Clinical expression profiles of complex regional pain syndrome, fibromyalgia and a-specific repetitive strain injury: More common denominators than pain?

Modern Principles of Diagnosis and Treatment in Complex Regional Pain Syndrome

BACKGROUND

Background: Complex regional pain syndrome (CRPS) is a relatively common complication, occurring in 5% of cases after injury or surgery, particularly in the limbs. The incidence of CPRS is around 5-26/100 000. The latest revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-11) now categorizes CRPS as a primary pain condition of multifactorial origin, rather than a disease of the skeletal system or the autonomic nervous system.

METHODS

Method: Based on a selective search of the literature, we summarize current principles for the diagnosis and treatment of CRPS.

RESULTS

Results: Regional findings in CRPS are accompanied by systemic symptoms, especially by neurocognitive disorders of body perception and of symptom processing. The therapeutic focus is shifting from predominantly passive peripheral measures to early active treatments acting both centrally and peripherally. The treatment is centered on physiotherapy and occupational therapy to improve sensory perception, strength, (fine) motor skills, and sensorimotor integration/ body perception. This is supported by stepped psychological interventions to reduce anxiety and avoidance behavior, medication to decrease inflammation and pain, passive physical measures for reduction of edema and of pain, and medical aids to improve functioning in daily life. Interventional procedures should be limited to exceptional cases and only be performed in specialized centers. Spinal cord and dorsal root ganglion stimulation, respectively, are the interventions with the best evidence.

CONCLUSION

Conclusion: The modern principles for the diagnosis and treatment of CRPS consider both, physiological and psychological mechanisms, with the primary goal of restoring function and participation. More research is needed to strengthen the evidence base in this field.

Visual Sensitivity in Complex Regional Pain Syndrome and Fibromyalgia: An Online Study

Perceptual anomalies can provide insights into underlying pathologies even when they are not the main symptom of many clinical conditions. Complex regional pain syndrome (CRPS) and fibromyalgia are chronic pain conditions associated with changes in the central nervous system, possibly leading to enhanced visual sensitivity. It is unclear whether this occurs more than for people with other types of pain. We examined visual sensitivity elicited by different stimuli and in daily life, through an online study of people with CRPS (n = 57), fibromyalgia (n = 74), other pain (n = 50), and no pain (n = 89). Respondents rated changes in pain, discomfort, or distress from viewing patterns with different spatial frequencies (lower-order visual processing), and reversible figures (bistable images; higher-order visual processing). We assessed visual sensitivity in daily life using the Leiden Visual Sensitivity Scale and Visual Discomfort Scale. Respondents with CRPS or fibromyalgia reported more visual discomfort than pain-related and pain-free controls while viewing striped patterns and a circle, with no effect of spatial frequency. They reported more pain while viewing a nonreversible square, but not reversible figures (Necker Cube, Duck/Rabbit). Finally, they reported more daily visual sensitivity than pain-related and pain-free controls. Suppressing visual cortical activity might benefit people with CRPS or fibromyalgia.

Predictors of Self-Reported Neglect-like Symptoms and Involuntary Movements in Complex Regional Pain Syndrome Compared to Other Chronic Limb Pain Conditions

Objective

In addition to pain, people with complex regional pain syndrome (CRPS) often report inattention to and disengagement from their affected limb (i.e., “neglect-like symptoms”). Understanding how these symptoms relate to other characteristics of CRPS, and chronic pain generally, could provide insights for preventing and treating CRPS.

Methods

We administered an online survey to people who received a diagnosis of CRPS (n = 335) and other chronic limb pain (n = 407). Neglect-like symptoms were assessed using the Neurobehavioral questionnaire.

Results

A principal component analysis identified two components: motor and cognitive neglect-like symptoms, and involuntary movements. Internal consistency of the components was acceptable. We conducted regression analyses with these as outcomes. Having CRPS, a painful lower limb, higher pain intensity, and somatic symptoms were associated with more motor and cognitive neglect-like symptoms. Having CRPS, higher pain intensity, depression, and somatic symptoms were associated with more involuntary movements. Age, gender, anxiety, disease duration, hours of pain per day, affected side, whether the limb was the most painful body part, and number of pain-related medical diagnoses were no predictors. Finally, motor and cognitive neglect-like symptoms were related to tremor; and involuntary movements to changes in skin color, swelling, sweating, toenails, weakness, and tremor.

Conclusions

This study confirms the specificity of inattention to and disengagement from the affected limb in CRPS, independent of other factors. Furthermore, two components of the Neurobehavioral questionnaire were disentangled: motor and cognitive neglect-like symptoms, and involuntary movements. Results could potentially help clinicians to better assess neglect-like symptoms in chronic pain .

