Complex regional pain syndrome in children: a systematic review of clinical features and movement disorders

Complex Regional Pain Syndrome: Evidence-Based Advances in Concepts and Treatments

PURPOSE OF REVIEW

This review presents the most current information about the epidemiology of complex regional pain syndrome (CRPS), classification and diagnostic criteria, childhood CRPS, subtypes, pathophysiology, conventional and less conventional treatments, and preventive strategies.

RECENT FINDINGS

CRPS is a painful disorder with multifactorial pathophysiology. The data describe sensitization of the central and peripheral nervous systems, inflammation, possible genetic factors, sympatho-afferent coupling, autoimmunity, and mental health factors as contributors to the syndrome. In addition to conventional subtypes (type I and type II), cluster analyses have uncovered other proposed subtypes. Prevalence of CRPS is approximately 1.2%, female gender is consistently associated with a higher risk of development, and substantial physical, emotional, and financial costs can result from the syndrome. Children with CRPS seem to benefit from multifaceted physical therapy leading to a high percentage of symptom-free patients. The best available evidence along with standard clinical practice supports pharmacological agents, physical and occupational therapy, sympathetic blocks for engaging physical restoration, steroids for acute CRPS, neuromodulation, ketamine, and intrathecal baclofen as therapeutic approaches. There are many emerging treatments that can be considered as a part of individualized, patient-centered care. Vitamin C may be preventive. CRPS can lead to progressively painful sensory and vascular changes, edema, limb weakness, and trophic disturbances, all of which substantially erode healthy living. Despite some progress in research, more comprehensive basic science investigation is needed to clarify the molecular mechanisms of the disease so that targeted treatments can be developed for better outcomes. Incorporating a variety of standard therapies with different modes of action may offer the most effective analgesia. Introducing less conventional approaches may also be helpful when traditional treatments fail to provide sufficient improvement.

Distress and Resilience Narratives within Pain Memories of Adolescents and Young Adults with Complex Regional Pain Syndrome: A Multi-Method Study

A comprehensive understanding of pain memories requires consideration of risk and resilience factors across biopsychosocial domains. Previous research has typically focused on pain-related outcomes, largely ignoring the nature and context of pain memories. Using a multiple-method approach, this study explores the content and context of pain memories in adolescents and young adults with complex regional pain syndrome (CRPS). Recruited via social media and pain-related organizations, participants completed an autobiographical pain memory task. Two-step cluster analysis was conducted on the pain memory narratives of adolescents and young adults with CRPS (n=50) using a modified version of the Pain Narrative Coding Scheme. Narrative profiles generated from the cluster analysis subsequently guided a deductive thematic analysis. Cluster analysis identified two narrative profiles of Distress and Resilience, with the role of coping and positive affect emerging as important profile predictors across pain memories. Subsequent deductive thematic analysis, utilizing Distress and Resilience codes, demonstrated the complex interplay between affect, social, and coping domains. Findings highlight the importance of applying a biopsychosocial framework to pain memory research, accounting for both risk and resilience perspectives and encourage the use of multiple method approaches to improve understanding of autobiographic pain memories. Clinical implications of reframing and recontextualizing pain memories and narratives are discussed, and the importance of exploring the origins of pain and possible application to developing resilience-based, preventative interventions is highlighted. PERSPECTIVE: Using multiple methods, this paper presents a comprehensive account of pain memories in adolescents and young adults with CRPS. Study findings promote the importance of adopting a biopsychosocial approach to examining both risk and resilience factors in understanding autobiographical pain memories in the context of pediatric pain.

