Decreased Pain Threshold in Juvenile Idiopathic Arthritis: A Cross-sectional Study

Impact of Musculoskeletal Pain on Functioning and Disability in Children with Juvenile Idiopathic Arthritis in Iceland

AIMS

1) to map questions of pain from a survey to the International Classification of Functioning, Disability and Health (ICF) 2) to compare the impact of musculoskeletal pain on functioning based on the different components of the ICF in children with juvenile idiopathic arthritis (JIA) and age-matched peers.

METHOD

A cross-sectional case-control survey. A total of 28 children with JIA and 36 age-matched children participated. The survey included questions on the child's sex and age, about pain experienced, number of painful body areas, pain frequency and three short forms of Patient-Reported Outcome Measurement Information System (PROMIS) pain questionnaires. Sixteen children with JIA (57%) and 10 peers (28%) reported pain during past seven days. Their responses were used in the description of impact of pain.

RESULTS

After the mapping of the questions to ICF, a comparison between the two groups indicated that a higher number of children with JIA described effects of pain on mental function, mobility, general tasks and demands, than their peers. More children with JIA expressed to others that they had pain, non-verbally and verbally.

CONCLUSION

The findings provide important information about the impacts of pain on daily life in children with JIA and about their intervention needs.

Pain history and experimental pressure pain responses in adolescents: Results from a population-based birth cohort

BACKGROUND

Sensitized pain mechanisms are often reported in musculoskeletal pain conditions, but population-based paediatric studies are lacking. We assessed whether adolescents with musculoskeletal pain history had evidence of increased responsiveness to experimental pressure stimuli.

METHODS

Data were from 1496 adolescents of the Generation XXI birth cohort. Pain history was collected using the Luebeck Pain Questionnaire (self-reported at 13, parent-reported at 7 and 10 years). Two case definitions for musculoskeletal pain were considered: (1) cross-sectional-musculoskeletal pain lasting more than 3 months at age 13 and (2) longitudinal-musculoskeletal pain at age 13 with musculoskeletal pain reports at ages 7 and/or 10. Lower limb cuff pressure algometry was used to assess pain detection and tolerance thresholds, conditioned pain modulation effects (CPM, changes in thresholds in the presence on painful conditioning) and temporal summation of pain effects (TSP, changes in pain intensity to 10 phasic painful cuff stimulations).

RESULTS

Adolescents with musculoskeletal pain at age 13 plus a history of pain in previous evaluations (longitudinal definition) had lower pain tolerance thresholds compared to the remaining sample (40.2 v. 49.0 kPa, p = 0.02), but showed no differences in pain detection threshold, CPM effect and TSP effect. Pain sensitivity, CPM effects and TSP effects were not significantly different when the current pain only case definition (cross-sectional) was used.

CONCLUSIONS

Adolescents with current musculoskeletal pain who had a history of pain since childhood had lower tolerance to cuff stimulation. This may suggest long-standing musculoskeletal pain since childhood may contribute to sensitisation, rather than the presence of current pain only.

SIGNIFICANCE

Repeated musculoskeletal pain up to age 13 years may contribute to higher pain sensitivity (particularly lowered pressure pain tolerance) in the general adolescent population. This does not seem to be the case when reported pain experiences are recent or when the outcomes are temporal pain summation or CPM. In this community-based paediatric sample, the vast majority showed no sign of altered pain processing, but a small fraction may reveal some pain sensitization at 13 years of age.

Significant pain decrease in children with non-systemic Juvenile Idiopathic Arthritis treated to target: results over 24 months of follow up

BACKGROUND

The aim of this study was to compare pain-scores in three targeted treatment-strategies in JIA-patients and to identify characteristics predicting persistent pain.

METHODS

In the BeSt-for-Kids-study 92 DMARD-naïve JIA-patients were randomized in 3 treatment-strategies: 1) initial sequential DMARD-monotherapy 2) initial methotrexate (MTX)/prednisolone-bridging or 3) initial MTX/etanercept. Potential differences in VAS pain scores (0-100 mm) over time between treatment-strategies were compared using linear mixed models with visits clustered within patients. A multivariable model was used to assess the ability of baseline characteristics to predict the chance of high pain-scores during follow-up.

RESULTS

Pain-scores over time reduced from mean 55.3 (SD 21.7) to 19.5 (SD 25.3) mm after 24 months. On average, pain-scores decreased significantly with β -1.37 mm (95% CI -1.726; -1.022) per month. No significant difference was found between treatment-strategies (interaction term treatment arm*time (months) β (95% CI) arm 1: 0.13 (-0.36; 0.62) and arm 2: 0.37 (-0.12; 0.86) compared to arm 3). Correction for sex and symptom duration yielded similar results. Several baseline characteristics were predictive for pain over time. Higher VAS pain [β 0.44 (95% CI 0.25; 0.65)] and higher active joint count [0.77 (0.19; 1.34)] were predictive of higher pain over time, whereas, low VAS physician [ -0.34 (-0.55; -0.06)], CHQ Physical [ -0.42 (-0.72; -0.11)] and Psychosocial summary Score [ -0.42 (-0.77; -0.06)] were predictive of lower pain.

CONCLUSIONS

Treatment-to-target seems effective in pain-reduction in non-systemic JIA-patients irrespective of initial treatment-strategy. Several baseline-predictors for pain over time were found, which could help to identify patients with a high risk for development of chronic pain.

TRIAL REGISTRATION

Dutch Trial Registry number 1574.

An explorative study on proteomic analyses related to inflammation and pain in children with juvenile idiopathic arthritis

BACKGROUND

Our aim was attempting to find proteins involved in the pain process and correlating with pain but not degree of inflammation in children with juvenile idiopathic arthritis (JIA), using a proteomics panel.

METHODS

A total of 87 plasma samples were collected from 51 children with JIA (51 at diagnosis in a higher disease activity state, 18 at follow-up in a lower disease activity state) and 18 healthy controls. Relative levels of 92 proteins related to a wide range of biological processes in inflammation were obtained using a proximity extension assay panel. Comparisons between children with and without JIA, in different disease categories, by juvenile disease activity score (JADAS27) and degree of pain on a visual analogue scale (VAS), were performed using parametric and non-parametric statistical methods.