Multicenter survey of symptoms, work life, economic status, and quality of life of complex regional pain syndrome patients

Background

Complex regional pain syndrome (CRPS) is an intractable pain disease with various symptoms. Here, we investigated the disease status, work life, sleep problems, medical insurance, economic status, psychological problems, and quality of life (QOL) of CRPS patients.

Methods

CRPS patients from 37 university hospitals in South Korea were surveyed. The survey questionnaire consisted of 24 questions on the following aspects of CRPS patients sex, age, occupation, cause of injury, activities of daily living (ADL), pain severity, sleep disturbance, level of education, economic status, therapeutic effect, and suicidal ideation. Additionally, the abbreviated World Health Organization Quality of Life (WHOQOL-BREF) questionnaire, consisting of 26 questions, was used to identify the status of QOL.

Results

A total of 251 patients completed the questionnaire. According to the survey, 54.2% patients could not perform ADL on their own. Over the previous week, the mean pain score was 7.15 ± 1.78 (out of a total of 10 points); 92.1% of patients had sleep disorders and 80.5% had suicidal ideation, with most patients suffering from psychological problems. The average for each domain of WHOQOL-BREF was as follows 21.74 ± 14.77 for physical, 25.22 ± 17.66 for psychological, 32.02 ± 22.36 for social relationship, and 30.69 ± 15.83 for environmental (out of a total of 100 points each). Occupation, ADL, sleep time, therapeutic effect, and suicidal ideation were statistically correlated with multiple domains.

Conclusions

Most patients had moderate to severe pain, economic problems, limitations of their ADL, sleep problems, psychological problems, and a low QOL score.

Validation of the Leiden Visual Sensitivity Scale and Visual Discomfort Scale in Chronic Pain Conditions

Discomfort provoked by normally innocuous visual stimuli has been reported by people with chronic pain. Visual discomfort may be higher in pain conditions in which central sensitization is implicated, such as Complex Regional Pain Syndrome (CRPS) and fibromyalgia. In an online study, we validated the Leiden Visual Sensitivity Scale (L-VISS) and Visual Discomfort Scale (VDS) in people with CRPS (n = 57), fibromyalgia (n = 75), and general chronic pain (n = 53); investigated whether these groups and pain-free controls (n = 125) differed in visual discomfort; and evaluated the effect of age. The L-VISS and VDS had good internal consistency. Both scales were positively related with experimentally induced visual distortions for mid-spatial frequency striped patterns, suggesting good construct validity. The scales were positively related with each other, and dissociated between the pain and pain-free groups in similar ways, suggesting good construct validity. There was no relationship between age and L-VISS scores and a small negative relationship between age and VDS scores. Visual discomfort was highest in the fibromyalgia group, followed by the CRPS group. This research confirms the utility of the L-VISS and VDS for measuring visual sensitivity in chronic pain and adds to evidence that central sensitization is an important mechanism of visual discomfort.

Complex regional pain syndrome - Autoimmune or functional neurologic syndrome

Complex regional pain syndrome (CRPS) purports to explain extremity pain accompanied by a variety of subjective complaints, including sensitivity to touch, fatigue, burning sensations, allodynia and signs consistent with voluntary immobilization, including skin changes, edema and trophic changes. By its own definition, CRPS pain is disproportionate to any inciting event or underlying pathology, which means that the syndrome describes non-anatomic and exaggerated symptoms. Although CRPS was coined in the early 1990s, physicians have described unexplained exaggerated pain for centuries. Before a small group of researchers assigned this historical phenomenon with the name CRPS, other physicians in various subspecialties investigated the existence of a common pathophysiologic mechanism but found none. The literature was searched for evidence of a reproducible pathologic mechanism for CRPS. Although some have suggested that CRPS is an autoimmune disease, there is a paucity of evidence to support this. While cytokines such as IL-1β, IL-6 and TNF-α have been detected during the early phases of CRPS, this cannot lead to the conclusion that CRPS is an autoimmune disease, nor that it is an autoinflammatory disorder. Moreover, intravenous immunoglobulin has showed inconsistent results in the treatment of CRPS. On the other hand, CRPS has been found to meet at least three out of four criteria of malingering, which was previously a DSM-IV diagnosis; and its diagnostic criteria are virtually identical to current DSM-5 Functional Neurological Disorder ("FND"), and proposed ICD-11 classification, which includes FND as a distinct neurological diagnosis apart from any psychiatric condition. Unfortunately, the creation of CPRS is not merely misguided brand marketing. It has serious social and health issues. At least in part, the existence of CRPS has led to the labeling of many patients with a diagnosis that allows the inappropriate use of invasive surgery, addictive opioids, and ketamine. The CRPS hypothesis also ignores the nature and purpose of pain, as a symptom of some organic or psychological process. Physicians have long encountered patients who voice symptoms that cannot be biologically explained. Terminology historically used to describe this phenomenon have been medically unexplained symptoms ("MUS"), hysterical, somatic, non-organic, psychogenic, conversion disorder, or dissociative symptoms. The more recent trend describes disorders where there is a functional, rather than structural cause of the symptoms, as "functional disorders." Physicians report high success treating functional neurological symptoms with reassurance, physiotherapy, and cognitive behavior therapy measured in terms of functional improvement. The CRPS label, however, neither leads to functional improvement in these patients nor resolution of symptoms. Under principles of evidence-based medicine, the CRPS label should be abandoned and the syndrome should simply be considered a subset of FNDs, specifically Functional Pain Disorder; and treated appropriately.

