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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

Abstract is missing (Short communication)

Incidence and risk factors for complex regional pain syndrome in radius fractures: meta-analysis

PURPOSE

This meta-analysis aimed to evaluate the incidence and risk factors for complex regional pain syndrome (CRPS) in radius fractures.

METHODS

The meta-analysis was performed using the PubMed, Embase, Scopus, and Cochrane Collaboration Library databases. Studies focusing on patients with conservative or surgically treated radius fractures leading to CRPS were included. A control group consisting of patients with radius fractures and no CRPS (-) was included. The outcome measures were incidence and risk factors. Comparative studies were also included. Data were combined using Review Manager 5.4.

RESULTS

Out of 610 studies, nine studies were included. The incidence of CRPS after radius fractures ranged from 0.19 to 13.63% (95% CI: 11.12-16.15%). Open fractures, high-energy mechanisms in radial head fractures, and associations with ulnar fractures were risk factors for CRPS [(RR: 0.98; 95% CI: 0.97-1.00), (RR: 0.18; 95% CI: 0.07-0.47), and (RR: 1.25; 95% CI: 1.17-1.35), respectively]. Other risk factors were female sex and high body mass index [(RR: 1.20; 95% CI: 1.05-1.37) and (MD: 1.17; 95% CI: 0.45-1.88)]. Psychiatric factors also increased the incidence of CRPS (RR: 2.04; 95% CI: 1.83-2.28). On the other hand, the type of surgery (external fixation or open reduction and internal fixation) and manipulations; associated comorbidities (diabetes and hypertension) together with tobacco and alcohol abuse; marital status, educational level, employment status, and socioeconomic status were not risk factors (p > 0.05).

CONCLUSION

The incidence of CRPS in radius fractures was 13.63%. Fractures with greater complexity or greater associated tissue damage, female sex, high BMI, and psychiatric disorders were risk factors for the development of CRPS.

LEVEL OF EVIDENCE

Meta-analysis of cohort and case series studies; II.

Baseline predictors related to functional outcomes in patients older than sixty years with complex regional pain syndrome type 1 after distal radius fracture treated conservatively: a prospective observational study

PURPOSE

This study aimed to analyze baseline predictors of functional outcomes six weeks and at one year follow-up in patients older than 60 years with complex regional pain syndrome type 1 (CRPS I) after distal radius fracture (DRF).

METHODS

A total of 120 patients with CRPS I after DRF were prospectively recruited. Presumptive relevant factors were collected and analyzed as potential baseline predictors. Additionally, functional outcomes were assessed at the beginning of physiotherapy treatment, at six weeks after finishing physiotherapy treatment, and at one year follow-up. Patient-Rated Wrist Evaluation; Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire; Jamar dynamometer; and visual analog scale (VAS) were assessed.

RESULTS

All participants completed the study. At 6 weeks, the main results showed an association of lower values of grip strength with female sex (p = 0.010), intra-articular DRFs (p = 0.030), longer immobilization time (p = 0.040), lower levels of physical activity (p < 0.001), higher levels of kinesiophobia (p = 0.010), and anxiety (p = 0.020). At 1-year follow-up, the results showed an association of lower values of DASH with higher BMI (p < 0.001) and longer immobilization time (p < 0.001); and higher values of VAS showed an association with older age (p = 0.010), higher BMI (p = 0.010), and lower levels of physical activity (p = 0.040).

CONCLUSION

At six weeks, factors such as BMI, immobilization time, physical activity, and kinesiophobia are associated with lower functional outcomes. Additionally, at one year follow-up, BMI, immobilization time, and physical activity continue to be associated with lower functional outcomes in patients with CRPS I after DRF treated conservatively.

Auditory disturbances in patients with complex regional pain syndrome

ABSTRACT

Complex regional pain syndrome (CRPS) is often associated with reduced sound tolerance (hyperacusis) on the affected side, but the mechanism of this symptom is unclear. As compensatory increases in central auditory activity after cochlear injury may trigger hyperacusis, hearing and discomfort thresholds to pure tones (250, 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz) were assessed in 34 patients with CRPS and 26 pain-free controls. In addition, in 31 patients and 17 controls, auditory-evoked potentials to click stimuli (0.08 ms duration, 6 Hz, 60 dB above the hearing threshold) were averaged across 2000 trials for each ear. Auditory discomfort thresholds were lower at several pitches on the CRPS-affected than contralateral side and lower at all pitches on the affected side than in controls. However, ipsilateral hyperacusis was not associated with psychophysical or physiological signs of cochlear damage. Instead, neural activity in the ipsilateral brainstem and midbrain was greater when repetitive click stimuli were presented on the affected than contralateral side and greater bilaterally than in controls. In addition, click-evoked potentials, reflecting thalamo-cortical signal transfer and early cortical processing, were greater contralaterally in patients than controls. Together, these findings suggest that hyperacusis originates in the ipsilateral brainstem and midbrain rather than the peripheral auditory apparatus of patients with CRPS. Failure of processes that jointly modulate afferent auditory signalling and pain (eg, inhibitory influences stemming from the locus coeruleus) could contribute to ipsilateral hyperacusis in CRPS.

Spinal cord stimulator medullary compression-a very rare SCS complication and surgical treatment

INTRODUCTION

The risk of spinal cord damage after Spinal Cord Stimulator (SCS) implant is a very rare event. In our case report, the patient was affected by a progressively worsening spinal stenosis due to SCS compression.