RESULTS

Nineteen proteins involved in arthritic inflammation, such as interleukin 6 (IL-6) and S100 protein A12, were higher in patients with JIA than controls, seven decreased significantly during treatment, and 18 correlated significantly with JADAS27. Three proteins correlated with pain VAS scores in unadjusted analyses: the glial cell line-derived neurotrophic factor (GDNF), transforming growth factor beta, and IL-18R1. Levels of GDNF correlated significantly with pain VAS scores but not with JADAS27.

CONCLUSIONS

Plasma levels of 18 of 92 tested proteins correlated with degree of disease activity. Levels of three proteins correlated with pain, and levels of one, GDNF, originating from neural cells, correlated with pain without correlating with inflammatory degree, suggesting that it may play a role in pain in JIA. Further studies in larger cohorts are warranted.

The relationships of kinesiophobia and physical function and physical activity level in juvenile idiopathic arthritis

BACKGROUND

Kinesiophobia may hinder physical performance measures and functional quality of life in children with juvenile idiopathic arthritis (JIA). This study aims to quantify differences in physical function in patients with JIA compared to healthy controls, and determine the effects of kinesiophobia on physical function and physical activity.

METHODS

This was a comparative study of participants with JIA and healthy controls (JIA n = 26, control n = 17). All children with JIA had lower extremity joint involvement. Performance-based measures included gait speed, chair and stair navigation performance. Self-reported measures included Patient Reported Outcome Measurement Information System (PROMIS®) Physical Function Mobility, and Pain Interference and the Pediatric Functional Activity Brief Scale (Pedi-FABS). The Tampa Scale of Kinesiophobia (TSK-11) assessed patient fear of movement due to pain. Linear regression models were used to determine the contribution of TSK-11 scores on performance test and Pedi-FABS scores.

RESULTS

Gait speeds were 11-15% slower, chair rise repetitions were 28% fewer, and stair ascent and descent times were 26-31% slower in JIA than controls (p < .05). PROMIS® Physical Function Mobility scores were 10% lower and Pain Interference scores were 2.6 times higher in JIA than healthy controls (p = .003). TSK-11 scores were higher in JIA than controls (p < .0001). After controlling for covariates, TSK-11 scores explained 11.7-26.5% of the variance of regression models for stair climb time, chair rise performance and Pedi-FABS scores (p < .05).

CONCLUSIONS

Children with JIA experience difficulty with tasks related to body transfers. Kinesiophobia is a significant contributor to the functional task performance and may impact clinical outcomes.

Musculoskeletal pain and its effect on daily activity and behaviour in Icelandic children and youths with juvenile idiopathic arthritis: a cross-sectional case-control study

BACKGROUND

Juvenile idiopathic arthritis is characterised by recurring episodes of acute inflammation, with joint swelling in one or more joints, often accompanied by pain. These episodes can now be controlled better than in the past because of a new category of medications. However, despite more stable disease activity, pain may continue to cause problems in the children with juvenile idiopathic arthritis and can reduce their performance of routine physical activities and participation in social or school activities.

AIM

To evaluate the prevalence of pain, pain intensity, pain behaviour, and pain interference in Icelandic children with juvenile idiopathic arthritis compared with healthy peers.

METHODS

A cross-sectional, case-control study including 8-18 years old children; 28 with juvenile idiopathic arthritis and 36 in a control group. The children answered questions on pain experienced during the last 7 days, painful areas of the body and pain frequency. They completed short form versions of the Patient-Reported Outcome Measurement Information System (PROMIS) questionnaires on pain intensity, pain behaviour, and pain interference.

RESULTS

Significantly more children with juvenile idiopathic arthritis had pain compared with the control group (p = 0.02). Children with JIA also had a greater number of painful body areas (p = 0.03), more pain intensity (p = 0.009), and showed more pain behaviour (p = 0.006), and pain interference (p = 0.002). Children with juvenile idiopathic arthritis who had pain, experienced more pain interference (p = 0.023) than their peers who had pain. However, the groups did not differ in terms of pain intensity (p = 0.102) and pain behaviour (p = 0.058).

CONCLUSION

The research results indicate that pain experience was different between children with juvenile idiopathic arthritis and the control group. The results suggest that further research of the role of pain management on functional outcomes in children with juvenile idiopathic arthritis is needed.

The Brain Structural-Functional Vulnerability in Drug-Naive Children With Juvenile Idiopathic Arthritis: Insights From the Hippocampus

Objective

Leveraging an integrative multimodal MRI paradigm to elaborate on the hippocampus-derived structural and functional changes in children and adolescents with juvenile idiopathic arthritis (JIA) and to explore potential correlations within the “joint-inflammation-brain” axis during the period of central neural system (CNS) development.

Methods

Twenty-one patients with JIA all completed the multimodal MRI scanning, laboratory tests, and neuropsychological assessments; meanwhile, 23 matched controls were recruited. We then harnessed the spherical harmonics with a point distribution model (SPHARM-PDM) and the ROI-to-voxel functional connectivity (FC) to measure the hippocampal shape and hippocampo-cortical FC patterns. Correlation analysis was performed to explore the potential links in neuroimaging features with disease-related indices.

Results

Compared to controls, JIA patients only presented an atrophic tendency in the posterior part of the bilateral hippocampus. The hippocampo-cortical FC revealed the between-group divergences mainly located at the pain matrix, striatum, and temporal lobe. Remarkably, the enhanced FC between the right hippocampus and postcentral cortex is positively correlated with the disability index, while the weakened FC of right anterior hippocampus with right insula and that of left posterior hippocampus with left superior temporal gyrus was inversely related to the erythrocyte sedimentation rate and anxiety status, separately.

Conclusion

As with macroscopic damages, the altered functional-connectome patterns of the hippocampus in JIA patients might be more sensitive to detect the early neuropathological changes. Moreover, the functional disturbances were demonstrated associated with the physical disability, inflammation, and emotional status. These findings may enlighten us on the underlying neuropathological mechanism of CNS comorbidities in JIA.

Pain pressure thresholds in children and adolescents with idiopathic chest pain

OBJECTIVES

The pathophysiology of idiopathic chest pain remains unclear. Studies evaluating pain pressure thresholds in other idiopathic pain syndromes have revealed pain sensitivity in both affected and unaffected areas. The present study aimed to evaluate thoracic and extrathoracic pain pressure thresholds and their correlation with patients' pain characteristics and quality of life.

