Neurobiological antecedents of multisite pain in children

From fibrositis to fibromyalgia to nociplastic pain: how rheumatology helped get us here and where do we go from here?

Rheumatologists and rheumatology have had a prominent role in the conceptualisation of nociplastic pain since the prototypical nociplastic pain condition is fibromyalgia. Fibromyalgia had been previously known as fibrositis, until it became clear that this condition could be differentiatied from autoimmune disorders because of a lack of systemic inflammation and tissue damage. Nociplastic pain is now thought to be a third descriptor/mechanism of pain, in addition to nociceptive pain (pain due to peripheral damage or inflammation) and neuropathic pain. Nociplastic pain can occur in isolation, or as a co-morbidity with other mechanisms of pain, as commonly occurs in individuals with autoimmune disorders. We now know that the cardinal symptoms of nociplastic pain are widespread pain (or pain in areas not without evidence of inflammation/damage), accompanied by fatigue, sleep and memory issues. There is objective evidence of amplification/augmentation of pain, as well as of non-painful stimuli such as the brightness of lights and unpleasantness of sound or odors. Nociplastic pain states can be triggered by a variety of stressors such as trauma, infections and chronic stressors. Together these features suggest that the central nervous system (CNS) is playing a major role in causing and maintaining nociplastic pain, but these CNS factors may in some be driven by ongoing peripheral nociceptive input. The most effective drug therapies for nociplastic pain are non-opioid centrally acting analgesics such as tricyclics, serotonin-norepinephrine reuptake inhibitors and gabapentinoids. However the mainstay of therapy of nociplastic pain is the use of a variety of non-pharmacological integrative therapies, especially those which improve activity/exercise, sleep and address psychological co-morbidities.

Deciphering nociplastic pain: clinical features, risk factors and potential mechanisms

Nociplastic pain is a mechanistic term used to describe pain that arises or is sustained by altered nociception, despite the absence of tissue damage. Although nociplastic pain has distinct pathophysiology from nociceptive and neuropathic pain, these pain mechanisms often coincide within individuals, which contributes to the intractability of chronic pain. Key symptoms of nociplastic pain include pain in multiple body regions, fatigue, sleep disturbances, cognitive dysfunction, depression and anxiety. Individuals with nociplastic pain are often diffusely tender - indicative of hyperalgesia and/or allodynia - and are often more sensitive than others to non-painful sensory stimuli such as lights, odours and noises. This Review summarizes the risk factors, clinical presentation and treatment of nociplastic pain, and describes how alterations in brain function and structure, immune processing and peripheral factors might contribute to the nociplastic pain phenotype. This article concludes with a discussion of two proposed subtypes of nociplastic pain that reflect distinct neurobiological features and treatment responsivity.

Broadening the Scope of Resilience in Chronic Pain: Methods, Social Context, and Development

PURPOSE OF REVIEW

A wellspring of new research has offered varying models of resilience in chronic pain populations; however, resilience is a multifaceted and occasionally nebulous construct. The current review explores definitional and methodological issues in existing observational and clinical studies and offers new directions for future studies of pain resilience.

RECENT FINDINGS

Definitions of pain resilience have historically relied heavily upon self-report and from relatively narrow scientific domains (e.g., positive psychology) and in narrow demographic groups (i.e., Caucasian, affluent, or highly educated adults). Meta-analytic and systematic reviews have noted moderate overall quality of resilience-focused assessment and treatment in chronic pain, which may be attributable to these narrow definitions. Integration of research from affiliated fields (developmental models, neuroimaging, research on historically underrepresented groups, trauma psychology) has the potential to enrich current models of pain resilience and ultimately improve the empirical and clinical utility of resilience models in chronic pain.