CASE REPORT

The authors describe a progressive paraparesis in a 58-year-old woman with a long history of back pain and multiple spine surgeries. Computed tomography (CT) outlined vertebral canal stenosis corresponding to an electrode array implanted in T9. A posterior T8-T10 spinal cord decompression with explanation of the SCS device was performed and a partial neurological improvement was observed immediately postoperative.

DISCUSSION

Spinal cord stimulation has been used since 1967 for the treatment of refractory chronic pain, particularly failed back surgery syndrome (FBSS) and complex regional pain syndrome (CRPS). Still, the mechanism underlying its function is not completely clear. Moreover, complications are mainly related to implant dysfunction and the risk of direct and indirect spinal cord compression is described as exceptional in the literature. Our aim is to describe the case SCS device spinal cord direct compression and its surgical treatment.

Spinal cord stimulation for neuropathic pain following traumatic spinal cord injury: a case report

INTRODUCTION

Neuropathic pain is a common complication of spinal cord injury (SCI), and is notoriously difficult to adequately treat. Gunshot wounds (GSW) near the spinal cord may cause intractable chronic pain through spinal/nerve root transection, or reactive tissue formation resulting in nerve root compression from retained bullet fragments (RBF).

CASE PRESENTATION

This case report describes a 30-year-old man with a T12 AIS B incomplete spinal cord injury with paraplegia secondary to multiple GSW who presented with severe bilateral lower extremity dysesthesias and muscle spasms. Symptoms failed to improve with oral antispasmodic medications. After being diagnosed with Complex regional pain syndrome (CRPS) type I secondary to an SCI via GSW, he underwent a spinal cord stimulator (SCS) trial, which improved his symptoms by greater than 80%.

DISCUSSION

Neuropathic pain refractory to conservative treatment may benefit from SCS. Effects of therapy go beyond gate-theory in SCI patients, and may benefit patients at the cellular and molecular level. Our case demonstrates the effectiveness of SCS treatment in a patient who developed CRPS type 1 after GSW resulting in SCI.

Risks of therapeutic versus prophylactic neurectomies

INTRODUCTION

Neuralgia due to a peripheral nerve injury may result in chronic pain, requiring a therapeutic surgical neurectomy. Meanwhile, some neurectomies are performed prophylactically, such as during inguinal mesh removal. Outcomes and risks associated with neurectomies are largely unknown despite consensus panels recommending them.

METHODS

All patients who underwent neurectomy 2013-2020 were analyzed. Data collection included demographics, preoperative symptoms, and postoperative outcomes. Indications for neurectomy were categorized as "therapeutic" if the patient had preoperative neuralgia or "prophylactic" if neurectomy was deemed necessary intra-operatively.

RESULTS

66 patients underwent 80 operations and a total of 122 neurectomies. On average, 1.5 neurectomies were performed per operation. Therapeutic neurectomies were performed in 42 (64%) patients and prophylactic in 34 (52%). The most commonly transected nerve was the ilioinguinal nerve. Average preoperative pain score was 5.8/10. On paired analysis, there was a significant reduction in pain after prophylactic neurectomy (2.5 points, p = 0.002) but not after therapeutic neurectomy. None of the nerves transected prophylactically had postoperative neuralgia, whereas 35% of the nerves transected therapeutically resulted in persistent or recurrent neuralgia (p < 0.001). To treat this, 21% required only nerve blocks and 9% required ablation or reoperative neurectomy. Three patients had complex regional pain syndrome (CRPS), a severe complication; all three were diagnosed with chronic pain syndrome pre-operatively.

DISCUSSION

We demonstrate that prophylactic neurectomy is largely safe. In contrast, a therapeutic neurectomy had a 35% risk of persistent or recurrent neuralgia, 9% required additional ablative or reoperative neurectomy. Three patients advanced from chronic pain syndrome to CRPS. We recommend the decision to perform a neurectomy be judicious and selective, especially in patients with known chronic pain syndrome. Prior to planning surgical neurectomy, other less invasive modalities should be exhausted and patients should be aware of its risks.

Effectiveness of perampanel in managing chronic pain caused by the complex regional pain syndrome: A case report

RATIONALE

The α-amino-3-hydroxy-5-methy-4-isoxazole propionate (AMPA) receptor plays a critical role in the development and persistence of pain, and AMPA receptor antagonists are considered possible therapeutic targets for controlling pain. This report describes a patient with complex regional pain syndrome (CRPS) type I in the right lower leg and foot who responded well to perampanel, an AMPA receptor antagonist, for managing the chronic pain.

PATIENT CONCERN

A 61-year-old woman complained of pain in her right lower leg and foot over a period of 7 year (numeric rating scale: 8) due to CRPS type I.

DIAGNOSIS

CRPS type 1.

INTERVENTIONS

Despite the combination of 300 mg pregabalin, 225 mg/1950 mg tramadol/acetaminophen, and 10 mg nortriptyline per day, her right lower leg and foot were nearly disabled due to the severity of the pain. High-dose prednisolone was found to be ineffective. Then, perampanel (4 mg; 2 mg twice) was administered to this patient daily.

OUTCOMES

The day after treatment with perampanel, her pain completely disappeared. Additionally, at day 7 and 1 month follow-up, she reported no pain in the right lower leg and foot. Moreover, no adverse effects were reported after the application of perampanel.

LESSONS

These results suggest that perampanel may potentially be used to treat centralized pain.

Associated Neurotrophic Keratopathy in Complex Regional Pain Syndrome

PURPOSE

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

METHODS

Case report.