METHODS

This cross-sectional, single-blind, controlled study included children and adolescents with idiopathic chest pain. The patients' pain characteristics, including their symptom duration, type of pain, mean pain intensity, mean duration of painful periods, pain frequency, and Pediatric Quality of Life Inventory Child Version scores, were assessed by a paediatric cardiologist via a face-to-face interview. Pain pressure thresholds were measured using an algometer by an algologist who was blinded to the study groups.

RESULTS

There was a statistically significant difference in pain pressure thresholds in the trapezius; supraspinatus; thoracic 2, 4, and 10 areas; deltoid; and tibia between the patient and healthy control groups. In the patient group, while there was a positive correlation between the mean all-region pain pressure thresholds and age (p = 0.047, r = 0.235), there was no correlation between pain pressure thresholds and symptom duration, pain intensity, and quality of life.

CONCLUSION

The present study is the first step towards investigating probable pain sensitivity mechanisms in children and adolescents with idiopathic chest pain. We noted lower thoracic and extrathoracic pain pressure thresholds in children and adolescents with idiopathic chest pain than in healthy controls.

Altered sensory innervation and pain hypersensitivity in a model of young painful arthritic joints: short- and long-term effects

BACKGROUND

Early life experience can cause long-term alterations in the nociceptive processes underlying chronic pain, but the consequences of early life arthritic joint inflammation upon the sensory innervation of the joint is not known. Here, we measure pain sensitivity and sensory innervation in a young, juvenile and adult rodent model of arthritic joints and test the consequences of joint inflammation in young animals upon adult arthritic pain and joint innervation.

METHODS

Unilateral ankle joint injections of complete Freund's adjuvant (CFA) (6-20 µl) were performed in young, postnatal day (P)8, adolescent (P21) and adult (P40) rats. A separate cohort of animals were injected at P8, and again at P40. Hindpaw mechanical sensitivity was assessed using von Frey monofilaments (vF) for 10 days. Nerve fibres were counted in sections through the ankle joint immunostained for calcitonin gene-related peptide (CGRP) and neurofilament 200 kDa (NF200).

RESULTS

Ankle joint CFA injection increased capsular width at all ages. Significant mechanical pain hypersensitivity and increased number of joint CGRP + ve sensory fibres occurred in adolescent and adult, but not young, rats. Despite the lack of acute reaction, joint inflammation at a young age resulted in significantly increased pain hypersensitivity and CGRP+ fibre counts when the rats were re-inflamed as adults.

CONCLUSIONS

Joint inflammation increases the sensory nociceptive innervation and induces acute pain hypersensitivity in juvenile and adult, but not in young rats. However, early life joint inflammation 'primes' the joint such that adult inflammatory pain behaviour and nociceptive nerve endings in the joint are significantly increased. Early life joint inflammation may be an important factor in the generation and maintenance of chronic arthritic pain.

Pain sensitivity in young adults with juvenile idiopathic arthritis: a quantitative sensory testing study

BACKGROUND

To study for the first-time, pain perception, pain sensitivity, and self-reported pain in young adults with long disease duration of juvenile idiopathic arthritis (JIA) compared with controls.

METHODS

Children from Central Norway diagnosed with JIA between 1997 and 2004 were included consecutively in a population-based prospective study. Children with onset 1997-2000 were part of the Nordic JIA cohort. Controls were age- and sex-matched. In 2015-2017, study visits with investigator-blinded quantitative sensory testing (QST) comprising cold and warm detection thresholds (CDT/WDT), cold and heat pain thresholds (CPT/HPT), pressure pain threshold (PPT), and a suprathreshold heat pain test were performed. We constructed separate multilevel models for each variable of detection and pain thresholds with interaction between groups and site adjusted for the effect of age and sex.

RESULTS

Among 96 young adults with JIA, 71% were female, median age was 22.7 years, disease duration was 16.1 years, and 47% had oligoarticular disease. Among 109 controls, 71% were female, and median age was 23.5 years. Participants with JIA had lower pressure pain thresholds (PPTs) (95% CI) compared to controls, upper limb 888 (846,930) versus 1029 (999,1059) kPa and lower limb 702 (670,734) versus 760 (726,794) kPa. Participants with inactive disease had the lowest PPTs and cold pain thresholds (CPTs), compared to those in remission off medication and those with active disease. Minor differences were found regarding CDT/WDT and CPT/HPT in JIA compared to controls. The median (IQR) temperature needed to evoke pain = 6 on a 0-10 numeric rating scale (NRS) in the suprathreshold heat pain tests were lower in JIA than in controls (46 °C (45-47 °C) versus 47 °C (46-48 °C)). We found no associations between self-reported pain and pain thresholds.

CONCLUSIONS

Our results indicate for the first time that young adults with long disease duration of JIA may have altered pain perception and sensitivity compared to controls. A clinical implication may be the importance of early treatment to quickly achieve pain-free remission and avoid long-term pain sensitization.

Spinal interleukin-6 contributes to central sensitisation and persistent pain hypersensitivity in a model of juvenile idiopathic arthritis

Pain is the most debilitating symptom in juvenile idiopathic arthritis. As pain correlates poorly to the extent of joint pathology, therapies that control joint inflammation are often inadequate as analgesics. We test the hypothesis that juvenile joint inflammation leads to sensitisation of nociceptive circuits in the central nervous system, which is maintained by cytokine expression in the spinal cord. Here, transient joint inflammation was induced in postnatal day (P)21 and P40 male Sprague-Dawley rats with a single intra-articular ankle injection of complete Freund's adjuvant. Hindpaw mechanical pain sensitivity was assessed using von Frey hair and weight bearing tests. Spinal neuron activity was measured using in vivo extracellular recording and immunohistochemistry. Joint and spinal dorsal horn TNFα, IL1β and IL6 protein expression was quantified using western blotting. We observed greater mechanical hyperalgesia following joint inflammation in P21 compared to P40 rats, despite comparable duration of swelling and joint inflammatory cytokine levels. This is mirrored by spinal neuron hypersensitivity, which also outlasted the duration of active joint inflammation. The cytokine profile in the spinal cord differed at the two ages: prolonged upregulation of spinal IL6 was observed in P21, but not P40 rats. Finally, spinal application of anti-IL-6 antibody (30 ng) reduced the mechanical hyperalgesia and neuronal activation. Our results indicate that persistent upregulation of pro-inflammatory cytokines in the spinal dorsal horn is associated with neuronal sensitisation and mechanical hyperalgesia in juvenile rats, beyond the progress of joint pathology. In addition, we provide proof of concept that spinal IL6 is a key target for treating persistent pain in JIA.