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.

Functional Magnetic Resonance Imaging Evaluation of Auricular Percutaneous Electrical Neural Field Stimulation for Fibromyalgia: Protocol for a Feasibility Study

Background

Fibromyalgia is a chronic pain state that includes widespread musculoskeletal pain, fatigue, psychiatric symptoms, cognitive and sleep disturbances, and multiple somatic symptoms. Current therapies are often insufficient or come with significant risks, and while there is an increasing demand for non-pharmacologic and especially non-opioid pain management such as that offered through complementary and alternative medicine therapies, there is currently insufficient evidence to recommend these therapies. Percutaneous electrical neural stimulation (PENS) is an evidence-based treatment option for pain conditions that involves electrical current stimulation through needles inserted into the skin. Percutaneous electrical neural field stimulation (PENFS) of the auricle is similar to PENS, but instead of targeting a single neurovascular bundle, PENFS stimulates the entire ear, covering all auricular branches of the cranial nerves, including the vagus nerve. The neural mechanisms of PENFS for fibromyalgia symptom relief are unknown.

Objective

We hypothesize that PENFS treatment will decrease functional brain connectivity between the default mode network (DMN) and right posterior insula in fibromyalgia patients. We expect that the decrease in functional connectivity between the DMN and insula will correlate with patient-reported analgesic improvements as indicated by the Defense and Veterans Pain Rating Scale (DVPRS) and will be anti-correlated with patient-reported analgesic medication consumption. Exploratory analyses will be performed for further hypothesis generation.

Methods

A total of 20 adults from the Atlanta Veterans Affairs Medical Center diagnosed with fibromyalgia will be randomized into 2 groups: 10 subjects to a control (standard therapy) group and 10 subjects to a PENFS treatment group. The pragmatic, standard therapy group will include pharmacologic treatments such as anticonvulsants, non-steroidal anti-inflammatory drugs, topical agents and physical therapy individualized to patient comorbidities and preferences, prescribed by a pain management practitioner. The PENFS group will include the above therapies in addition to the PENFS treatments. The PENFS subject group will have the Neuro-Stim System placed on the ear for 5 days then removed and replaced once per week for 4 weeks. The primary outcome will be resting functional magnetic resonance imaging connectivity between DMN and insula, which will also be correlated with pain relief and functional improvements. This connectivity will be analyzed utilizing functional connectivity magnetic resonance imaging (fcMRI) and will be compared with patient-reported analgesic improvements as indicated by the DVPRS and patient-reported analgesic medication consumption. Pain and function will be further evaluated using Patient-Reported Outcomes Measurement Information System measures and measures describing a person’s functional status from Activity and Participation section of the International Classification of Functioning Disability and Health.

Results

This trial has been funded by the Veterans Health Administration Program Office. This study attained approval by the Emory University/Veterans Affairs (VA) institutional review board and VA Research & Development committee. Institutional review board expedited approval was granted on 2/7/17 (IRB00092224). The study start date is 6/1/17 and estimated completion date is 5/31/20. The recruitment started in June 2017.

Conclusions

This is a feasibility study that is meant to demonstrate the practicality of using fcMRI to study the neural correlates of PENFS outcomes and provide information regarding power calculations in order to design and execute a larger randomized controlled clinical trial to determine the efficacy of PENFS for improving pain and function.

Trial Registration

ClinicalTrials.gov NCT03008837; https://clinicaltrials.gov/ct2/show/NCT03008837 (Archived by WebCite at http://www.webcitation.org/6wrY3NmaQ).

Evidence of motor system reorganization in complex regional pain syndrome type 1: A case report

Background

Central nervous system reorganization, particularly in networks devoted to somatosensation, is thought to be a significant feature of complex regional pain syndrome (CRPS).

Aims

In the present case report, we evaluated the corticomotor system of a woman suffering from CRPS, as she started and completed her rehabilitation, in order to explore whether CRPS could also be linked to changes in motor networks.

Methods

The patient, a 58-year-old woman, was diagnosed with right-hand CRPS. Transcranial magnetic stimulation measures, reflecting the strength of the corticospinal projections, were evaluated before, during, and after an 8-week graded motor imagery (GMI) program.