RESULTS

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

CONCLUSIONS

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

Novel Presentation of Pediatric Complex Regional Pain Syndrome with Concurrent Chromhidrosis: A Case Report

CASE

An 11-year-old female patient presented to our clinic with a low-grade lateral ankle sprain that was subsequently treated with a lace-up ankle brace. On the reintroduction of weight bearing, the patient developed recurrent ankle pain and symptoms consistent with complex regional pain syndrome (CRPS) Type 1. On physical examination, the patient was found to have a concurrent chromhidrosis in the injured area, which is a novel presentation of CRPS.

CONCLUSION

Patients with CRPS found to have superficial skin discoloration should be evaluated further to investigate for chromhidrosis. Early diagnosis can improve the treatment of CRPS and allow for appropriate management of varying manifestations, such as chromhidrosis.

Successful Treatment of Complex Regional Pain Syndrome with Pseudoaneurysm Excision and Median Nerve Neurolysis

BACKGROUND

Complex regional pain syndrome (CRPS), formerly referred to as reflex sympathetic dystrophy, is a pain syndrome characterized by severe pain, altered autonomic and motor function, and trophic changes. CRPS is usually associated with soft tissue injury or trauma. It has also been described as a rare complication of arterial access for angiography secondary to pseudoaneurysm formation.

CASE DESCRIPTION

A 73-year-old woman underwent catheterization of the left brachial artery for angiography of the celiac artery. The following day, the patient noticed numbness and severe pain in the median nerve distribution of the left upper extremity. Over the next 6 months, the patient developed CRPS in the left hand with pain and signs of autonomic dysfunction. Further work-up revealed the formation of a left brachial artery pseudoaneurysm with impingement on the median nerve. She underwent excision of the pseudoaneurysm with decompression and neurolysis of the left median nerve. Approximately 6 weeks after surgery, the patient had noticed significant improvement in autonomic symptoms.

CONCLUSIONS

This case involves a unique presentation of CRPS caused by brachial artery angiography and pseudoaneurysm formation. In addition, the case demonstrates the efficacy of pseudoaneurysm excision and median nerve neurolysis in the treatment of CRPS as a rare complication of arterial angiography.

Periungual pyogenic granuloma formation in a patient with complex regional pain syndrome

Peripheral nerve injury has been associated with the development of periungual pyogenic granuolomas (PGs). We present the case of a 39-year-old woman with an eight-month history of periungual PGs in the setting of a four-to-five year history of a traumatic inciting event that produced symptoms consistent with complex regional pain syndrome (CRPS). Although recurrent, these periungual PGs have remitted after treatment with topical timolol maleate. This case exhibits an underappreciated association between peripheral neurologic abnormalities, which include CRPS, and cutaneous abnormalities. It also presents evidence that supports the concept that PGs that are not appropriate for surgical treatments may be treated with topical timolol maleate.

Immediate resolution of severe bullous chronic regional pain syndrome with onset of spinal paralysis

Complex regional pain syndrome (CRPS) is an incompletely understood disorder characterized by progressive regional pain and sensory changes, with fluctuating cutaneous edema and erythema. We describe a patient with a rarely reported severe bullous CRPS variant on the left lower extremity, which resolved immediately upon developing spinal paralysis.

Objective sensory evaluation of the spread of complex regional pain syndrome

BACKGROUND

The spread of complex regional pain syndrome (CRPS) has been well documented. Many severe refractory long-standing patients have total body pain (TBP) that evolved from a single extremity injury.

OBJECTIVE

The purpose of this study was to document by objective sensory threshold testing the extent of body area involvement in 20 long-standing patients with CRPS who have TBP.

STUDY DESIGN

A comparison of sensory threshold testing parameters between 20 long-standing refractory patients with CRPS who have TBP versus 10 healthy participants.

METHODS

Twenty patients with CRPS who stated that they suffered from total body pain were chosen from the Drexel University College of Medicine CRPS database. They were compared to 10 healthy participants that were age and gender matched to the patients with CRPS. The sensory parameters tested were: skin temperature; static and mechanical allodynia; thermal allodynia; mechanical hyperalgesia; after sensations following all sensory tests. The sites chosen for testing in the patients with CRPS were the most painful area in each of 8 body regions that comprised the total body area.

RESULTS

Five patients with CRPS had signs of CRPS over 100% of their body (20%). One patient had pain over 87% and another had pain over 90% of their body area. The average percentage of body involvement was 62% (range 37% - 100%). All patients with CRPS had at least one sensory parameter abnormality in all body regions. All patients with CRPS had lower pain thresholds for static allodynia in all body areas, while 50% demonstrated a lower threshold for dynamic allodynia in all body regions compared to the healthy participants. Cold allodynia had a higher median pain rating on the Likert pain scale in all body areas versus healthy participants except for the chest, abdomen, and back. Eighty-five percent of the patients with CRPS had a significantly lower pain threshold for mechanical hyperalgesia in all body areas compared to the healthy participants. After sensations occurred after all sensory parameters in the extremities in patients with CRPS.

LIMITATIONS

The primary limitations of this study would be the variability of self-reported data (each subject's assessment of pain/ discomfort to a tested parameter) and the challenge to uniformly administer each parameter's assessment since simple tools and not precision instruments were used (with the exception of skin temperature).

CONCLUSIONS

TBP and objective sensory loss occur in 20% of patients with refractory long-standing CRPS.