Association of Anxiety With Pain and Disability but Not With Increased Measures of Inflammation in Adolescent Patients With Juvenile Idiopathic Arthritis

Objective

To explore whether anxiety and depression are associated with clinical measures of disease for adolescent patients with juvenile idiopathic arthritis (JIA) and whether anxiety and depression are associated with increased peripheral proinflammatory cytokine levels in adolescent patients with JIA and in healthy adolescent controls.

Methods

A total of 136 patients with JIA and 88 healthy controls ages 13–18 years completed questionnaires on anxiety and depressive symptoms. For patients with JIA, pain, disability, physician global assessment (using a visual analog scale [VAS]), and number of joints with active inflammation (active joint count) were recorded. In a subsample, we assessed lipopolysaccharide‐stimulated interleukin 6 (IL‐6) production from peripheral blood mononuclear cells, serum IL‐6, cortisol, and C‐reactive protein levels. Data were analyzed by linear regression analysis.

Results

Levels of anxiety and depressive symptoms in patients with JIA were not significantly different than those in healthy controls. For patients with JIA, anxiety was significantly associated with disability (β = 0.009, P = 0.002), pain (β = 0.029, P = 0.011), and physician global assessment VAS (β = 0.019, P = 0.012), but not with active joint count (β = 0.014, P = 0.120). Anxiety was not associated with any laboratory measures of inflammation for JIA patients. These relationships were also true for depressive symptoms. For healthy controls, there was a trend toward an association of anxiety (but not depressive symptoms) with stimulated IL‐6 (β = 0.004, P = 0.052).

Conclusion

Adolescent patients with JIA experience equivalent levels of anxiety and depressive symptoms as healthy adolescents. For adolescent patients with JIA, anxiety and depressive symptoms are associated with pain, disability, and physician global assessment VAS, but not with inflammation.

The pain trajectory of juvenile idiopathic arthritis (JIA): translating from adolescent patient report to behavioural sensitivity in a juvenile animal model

BACKGROUND

While pain is a common symptom in JIA patients, it remains unclear why some JIA patients develop ongoing or persistent pain. Complex clinical and social settings confound analysis of individual factors that may contribute to this pain. To address this, we first undertook a retrospective analysis of pain reports in a JIA patient cohort with the aim of identifying potential factors contributing to persistent pain. We then carried out an experimental laboratory study, using joint inflammatory pain behaviour in rodents, to validate the role of these factors in the onset of persistent pain under controlled conditions.

METHODS

Patients: Retrospective analysis of anonymised pain visual analogue scale (VAS) scores and accompanying clinical scores from 97 JIA patients aged 13-19 (mean: 16.40 ± 1.21) collected over 50 weeks. Rats: Experimental study of pain behaviour following intra-articular microinjection of complete Freund's adjuvant (CFA) in adolescents (n = 25) and young adults (n = 43). Some animals (n = 21) had been previously exposed to joint inflammation in infancy or adolescence.

RESULTS

Patients: Cluster analysis of patient pain VAS scores revealed three trajectories over 50 weeks: consistently low pain (n = 45), variable pain (n = 30) and persistently high pain (n = 22). Number of actively inflamed joints did not differ in the three groups. High pain at a single visit correlated with greater physician global assessment of disease activity, while a high pain trajectory over 50 weeks was associated with more limited joints but fewer actively inflamed joints. Rats: Rodents administered ankle joint CFA also exhibit low, medium and high joint pain sensitivities, independent of joint inflammation. Prolonged inflammatory pain behaviour was associated with high background pain sensitivity, following joint inflammation at an earlier stage in life.

CONCLUSIONS

Both JIA patients and rodents differ in their individual pain sensitivity independent of the concurrent joint inflammation. Using experimental animal models allows us to isolate physiological factors underlying these differences, independently of social or clinical factors. The results suggest that a history of prior arthritic activity/joint inflammation may contribute to high pain sensitivity in adolescents with JIA.

Hyperexcitability of the Central Nervous System in Children with Chronic Pain: A Systematic Review

Objective

Hyperexcitability of the central nervous system plays an important role in the development and maintenance of chronic pain in adults. This knowledge has led to improved treatment strategies within this population. In children, however, research on the presence of central hyperexcitability is scarce. To further investigate this topic in children with chronic pain, there is a need for a clear literature overview.

Design

Systematic review.

Methods

The literature search was performed using the electronic databases PubMed and Web of Science. An article was considered eligible if it included children (age two to 12 years) diagnosed with chronic pain. Articles had to report original research outcomes related to central hyperexcitability, and a comparison with a healthy control group was necessary. Characteristics of the study sample, the assessment, and conclusions regarding central hyperexcitability were extracted from each included article.

Results

Twelve case-control studies were included with moderate to good methodological quality (510 children with chronic pain and 670 healthy controls). After summarizing the articles' results on indices of central hyperexcitability, we concluded that secondary hyperalgesia might be present in children with recurrent abdominal pain, juvenile fibromyalgia, and juvenile idiopathic arthritis. Preliminary evidence exists for altered cortical nociceptive processing in children with migraine and recurrent abdominal pain.

Conclusion

Based on the results of this review, central hyperexcitability might be present in in several pediatric chronic pain conditions. Further research on other manifestations of central hyperexcitability (e.g., bottom-up and top-down mechanisms and nociceptive brain changes) is necessary to provide firm evidence about its presence in children with chronic pain.

Physical activity and sedentary levels in children with juvenile idiopathic arthritis and inflammatory bowel disease. A systematic review and meta-analysis

BACKGROUND

Physical activity (PA) is essential for children throughout their growth and maturation. It improves physiological and psychological health and limits the risk of developing metabolic disorders. However, some chronic physiological and metabolic diseases may lead to decreased PA. The diversity of outcomes in the literature offers no consensus for physical activity and sedentary levels in children with juvenile idiopathic arthritis (JIA) or inflammatory bowel disease (IBD).

