An update on complex regional pain syndromes in children and adolescents

The Neurostimulation Appropriateness Consensus Committee (NACC)®: Recommendations for the Mitigation of Complications of Neurostimulation

INTRODUCTION

The International Neuromodulation Society convened a multispecialty group of physicians based on expertise and international representation to establish evidence-based guidance on the mitigation of neuromodulation complications. This Neurostimulation Appropriateness Consensus Committee (NACC)® project intends to update evidence-based guidance and offer expert opinion that will improve efficacy and safety.

MATERIALS AND METHODS

Authors were chosen on the basis of their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from 2017 (when NACC last published guidelines) to October 2023. Identified studies were graded using the United States Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on the strength of evidence or consensus when evidence was scant.

RESULTS

The NACC examined the published literature and established evidence- and consensus-based recommendations to guide best practices. Additional guidance will occur as new evidence is developed in future iterations of this process.

CONCLUSIONS

The NACC recommends best practices regarding the mitigation of complications associated with neurostimulation to improve safety and efficacy. The evidence- and consensus-based recommendations should be used as a guide to assist decision-making when clinically appropriate.

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.

Signs and symptoms of pediatric complex regional pain syndrome -type 1: A retrospective cohort study

Background

Complex regional pain syndrome (CRPS) presents with an array of symptoms that can vary from child to child, making it difficult to diagnose and differentiate from other pain conditions such as chronic musculoskeletal (MSK) pain. Thirteen symptoms and signs are outlined in the Budapest criteria for CRPS (developed and validated for adults) but have not been well described in pediatrics.

Aims

The aim of this study was to describe the signs and symptoms of pediatric CRPS type 1 (CRPS 1) and determine whether a cluster of symptoms can differentiate CRPS 1 from chronic MSK pain.

Methods

A retrospective cohort study of pediatric patients with CRPS 1 and MSK pain in a pediatric pain program was conducted. Descriptive statistics were used to report demographics and pain characteristics. The chi-square test was used to evaluate differences in signs and symptoms between patients with CRPS and MSK pain. A logistic regression model was used to evaluate whether a cluster of symptoms could predict a diagnosis of CRPS 1.

Results

The sample included 187 patients (99 with CRPS 1 and 88 with MSK pain); 81% were female with a mean age 14.1 years. The most prevalent CRPS symptoms were hyperalgesia (54%) and allodynia (52%). A cluster of symptoms (hyperalgesia, color changes, and range of motion) predicted the probability of a diagnosis of CRPS 1.

Conclusions

A cluster of symptoms may be critical in differentiating pediatric CRPS 1 and MSK pain. Future research is needed to determine if this model is valid in external populations and to explore whether a similar model can differentiate CRPS 1 from other pain conditions (e.g., neuropathic pain).

Functional neurological symptom disorder: Preliminary findings of factors associated with walking ability post integrative pediatric rehabilitation

PURPOSE

The current study's aims were to (1) examine long-distance walking ability (6-minute walking test [6MWT]) and walking hemodynamic responses (i.e., heart rate) among youth with functional neurological symptom disorder (FNSD) before and after an integrative pediatric rehabilitation (IPR) program; and (2) explore factors predicting improvement in walking ability.

METHODS

Thirty-one youth with FNSD participating in an IPR program were recruited. The IPR program was activated biweekly in an ambulatory format. Study measures included the 6MWT, hemodynamic characteristics, rate of perceived exertion (RPE), pain-intensity perception, and Child's Somatization Inventory-24 (CSI-24). All measures were conducted upon admission to the IPR and discharge.

RESULTS

Findings indicated a significant increase in 6MWT distance, as well as decreases in heart rate, RPE, and pain-intensity perception from admission to discharge. At admission, CSI-24 and pain intensity predicted 6MWT distance (adjusted R2 = 0.68). Pain intensity predicted discharge 6MWT distance (adjusted R2 = 0.18). Initial 6MWT predicted changes in 6MWT distance from admission to discharge (adjusted R2 = 0.33).

CONCLUSION

Using an integrative rehabilitation approach increases walking distance and decreases pain-related symptoms in youth with FNSD, emphasizing the need for collaboration between physical therapists and pediatric psychologists. Moreover, changes in walking ability may increase participation and thus should be the focus of IPR.