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 interaction of sensory and motor signs and symptoms in chronic CRPS

Spontaneous pain, hyperalgesia as well as sensory abnormalities, autonomic, trophic, and motor disturbances are key features of Complex Regional Pain Syndrome (CRPS). This study was conceived to comprehensively characterize the interaction of these symptoms in 118 patients with chronic upper limb CRPS (duration of disease: 43±23 months). Disease-related stress, depression, and the degree of accompanying motor disability were likewise assessed. Stress and depression were measured by Posttraumatic Stress Symptoms Score and Center for Epidemiological Studies Depression Test. Motor disability of the affected hand was determined by Sequential Occupational Dexterity Assessment and Michigan Hand Questionnaire. Sensory changes were assessed by Quantitative Sensory Testing according to the standards of the German Research Network on Neuropathic Pain. Almost two-thirds of all patients exhibited spontaneous pain at rest. Hand force as well as hand motor function were found to be substantially impaired. Results of Quantitative Sensory Testing revealed a distinct pattern of generalized bilateral sensory loss and hyperalgesia, most prominently to blunt pressure. Patients reported substantial motor complaints confirmed by the objective motor disability testings. Interestingly, patients displayed clinically relevant levels of stress and depression. We conclude that chronic CRPS is characterized by a combination of ongoing pain, pain-related disability, stress and depression, potentially triggered by peripheral nerve/tissue damage and ensuing sensory loss. In order to consolidate the different dimensions of disturbances in chronic CRPS, we developed a model based on interaction analysis suggesting a complex hierarchical interaction of peripheral (injury/sensory loss) and central factors (pain/disability/stress/depression) predicting motor dysfunction and hyperalgesia.

Neuropathic pain in children: Special considerations

Neuropathic pain is relatively uncommon in children. Although some syndromes closely resemble those found in adults, the incidence and course of the condition can vary substantially in children, depending on developmental status and contextual factors. There are some neuropathic pain syndromes that are rare and relatively unique to the pediatric population. This article discusses the array of neuropathic pain conditions in children and available treatment strategies. Data are limited by small numbers and few randomized controlled trials. Research and clinical implications are discussed.

Complex regional pain syndrome (CRPS) impairs visuospatial perception,whereas post-herpetic neuralgia does not: possible implications for supraspinal mechanism of CRPS

INTRODUCTION

Complex regional pain syndrome (CRPS) patients show impaired visuospatial perception in the dark, as compared to normal patients with acute nociceptive pain. The purpose of this study is 2-fold: (i) to ascertain whether this distorted visuospatial perception is related to the chronicity of pain, and (ii) to analyse visuospatial perception of CRPS in comparison with another neuropathic pain condition.

MATERIALS AND METHODS

We evaluated visual subjective body-midline (vSM) representation in 27 patients with post-herpetic neuralgia (PHN) and 22 with CRPS under light and dark conditions. A red laser dot was projected onto a screen and moved horizontally towards the sagittal plane of the objective body-midline (OM). Each participant was asked to direct the dot to a position where it crossed their vSM. The distance between the vSM and OM was analysed to determine how and in which direction the vSM deviated.

RESULTS

Under light condition, all vSM judgments approximately matched the OM. However, in the dark, CRPS patients, but not PHN patients, showed a shifted vSM towards the affected side.

CONCLUSION

We demonstrated that chronic pain does not always impair visuospatial perception. The aetiology of PHN is limited to the peripheral nervous system, whereas the distorted visuospatial perception suggests a supraspinal aetiology of CRPS.

Atypical chest pain: evidence of intercostobrachial nerve sensitization in Complex Regional Pain Syndrome

BACKGROUND

Atypical chest pain is a common complaint among Complex Regional Pain Syndrome (CRPS) patients with brachial plexus involvement. Anatomically, the intercostobrachial nerve (ICBN) is connected to the brachial plexus and innervates the axilla, medial arm and anterior chest wall. By connecting to the brachial plexus, the ICBN could become sensitized by CRPS spread and become a source of atypical chest pain.

OBJECTIVE

To evaluate the sensitivity of chest areas in CRPS patients and normal controls.

DESIGN

Prospective investigation of pressure algometry in chest areas to determine chest wall sensitivity.

METHODS

CRPS patients and normal controls volunteered to participate in our study. Each individual was examined to meet inclusion criteria. Patients' report of chest pain history was collected from every participant. Pressure algometry was used to measure pressure sensitivity in the axilla, anterior axillary line second intercostal space, mid-clavicular third rib, mid-clavicular tenth rib, and midsternal. Each of these measurements were compared to an intra-participant abdominal measure to control for an individuals generalized sensitivity. The ratios of chest wall sensitivities were compared between CRPS patients and normal controls.

RESULTS

A history of chest pain was reported by a majority (94%) of CRPS patients and a minority (19%) of normal controls. CRPS patients reported lifting their arm as a major initiating factor for chest pain. To pressure algometry, the ratios of CRPS patients were significantly greater than control subjects (p< 0.02 throughout), indicating increased chest wall sensitivity.

LIMITATIONS

This study is limited by the relatively small number of patients (n=35) and controls (n=21) used.

CONCLUSION

The results of this study support the idea that chest pain is greater in CRPS patients than normal controls. The ICBN could be the source of this sensitization by CRPS spread from the brachial plexus.