Results

Before treatment, the patient reported significant pain and disability, and the strength of the corticospinal projections of the first dorsal interosseous of the affected hand was reduced compared to the healthy, unaffected hand. Pain and disability decreased as the patient completed the GMI program. These changes were paralleled by an increase in the strength of the corticospinal projections.

Conclusions

These observations suggest that corticomotor changes can be observed in individuals suffering from CRPS and that some of the clinical manifestations observed in these patients (e.g., pain, disability) could possibly be linked to these neurophysiological changes.

Physical therapy under hypnosis for the treatment of patients with type 1 complex regional pain syndrome of the hand and wrist: Retrospective study of 20 cases

Type 1 complex regional painful syndrome (CRPS-1) has a complex physiopathology. The aim of this study was to evaluate the effectiveness of physical therapy under hypnotherapy to treat this condition. Twenty patients with CRPS-1 at the wrist and hand were evaluated retrospectively: 13 women and 7 men with an average age of 56 years (34-75). Thirteen patients were in the inflammatory phase and 7 in the dystrophic phase. The main endpoints were pain (VAS, analgesic use), stiffness (wrist and finger range of motion), and strength (pinch and grasp). Secondary endpoints were functional scores (QuickDASH, PWRE), patient satisfaction, return to work, and side effects. Results were satisfactory in all cases after 5.4 sessions on average. VAS decreased by 4 points, PWRE-pain by 4.1 points, and analgesic use was limited to paracetamol upon request. Finger and wrist range of motion increased and the QuickDASH decreased by 34 points, PRWE-function by 3.8 points, pinch strength increased 4 points, and grasp strength by 10 points. Return to work was possible in 80% of the cases. All patients were satisfied or very satisfied with the treatment. Physical therapy under hypnosis appears to be an effective treatment for CRPS-1 at the wrist and hand no matter the etiology.

The Effects of Fibromyalgia Syndrome on Physical Function and Psychological Status of Pregnant Females

Objectives

This study aims to investigate the frequency and most common symptoms of fibromyalgia syndrome (FS) among pregnant females and determine the impacts of FS on physical functioning and psychological status.

Patients and methods

A total of 360 pregnant females (mean age 26.5 years, range 19 to 42 years) were included. The subjects were divided into two groups in terms of having (FS group; n=136; mean age 27 years; range 19 to 41 years) or not having FS (control group; n=224; mean age 26.5 years; range 20 to 42 years). The impact of FS on physical functions was evaluated using Fibromyalgia Impact Questionnaire. Psychological statuses of the subjects were evaluated using State-Trait Anxiety Inventory, Wijma Delivery Expectancy/Experience Questionnaire, and Beck Depression Inventory.

Results

Low back pain was the most common complaint while fatigue was the most common symptom in FS group. FS group had higher levels of pain and physical disability (p<0.001) and also higher values of anxiety, fear of childbirth, and depression (p<0.001, for all values) compared to control group. Symptom severity and physical function scores were significantly correlated with increased levels of pain, depression, anxiety, and fear of childbirth (p<0.001, for all values).

Conclusion

Fibromyalgia syndrome is common among pregnant females. The existence of FS in pregnancy is a severe factor contributing to maternal stress, anxiety, and depression. Therapeutic measures for fibromyalgia syndrome should be well-established to support healthy pregnancy and good child health outcome.

Musculoskeletal Ultrasonography to Distinguish Muscle Changes in Complex Regional Pain Syndrome Type 1 from Those of Neuropathic Pain: An Observational Study

Musculoskeletal ultrasonography (MSK USG) can identify myofascial structural lesions. We describe in this retrospective report the observational findings of USG data of muscles from limbs affected with neuropathic pain in 7 patients and compare them with muscles affected with complex regional pain syndrome type 1 (CRPS-1) in 7 patients. We highlight findings that distinguish between the 2 conditions. Musculoskeletal ultrasonography of muscles in CRPS was characterized by a variable or/and global intramuscular structural disruption with loss of muscle bulk. Adjacent muscles coalesced with one another to present an uniform hyperechogenic mass of tissue. Muscle edema was found in some patients. In comparison, MSK USG in muscles affected by neuropathic pain exhibited structural normalcy, but also showed considerable reduction in muscle bulk. Musculoskeletal ultrasonography shows promise as a diagnostic modality to distinguish between these 2 conditions which presently have only clinical diagnostic criteria to aid diagnosis.

Survey of UK sonographers on the prevention of work related muscular-skeletal disorder (WRMSD)

BACKGROUND

To establish whether the current training of student sonographers in both academic and clinical settings is sufficient for educating about the dangers of work-related musculoskeletal disorders (WRMSDs).

METHODS

A dual method of data collection was undertaken. Initially, a focus group was set up, involving a small group of practicing sonographers from a hospital in the United Kingdom, with the results of that survey being used to design a postal survey questionnaire. The questionnaire focused on ergonomics, scanning technique, training in physical techniques, personal general health, risk, stress, and task management. It was sent to seven participating universities across the United Kingdom. Approvals were obtained from the local ethics committees, the hospital Trust, and the academic institution.