METHODS

A literature review and a meta-analysis were carried out with original studies from a Medline database search. Only high-quality studies (STROBE checklist) written in English comparing PA level or sedentary behavior (SB) between children with the disorders and their healthy peers were considered. The aim was to examine PA and SB in children with JIA or IBD compared to their healthy peers.

RESULTS

The literature review and meta-analysis identified decreased PA and increased time spent in SB in these populations, which may exacerbate both their lower physical fitness and the symptoms of their health disorders.

CONCLUSION

Results nevertheless show discrepancies due to the different materials and methods used and the variables measured. Further studies are needed to establish a gold standard method for assessing PA level in these populations.

The effect of repeated methotrexate injections on the quality of life of children with rheumatic diseases

In clinical practice, the burden of repeated injections in children with rheumatic disease receiving disease-modifying anti-rheumatic drugs is significant. To investigate the nature and extent of impact on the quality of life after repeated injections, we conducted a literature review. Two relevant papers were identified, both about children with juvenile idiopathic arthritis (JIA) being administered methotrexate. The results suggest that the combination of needle fear, impact of methotrexate treatment, and procedural consequences, e.g., blood sampling, all contribute to the distress and the loss of quality of life of children with JIA. Remarkably, no studies examining fear of injections or injection pain in children with rheumatic diseases receiving biologicals were identified.Conclusion: Strategies to optimize administration of disease modifying anti-rheumatic drugs should be systematically investigated. What is Known: • Repeated parenteral administration of drugs is burdensome for children with rheumatic diseases. What is New: • Needle fear should be investigated systematically to optimize administration of disease-modifying anti-rheumatic drugs.

A new biopsychosocial and clinical questionnaire to assess juvenile idiopathic arthritis: JAB-Q

OBJECTIVE

To create a new multidimensional questionnaire for the assessment of juvenile idiopathic arthritis (JIA) patients in standard clinical practice and study the validity and reliability of this questionnaire.

METHODS

The Juvenile Arthritis Biopsychosocial and Clinical Questionnaire (JAB-Q) was created using the Delphi technique and consensus conference following an initial literature search. The questionnaire has three parts including a clinician form, child form and parent form. This is a patient/parent-centered outcome tool, which helps us to evaluate the biopsychosocial aspects of the patient, including disease activity, posture, functional and psychosocial status, fatigue, and performance in school. From January 2015 to January 2018, 6-18 years old children with JIA were enrolled in the study. The previously validated questionnaires were also applied to each participant to validate the JAB-Q: Juvenile Idiopathic Disease Arthritis Score (JADAS) and Childhood Health Assessment Questionnaire (CHAQ), and the Family Impact Questionnaire (FIS). The same questionnaire was re-administered after one week to assess the test-retest reliability in randomly selected 50 children and their parents.

RESULTS

A group of experts were invited to the Delphi survey. After the Delphi tours, the final form of the questionnaire containing three parts as clinician form, child form and parent form was created. This tool was applied to 310 JIA patients and their parents. The children and parents easily handled the JAB-Q and filled the forms in around 10-15 min. The validity of the clinician, child and parents' forms were assessed by the JADAS, CHAQ, and FIS, respectively. The validity of these three scales were determined as moderate. In addition, the test-retest reliability of the clinician, child and parents' forms were considerably high.

CONCLUSION

JAB-Q is a valid and reliable multidimensional biopsychosocial outcome tool that can be used routinely in clinical practice of pediatric rheumatology. The main advantage of this tool is incorporation of patients' and parents' perspectives separately while providing a practical and standard setting for the clinician's evaluation. However, further validation of this tool in an independent cohort is needed to improve its applicability.

Modern pain neuroscience in clinical practice: applied to post-cancer, paediatric and sports-related pain

•

Generalized hypersensitivity in post-cancer, sports-related and pediatric pain.

•

Rationale for pain education, stress management and cognition targeted exercises.

•

Need to change from a biomedical or psychosocial to an integrated approach.

In the last decade, evidence regarding chronic pain has developed exponentially. Numerous studies show that many chronic pain populations show specific neuroplastic changes in the peripheral and central nervous system. These changes are reflected in clinical manifestations, like a generalized hypersensitivity of the somatosensory system. Besides a hypersensitivity of bottom-up nociceptive transmission, there is also evidence for top-down facilitation of pain due to malfunctioning of the endogenous descending nociceptive modulatory systems. These and other aspects of modern pain neuroscience are starting to be applied within daily clinical practice. However, currently the application of this knowledge is mostly limited to the general adult population with musculoskeletal problems, while evidence is getting stronger that also in other chronic pain populations these neuroplastic processes may contribute to the occurrence and persistence of the pain problem. Therefore, this masterclass article aims at giving an overview of the current modern pain neuroscience knowledge and its potential application in post-cancer, paediatric and sports-related pain problems.

Physical activity in children with Juvenile Idiopathic Arthritis compared to controls

BACKGROUND

To compare physical activity (PA) in children with juvenile idiopathic arthritis (JIA) with controls and to analyse the effect of disease specific factors on PA in children with JIA treated according to current treatment regimes.

METHODS

PA was measured with a 7-day activity diary and expressed as physical activity level (PAL). Moderate to vigorous physical activity (MVPA) (hours/day) and sedentary time (hours/day) was determined. In children with JIA, medication, the number of swollen and/or painful joints, disease activity, functional ability, pain and well-being was determined. Multivariate regression analysis was performed to analyze differences in PA between JIA and controls, adjusted for influences of age, gender, season, Body Mass Index (BMI) and to analyze predictors of PA in JIA patients.

RESULTS

Seventy-six children with JIA (26 boys and 50 girls, mean ± SD age 10.0 ± 1.4 years) and 131 controls (49 boys and 82 girls, mean ± SD age 10.4 ± 1.2 years) participated in this study. Children with JIA had a significantly lower PAL (0.10, p = 0.01) corrected for age, BMI, gender and season. They spent less time in MVPA (0.41 h/day, p = 0.06) and had a significantly higher mean time spent in sedentary activities (0.59 h/day, p 0.02) compared to controls. The activity level of children with JIA was related to age, gender, season, feeling of well-being and pain.