Phantoms in Rheumatology

This paper examines rheumatology pain and how it may relate to amputee phantom limb pain (PLP), specifically as experienced in rheumatoid arthritis, fibromyalgia and complex regional pain syndrome (CRPS). Clinical findings, which suggest cortical sensory reorganization, are discussed and illustrated for each condition. It is proposed that this sensory reorganization generates pain and altered body image in rheumatology patients in the same manner as has previously been hypothesized for amputees with PLP; that is via a motor/sensory conflict. The correction of this conflict through the provision of appropriate visual sensory input, using a mirror, is tested in a population of patients with CRPS. Its analgesic efficacy is assessed in those with acute, intermediate and chronic disease. Finally, the hypothesis is taken to its natural conclusion whereby motor/sensory conflict is artificially generated in healthy volunteers and chronic pain patients to establish whether sensory disturbances can be created where no pain symptoms exists and exacerbated when it is already present. The findings of our studies support the hypothesis that a mismatch between motor output and sensory input creates sensory disturbances, including pain, in rheumatology patients and healthy volunteers. We propose the term 'ominory' to describe the central monitoring mechanism and the resultant sensory disturbances as a dissensory state.

Body perception disturbance: A contribution to pain in complex regional pain syndrome (CRPS)

In spite of pain in the CRPS limb, clinical observations show patients pay little attention to, and fail to care for, their affected limb as if it were not part of their body. Literature describes this phenomenon in terms of neurological neglect-like symptoms. This qualitative study sought to explore the nature of the phenomenon with a view to providing insights into central mechanisms and the relationship with pain. Twenty-seven participants who met the IASP CRPS classification were interviewed using qualitative methods to explore feelings and perceptions about their affected body parts. These semi-structured interviews were analysed utilising principles of grounded theory. Participants revealed bizarre perceptions about a part of their body and expressed a desperate desire to amputate this part despite the prospect of further pain and functional loss. A mismatch was experienced between the sensation of the limb and how it looked. Anatomical parts of the CRPS limb were erased in mental representations of the affected area. Pain generated a raised consciousness of the limb yet there was a lack of awareness as to its position. These feelings were about the CRPS limb only as the remaining unaffected body was felt to be normal. Findings suggest that there is a complex interaction between pain, disturbances in body perception and central remapping. Clinically, findings support the use of treatments that target cortical areas, which may reduce body perception disturbance and pain. We propose that body perception disturbance is a more appropriate term than 'neglect-like' symptoms to describe this phenomenon.

Treatment of CRPS with ECT

BACKGROUND

Electroconvulsive therapy (ECT) is a well-established treatment method for medically refractory depression. ECT has also been used in the treatment of pain for over 50 years. The mechanism of action of ECT is still unknown, although several observations have been made regarding the effect of ECT on pain processes. It has been reported that several patients with medically refractory depression and Complex Regional Pain Syndrome who were treated with ECT for their depression were also cured of their CRPS symptoms.

OBJECTIVE

We report a case of CRPS in a patient who also suffered from medically refractory depression. She was treated with ECT for her depression and subsequently was relieved of all her CRPS symptoms.

CASE REPORT

A 42 year-old female patient underwent a series of 12 standard bitemporal electroconvulsive therapy treatments for medically refractory depression. Physical examination and Quantitative Sensory Testing was done before and after the patient's treatment with ECT. This standard treatment procedure for refractory depression completely resolved the patient's depressive symptoms. In addition, the patient's CRPS symptoms were also reversed. Physical examination as well as Quantitative Sensory Testing done before and after the ECT treatment correlated with her CRPS symptom improvement.

CONCLUSION

ECT was effective in the treatment of severe refractory CRPS in this patient.

Onset and progression of dystonia in complex regional pain syndrome

Complex regional pain syndrome (CRPS) may lead to movement disorders (MDs) in some patients. Reliable information on the nature, chronology and clinical determinants of MDs in CRPS patients is lacking but could provide better insight in to the underlying pathophysiological mechanism. We retrospectively evaluated the clinical and temporal characteristics of MDs in patients with CRPS. Cox's proportional hazards model was used to evaluate factors influencing the onset of MDs. One-hundred and eighty-five patients suffered CRPS in one or more extremities. MDs occurred in 121 patients, with dystonia (91%) being the most prevalent. Sixty-two percent of these patients displayed dystonia in multiple extremities. Patients with dystonia were on average 11 years younger and more often had CRPS in multiple extremities. The interval between the onset of CRPS and dystonia in the first affected extremity varied from less than 1 week in 26% of the patients to more than 1 year in 27%. The hazard of developing dystonia in subsequent extremities increased with the number of extremities affected by dystonia. We conclude that dystonia in CRPS shows highly variable onset latency and is associated with younger age at onset and increased risk of developing dystonia in other extremities. The delayed onset and progression of dystonia in CRPS may indicate the involvement of a different underlying mechanism, possibly associated with maladaptive neuroplasticity.

Clinical presentation of cutaneous manifestations in complex regional pain syndrome (type 1)

OBJECTIVE

Complex regional pain syndrome type I (CRPS I) is a primary polymorphic condition of persistent pain and swelling that frequently occurs secondary to trauma associated with vasomotor disorders. The aim of this study was to evaluate the cutaneous findings in patients with CRPS I.

METHODS

Eighteen patients with CRPS I were included in the study. Written informed consent was obtained from all participants.

RESULTS

Of the 18 patients with CRPS I, 9 (50%) had hyperhidrosis, while hypohidrosis was present in 2 patients (11.1%). Eight patients (44.4%) had hypertrichosis, and 1 patient (5.6%) had hypotrichosis. Five of the patients (27.8%) had nail changes.

CONCLUSIONS

These cutaneous changes are not rare in CRPS I and generate difficulties for the patient; therefore, they should be prevented during the early stages of CRPS I with use of an effective treatment.