Rheumatology and Long COVID: lessons from the study of fibromyalgia

Rheumatology, such as other subspecialties, has both a unique perspective to offer as well as an evolving role to play in the global COVID-19 pandemic. Our field has already contributed meaningfully to the development and repurposing of many of the immune-based therapeutics which are now standard treatments for severe forms of the disease as well as to the understanding of the epidemiology, risk factors and natural history of COVID-19 in immune-mediated inflammatory diseases. Still in evolution is our potential to contribute to burgeoning research efforts in the next phase of the pandemic: the syndrome of postacute sequelae of COVID-19 or Long COVID. While our field brings many assets to the study of Long COVID including our expertise in the investigation of chronic inflammation and autoimmunity, our Viewpoint focuses on the strong similarities between fibromyalgia (FM) and Long COVID. While one can speculate on how embracing and confident practising rheumatologists already are regarding these interrelationships, we assert that in the emerging field of Long COVID the potential lessons from the field of fibromyalgia care and research have been underappreciated and marginalised and most importantly now deserve a critical appraisal.

Is fibromyalgia an autoimmune disorder?

Fibromyalgia (FM) is a multifactorial syndrome which includes not only widespread pain and stiffness, now recognized as major symptoms, but also numerous other somatic, emotional, and neuropsychic manifestation. The lack of specific validated biological and instrumental biomarkers has made FM a condition of unexplained medical significance, and its pathophysiology remains controversial and subject to debate. The current hypothesis regarding the pathogenesis of FM proposes that its development is influenced by various mechanism, including genetic predisposition, stressful life events, inflammatory processes, and cognitive-emotional factors. However, despite the extensive research conducted to date, the available data do not provide a clear understanding of the pathogenesis of FM. In this article, we report the opposing viewpoints of two leading experts who debate the question of whether FM is an autoimmune disease, based on scientific data regarding this condition. Both perspectives are discussed and the latest evidence on the pathophysiology of FM is reported to provide a comprehensive understanding of this complex syndrome.

Pubertal development and pain incidence and characteristics in children: a 1-year prospective cohort study of a national sample

ABSTRACT

Sex differences in pain become apparent during puberty. However, the influence of key pubertal characteristics and pubertal hormones on pain is largely unknown. We examined the prospective associations between self-reported and hormone-indicated pubertal characteristics and pain incidence and severity in 10- to 11-year-old pain-free youth in the Adolescent Brain Cognitive Development (ABCD) Study over 1 year. Puberty was measured at baseline and follow-up with self-report (Pubertal Development Scale [PDS]) and hormonal assessment (salivary dehydroepiandrosterone [DHEA], testosterone, and estradiol). Pain status (yes/no), intensity, and interference (0-10 numerical rating scale) in the past month were self-reported at follow-up. Pubertal maturity, progression, and asynchrony were examined in relation to pain onset and severity through confounder-adjusted generalized estimating equations modified Poisson and linear mixed regression models. Among 6631 pain-free youth at baseline, 1-year incident pain was 30.7%. In both sexes, higher PDS scores were associated with greater risk of pain onset (relative risk [RR] = 1.10 to 1.27, P s < 0.01). In boys, higher PDS item variance was associated with greater pain incidence (RR = 1.11, 95% CI, 1.03-1.20) and interference (beta = 0.40, 95% CI, 0.03-0.76); higher PDS overall and gonadal scores were associated with higher pain intensity ( P s < 0.05). Associations with hormones were seen in boys only, with each 10-fold higher testosterone levels associated with a 40% lower risk of pain incidence (95% CI, -55% to -22%) and 1.30-point lower (95% CI, -2.12 to -0.48) pain intensity, and higher DHEA levels were associated with lower pain intensity ( P = 0.020). Relationships between pubertal development and pain in peripubertal adolescents are sex specific and puberty measurement specific and warrant further investigation.

Risk Factors for the Development of Multisite Pain in Children

OBJECTIVE

Chronic pain has economic costs on par with cardiovascular disease, diabetes, and cancer. Despite this impact on the health care system and increasing awareness of the relationship between pain and mortality, efforts to identify simple symptom-based risk factors for the development of pain, particularly in children, have fallen short. This is critically important as pain that manifests during childhood often persists into adulthood. To date, no longitudinal studies have examined symptoms in pain-free children that presage a new, multisite manifestation of pain in the future. We hypothesized that female sex, sleep problems, and heightened somatic symptoms complaints at baseline would be associated with the risk of developing new multisite pain 1 year later.