Clinical Assessment of Mechanical Allodynia in Youth With Complex Regional Pain Syndrome: Development and Preliminary Validation of the Pediatric Tactile Sensitivity Test of Allodynia (Pedi-Sense)

Youth with complex regional pain syndrome (CRPS) commonly experience mechanical allodynia and disability. Assessment of mechanical allodynia is typically binary (present or absent), making it difficult to assess the quality and degree of mechanical allodynia before and after treatment. This study developed and validated the Pediatric Tactile Sensitivity Test of Allodynia (Pedi-Sense) to provide an easy way for rehabilitation clinicians to evaluate mechanical allodynia before and after intensive interdisciplinary pain treatment. The 6 Pedi-Sense items demonstrated adequate internal consistency reliability (CR) at admission (CR = .956) and discharge (CR = .973), reasonably fit the hypothesized linear model of stimulus intensity (P < .0001), and significantly loaded onto a single latent factor, mechanical allodynia (P < .0001), at admission and discharge. Pedi-Sense scores significantly correlated with disability (r_s = .40; P = .004) and pain catastrophizing (r_s = .33; P = .017) at admission. The Pedi-Sense appeared responsive to intervention as participants' total scores improved by 1.44 points (95% CI: .72, 2.15) after IIPT interventions that included daily tactile desensitization. However, test-retest and interrater reliability and the specific contribution of desensitization treatment to the overall success of multi-modal pain rehabilitation still needs to be evaluated. PERSPECTIVE: This article presents the development and preliminary validation of a novel clinical assessment of static and dynamic mechanical allodynia. The Pediatric Tactile Sensitivity Test of Allodynia (Pedi-Sense) allows rehabilitation clinicians to easily evaluate mechanical allodynia at the bedside with minimal training and simple equipment to guide desensitization treatment in clinical settings.

Processing of pain by the developing brain: evidence of differences between adolescent and adult females

ABSTRACT

Adolescence is a sensitive period for both brain development and the emergence of chronic pain particularly in females. However, the brain mechanisms supporting pain perception during adolescence remain unclear. This study compares perceptual and brain responses to pain in female adolescents and adults to characterize pain processing in the developing brain. Thirty adolescent (ages 13-17 years) and 30 adult (ages 35-55 years) females underwent a functional magnetic resonance imaging scan involving acute pain. Participants received 12 ten-second noxious pressure stimuli that were applied to the left thumbnail at 2.5 and 4 kg/cm 2 , and rated pain intensity and unpleasantness on a visual analogue scale. We found a significant group-by-stimulus intensity interaction on pain ratings. Compared with adults, adolescents reported greater pain intensity and unpleasantness in response to 2.5 kg/cm 2 but not 4 kg/cm 2 . Adolescents showed greater medial-lateral prefrontal cortex and supramarginal gyrus activation in response to 2.5 kg/cm 2 and greater medial prefrontal cortex and rostral anterior cingulate responses to 4 kg/cm 2 . Adolescents showed greater pain-evoked responses in the neurologic pain signature and greater activation in the default mode and ventral attention networks. Also, the amygdala and associated regions played a stronger role in predicting pain intensity in adolescents, and activity in default mode and ventral attention regions more strongly mediated the relationship between stimulus intensity and pain ratings. This study provides first evidence of greater low-pain sensitivity and pain-evoked brain responses in female adolescents (vs adult women) in regions important for nociceptive, affective, and cognitive processing, which may be associated with differences in peripheral nociception.

Long-term biopsychosocial issues and health-related quality of life in young adolescents and adults treated for childhood Complex Regional Pain Syndrome, type 1

OBJECTIVES

Treatment for childhood Complex Regional Pain Syndrome (CRPS) is associated with long-term recovery. The present study aimed to investigate the long-term biopsychosocial status and quality of life in young adolescents and adults after the treatment of childhood CRPS.

METHODS

A 4 year follow-up of individuals with childhood-CRPS, type 1 (n=22; age:12 years (years) [median] at treatment and 17 years at follow-up) was completed. Biopsychosocial status and quality of life were assessed with structured interviews, using the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), the Strengths and Difficulties Questionnaire (SDQ), the Pediatric Pain Coping Inventory (PPCI), and the Pediatric Quality of Life Inventory (PedsQL). Comparisons were made with normative samples of age-matched controls.

RESULTS

CRPS at follow-up was still present in seven out of 22, and non-CRPS pain symptoms were found in 12 out of 22 individuals. Signs of mental health pain-related problems, including phobias and obsessive-compulsive disorder, were observed in ten out of 19 individuals. Mental well-being, social functioning, and quality of life (SDQ and PedsQL) were independent of pain status (p>0.05). Adaptive pain coping strategies were utilized regardless of pain status (PPCI). Social functioning (p<0.01) and the quality of life (p=0.01) were attenuated and statistically significantly poorer than healthy age-matched young adults but better than for fibromyalgia subjects.