Severity and specificity of neglect-like symptoms in patients with complex regional pain syndrome (CRPS) compared to chronic limb pain of other origins

In the literature, the neglect-like syndrome is described as an additional phenomenon of CRPS. The perception of the affected limb as strange, disordered and not belonging to the body is typical of and characterises this syndrome. Since this phenomenon has never been studied in other pain conditions, we assessed occurrence and extent of neglect-like symptoms in patients with CRPS of the upper and lower limb (n = 123) and in a control group with chronic limb pain of other origins (n = 117). Our questionnaire for describing the neglect-like syndrome encompassed five items following Galer and Jensen [Galer BS, Jensen M. Neglect-like symptoms in complex regional pain syndrome: results of a self-administered survey. Journal of Pain and Symptom Management 1999;18:213-6], with a six-point response scale inquiring the extent of respective symptoms. Results show that CRPS-patients as well as patients with non-CRPS limb pain exhibit the so-called neglect-like syndrome. However, the number of patients confirming such symptoms was significantly higher (OR = 2.87) in the CRPS group, moreover, these patients reported more severe symptoms (F = 17.74; p = 0.001). If the neglect-like total score is > or = 5, the diagnostic sensitivity is low (21.1%), but the specificity for the diagnosis of CRPS reaches 90.6%. In this study, patients with CRPS of the upper and lower limb were included. The only difference between these two localisations concerning the neglect-like syndrome was the symptom of 'involuntary movements', which occurs significantly more often in affected legs. In conclusion, we recommend to evaluate neglect-like symptoms and to use them as an additional criterion in the diagnosis of CRPS. High scores of > or = 5 confirm the diagnosis of CRPS, whereas lower scores must not be used for disease classification.

Sensory changes in the forehead of patients with complex regional pain syndrome

The aim of this study was to investigate involvement of central mechanisms in complex regional pain syndrome (CRPS). In particular, we wished to determine whether hyperalgesia extends ipsilaterally from the affected limb to the forehead. The heat-pain threshold, pressure-pain threshold, and ratings of cold and sharpness were investigated on each side of the forehead and in the affected and unaffected limbs of 38 patients with features of CRPS. In addition, touch thresholds were investigated in the limbs. The pressure-pain threshold was lower on the ipsilateral forehead than contralaterally, consistent with the presence of static mechanical hyperalgesia. Although the heat-pain threshold and ratings of sharpness and cold did not differ between the two sides of the forehead in the group as a whole, the sharpness of pinprick sensations in the affected limb was mirrored by similar sensations in the ipsilateral forehead. Conversely, diminished sensitivity to light touch in the affected limb was associated with diminished sensitivity to sharpness, cold and heat-pain in the ipsilateral forehead. These findings suggest that central nociceptive processing is disrupted in CRPS, possibly due to disturbances in the thalamus or higher cortical centres.

Pathophysiology of complex regional pain syndrome

Complex regional pain syndrome (CRPS) most often follows injury to peripheral nerves or their endings in soft tissue. A combination of prostanoids, kinins and cytokines cause peripheral nociceptive sensitization. In time, the Mg(2+) block of the N-methyl-D-aspartate receptor is removed, pain transmission neurons (PTN) are altered by an influx of Ca(2+) that activates kinases for excitation and phosphatases for depression, activity-dependent plasticity that alters the firing of PTN. In time, these neurons undergo central sensitization that lead to a major physiological change of the autonomic, pain and motor systems. The role of the immune system and the sickness response is becoming clearer as microglia are activated following injury and can induce central sensitization while astrocytes may maintain the process.

Complex Regional Pain Syndromes in Children and Adolescents

OBJECTIVE

Complex regional pain syndromes (CRPS) involve neuropathic limb pain and localized circulatory abnormalities. The authors hypothesized that (1) pediatric CRPS patients exhibit systemic autonomic symptoms and orthostatic and/or cardiac sympatho-vagal dysregulation and (2) their orthostatic regulation differs from healthy controls and pediatric patients with postural orthostatic tachycardia syndrome (POTS).

METHODS

CRPS children and adolescents (n=20) underwent a 6-week trial of physical therapy and cognitive-behavioral treatment. Measures included pain and function scores, regional and systemic autonomic symptom profiles, heart rate and blood pressure with tilt, heart rate variability indices, and baroreflex gain. Systemic autonomic symptoms were recorded in 55 healthy pediatric controls. Tilt responses in CRPS patients were compared with those of 21 POTS patients and 39 healthy controls.

RESULTS

CRPS patients' regional autonomic symptoms, pain, and limb function improved over 6 weeks (P<0.01). At baseline CRPS patients reported more systemic autonomic symptoms than controls (P<0.05). Tilt table test showed orthostatic stability, but the mean heart rate increase with tilt was greater in CRPS patients than controls (P<0.001). POTS patients showed significant increases with tilt in mean heart rate and diastolic and systolic blood pressures compared with controls (P<0.001). There were significant increases in the mean systolic and diastolic blood pressures in POTS compared with CRPS patients but no difference in the mean heart rate between groups.

DISCUSSION

CRPS patients reported multiple regional and systemic autonomic symptoms that improved during the study course, and they experienced minimal and transient tilt table-induced hemodynamic changes compared with POTS patients but relatively similar to controls.