METHODS

Symptom assessments were completed by parents of youth (ages 9 to 10) enrolled in the Adolescent Brain Cognitive Development study. Multivariate logistic regression models focused on children who developed multisite pain 1 year later (n=331) and children who remained pain free (n=3335).

RESULTS

Female sex (odds ratio [OR]=1.35; 95% CI, 1.07, 1.71; P =0.01), elevated nonpainful somatic symptoms (OR=1.17; 95% CI, 1.06, 1.29; P <0.01), total sleep problems (OR=1.20; 95% CI, 1.07, 1.34; P <0.01), and attentional issues (OR=1.22; 95% CI, 1.10, 1.35; P <0.001) at baseline were associated with new multisite pain 1 year later. Baseline negative affect was not associated with new multisite pain.

DISCUSSION

Identifying symptom-based risk factors for multisite pain in children is critical for early prevention. Somatic awareness, sleep and attention problems represent actionable targets for early detection, treatment, and possible prevention of multisite pain in youth.

Identifying and Managing Nociplastic Pain in Individuals With Rheumatic Diseases: A Narrative Review

Chronic pain is a burdensome and prevalent symptom in individuals with rheumatic disease. The International Association for the Study of Pain classifies pain into 3 descriptive categories: nociceptive, neuropathic, and nociplastic. These categories are intended to provide information about the mechanisms underlying the pain, which can then serve as targets for drug or non-drug treatments. This review describes the 3 types of pain as they relate to patients seen by rheumatology health care providers. The focus is on identifying individuals with nociplastic pain, which can either occur in isolation as in fibromyalgia, or as a comorbidity in individuals with primary autoimmune conditions, such as rheumatoid arthritis and systemic lupus erythematosus. Practical information about how rheumatology health care providers can approach and manage chronic pain is also provided.

Pain Management in Pediatric Burns: A Review of the Science behind It

Pediatric burns are a significant medical issue that can have long-term effects on various aspects of a child's health and well-being. Pain management in pediatric burns is a crucial aspect of treatment to ensure the comfort and well-being of young patients. The causes and risk factors for pediatric burns vary depending on various factors, such as geographical location, socioeconomic status, and cultural practices. Assessing pain in pediatric patients, especially during burn injury treatment, poses several challenges. These challenges stem from various factors, including the age and developmental stage of the child, the nature of burn injuries, and the limitations of pain assessment tools. In pediatric pain management, various pain assessment tools and scales are used to evaluate and measure pain in children. These tools are designed to account for the unique challenges of assessing pain in pediatric patients, including their age, developmental stage, and ability to communicate effectively. Pain can have significant physical, emotional, and psychological consequences for pediatric patients. It can interfere with their ability to engage in daily activities, disrupt sleep patterns, and negatively affect their mood and behavior. Untreated pain can also lead to increased stress, anxiety, and fear, which can further exacerbate the pain experience. Acute pain, which is short-term and typically associated with injury or illness, can disrupt a child's ability to engage in physical activities and impede their overall recovery process. On the other hand, chronic pain, which persists for an extended period, can have long-lasting effects on physical functioning and quality of life in children. The psychological consequences of burns can persist long after the physical wounds have healed, leading to ongoing emotional distress and impaired functioning. Multimodal pain management, which involves the use of multiple interventions or medications targeting different aspects of the pain pathway, has gained recognition as an effective approach for managing pain in both children and adults. However, it is important to consider the specific needs and considerations of pediatric patients when developing evidence-based guidelines for multimodal pain management in this population. Over the years, there have been significant advances in pediatric pain research and technology, leading to a better understanding of pain mechanisms and the development of innovative approaches to assess and treat pain in children. Overall, pain management in pediatric burns requires a multidisciplinary approach that combines pharmacologic and nonpharmacologic interventions.