CONCLUSIONS

A subset of individuals treated for childhood-CRPS, type 1 experiences long-term consequences of persistent pain, a decrease in quality of life indicators, and demonstrates significant psychosocial issues. Childhood-CRPS is suggested to be associated with long-term psychosocial consequences and poorer quality of life than found in age-related healthy peers. Subjects treated for childhood CRPS may need a longer clinical follow-up attempting to preclude relapse of CRPS and non-CRPS pain.

Canadian surveillance study of complex regional pain syndrome in children

ABSTRACT

This study describes the minimum incidence of pediatric complex regional pain syndrome (CRPS), clinical features, and treatments recommended by pediatricians and pain clinics in Canada. Participants in the Canadian Paediatric Surveillance Program reported new cases of CRPS aged 2 to 18 years monthly and completed a detailed case reporting questionnaire from September 2017 to August 2019. Descriptive analysis was completed, and the annual incidence of CRPS by sex and age groupings was estimated. A total of 198 cases were reported to the Canadian Paediatric Surveillance Program, and 168 (84.8%) met the case definition. The minimum Canadian incidence of CRPS is estimated at 1.14/100,000 (95% confidence interval 0.93-1.35/100,000) children per year. Incidence was highest among girls 12 years and older (3.10, 95% confidence interval 2.76-3.44/100,000). The mean age of CRPS diagnosis was 12.2 years (SD = 2.4), with the mean time from symptom onset to diagnosis of 5.6 months (SD = 9.9) and no known inciting event for 19.6% of cases. Most cases had lower limb involvement (79.8%). Nonsteroidal anti-inflammatory drugs (82.7%) and acetaminophen (66.0%) were prescribed more commonly than antiepileptic drugs (52.3%) and antidepressants (32.0%). Referrals most commonly included physical therapy (83.3%) and multidisciplinary pain clinics (72.6%); a small number of patients withdrew from treatment because of pain exacerbation (5.3%). Pain education was recommended for only 65.6% of cases. Treatment variability highlights the need for empiric data to support treatment of pediatric CRPS and development of treatment consensus guidelines.

Screening and diagnostic tools for complex regional pain syndrome: a systematic review

ABSTRACT

Complex regional pain syndrome (CRPS) is a severely painful condition that presents with a constellation of symptoms. The understanding of the pathophysiology of CRPS has evolved over time, as have the diagnostic criteria. Our primary objective was to identify screening and diagnostic tools for CRPS and summarize their feasibility, measurement properties, and study quality. A secondary objective was to identify screening and diagnostic tools used for CRPS in pediatric populations (0-21 years of age). A systematic review of English articles in electronic databases (PsycINFO, MEDLINE, Embase, CINAHL, CENTRAL, and Web of Science) was conducted with the aid of a librarian in November 2018 and updated in July 2020. Studies were included if the tool was a screening or diagnostic tool, the tool included self-report or physical examination, and the primary objective of the study was to evaluate the measurement properties or feasibility of use. For each study, data were extracted for quality indicators using the QUADAS-2 tool. No screening tools were identified. Four diagnostic tools were identified: the Veldman criteria, International Association for the Study of Pain criteria, Budapest Criteria, and Budapest Research Criteria. There are no diagnostic tools validated for use in pediatric CRPS. Because there are no extant screening tools for CRPS, all people with suspected disease should undergo rapid diagnostic assessment by a clinician. For adults, the Budapest Criteria are the preferred diagnostic tool. Future research is recommended to develop a diagnostic tool for pediatric populations and screening tools for both pediatric and adults.

Impact of adolescent complex regional pain syndrome on the psychopathology of young men ahead of military service: a retrospective cohort analysis of Korean conscription data

BACKGROUND

The relationship between physical and psychopathological features in complex regional pain syndrome (CRPS) has been a subject of constant interest, but no data are available in adolescents. Therefore, we aimed to identify the factors associated with psychopathology in adolescents with CRPS ahead of military service.