CONCLUSION

Children with JIA have a lower PAL, spent less time in MVPA and spent more time on sedentary activities compared to controls despite current medical treatment and PA encouragement.

TRIAL REGISTRATION

Data of the children with JIA are from the Rheumates@work study ISRCTN92733069 .

The Effects of Orthopedic Manual Physical Therapy in the Management of Juvenile Idiopathic Arthritis: A Case Report

PURPOSE

Juvenile idiopathic arthritis (JIA) is a cause of disability in childhood. Little research exists concerning physical therapy management, and no evidence exists for orthopedic manual physical therapy (OMPT) for JIA. The purpose of this case report is to describe the use of OMPT in combination with therapeutic exercise in the successful treatment of a child with oligoarticular JIA.

KEY POINTS

A 6-year-old girl with oligoarticular JIA presented with elbow pain and stiffness interfering with function. Treatment consisted of OMPT in combination with therapeutic exercise and a home exercise program.

CONCLUSIONS

Improvements were demonstrated in elbow range of motion, pain, Childhood Health Assessment Questionnaire, Pediatric Outcomes Data Collection Instrument, and the Patient Specific Functional Scale.

RECOMMENDATIONS FOR CLINICAL PRACTICE

Orthopedic manual physical therapy may be considered as a treatment of a child with JIA.

RECOMMENDATIONS

We provide evidence that OMPT may be considered as a treatment of a child with JIA.

Randall Selitto pressure algometry for assessment of bone-related pain in rats

BACKGROUND

Deep pain is neglected compared with cutaneous sources. Pressure algometry has been validated in the clinic for assessment of bone-related pain in humans. In animal models of bone-related pain, we have validated the Randall Selitto behavioural test for assessment of acute and pathological bone pain and compared the outcome with more traditional pain-related behaviour measures.

METHODS

Randall Selitto pressure algometry was performed over the anteromedial part of the tibia in naïve rats, sham-operated rats, and rats inoculated with MRMT-1 carcinoma cells in the left tibia, and the effect of morphine was investigated. Randall Selitto measures of cancer-induced bone pain were supplemented by von Frey testing, weight-bearing and limb use test. Contribution of cutaneous nociception to Randall Selitto measures were examined by local anaesthesia.

RESULTS

Randall Selitto pressure algometry over the tibia resulted in reproducible withdrawal thresholds, which were dose-dependently increased by morphine. Cutaneous nociception did not contribute to Randall Selitto measures. In cancer-bearing animals, compared with sham, significant differences in pain-related behaviours were demonstrated by the Randall Selitto test on day 17 and 21 post-surgery. A difference was also demonstrated by von Frey testing, weight-bearing and limb use tests.

CONCLUSION

Our results indicate that pressure applied by the Randall Selitto algometer on a region, where the bone is close to the skin, may offer a way to measure bone-related pain in animal models and could provide a supplement to the traditional behavioural tests and a means to study deep pain.

Patient-reported Outcomes across Categories of Juvenile Idiopathic Arthritis

OBJECTIVE

Although there is increasing reliance on patient-reported outcomes (PRO) for disease management, there is little known about the differences in PRO across juvenile idiopathic arthritis (JIA) categories. The purpose of our study was to assess PRO across JIA categories, including pain, quality of life, and physical function, and to determine clinical factors associated with differences in these measures across categories.

METHODS

This was a longitudinal cohort study of patients with JIA at a tertiary care pediatric rheumatology clinic. Subjects, PRO, and clinical variables were identified by querying the electronic medical record. Mixed-effects regression assessed pain, quality of life, and function.

RESULTS

Subjects with enthesitis-related arthritis (ERA) and undifferentiated JIA had significantly more pain, poorer quality of life, and poorer physical function. The ERA and undifferentiated JIA categories, physician's global disease activity assessment, female sex, and nonsteroidal antiinflammatory drug use were significantly associated with more pain, poorer quality of life, and poorer function. In models limited to ERA, female sex and tender enthesis count were significant predictors of decreased function.

CONCLUSION

ERA and undifferentiated JIA categories had poorer PRO than other JIA categories. Further work is needed to address ways to improve PRO in children with JIA, with a special focus on children with ERA and undifferentiated JIA.

The effect of sleep deprivation on pain perception in healthy subjects: a meta-analysis

BACKGROUND

There is strong evidence indicating an interaction between sleep and pain. However, the size of this effect, as well as the clinical relevance, is unclear. Therefore, this meta-analysis was conducted to quantify the effect of sleep deprivation on pain perception.

METHODS

A systematic literature search was conducted using the electronic databases PubMed, Cochrane, Psyndex, Psycinfo, and Scopus. By conducting a random-effect model, the pooled standardized mean differences (SMDs) of sleep deprivation on pain perception was calculated. Studies that investigated any kind of sleep deprivation in conjunction with a pain measurement were included. In cases of several pain measurements within a study, the average effect size of all measures was calculated.

RESULTS

Five eligible studies (N = 190) for the between-group analysis and ten studies (N = 266) for the within-group analysis were identified. Sleep deprivation showed a medium effect in the between-group analysis (SMD = 0.62; CI95: 0.12, 1.12; z = 2.43; p = 0.015) and a large effect in the within-group analysis (SMD = 1.49; CI95: 0.82, 2.17; z = 4.35; p <0.0001). The test for heterogeneity was not significant in the between-group analysis (Q = 5.29; df = 4; p = 0.2584), but it was significant in the within-group analysis (Q = 53.49; df = 9; p <0.0001).

CONCLUSION

This meta-analysis confirms a medium effect (SMD = 0.62) of sleep deprivation on pain perception. As this meta-analysis is based on experimental studies in healthy subjects, the clinical relevance should be clarified.

Persistent pain in chronically ill children without detectable disease activity

Children with organic diseases may experience persistent pain in the presence of controlled disease, as evidenced by little or no measurable disease activity or inflammation. Historically, dualistic definitions of pain have informed standard diagnostic approaches to persistent pain; aggressive investigation and treatment targeting underlying disease, even in the absence of evidence indicating disease escalation. Evidence across disease populations, in children with inflammatory bowel disease, sickle cell disease, and juvenile idiopathic arthritis indicates that persistent pain in these conditions may be better conceptualized as functional in nature, potentially resulting from disordered somatosensory processing including central sensitization. Applying a biopsychosocial understanding of persistent pain and multidisciplinary functional pain management strategies may lead to improved health outcomes.

