a significantly shorter symptom duration at the initial visit in comparison with children who experienced an unfavorable outcome. DISCUSSION: In this cohort, pediatric CRPS was most common in girls around the age of 12, usually in the lower extremity, and most experienced a favorable outcome. Further research is needed to better understand the prognosis and relapse rate of pediatric CRPS.

Psychological features of patients with complex regional pain syndrome type I related dystonia.

The objective of this study was to evaluate psychological features in severely affected patients with complex regional pain syndrome type I- (CRPS-I) related dystonia. Personality traits, psychopathology, dissociative experiences, the number of traumatic experiences, and quality of life were studied in 46 patients. Findings were compared with two historical psychiatric control groups [54 patients with conversion disorder (CD) and 50 patients with affective disorders (AD)] and normative population data. The CRPS-I patients showed elevated scores on the measures for somatoform dissociation, traumatic experiences, general psychopathology, and lower scores on quality of life compared with general population data, but had significantly lower total scores on the measures for personality traits, recent life events, and general psychopathology compared with the CD and AD patients. Rates of early traumatic experiences were comparable with the CD and AD patients, and the level of somatoform dissociation was comparable to the CD patients, but was elevated in comparison to the AD patients. Early traumatic experiences were reported in 87% of the CRPS-I patients and were found to be moderately related to somatoform dissociative experiences, indicating that early traumatic experiences might be a predisposing, although not a necessary factor for the development of CRPS-I-related dystonia. Although the psychological profile of the patients with CRPS-I-related dystonia shows some elevations, there does not seem to be a unique disturbed psychological profile on a group level.

Effect of spinal cord stimulation for chronic complex regional pain syndrome Type I: five-year final follow-up of patients in a randomized controlled trial.

OBJECT: Chronic complex regional pain syndrome-Type I (CRPS-I) is a painful, disabling disorder for which no treatment with proven effect is available. In the present randomized controlled trial, the authors assessed the effectiveness of spinal cord stimulation (SCS) in reducing pain due to CRPS-I at the 5-year follow-up. METHODS: The authors performed a randomized trial in a 2:1 ratio in which 36 patients with CRPS-I were allocated to receive SCS and physical therapy (PT) and 18 patients to receive PT alone. Twenty-four patients who received SCS+PT also underwent placement of a permanent spinal cord stimulator after successful test stimulation; the remaining 12 patients did not receive a permanent stimulator. The authors assessed pain intensity, global perceived effect, treatment satisfaction, and health-related quality of life. Patients were examined before randomization, before implantation, and every year until 5 years thereafter. Ten patients were excluded from the final analysis. RESULTS: At 5 years posttreatment, SCS+PT produced results similar to those following PT for pain relief and all other measured variables. In a subgroup analysis, the results with regard to global perceived effect (p=0.02) and pain relief (p=0.06) in 20 patients with an implant exceeded those in 13 patients who received PT. CONCLUSIONS: Despite the diminishing effectiveness of SCS over time, 95% of patients with an implant would repeat the treatment for the same result.

Increased plasma serotonin in complex regional pain syndrome type 1.

BACKGROUND: In patients with complex regional pain syndrome type 1 (CRPS1), some improvement can be achieved by the administration of ketanserin, a 5-HT(2A) receptor antagonist. We measured plasma levels of serotonin (5-HT) during CRPS1 and correlated these levels with disease characteristics. METHODS: Plasma 5-HT was measured in 35 patients who had CRPS1 for 3 yr and compared with 35 age-matched healthy controls. RESULTS: The plasma 5-HT levels were 411 +/- 263 nmol/L and 29 +/- 18 nmol/L, respectively (P < 0.001). No correlations with disease characteristics were observed. CONCLUSIONS: The markedly elevated levels of plasma 5-HT in CRPS1 patients suggest a role for 5-HT during the course of this disease. However, because of the lack of correlations with distinct disease characteristics, 5-HT is probably one of a number of mediators in CRPS1.

Increased plasma glutamate, glycine, and arginine levels in complex regional pain syndrome type 1.