RESULTS

The focus group highlighted several areas in which improvements could be made in educating sonographers on the reduction of WRMSDs. The questionnaire results indicated that students are being taught about certain aspects of WRMSD prevention by both their university and clinical mentors. Respondents received training on the prevention of WRMSDs: 97% in the university setting and 81% from clinical mentors.

CONCLUSIONS

Improvements need to be made in terms of educating students to perform muscle-strengthening exercises during the workday; to have a system of reporting injury; to consider personal health, well-being, and stress management in the workplace; and to evaluate the ergonomics of computer workstations.

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.

Type I complex regional pain syndrome

First described by Ambroise Paré in the mid-17th century complex, regional pain syndrome (CRPS) can be defined as an articular and periarticular pain syndrome associated with vasomotor deregulation triggered by various stresses with no relationship between the intensity of the initial injury and severity of the continuing pain. Several names have been given to Type 1 complex regional pain syndrome (CRPS-I): causalgia, reflex sympathetic dystrophy, shoulder-hand syndrome and algodystrophy. The reported incidence of CRPS-I is about 25 per 100,000. Predisposing factors are tobacco consumption and being female (W/M ratio=4). Although all the limbs can be affected, the upper limb is by far the most affected. CRPS-I is a classic complication of distal radius fractures (4-37%) and carpal tunnel surgery (2-4%). Early diagnosis and management are the most important elements of treatment because this syndrome has a long and disabling course. Some of the proposed treatments include NSAIDs, antidepressants and anticonvulsants. The latter, despite their good analgesic effects, do not cure CRPS-I. In select cases, a surgical procedure aiming at removing a nociceptive stimulus can lead to spectacular improvements.

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.

Trauma and work-related pain syndromes: risk factors, clinical picture, insurance and law interventions

In the past decade, major progress has been made in our understanding of fibromyalgia syndrome (FMS). Various triggers have been implicated as contributing to symptom development in FMS when genetically susceptible individuals are challenged. A substantial amount of data points towards the association between trauma and chronic widespread pain/fibromyalgia syndrome (CWP/FMS). There is abundant data suggesting that the pathogenesis of CWP/FMS might be related to cervical spine injury. Furthermore, several persistent local pain conditions may progress to CWP/FMS. These conditions may share a common pathogenic mechanism namely, central sensitisation. Physical trauma and emotional trauma co-exist in many traumatic events and may interact in the pathogenesis of CWP/FMS.

Diagnostic criteria for CRPS I: Differences between patient profiles using three different diagnostic sets

Complex Regional Pain Syndrome type I (CRPS I) is an illness which usually occurs due to major or minor tissue injury to the extremities. Because a unique pathophysiological mechanism for CRPS I has not yet been established, the diagnosis is based on observation and measurement of clinical symptoms and signs. In this study, a comparison was made between three sets of diagnostic criteria (the IASP, Bruehl et al. and Veldman et al.) based on patient reports and physicians' assessments of signs and symptoms associated with CRPS I, in 372 outpatients suspected of having CRPS I. Agreement between CRPS I diagnosis among the three sets was poor (kappa-range: 0.29-0.42), leading to positive CRPS I diagnoses according to Veldman et al.'s criteria in 218 cases (59%), according to the IASP in 268 cases (72%), and according to Bruehl et al. in 129 cases (35%). Significant differences in patient profiles were found between the diagnostic sets for the number of patients reporting continuing disproportionate pain, larger area affected than the initial trauma (both p<0.001), increase of symptoms due to exercise (p=0.009), edema (p=0.015), temperature asymmetry (p=0.015), hyperesthesia, allodynia (both p<0.001) and hyperalgesia (p=0.036). Similarly, significant differences emerged for physicians' observations of hyperesthesia and allodynia (both p<0.001). Highest combined values of sensitivity (SE) and specificity (SP) for the strongest cases of presence (n=108) or absence (n=62) of CRPS I were found for reported hyperesthesia (SE+SP:165%), allodynia (160%), observed color asymmetry (162%), hyperesthesia (157%), temperature asymmetry (154%) and edema (152%). The lack of agreement between the different diagnostic sets for CRPS I and the different clinical profiles that result from it may lead to different therapeutic and study populations, hampering adequate treatment and scientific development for this illness. We propose explicit reference to diagnostic criteria used in studies, and registration in trials of a broad variety of CRPS I features, as used in this study, to make subgroup phenotyping and post hoc analyses based on different diagnostic criteria possible.