Continuous extradural analgesia in a cow with complex regional pain syndrome

A chronic pain syndrome, similar to the complex regional pain syndrome (CRPS) described in human beings, was diagnosed in a cow with persisting severe pelvic limb lameness. Diagnosis was based on the disproportionate relationship between the severity and duration of pain and the lesion, the failure of conventional analgesic and surgical therapy and the presence of characteristic clinical features. Multimodal therapy, i.e. a mixture of methadone, ketamine and bupivacaine was administered continuously for 17 days via an extradural catheter to counteract nociceptive hypersensitization. Doses were adjusted daily after assessing the effect, using a composite pain score. Physiotherapy was also performed. The diagnosis of CRPS in cattle is unusual. In this case, treatment was successful and the cow was discharged mildly lame and in improving physical condition. Long-term extradural analgesia proved to be safe and effective in the treatment of this syndrome, which was nonresponsive to conventional therapy.

Sympathetic skin responses in hemiplegic patients with and without complex regional pain syndrome

BACKGROUND AND AIMS

To investigate whether there were changes in the sympathetic skin responses (SSR) in the limbs with complex regional pain syndrome (CRPS) type I in hemiplegic patients.

SETTING

A physical medicine and rehabilitation center in Turkey.

MATERIALS AND METHODS

Sympathetic skin responses were evaluated in 69 stroke patients (41 with CRPS and 28 without CRPS) and 20 healthy volunteers. SSR were recorded on the paretic and healthy hands after stimulation of the ipsilateral median nerve. Patients' ages ranged from 33 to 77 years, with a mean of 60.0+/-12.9 years.

RESULTS

The SSR were obtained in all patients with CRPS, whereas SSR was absent in 9 of 28 patients with hemiplegia who did not have CRPS after stimulation of the plegic side and the difference was statistically significant (P=0.023). SSR amplitudes were increased at the hemiplegic limbs in patients affected by CRPS compared to individuals unaffected; this group difference was statistically significant (P=0.014). The mean amplitude of the SSR in the advanced stage of CRPS was greater than lower stage and the difference was statistically significant (P=0.035).

CONCLUSION

Our results suggest that SSR can be obtained in stroke patients with CRPS even in the early stages of CRPS. SSR acquirability and amplitude increase as the stage of the disease advances. As an electrophysiologic technique, SSR may be used in the evaluation of the sympathetic function in hemiplegic patients and also in the diagnosis of CRPS and in monitoring of its treatment.

Dextrose 5% in water: fluid medium for maintaining electrical stimulation of peripheral nerves during stimulating catheter placement

It is well documented that a higher electrical current is required to elicit a motor response following a normal saline (NS) injection during the placement of stimulating catheters for peripheral nerve block. We present three cases of continuous brachial plexus catheter placement in which Dextrose 5% in water (D5W) was used to dilate the perineural space instead of NS. Three brachial plexus blocks (two interscalene and one axillary) were performed in three different patients for pain relief. In each case, an insulated needle was advanced towards the brachial plexus. A corresponding motor response was elicited with a current less than 0.5 mA after needle repositioning. A stimulating catheter was advanced with ease after 3-5 ml of D5W was injected to dilate the perineural space. A corresponding motor response was maintained when the current applied to the stimulating catheter was less than 0.5 mA. Local anesthetic was then injected and the motor response immediately ceased. All blocks were successful and provided excellent pain relief with the continuous infusion of local anesthetics.

Changes in cerebrospinal fluid levels of pro-inflammatory cytokines in CRPS

Complex Regional Pain Syndrome (CRPS) Types I and II are characterized by various combinations of sensory, autonomic and motor abnormalities. Pain disproportionate to the severity and duration of the inciting event is the most devastating symptom. In animal studies, conditions resulting in exaggerated pain states demonstrate elevated pro-inflammatory cytokines. In addition, pro-inflammatory cytokines have been shown to induce or increase neuropathic and inflammatory pain. Utilizing high sensitivity enzyme linked immunosorbent assay (ELISA), we compared the levels of the pro-inflammatory cytokines interleukin-1beta (IL-1beta), interleukin-6 (IL-6) and Tumor Necrosis Factor-alpha (TNF-alpha) in the cerebrospinal fluid (CSF) of patients afflicted with CRPS to CSF levels found in other patients with and without painful conditions. The results from this study demonstrated significant increases in IL-1beta and IL-6, but not TNF-alpha in the CSF of individuals afflicted with CRPS as compared to controls. CSF cytokine levels in controls with painful conditions did not differ from levels in controls without pain. These increases showed no correlation with the patient's gender or weight. These results are consistent with studies that suggest that the pathogenesis of CRPS is due in part to central neuroimmune activation.

Substance-P-induced protein extravasation is bilaterally increased in complex regional pain syndrome

Pain, mechanical hyperalgesia, edema, increased skin temperature, and skin reddening are characteristic symptoms of acute complex regional pain syndrome (CRPS). We have recently demonstrated facilitated neurogenic inflammation on the affected limb. To further elucidate the underlying mechanisms, exogenous substance P (SP) in ascending concentrations (10(-9), 10(-8), 10(-7), 10(-6) M) was intradermally applied to the affected and the unaffected limbs, respectively, in two groups of 11 CRPS patients each using the microdialysis technique. Fourteen healthy volunteers served as controls for SP application, and 9 volunteers and 10 patients served as controls for saline perfusion. Dialysate protein content was measured photometrically to assess plasma protein extravasation. Significant differences in dialysate protein content were found after 10(-9) M SP (affected side, 98.4 +/- 8.4% of baseline value; unaffected side, 104.4 +/- 5.6%; controls, 70.7 +/- 4.1%; P < 0.005) and after 10(-6) M SP (affected, 169.7 +/- 24.2%; unaffected, 189.4 +/- 19.1%; controls, 122.2 +/- 12.0%; P < 0.05). While 10(-9) M SP induced no protein extravasation in controls, it provoked protein extravasation in 6 of 11 patients on the affected and in 5 of 11 patients on the unaffected side (P < 0.01). We conclude that SP-induced plasma protein extravasation is increased in CRPS patients on both the affected and unaffected limbs. The underlying mechanism might be impaired SP inactivation. Thus, our results further support the hypothesis that neurogenic inflammation plays an important role in the initiation of CRPS.