Neurophysiological and Psychosocial Mechanisms of Fibromyalgia: A Comprehensive Review and Call for An Integrative Model

Research into the neurobiological and psychosocial mechanisms involved in fibromyalgia has progressed remarkably in recent years. Despite this, current accounts of fibromyalgia fail to capture the complex, dynamic, and mutual crosstalk between neurophysiological and psychosocial domains. We conducted a comprehensive review of the existing literature in order to: a) synthesize current knowledge on fibromyalgia; b) explore and highlight multi-level links and pathways between different systems; and c) build bridges connecting disparate perspectives. An extensive panel of international experts in neurophysiological and psychosocial aspects of fibromyalgia discussed the collected evidence and progressively refined and conceptualized its interpretation. This work constitutes an essential step towards the development of a model capable of integrating the main factors implicated in fibromyalgia into a single, unified construct which appears indispensable to foster the understanding, assessment, and intervention for fibromyalgia.

Fibromyalgia and centralized pain in the rheumatoid arthritis patient

PURPOSE OF REVIEW

Individuals with rheumatoid arthritis (RA) have traditionally been characterized as having nociceptive pain, leading to the assumption that effective immunosuppression should be enough to provide effective pain management. However, despite therapeutic advancements providing excellent control of inflammation, patients continue to have significant pain and fatigue. The presence of concurrent fibromyalgia, driven by augmented central nervous system processing and largely unresponsive to peripheral therapies, may contribute to this pain persistence. This review provides updates on fibromyalgia and RA as relevant for the clinician.

RECENT FINDINGS

Patients with RA have high levels of concomitant fibromyalgia and nociplastic pain. The presence of fibromyalgia can lead to higher scores on disease measures, erroneously indicating that worse disease is presently leading to the increased use of immunosuppressives and opioids. Disease scores that provide a comparison between patient-reported and provider-reported and clinical factors may be helpful to indicate centralized pain. IL-6 and Janus kinase inhibitors, in addition to targeting peripheral inflammation, may provide pain relief by acting on peripheral and central pain pathways.

SUMMARY

Central pain mechanisms that may be contributing to pain in RA are common and should be distinguished from pain directly arising from peripheral inflammation.

The Psychosocial Characteristics and Somatosensory Function of Children and Adolescents Who Meet the Criteria for Chronic Nociplastic Pain

Purpose

Nociplastic pain distinguishes individuals with pain and hypersensitivity in body regions with apparently normal tissues, without any signs of neuropathy, but with contribution of central and/or peripheral sensitization. There is a lack of literature describing nociplastic pain in the pediatric population. The objective of this study was to investigate the differences between pediatric patients with nociplastic pain compared with patients with non-nociplastic pain.

Patients and Methods

This study included 414 pediatric patients followed at an interdisciplinary centre for complex pain. All patients underwent an exhaustive pain assessment consisting of face-to-face interviews, validated self-report questionnaires and quantitative sensory testing. Recently established criteria for chronic nociplastic pain, and quantitative sensory testing was used to describe and stratify our cohort.

Results

One hundred and sixty-five patients (40%) were stratified as having possible nociplastic pain and two hundred and forty-nine (60%) patients, as non-nociplastic pain. Patients with nociplastic pain displayed pain hypersensitivity in the region of pain, more symptoms of panic and social phobia, and worse sleep quality than patients with non-nociplastic pain. The proportion of patients achieving a meaningful clinical outcome after completion of their treatment (medications, physiotherapy, psychology, nursing, social worker, and/or interventional procedures) was lower in patients with nociplastic pain (62%) than those without nociplastic pain (86%).

Conclusion

Our results suggest that patients who meet the criteria for nociplastic pain can be identified in a population of children and adolescents being treated in a center for complex pain. Combining screening with validated questionnaires and quantitative sensory testing facilitates the phenotyping and graded severity of patients with nociplastic pain in daily clinical practice.