BACKGROUND: Various inflammatory mediators have been identified as potential contributors to complex regional pain syndrome type 1 (CRPS1), but these mediators do not entirely explain certain manifestations of the syndrome, such as pain. The objective of this study was to investigate the role of amino acids in the pathogenesis of CRPS1. METHODS: We used HPLC to determine plasma concentrations of 16 amino acids, especially those related to the NMDA receptor (e.g., glutamate and glycine) and nitric oxide (NO) synthesis (e.g., arginine and citrulline) in patients with CRPS1 (n=64) and age- and sex-matched healthy controls (n=51). Patients rated pain intensity (visual analog scale) and the subjective experience of pain intensity (McGill Pain Questionnaire). Psychological dysfunction was assessed using the SCL-90. RESULTS: Relative to controls, in CRPS1 patients, plasma levels of glutamate, arginine, taurine, and glycine were increased, and plasma levels of glutamine and the ratio of citrulline to arginine were decreased. Remarkably, in CRPS1 patients there was a highly significant inverse correlation between glutamine and glutamate, although the sum of molar concentrations of glutamate and glutamine remains unchanged. Subjective measures of pain and indicators of psychoneuroticism and emotional instability did not correlate with amino acid levels. CONCLUSION: This study shows for the first time a pronounced increase in amino acid levels in this chronic pain syndrome. The marked differences in glutamate, glutamine, glycine, taurine and arginine levels between patients and controls suggest the involvement of both the NDMA receptor and the endothelium-dependent arginine-NO system in CRPS1.

Investigate the Effect of Psychological Factors in Development of Complex Regional Pain Syndrome Type I in Patients with Fracture of the Distal Radius: A Prospective Study.

BACKGROUND: To investigate the role of psychological factors (anxiety and depression) and pain measured on a visual analogue scale (VAS) in the development of complex regional pain syndrome type I (CRPS I) following the distal radius fracture (DRF). METHODS: A consecutive sample of patients (N=60) with a distal radius fracture was measured for signs of CRPS by Budapest criteria weekly till 8 weeks and then another follow-up one year after injury to determine the incidence and predictors of developing CRPS I in a prospective cohort study and also to discover whether there is difference between pain, depression, and anxiety level in the patients with and without CRPS I. The most of the patients were treated by Pin stabilization. The Beck depression inventoryshort form (BDI), State-Trait Anxiety Inventory, and Numerical pain rating scale were used to determine the patients' psychological features and pain intensity at the base line and 8 weeks after the fracture. RESULTS: CRPS I developed in 15 (25%) patients after eight weeks and just last in 10 (16.67%) patients after one year. No difference was found between the two groups (CRPS and non-CRPS group) in terms of state (STAI-I) and trait (STAI-II) anxiety, and BDI score. Pain at the base line was the most important risk factor in developing CRPS (odds ratio [OR] =1.52; 95% CI). CONCLUSIONS: After fracturing the distal radius, patients who have high pain intensity have a higher risk of developing CRPS I. To following these patients closely for the development of CRPS I may be advantageous for early preventative and therapeutic interventions.

Mental load during cognitive performance in complex regional pain syndrome I.

BACKGROUND: Complex regional pain syndrome (CRPS) is associated with deficits in limb recognition. The purpose of our study was to determine whether mental load during this task affected performance, sympathetic nervous system activity or pain in CRPS patients. METHODS: We investigated twenty CRPS-I patients with pain in the upper extremity and twenty age- and sex-matched healthy controls. Each participant completed a limb recognition task. To experimentally manipulate mental load, the presentation time for each picture varied from 2 s (greatest mental load), 4, 6 to 10 s (least mental load). Before and after each run, pain intensity was assessed. Skin conductance was recorded continuously. RESULTS: Patients with CRPS did not differ from controls in terms of limb recognition and skin conductance reactivity. However, patients with CRPS reported an increase in pain during the task, particularly during high mental load and during the latter stages of the task. Interestingly, state anxiety and depressive symptoms were also associated with increases in pain intensity during high mental load. CONCLUSIONS: These findings indicate that high mental load intensifies pain in CRPS. The increase of pain in association with anxiety and depression indicates a detrimental effect of negative affective states in situations of high stress and mental load in CRPS. SIGNIFICANCE: The effects of mental load need to be considered when patients with CRPS-I are investigated for diagnostic or therapeutic reasons.

Complex regional pain syndrome type 1 in the medico-legal setting: High rates of somatoform disorders, opiate use and diagnostic uncertainty.