Review of neuroimaging studies related to pain modulation

Background and purpose: A noxious stimulus does not necessarily cause pain. Nociceptive signals arising from a noxious stimulus are subject to modulation via endogenous inhibitory and facilitatory mechanisms as they travel from the periphery to the dorsal horn or brainstem and on to higher brain sites. Research on the neural structures underlying endogenous pain modulation has largely been restricted to animal research due to the invasiveness of such studies (e.g., spinal cord transection, brain lesioning, brain site stimulation). Neuroimaging techniques (e.g., magnetoencephalography (MEG), positron emission tomography (PET) and functional magnetic resonance imaging (fMRI)) provide non-invasive means to study neural structures in humans. The aim is to provide a narrative review of neuroimaging studies related to human pain control mechanisms.

Methods: The approach taken is to summarise specific pain modulation mechanisms within the somatosensory (diffuse noxious inhibitory controls, acupuncture, movement), affective (depression, anxiety, catastrophizing, stress) and cognitive (anticipation/placebo, attention/distraction, hypnosis)domains with emphasis on the contribution of neuroimaging studies.

Results and conclusions: Findings from imaging studies are complex reflecting activation or deactivation in numerous brain areas. Despite this, neuroimaging techniques have clarified supraspinal sites involved in a number of pain control mechanisms. The periaqueductal grey (PAG) is one area that has consistently been shown to be activated across the majority of pain mechanisms. Activity in the rostral ventromedial medulla known to relay descending modulation from the PAG, has also been observed both during acupuncture analgesia and anxiety-induced hyperalgesia. Other brain areas that appear to be involved in a number of mechanisms are the anterior cingulate cortex, prefrontal cortex, orbitofrontal cortex and nucleus accumbens, but their exact role is less clear.

Implications: Neuroimaging studies have provided essential information about the pain modulatory pathways under normal conditions, but much is still to be determined. Understanding the mechanisms of pain control is important for understanding the mechanisms that contribute to failed pain control in chronic pain. Applying fMRI outside the brain, such as in the trigeminal nucleus caudalis of the spinotrigeminal pathway and in the dorsal horn of the spinal cord, and coupling brain activity with activity at these sites may help improve our understanding of the function of brain sites and shed light on functional connectivity in the pain pathway.

© 2011 Scandinavian Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Cluster analysis of symptoms among patients with upper extremity musculoskeletal disorders

INTRODUCTION

Some musculoskeletal disorders of the upper extremity are not readily classified. The study objective was to determine if there were symptom patterns in self-identified repetitive strain injury (RSI) patients.

METHODS

Members (n = 700) of the Dutch RSI Patients Association filled out a detailed symptom questionnaire. Factor analysis followed by cluster analysis grouped correlated symptoms.

RESULTS

Eight clusters, based largely on symptom severity and quality were formulated. All but one cluster showed diffuse symptoms; the exception was characterized by bilateral symptoms of stiffness and aching pain in the shoulder/neck.

CONCLUSIONS

Case definitions which localize upper extremity musculoskeletal disorders to a specific anatomical area may be incomplete. Future clustering studies should rely on both signs and symptoms. Data could be collected from health care providers prospectively to determine the possible prognostic value of the identified clusters with respect to natural history, chronicity, and return to work.

[Global approach to chronic pelvic and perineal pain: from the concept of organ pain to that of dysfunction of visceral pain regulation systems]

OBJECTIVE

Analysis of complex pelvic and perineal pain.

MATERIAL AND METHODS

Review of the literature concerning the various types of functional pelvic pain.

RESULTS

Various forms of pelvic pain are frequently associated: painful bladder syndrome (interstitial cystitis), irritable bowel syndrome, endometriosis pain, vulvodynia, chronic pelvic pain syndrome (chronic prostatitis). Pelvic pain is often associated with fibromyalgia or complex regional pain syndrome (reflex sympathetic dystrophy). The pathophysiological mechanisms involved in these syndromes are all very similar, suggesting a triggering element, neurogenic inflammation, reflex muscular and autonomic responses, central hypersensitization, emotional reactions and biopsychosocial consequences.

DISCUSSION

The concept of visceral pain is evolving and, in practice, complex pelvic pain can comprise neuropathic components, complex regional pain syndrome components, hypersensitization components, and emotional components closely resembling posttraumatic stress syndrome.

CONCLUSIONS

When pain cannot be explained by an organ disease, the pain must be considered to be expressed via this organ. Chronic pelvic and perineal pain can become self-perpetuating and identification of its various mechanisms can allow the proposal of individually tailored treatments.

Shockwave therapy in the management of complex regional pain syndrome in medial femoral condyle of the knee

The aim of this prospective study was to assess the efficacy of shockwave (SW) therapy in the management of complex regional pain syndrome (CRPS). In this study, 30 patients (pts) who were affected by CRPS of the medial femoral condyle and unresponsive to previous standard physiotherapeutic and pharmacological treatment underwent 3 SW sessions at 72-h intervals, each consisting of 4000 shocks emitted by a MiniLith SL1 Storz electromagnetic generator. An energy flux density (EFD) of 0.035 or 0.09 mJ/mm(2) was used, depending on how well the patient endured the pain during the treatment. Satisfactory results were observed in 76.7% of the cases (23 pts) at the 2-month follow-up (FU) visit, and in 80% (24 pts) at the 6-month FU visit. The therapeutic effects of SW were caused by decreasing pain. The significant improvements we obtained bear witness to the potential value of SW therapy in the management of CRPS.