METHODS

We retrospectively reviewed all conscription examinees who had completed a Military Personality Inventory (MPI) during a period between February 2013 and December 2016. A total of 63 persons with a history of CRPS (19-years of age for all) were enrolled. Basic demographic and pain-related data were analyzed to examine their association with MPI results. The mean FGR score as well as the 8 subdomain scores were compared between those with pain duration at < 15 months (n = 30) versus ≥15 months (n = 33). Binary MPI results (normal-abnormal) were also compared between the two groups.

RESULTS

In multivariate analysis, abnormal MPI was associated with pain duration, with an odds ratio (OR) at 1.05 for every 1-month increase (95% confidence interval (CI) 1.02-1.08; P = 0.002). Subjects with pain duration at ≥15 months have lower faking good response score (P < 0.001 vs. those with pain duration at < 15 months), and higher abnormal MPI result rate, faking bad response, inconsistency, anxiety, depression, somatization, paranoid, personality disorder cluster A, and personality disorder cluster B scores (P < 0.05). Pain duration was significantly associated with the MPI variables.

CONCLUSIONS

Pain duration is associated with psychopathology in adolescents with CRPS. Psychopathologic features increased as the disease duration increased. A comprehensive understanding of time-dependent psychopathological factors could support the planning of multimodal approaches for managing adolescent CRPS.

A linguistic analysis of future narratives in adolescents with Complex Regional Pain Syndrome and their pain-free peers

BACKGROUND

Complex Regional Pain Syndrome (CRPS) is a chronic pain condition that often develops after injury, with a typical onset in adolescence. The impact of chronic pain is far-reaching, with many adolescents reporting atypical developmental trajectories compared with peers. Social Comparison Theory offers a framework for understanding how such comparisons influence well-being, whereby a heightened sense of disparity places adolescents at risk of poor cognitive, affective and social outcomes. Using a novel linguistic analysis programme, this study aims to investigate cognitive, affective and social language used by adolescents with CRPS in comparison to their peers during a task reflecting on their futures.

METHODS

A story completion task was completed by adolescents with CPRS (n = 49) and adolescents without pain (n = 48). This task involved asking adolescents to describe their imagined future. Narratives were analysed using a novel linguistic analysis programme, focusing on the cognitive, affective and social dimensions.

RESULTS

Findings revealed significant group differences in how adolescents with CRPS described their imagined futures. Adolescents with CRPS used significantly fewer positive affect and more negative affect, anger and sadness words, and greater insight and discrepancy words. No significant groups differences were found for social words.

CONCLUSIONS

Substantial differences in cognitive and affective words were found between adolescents with and without CRPS. Findings provide novel insights into current understandings of cognitive, affective and social processes in adolescents living with chronic pain, particularly with regard to adolescent developmental trajectories, and may in turn highlight potential targets in psychosocial interventions for adolescents living with chronic pain.

SIGNIFICANCE

Social comparisons are commonly undertaken by adolescents with CRPS in relation to peers, increasing risk for poor cognitive, affective and social outcomes. Findings promote the potential importance of targeting psychosocial factors in treatments for paediatric chronic pain.

Severe Pediatric Wrist Joint Sequelae following Blunt Trauma in the Presence of Chronic Regional Pain Syndrome

Introduction The pediatric chronic regional pain syndrome (CRPS) type I is a recognized syndrome that follows a preliminary event (e.g., trauma, fracture) with amplified spontaneous or stimuli-induced extremity pain that differs from its adult form with rather favorable outcomes. Conservative treatment is usually indicated for CRPS treatment. Case Description We present a unique case of an adolescent girl who revealed severe wrist joint sequelae following a blunt trauma, complicated by a challenging CRPS resistant to treatment. Diagnostic wrist arthroscopy eventually revealed a massive cartilage degeneration and scapholunate tear as underlying causes for the pain and CRPS. It was decided to proceed with radioscapholunate wrist fusion, which promptly led to pain relief and disappearance of the CRPS. Conclusion The relevance of this report is therefore to emphasize the possibility, against earlier thoughts, that well-indicated surgeries in pediatric CRPS patients may lead to prompt symptom improvement and may not be uniformly predicted to fail. With the clinical probability of a presence of an uncontrolled, symptomatic causative factor such as cartilage degeneration and chondrolysis, further early diagnostic and therapeutic interventions may be indicated to control the disease.