Back Pain without Disease or Substantial Injury in Children and Adolescents: A Twin Family Study Investigating Genetic Influence and Associations

This twin family study first aimed to investigate the evidence for genetic factors predicting the risk of lifetime prevalence of non-specific low back pain of at least three months duration (LBP (life)) and one-month current prevalence of thoracolumbar back pain (TLBP (current)) using a study of children, adolescents, and their first-degree relatives. Secondly, the study aimed to identify associations between pain in the back with pain in other regions and also with other conditions of interest. Randomly selected families (n = 2479) with child or adolescent twin pairs and their biological parents and first siblings were approached by Twins Research Australia. There were 651 complete twin pairs aged 6-20 years (response 26%). Casewise concordance, correlation, and odds ratios were compared for monozygous (MZ) and dizygous (DZ) pairs to enable inference about the potential existence of genetic vulnerability. Multivariable random effects logistic regression was used to estimate associations between LBP (life) or TLBP (current) as an outcome with the potentially relevant condition as predictors. The MZ pairs were more similar than the DZ pairs for each of the back pain conditions (all p values < 0.02). Both back pain conditions were associated with pain in multiple sites and with primary pain and other conditions using the combined twin and sibling sample (n = 1382). Data were consistent with the existence of genetic influences on the pain measures under the equal environments assumption of the classic twin model and associations with both categories of back pain were consistent with primary pain conditions and syndromes of childhood and adolescence which has research and clinical implications.

Emotion regulation and the salience network: a hypothetical integrative model of fibromyalgia

Fibromyalgia is characterized by widespread pain, fatigue, sleep disturbances and other symptoms, and has a substantial socioeconomic impact. Current biomedical and psychosocial treatments are unsatisfactory for many patients, and treatment progress has been hindered by the lack of a clear understanding of the pathogenesis of fibromyalgia. We present here a model of fibromyalgia that integrates current psychosocial and neurophysiological observations. We propose that an imbalance in emotion regulation, reflected by an overactive 'threat' system and underactive 'soothing' system, might keep the 'salience network' (also known as the midcingulo-insular network) in continuous alert mode, and this hyperactivation, in conjunction with other mechanisms, contributes to fibromyalgia. This proposed integrative model, which we term the Fibromyalgia: Imbalance of Threat and Soothing Systems (FITSS) model, should be viewed as a working hypothesis with limited supporting evidence available. We hope, however, that this model will shed new light on existing psychosocial and biological observations, and inspire future research to address the many gaps in our knowledge about fibromyalgia, ultimately stimulating the development of novel therapeutic interventions.

Changes in Degree Centrality and Functional Connectivity after the First Cycle of Neoadjuvant Chemotherapy in Newly Diagnosed Breast Cancer: A Longitudinal Study

Purpose

To evaluate the longitudinal changes of brain degree centrality (DC) and functional connectivity (FC) in breast cancer patients after the first cycle of neoadjuvant chemotherapy (NAC).

Methods

Thirty-five breast cancer patients were included in the NAC group. Resting-state functional magnetic resonance imaging (rs-fMRI) and neuropsychological test were performed at baseline before NAC (time point 0, TP0) and after the first cycle of NAC (time point 1, TP1). The healthy controls (HC) included 30 healthy subjects and received the same rs-fMRI scan and neuropsychological test as the above-mentioned NAC group at one time point. DC and FC analyses were conducted to assess brain connectivity of all participants. Receiver operating characteristic (ROC) curve was used to assess the ability of DC and FC in distinguishing patients before and after chemotherapy.

Results

In the NAC group, the Self-Rating Anxiety Scale scores decreased significantly over time. At TP0 and TP1, the Digital Span Test forward score of the NAC group was significantly lower than that of the HC group. In the NAC group, DC in the right middle frontal gyrus and left precentral gyrus/middle frontal gyrus decreased significantly at TP1, and FC between the left precentral gyrus/middle frontal gyrus and bilateral precuneus was significantly reduced at TP1. Through ROC analysis, we found that the area under the curve (AUC) of DC, FC, and the combined model in distinguishing patients in TP0 or TP1 was 0.7886, 0.7665, and 0.8278, respectively.

Conclusions

Brain connectivity, involving executive and motor function related brain areas, changes in the short term after NAC treatment in breast cancer patients.