Pilot study assessing balance in women with fibromyalgia syndrome

The purpose of current study was to assess postural control and balance self-efficacy in people with fibro-myalgia syndrome [FMS]. Thirty-two females with FMS completed the Activity-specific Balance Confidence Scale, Berg Balance test, NeuroCom Balance Master sensory-organization test, and limits of stability. There was a high prevalence of reported falls and a low mean score on the Activity-specific Balance Confidence Scale. A significant number of subjects scored below the population norm fifth percentile score on the sensory-organization test composite, visual, and vestibular sections. Preliminary evidence suggests that women with FMS may present with deficits in postural control, sensory organization, and balance self-efficacy.

Complex regional pain syndrome type 1 may be associated with menstrual cycle disorders: a case-control study

BACKGROUND

Complex regional pain syndrome type 1 (CRPS1) can develop after severe trauma or surgery in the limbs, and presents with chronic, changes in temperature, edema and dysfunction. Seventy-five percent of CRPS1 patients are female. While neurological and inflammatory components have been proposed, the etiology remains unclear. No consensus on optimal management of CRPS1 exists. In traditional Chinese medicine, menstrual disorders are related to the state of women's constitution and therefore identify their pain patterns. A classification by constitution might improve the pain management in CRPS1 patients. It is unknown whether associations exist between menstrual-cycle-conditions and CRPS1.

AIM

To investigate whether a specified menstrual condition is associated with the risk of developing CRPS1.

METHODS

A population-based case-control study of CRPS1 was conducted among Dutch women aged 18-82; i.e. 34 women with CRPS1 and 147 controls. A standard questionnaire consisting of 59 menstrual-cycle-symptom-based questions was administered. From this questionnaire, 15 CRPS1-related questions (DRQ 15) were analyzed. We used multivariate logistic regression to obtain odds ratios and 95% confidence intervals (CI) for specified menstrual disorders adjusting for age, oral contraceptives, hysterectomy and age at menarche < or = 12 and > or = 17 years.

RESULTS

On the basis of the DRQ 15, women with CRPS1 were 5.3 (95%CI 2.1, 12.9) times more likely to have menstrual disorders than comparable controls.

CONCLUSION

Our results suggest that selected menstrual conditions are associated with the risk of developing CRPS1.

Intravenous magnesium for complex regional pain syndrome type 1 (CRPS 1) patients: a pilot study

OBJECTIVES

To explore the feasibility of intravenous magnesium administration as a potential candidate intervention for a large size trial in Complex Regional Pain Syndrome Type 1 (CRPS 1).

DESIGN

Randomized clinical trial.

SETTING

Outpatient pain clinic.

PATIENTS

Ten CRPS 1 patients.

INTERVENTIONS

Eight patients received 70 mg/kg magnesium sulphate infusions in 4 hours for 5 days. For blinding purposes, 2 patients received equal amount NaCl 0.9% solutions (data not analyzed or presented). Interventions were accompanied by standardized physical therapy.

OUTCOME MEASURES

Pain was assessed using an 11-point Box scale (three times daily for a week) and the McGill Pain Questionnaire. Skin sensitivity was measured with the Semmes Weinstein Monofilaments, (other) impairments with the Impairment Level Sumscore. In addition, functional limitations (Radboud Skills Questionnaire, questionnaire rising and sitting down) and quality of life (Short Form-36 [SF-36], EuroQol) were evaluated. Assessments were performed at baseline, 1, 3, 6, and 12 weeks after intervention.

RESULTS

Mild systemic side effects were experienced and the infusions were locally well tolerated. Pain was significantly reduced at all follow up compared with baseline (T1: P = 0.01, T3: P = 0.04, T6: P = 0.02, T12: P = 0.02). McGill sensory subscale improved significantly at T1 (number of words chosen: P = 0.03 and pain rating index: P = 0.03). Impairment level (P = 0.03) and quality of life (EuroQol P = 0.04, SF-36 physical P = 0.01) were significantly improved at T12. No improvement was found for skin sensitivity and functional limitations.

CONCLUSION

Intravenous magnesium significantly improved pain, impairment and quality of life and was well tolerated. The results of this pilot study are encouraging and suggest that magnesium IV as a treatment in CRPS 1 should be further explored in a large size formal trial design.