Objective The aim of this study was to review demographic and clinical characteristics of patients with complex regional pain syndrome type 1 (CRPS) seen in a UK medico-legal setting - particularly the relationship between CRPS and somatoform disorders. Methods Fifty consecutive cases of CRPS (interviewed 2005-2016) undergoing psychiatric assessment were reviewed. A systematic assessment of mental states was conducted via interview and examination of medical/psychiatric records. Thirty patients also completed the Brief Illness Perception Questionnaire (BIPQ). Results Sixty per cent of patients ( n = 30) were female, and the mean age was 43 years. Twenty-two per cent ( n = 11) were employed, and 60% ( n = 30) received disability benefits. Symptoms were reported in the upper limb (62%; n = 31), lower limb (30%; n = 15), both (6%; n = 3) or elsewhere (2%; n = 1). Eighty-four per cent ( n = 42) satisfied DSM-5 criteria for current somatoform disorder. A history of more than two pain-related functional somatic syndromes (e.g. non-cardiac chest pain) was found in 42% ( n = 21) and functional neurological symptoms (e.g. 'claw-hand') in 42% ( n = 21). BIPQ scores resembled those associated with somatoform disorders and disorders mediated by psychological factors (e.g. irritable bowel syndrome). In 38% ( n = 19), the CRPS diagnosis was disputed among experts. A history of depression was noted in 60% ( n = 30), panic attacks in 20% ( n = 10) and alcohol/substance misuse in 18% ( n = 9). Opiates were prescribed to 64% ( n = 32). Conclusions Patients diagnosed with CRPS involved in litigation have high rates of prior psychopathology (mainly somatoform disorders) and pain-related disability for which opiate use is common. They risk an adverse reaction to limb pain 'shaped' by maladaptive illness beliefs. The CRPS diagnosis lacks reliability in medico-legal settings and may cause iatrogenic harm.

Approach to the Patient with Disproportionate Pain.

Faced with a patient who presents with unexplained disproportionate pain, a surgeon may be tempted to diagnose a low pain threshold, malingering, poor coping, anxiety, or other emotional condition. However, a variety of conditions must be ruled out before the orthopedist can prescribe watchful waiting. Computed tomography and magnetic resonance imaging can detect occult fractures, acute spinal conditions or vascular occlusions, but early on are inadequate to diagnose a compartment syndrome, necrotizing fasciitis, or reflex sympathetic dystrophy (RSD). These diagnoses underpin a pain-out-of-proportion situation whereby the patient presents with disproportionate pain following a sometimes minor trauma with normal imaging studies and otherwise nonspecific presentations. Though these conditions are well described in the literature, investigations of malpractice data reveal a non-negligible prevalence of missed diagnoses for each of these entities. Determining that a patient exhibits otherwise unexplained pain-out-of-proportion situation is the first step in making a timely diagnosis.

Lymphocyte subsets and the role of TH1/TH2 balance in stressed chronic pain patients.

BACKGROUND: The complex regional pain syndrome (CRPS) and fibromyalgia (FM) are chronic pain syndromes occurring in highly stressed individuals. Despite the known connection between the nervous system and immune cells, information on distribution of lymphocyte subsets under stress and pain conditions is limited. METHODS: We performed a comparative study in 15 patients with CRPS type I, 22 patients with FM and 37 age- and sex-matched healthy controls and investigated the influence of pain and stress on lymphocyte number, subpopulations and the Th1/Th2 cytokine ratio in T lymphocytes. RESULTS: Lymphocyte numbers did not differ between groups. Quantitative analyses of lymphocyte subpopulations showed a significant reduction of cytotoxic CD8+ lymphocytes in both CRPS (p < 0.01) and FM (p < 0.05) patients as compared with healthy controls. Additionally, CRPS patients were characterized by a lower percentage of IL-2-producing T cell subpopulations reflecting a diminished Th1 response in contrast to no changes in the Th2 cytokine profile. CONCLUSIONS: Future studies are warranted to answer whether such immunological changes play a pathogenetic role in CRPS and FM or merely reflect the consequences of a pain-induced neurohumoral stress response, and whether they contribute to immunosuppression in stressed chronic pain patients.

Chronic pain in rehabilitation medicine.

In this paper the chronicity of pain in non-specific pain syndromes is discussed. Experts in the study of pain with several professional backgrounds in rehabilitation are the authors of this paper. Clinical experience and literature form the basis of the paper. Non-specific low back pain and Complex Regional Pain Syndrome type I (CRPS-I) are discussed in the light of chronic pain. Many definitions of chronic pain exist. Yellow flags are important factors to identify possible chronic pain. In the acute phase of a non-specific pain complaint one should try to identify possible psychosocial inciting risk factors. Behavioural and cognitive treatment seems to be effective for chronic pain patients.