Phenotyping peripheral neuropathic pain in male and female adolescents: pain descriptors, somatosensory profiles, conditioned pain modulation, and child-parent reported disability

ABSTRACT

Neuropathic pain (NeuP) can be difficult to diagnose and manage in children. Data regarding prevalence and sex-dependent differences are limited, and more detailed phenotyping is needed. This observational cohort study recruited adolescents (10-17 years) with NeuP or complex regional pain syndrome (CRPS). After pain history and NeuP questionnaires, quantitative sensory testing was performed. Individual z-score plots were calculated with body-region control measures and matched to mechanism-related sensory profiles (sensory loss, thermal hyperalgesia, and mechanical hyperalgesia). Conditioned pain modulation was assessed with pressure pain threshold and a contralateral cold conditioning stimulus, and meaningful conditioned pain modulation defined as twice the standard error of measurement. Patients and parents completed validated questionnaires for child quality of life (QoL), pain catastrophizing, and self-reported anxiety/depression. Males (n = 23) and females (n = 43) with NeuP (n = 52) or CRPS (n = 14) reported moderate-severe pain with neuropathic sensory descriptors. Mixed patterns of sensory gain/loss at pain sites were not sex-dependent. Thermal hyperalgesia was common in both NeuP and CRPS, whereas sensory loss occurred only with NeuP and in a smaller proportion than adult cohorts. Conditioned pain modulation was inhibitory in 54%, facilitatory in 14%, and nonresponders had variable cold conditioning sensitivity. Males and females reported marked impairment of QoL, increased emotional distress, and pain catastrophising. Child-parent QoL scores correlated, but catastrophizing scores were discordant when parents or adolescents reported higher anxiety/depression. NeuP in adolescents is associated with significant pain, physical impairment, and psychosocial impairment. Quantifying alterations in somatosensory profiles, descending modulation, child and parent psychological function will inform individualized therapy and stratification for future clinical trials.

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.

Outcome in young adults who were diagnosed with complex regional pain syndrome in childhood and adolescence

Supplemental Digital Content is Available in the Text.

Most patients with childhood-onset complex regional pain syndrome continue to have some complex regional pain syndrome–related pain into young adulthood and have a lower health-related quality of life.

Introduction:

Complex regional pain syndrome (CRPS) is a neuropathic pain condition of unknown etiology. Little is known of long-term outcomes of young adults who were diagnosed with CRPS as children.

Methods:

In this study, surveys were mailed to adults who were treated for childhood CRPS at the Lucile Packard Children's Hospital between 1994 and 2018. Completed surveys were analyzed for pain symptoms. Health-related quality-of-life surveys, the Optum SF-8, were analyzed based on norm-based scoring.

Results:

This study had a 50% response rate. Patients were treated with physical and occupational therapy, peripheral or sympathetic nerve blocks, medication for neuropathic pain, and psychotherapy. Sixty-eight percent of the subjects reported pain. Each 1-year increase in the patient's age at the time of CRPS diagnosis increased the odds of having at least mild pain as an adult by 61% (P = 0.005). Most patients had slightly lower quality-of-life scores than the US population average in both the mental component score (43.4, 95%, confidence interval 3.4) and the physical component score (44.4, 95%, confidence interval 3.3).

Conclusions:

Young adults in our sample had long-lasting pain symptoms. More than two-thirds of adult patients reported some degree of pain, and these patients had a lower quality of life. Encouraging was that the majority did not have CRPS spreading to other areas, and their pain did not warrant further treatment. Understanding long-term outcomes may lead to risk stratification earlier in the disease to improve future quality of life.

Hazard of complex regional pain syndrome following human papillomavirus vaccination among adolescent girls in the United States: a case-cohort analysis of insurance claims data

Objectives: Complex regional pain syndrome (CRPS) cases have followed human papillomavirus (HPV) vaccination, but no causal link has been established.Methods: Using insurance claims, the authors observed unvaccinated 11-year-old girls for CRPS diagnoses. The authors used time-dependent Cox regression to identify health-related CRPS predictors using diagnosis codes. Next, the authors identified HPV vaccinations using procedural codes. HPV vaccination and CRPS predictors were considered time-dependent covariates to estimated adjusted hazard ratios (HR) and 95% confidence intervals (CI) for CRPS, 30, 90, and 180-days post-vaccination.Results: 1,232,572 girls received 563 unique CRPS diagnoses. In a 10% sub-cohort of 123,981 girls accounting for potential confounders and predisposing risk factors (i.e. injury, infection, mental illness, primary care use), CRPS hazard was not significantly elevated 30 days (HR: 0.90, 95% CI: 0.46, 1.73), 90 days (HR: 1.17, 95% CI: 0.83, 1.65), or 180-days post-vaccination (HR: 1.11, 95% CI: 0.83, 1.47).Conclusion: The results support the safety and continued administration of HPV vaccines to adolescents.