Referred sensations in patients with complex regional pain syndrome type 1

OBJECTIVES

This study sought to explore and characterize referred sensations (RS) in patients with complex regional pain syndrome (CRPS) type 1 and test the hypothesis that pain in CRPS is associated with central sensory changes.

METHODS

Subjects underwent standardized neurological examination involving light touch, pinprick and vibration sense with eyes closed and then with eyes open. The subjects described the location and sensation emanating from the stimulated site and whether they experienced any sensations (similar or different) elsewhere.

RESULTS

Five of 16 subjects recruited demonstrated RS. These were experienced in real time, were modality specific (touch and pinprick) and were located on the body part immediately adjacent, on Penfield's cortical homunculus, to the stimulated site. The RS were diminished or absent when the subject visualized the stimulated area. They disappeared when stimulation ceased and on clinical improvement.

CONCLUSIONS

This is the first report of RS in CRPS and provides further evidence of central reorganization in what was previously thought to be a peripheral disorder.

Treatment of tremors in complex regional pain syndrome

A 14-year-old girl presented with Complex Regional Pain Syndrome, Type I (CRPS-1) of the left ankle after a remote history of sprain. Allodynia, pain, temperature and color changes, and swelling were successfully treated with physical therapy, transcutaneous electrical nerve stimulation (TENS), gabapentin, amitriptyline, and tramadol. Five weeks later, she presented with a continuous, involuntary, intermittent coarse tremor of the left foot causing increased pain. The electromyogram showed rhythmic discharges of 3 Hz frequency lasting 20-80 milliseconds in the left tibialis, peroneus and gastrocnemius, suggestive of either basal ganglia or spinal origin. Tremor and pain were controlled with epidural bupivacaine, but the tremor reappeared after discontinuing epidural blockade. Carbidopa/levodopa 25/100 (Sinemet) was started and the tremor disappeared after two days. With continued physical therapy, pain and swelling resolved within two months and carbidopa/levodopa was discontinued after five weeks with no recurrence of the tremor. Our success in the treatment of CRPS-associated tremor in this young girl with carbidopa/levodopa suggests that this patient may have had underlying movement disorder which was unmasked by the peripheral injury.

Effect of lumbar 5 ventral root transection on pain behaviors: a novel rat model for neuropathic pain without axotomy of primary sensory neurons

A peripheral nerve injury often causes neuropathic pain but the underlying mechanisms remain obscure. Several established animal models of peripheral neuropathic pain have greatly advanced our understanding of the diverse mechanisms of neuropathic pain. A common feature of these models is primary sensory neuron injury and the commingle of intact axons with degenerating axons in the sciatic nerve. Here we investigated whether neuropathic pain could be induced without sensory neuron injury following exposure of their peripheral axons to the milieu of Wallerian degeneration. We developed a unilateral lumbar 5 ventral root transection (L5 VRT) model in adult rats, in which L5 ventral root fibers entering the sciatic nerve were sectioned in the spinal canal. This model differs from previous ones in that DRG neurons and their afferents are kept uninjured and intact afferents expose to products of degenerating efferent ventral root fibers in the sciatic nerve and the denervated muscles. We found that the L5 VRT produced rapid (24 h after transection), robust and prolonged (56 days) bilateral mechanical allodynia, to a similar extent to that in rats with L5 spinal nerve transection (L5 SNT), cold allodynia and short-term thermal hyperalgesia (14 days). Furthermore, L5 VRT led to significant inflammation as demonstrated by infiltration of ED-1-positive monocytes/macrophages in the DRG, sciatic nerve and muscle fibers. These findings demonstrated that L5 VRT produced behavioral signs of neuropathic pain with high mechanical sensitivity and thermal responsiveness, and suggested that neuropathic pain can be induced without damage to sensory neurons. We propose that neuropathic pain in this model may be mediated by primed intact sensory neurons, which run through the milieu of Wallerian degeneration and inflammation after nerve injury. The L5 VRT model manifests the complex regional pain syndrome in some human patients, and it may provide an additional dimension to dissect out the mechanisms underlying neuropathic pain.

Treatment of dystonic clenched fist with botulinum toxin

Fourteen patients with "dystonic clenched fist" (three with Corticobasal Ganglionic Degeneration, seven with Parkinson's disease, and four with Dystonic-Complex Regional Pain Syndrome) were treated with botulinum toxin A (BTXA, Dysport). The muscles involved were identified by the hand posture and EMG activity recorded at rest and during active and passive flexion/extension movements of the finger and wrist. EMG was useful in distinguishing between muscle contraction and underlying contractures and to determine the dosage of BTX. All patients had some degree of flexion at the proximal metacarpophalangeal joints and required injections into the lumbricals. The response in patients depended on the severity of the deformity and the degree of contracture. All patients had significant benefit to pain, with accompanying muscle relaxation, and palmar infection, when present, was eradicated. Four patients with Parkinson's disease and one patient with Dystonia-Complex Regional Pain Syndrome obtained functional benefit.