Medical history and the onset of complex regional pain syndrome (CRPS)

Knowledge concerning the medical history prior to the onset of complex regional pain syndrome (CRPS) might provide insight into its risk factors and potential underlying disease mechanisms. To evaluate prior to CRPS medical conditions, a case-control study was conducted in the Integrated Primary Care Information (IPCI) project, a general practice (GP) database in the Netherlands. CRPS patients were identified from the records and validated through examination by the investigator (IASP criteria) or through specialist confirmation. Cases were matched to controls on age, gender and injury type. All diagnoses prior to the index date were assessed by manual review of the medical records. Some pre-specified medical conditions were studied for their association with CRPS, whereas all other diagnoses, grouped by pathogenesis, were tested in a hypothesis-generating approach. Of the identified 259 CRPS patients, 186 cases (697 controls) were included, based on validation by the investigator during a visit (102 of 134 visited patients) or on specialist confirmation (84 of 125 unvisited patients). A medical history of migraine (OR: 2.43, 95% CI: 1.18-5.02) and osteoporosis (OR: 2.44, 95% CI: 1.17-5.14) was associated with CRPS. In a recent history (1-year before CRPS), cases had more menstrual cycle-related problems (OR: 2.60, 95% CI: 1.16-5.83) and neuropathies (OR: 5.7; 95% CI: 1.8-18.7). In a sensitivity analysis, including only visited cases, asthma (OR: 3.0; 95% CI: 1.3-6.9) and CRPS were related. Psychological factors were not associated with CRPS onset. Because of the hypothesis-generating character of this study, the findings should be confirmed by other studies.

Clinical and neurophysiological characterization of myoclonus in complex regional pain syndrome

The origin of myoclonus in patients with complex regional pain syndrome (CRPS) is unknown. Eight patients with CRPS related myoclonus were clinically evaluated and studied with intermuscular and corticomuscular coherence analysis. Jerks were present at rest, aggravated during action and were frequently associated with tremulousness or dystonia. Electromyography demonstrated a burst duration ranging from 25 to 240 ms with burst frequencies varying from <1 jerk/s during rest to 20 Hz during action. Coherence studies showed increased intermuscular coherence in 4 patients in the 6 to 12 Hz band, as reported in patients with enhanced physiological tremor. In 2 patients side-to-side coherence was observed, pointing to a central oscillatory drive. Significant coherence entrainment was detected in 5 patients. We conclude that the characteristics of myoclonus in CRPS are different from other forms of myoclonus.

Development of a symptoms questionnaire for complex regional pain syndrome and potentially related illnesses: the Trauma Related Neuronal Dysfunction Symptoms Inventory

OBJECTIVE

To develop a questionnaire to evaluate symptoms of complex regional pain syndrome type I (CRPS-I), fibromyalgia, and repetitive strain injury to determine the test-retest reliability and investigate concurrence in the clinical manifestations of CRPS-I and fibromyalgia.

DESIGN

The Trauma Related Neuronal Dysfunction Symptoms Inventory (TSI) was developed by determining the content validity and the practical use of the questionnaire. Furthermore, the test-retest reliability was assessed on 2 identical questionnaires filled out within a 7-day interval by CRPS-I and fibromyalgia patients.

SETTING

Outpatient pain clinic of a Dutch medical center.

PARTICIPANTS

CRPS-I (n=26; mean age, 54y) and fibromyalgia patients (n=42; mean age, 45.4y).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Test-retest reliability calculated with intraclass correlation (ICC).

RESULTS

Reliability scores were good for the whole questionnaire, its categories, and domains (ICC>.75) for both CRPS-I and fibromyalgia patients. Sensory complaints (except for change in cold perception), motor complaints, and visceral complaints (diarrhea and incontinence) were reported by both CRPS-I and fibromyalgia patients. A change in cold perception, discoloration, change in skin temperature, change in sweating behavior, change in the severity of edema during exercise, and trophic changes of skin were reported significantly more often by CRPS-I patients, whereas complaints of the (upper and lower) back, constipation, urine retention, and experiencing a dry mouth were reported significantly more often by fibromyalgia patients.

CONCLUSIONS

The TSI is a reliable instrument with good content validity, which can be used in the evaluation of similarities and differences between CRPS-I and fibromyalgia. The systematic evaluation of symptoms of CRPS-I and potentially related illnesses may provide a better basis for future research into the underlying mechanism(s).

Aetiology and management of work-related upper extremity disorders

Work-related upper extremity disorders are a major cause for complaints and disability in worker populations. They may consist of a range of symptoms in the upper extremity, either clearly localised or more widespread, and are usually preceded or affected by exposure to physical activities and/or postures at work. In order to develop effective management strategies, both from a prevention and treatment perspective, more knowledge is needed with regard to the nature, pathophysiological mechanisms and risk factors of this group of disorders. This chapter reviews the clinical manifestations, mechanisms and aetiology of work-related upper extremity disorders through an exploration of the literature. We also examine and discuss the evidence for the effectiveness of several preventative and therapeutic interventions.