Assessment and management of pain in juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease in childhood. Persistent pain is the most common and distressing symptom of JIA, and pain in childhood arthritis is multifactorial. Children and adolescents with persistent pain due to JIA experience significantly more problems with physical, emotional, social, and school functioning than healthy individuals. Assessment of pain at each office visit is the cornerstone of effective pain management and should include an evaluation of pain intensity, interference, and coping. Following the biopsychosocial model of pain management, a multi-modal approach is recommended for pain control in children with arthritis. Pharmacologic strategies for the treatment of pain in JIA include aggressive treatment of the underlying disease as well as the use of acetaminophen and systemic and topical non-steroidal anti-inflammatory drugs for persistent mild pain. Opioids can be considered in the case of moderate to severe persistent pain. Physical therapies and psychological interventions such as cognitive behavioral therapy are also key components of pain management in JIA.

Patient-reported Joint Count in Juvenile Idiopathic Arthritis: The Reliability of a Manikin Format

Objective.

To evaluate the reliability of a manikin format, patient-reported joint count in juvenile idiopathic arthritis (JIA), and to detect changes in agreement at a second visit.

Methods.

Patients with JIA aged 12–21 were asked to mark joints with active arthritis on a manikin before their regular clinic visit. The physician then performed a joint count without having seen the patient’s assessment. Agreement between scores of physician-reported and patient-reported joint counts was assessed using ICC. Kappa statistics were used to assess reliability of scoring individual joints.

Results.

The study included 75 patients with JIA. In general, patients had a low number of active joints (median 1 joint, indicated by the physician). ICC was moderate (0.61) and κ ranged from 0.3–0.7. At the second visit, κ were similar; the ICC was 0.19. When a patient scored 0 joints, the physician confirmed this 93%–100% of the time. When the patient marked ≥ 1 joints, the physician confirmed arthritis 59%–76% of the time. Sensitivity to change was moderate.

Conclusion.

Agreement between physician and patient on the number of joints with active arthritis was reasonable. Untrained patients tended to overestimate the presence of arthritis when they marked active joints on a manikin-format joint count. When the patient indicated absence of arthritis, the physician usually confirmed this. As the agreement did not improve at followup, future research should focus on the possibility of achieving this through training. For now, the patient-reported joint count cannot replace the physicians’ joint count in clinical practice; it may be used in epidemiological studies with caution.

Pain hypersensitivity in juvenile idiopathic arthritis: a quantitative sensory testing study

BACKGROUND

Juvenile Idiopathic Arthritis (JIA) is the most common cause of non-infectious joint inflammation in children. Synovial inflammation results in pain, swelling and stiffness. Animal and adult human studies indicate that localized joint-associated inflammation may produce generalized changes in pain sensitivity. The aim was to characterize pain sensitivity in children with JIA to mechanical and thermal stimulus modalities using quantitative sensory testing (QST) at an affected inflamed joint, and compare to children in clinical remission. Generalized hypersensitivity was evaluated by comparing QST measures at the thenar eminence between JIA and healthy control children.

METHODS

60 children aged 7-17 years with JIA participated. QST assessed sensory detection threshold and pain threshold at two sites: (1) affected joint (clinically active or inactive), (2) contralateral thenar eminence. Joint site included finger, wrist, knee and ankle. Clinical status was measured using objective and subjective markers of disease severity. Questionnaires assessed pain intensity and frequency, functional disability, anxiety, pain catastrophization and fatigue. QST data collected from joints were compared within JIA patients: active vs. inactive inflammation; and data from the contralateral thenar eminence were compared between JIA and healthy control cohorts in Europe [EU, (n = 151)] and the US (n = 92). Statistical analyses were performed using Kruskal-Wallis with Dunn's post-hoc comparison, Mann-Whitney or Fisher's exact test, where appropriate.

RESULTS

Overall, children with JIA reported low pain scores and low degrees of functional disability. Sensory detection thresholds and pain thresholds were similar in "active" compared to "inactive" joints. Despite this, children with JIA had generalized hypersensitivity at the thenar eminence when compared to healthy children for pressure (vs. EU p < 0.001), light touch (vs. EU p < 0.001), cold (vs EU, p < 0.01; vs US, p < 0.001) and heat pain (vs EU, p < 0.05; vs US p < 0.001).

CONCLUSIONS

JIA is associated with increased sensitivity to painful mechanical and thermal stimuli, even in absence of pain reports, or markers of disease activity. Future research investigating mechanisms underlying pain hypersensitivity in JIA is warranted; this will in turn guide pharmacologic and non-pharmacologic interventions to prevent or reverse these processes.

Overview of neurodevelopment and pain research, possible treatment targets

Pain is a common presenting and often persistent symptom for children with rheumatological disease. Pain is not clearly related to disease severity in children with inflammatory juvenile idiopathic arthritis, and presentations of non-inflammatory musculoskeletal pain are common but there is limited evidence to guide management. Pain assessment must extend beyond measures of pain severity to more fully evaluate characteristics of pain, functional impact and psychosocial effects and family interactions. Evaluation of mechanisms of joint pain in adults has identified potential treatment targets, but additional studies are required as the acute and long-term impacts of pain and injury change during postnatal development. Genotyping, sensory evaluation and neuroimaging may better characterize chronic musculoskeletal pain, identify high-risk groups and/or provide additional outcome measures to monitor disease and treatment progress. An integrated approach to management is required to effectively select and target interventions, reduce pain and disability and improve long-term outcome.

Detection of enthesitis in children with enthesitis-related arthritis: dolorimetry compared to ultrasonography

OBJECTIVE

To evaluate the distribution of enthesitis and the accuracy of physical examination with a dolorimeter for the detection of enthesitis in children, using ultrasound (US) assessment as the reference standard.

METHODS

We performed a prospective cross-sectional study of 30 patients with enthesitis-related arthritis (ERA) and 30 control subjects. The following tendon insertion sites were assessed by standardized physical examination with a dolorimeter and US: common extensor on the lateral humeral epicondyle, common flexor on the medial humeral epicondyle, quadriceps at the superior patella, patellar ligament at the inferior patella, Achilles, and plantar fascia at the calcaneus.