A Review of Neuromodulation for Treatment of Complex Regional Pain Syndrome in Pediatric Patients and Novel Use of Dorsal Root Ganglion Stimulation in an Adolescent Patient With 30-Month Follow-Up

OBJECTIVES

Complex regional pain syndrome (CRPS) is a disorder in which pain and discomfort are out of proportion to the amount of tissue damage. While prevalence is 20.57 per 100,000 adults, it has not been studied in the U.S. pediatric population. Conservative treatment options include pharmacologic, behavioral, and psychological treatment. If these fail, invasive therapies such as sympathetic blocks and neuromodulation may be performed. The ACCURATE study demonstrated efficacy of dorsal root ganglion (DRG) stimulation for the treatment of refractory CRPS, but did not include pediatric patients and there are no reported cases of its use in the pediatric population. We review the use of neuromodulation for CRPS in pediatric patients and present a novel case using DRG stimulation in an adolescent patient.

MATERIALS AND METHODS

A literature search was performed for any studies of neuromodulation as treatment of pediatric CRPS. The literature is reviewed and the case of a 17-year-old female with CRPS treated with DRG stimulation is presented.

RESULTS

A 15-year-old female developed CRPS type I of the left ankle after a sports injury. She was unable to wear a shoe or venture outside the home due to pain, swelling, and allodynia. Conservative therapies, including medications, physical therapy, and lumbosacral sympathetic plexus blocks, failed. At age 17, she underwent DRG stimulator lead placement targeting the left L4 and L5 nerve roots. Her therapy provided 100% relief of pain within four days of placement and was sustained at 30-month follow-up.

CONCLUSIONS

DRG stimulation has been shown to significantly alter the symptomatology in patients with CRPS. This case suggests that DRG stimulation may be as effective for the treatment of refractory CRPS in pediatric patients as in adults.

Evidence already exists for motor system reorganization in CRPS

Complex regional pain syndrome (CRPS) is a disabling condition that is usually preceded by trauma or surgical procedure. Involvement of the motor system is a well-known phenomenon in CRPS, though the pathophysiologic mechanisms of motor system affliction in CRPS are poorly understood. Graded motor imagery (GMI) has been proposed to be one of the therapeutic interventions to help improve pain and other disabling symptoms associated with CRPS, though the benefits noted are modest and inconsistent. The neurophysiological mechanisms implicated in motor imagery are intended to target the aberrant prefrontal and sensorimotor integration areas, which may potentially help restore the aberrant cortical plasticity in CRPS. Detailed well-controlled experiments using insights from the existing body of literature on motor system reorganization in CRPS are required to better understand this complicated disorder. Attempts to gain pathophysiologic insights about complicated disorders like CRPS based on case reports with poorly performed and uncontrolled interventions are misguided.

A mysterious case of complex regional pain syndrome in a 9-year-old girl

PURPOSE

To describe the clinical manifestation and the treatment of complex regional pain syndrome type II in childhood.

METHODS

Using information on the symptoms, diagnosis, rehabilitation and outcome of a young patient with complex regional pain syndrome type II.

RESULTS

A 9-year -old girl had severe pain in the region of the left foot, signs of a common fibular nerve entrapment, hyperalgesia not limited to the distribution of the injured nerve, weakness and temperature asymmetry unknown origin. She consulted few doctor's before she was given the right diagnosis of complex regional pain syndrome type II. Following the diagnosis the treatment started, it included intensive physiotherapy, electrical therapy and also supportive psychological therapy. Half a year later, the patient was free of the daily pain and returned to all physical activity without any restrictions.

CONCLUSIONS

The case report illustrates that peripheral nerve compression or injuries specifically, complex regional pain syndrome type II, should be taken into consideration when evaluating children with weakness and pain of the lower or upper limb. Implication of rehabilitation Raising the awareness of complex regional pain syndrome in the childhood is essential for an early diagnosis and appropriate treatment. The treatment options include early and adequate pain management inclusive electrical therapy and physiotherapy. Psychological therapy helps to avoid psychological stress reaction and the disease negative impact on the child's education and sports and the family social life.