Adolescents' experience of complex persistent pain

BACKGROUND AND AIMS

Persistent (chronic) pain is a common phenomenon in adolescents. When young people are referred to a pain clinic, they usually have amplified pain signals, with pain syndromes of unconfirmed ethology, such as fibromyalgia and complex regional pain syndrome (CRPS). Pain is complex and seems to be related to a combination of illness, injury, psychological distress, and environmental factors. These young people are found to have higher levels of distress, anxiety, sleep disturbance, and lower mood than their peers and may be in danger of entering adulthood with mental and physical problems. In order to understand the complexity of persistent pain in adolescents, there seems to be a need for further qualitative research into their lived experiences. The aim of this study was to explore adolescents' experiences of complex persistent pain and its impact on everyday life.

METHODS

The study has an exploratory design with individual in-depth interviews with six youths aged 12-19, recruited from a pain clinic at a main referral hospital in Norway. A narrative approach allowed the informants to give voice to their experiences concerning complex persistent pain. A hermeneutic analysis was used, where the research question was the basis for a reflective interpretation.

RESULTS

Three main themes were identified: (1) a life with pain and unpleasant bodily expressions; (2) an altered emotional wellbeing; and (3) the struggle to keep up with everyday life. The pain was experienced as extremely strong, emerging from a minor injury or without any obvious causation, and not always being recognised by healthcare providers. The pain intensity increased as the suffering got worse, and the sensation was hard to describe with words. Parts of their body could change in appearance, and some described having pain-attacks or fainting. The feeling of anxiety was strongly connected to the pain. Despair and uncertainty contributed to physical disability, major sleep problems, school absence, and withdrawal from leisure activities. Their parents were supportive, but sometimes more emotionally affected than themselves. The adolescents described how they strived for normality and to not become an outsider. Being met with necessary facilitation from school was important, as well as keeping up with friends. These adolescents had all been treated by an interdisciplinary pain team, and stated that they had an optimistic view of the future, despite still having some symptoms.

CONCLUSIONS

The study provides new insights into adolescents' own experiences of complex persistent pain occurring unexpectedly, developing dramatically over time, and influencing all parts of their everyday lives. The adolescents entered vicious cycles, with despair and decreased physical and social functioning, with the risk of isolation and role-loss. However, these young people seem to have a strong motivation to strive for normalcy.

IMPLICATIONS

These findings may encourage healthcare providers to perceive adolescents' persistent pain through the lenses of a biopsychosocial approach. We suggest that further research into adolescents with persistent pain should include longitudinal studies of quality of life and gender perspectives.

Neuropathic and Myopathic Pain

The evaluation and management of childhood pain syndromes of neuromuscular origin have distinct challenges, as the patterns of disease presentation and the ability of a child to describe symptoms may differ from that of an adult. Advances in scientific and clinical knowledge are leading to significant progress in the care of affected children. The genetic origins of Fabry disease and the inherited form of erythromelalgia are better understood. The increasing interest in neuroimmunology among pediatric neurologists has led to more sophisticated diagnostic and therapeutic approaches. Treatment protocols for complex regional pain syndrome have become more standardized. In addition, investigations continue into potential new interventions for metabolic muscle diseases such as McArdle disease and carnitine palmitoyl transferase deficiency type II. In the years to come, children with pain of neuromuscular origin will have access to more precise diagnostic tools and novel therapies that would alleviate this particularly distressing category of disease.

Complex regional pain syndrome

INTRODUCTION

Complex regional pain syndrome (CRPS) is a chronic pain condition that can occur after a minor trauma or surgery. It is a multifactorial condition with a complex cause and even more complex pathophysiology. There are disturbances and changes in the sympathetic, somatosensory and motor nervous system, resulting in severe pain and disability. Patients with CRPS can have their quality of life and functional ability greatly affected and they need appropriate and interdisciplinary interventions.

PURPOSE

This article contributes towards an up-to-date knowledge and an overall view of CRPS, which can contribute to a structured and systematic rehabilitation process for patients.

IMPLICATIONS

This Masterclass describes a functional restoration algorithm to assist therapists in the development of a treatment plan based on the available evidence and international guidelines. Early diagnosis and treatment is of great importance as patients (adults and children), can be severely affected in their functional capacity and quality of life.

Pediatric complex regional pain syndrome: a review

Complex regional pain syndrome (CRPS) is a chronic, intensified localized pain condition that can affect children and adolescents as well as adults, but is more common among adolescent girls. Symptoms include limb pain; allodynia; hyperalgesia; swelling and/or changes in skin color of the affected limb; dry, mottled skin; hyperhidrosis and trophic changes of the nails and hair. The exact mechanism of CRPS is unknown, although several different mechanisms have been suggested. The diagnosis is clinical, with the aid of the adult criteria for CRPS. Standard care consists of a multidisciplinary approach with the implementation of intensive physical therapy in conjunction with psychological counseling. Pharmacological treatments may aid in reducing pain in order to allow the patient to participate fully in intensive physiotherapy. The prognosis in pediatric CRPS is favorable.