RESULTS

Abnormal findings on US were detected most commonly at the insertion of the quadriceps (30% [18 of 60 sites]), common extensor (12% [7 of 60]), and Achilles (10% [6 of 60]) tendons. The intrarater reliability of US (kappa statistic) was 0.78 (95% confidence interval [95% CI] 0.63-0.93), and the interrater reliability was 0.81 (95% CI 0.67-0.95). Tenderness as detected by standardized dolorimeter examination had poor positive predictive value for US-confirmed enthesitis. In comparison to controls, patients with ERA reported more pain and had lower pain thresholds at every site, including control sites (P < 0.001 for all comparisons). The interrater reliability of dolorimeter examination for detection of enthesitis was low (κ = 0.49 [95% CI 0.33-0.65]).

CONCLUSION

Compared to US, standardized dolorimeter examination for the detection of enthesitis in children has poor accuracy and reliability. The decreased pain threshold of ERA patients likely contributed to the limited accuracy of the physical examination findings. Further research regarding the utility of US for identifying enthesitis at diagnosis of juvenile idiopathic arthritis, accurately predicting disease progression, and guiding therapeutic decisions is warranted.

Assessment of disease activity by patients with juvenile idiopathic arthritis and the parents compared to the assessment by pediatric rheumatologists

BACKGROUND

Self assessment of arthritis is important for recognition of disease activity and early initiation of therapy. Proper interpretation of physical symptoms is necessary for this. The purpose was to investigate the assessment by patients and parents of disease activity in juvenile idiopathic arthritis (JIA) and to compare their assessments to rheumatologists' assessments.

METHODS

Patients and parents assessed 69 joints on a paper homunculus and marked each joint with a different color according to presumed presence of disease: active disease (AD), doubt, and non-active disease (NAD). Their assessments were compared to the rheumatologists' assessments. If patients and/or parents marked an inflamed joint, it counted as AD. Pain, functional impairment, and disease duration were analyzed to differentiate more precise between true and false positive and true and false negative assessments.

RESULTS

We collected assessments of 113 patients and/or parents. AD was assessed 54 times, 33 of which were true positives. NAD was assessed 23 times, 22 of which were true negatives. Doubt was expressed 36 times, 9 of which were assessed by the rheumatologist as AD. Sensitivity and specificity of AD was 0.77 and 0.31. Pain and functional impairment scored highest in AD, intermediate in doubt, and lowest in NAD.

CONCLUSION

Patients and/or parents seldom missed arthritis but frequently overestimated disease activity. Pain, functional impairment, disease duration, gender, and age did not differentiate between true and false positives for. Patients perceived JIA as active if they experienced pain and functional impairment. To reduce overestimation of the presence of AD we need to improve their understanding of disease activity by teaching them to distinguish between primary symptoms of JIA and symptoms like pain and functional impairment.

Safety and feasibility of a home-based six week resistance training program in juvenile idiopathic arthritis

BACKGROUND

Juvenile idiopathic arthritis (JIA), among the most common chronic diseases of childhood, can be associated with attenuated physical activity levels, reduced fitness, decreased functionality and pain. This pilot study aimed to determine the safety, feasibility and effect of a six week resistance training program in children with JIA.

METHODS

Youth (8-18 years) with JIA participated in a home-based resistance training program. Participants reported pain on an electronic diary once a day for one week prior to training, then once a day on non-exercise days and three times a day (before-exercise, after-exercise, and end-of-day) on exercise days for the subsequent six weeks of training. Secondary outcome measures included inflammation (assessed by ultrasound), muscle size (assessed by ultrasound), muscle strength (assessed by dynamometer) and functional ability (assessed by childhood health assessment questionnaire), measured at baseline and post-training. Participants were also instructed to wear an accelerometer one week prior to training to estimate baseline physical activity levels. Statistical analyses included safety (pain changes and any adverse events), feasibility (adherence to program and modifications made to exercises) and effect of program (differences in secondary measures pre and post training). An alpha level of p < 0.05 was accepted as significant.

RESULTS

Seven participants completed an average of 12.7 ± 3.4 (range 8-17) exercise sessions out of a possible 18 (70.6%). No adverse events were reported and pain did not increase over the seven weeks. Secondary measures revealed a significant increase in vastus lateralis thickness from pre to post training (p < 0.05). End-of-day pain intensity was correlated to end-of-day stiffness, fatigue and mood (r = .864, r = .581, r = -.637, respectively, p < 0.001). Pain intensity was also correlated with ratings of perceived exertion of the exercise (r = 0.324, p < 0.01). Only two children met the recommended 60 minutes of moderate to vigorous physical activity per day.

CONCLUSIONS

A six week home-based resistance training program is both safe (absence of pain changes or adverse events over the six weeks) and feasible (comparable adherence rates to other exercise studies involving JIA and individually modifiable) in children with JIA.

Pain experience in children with juvenile idiopathic arthritis treated with anti-TNF agents compared to non-biologic standard treatment

BACKGROUND

Anti-TNF agents have proven efficacy in children with severe juvenile idiopathic arthritis (JIA) who are unresponsive to standard therapy. Therefore pain reduction or elimination could be expected. The aim of this study was to compare the pain experience in children with JIA treated with anti-TNF agents (n = 41) or non-biologic standard treatment (n = 50).

METHODS

All children completed a 2-week pain diary and, for children treated with anti-TNF agents, measures of pain-coping and pain-specific beliefs. Parents rated the child's level of functional disability. Clinical data were collected from the pediatric rheumatologists.

RESULTS

No significant differences were found between the anti-TNF group and non-biologic standard treatment group for average pain score, number of children with daily pain reported in the pain diary, or level of functional disability. Significantly more children in the anti-TNF group reported no pain at all. Children undergoing standard treatment had significantly higher disease activity. Significant differences were found between the high pain patients treated with anti-TNF agents and the rest of the anti-TNF group in regards to their pain-specific beliefs of disability and harm, and the pain-coping strategy of catastrophizing.

CONCLUSION

These results indicate that a great proportion of children treated with anti-TNF agents respond well to the treatment in regards to disease activity and pain, but pain was still a problem for a subgroup of children though they were in remission with biological agents. More focus on pain management is needed.