Central nervous system mechanisms of pain in fibromyalgia and other musculoskeletal disorders: behavioral and psychologic treatment approaches

Impact of migraine and fibromyalgia on temporomandibular disorder: A retrospective study on pain, psychological factors and quality of life

OBJECTIVES

This study assessed the impact of migraine and fibromyalgia (FM) in TMD patients, focusing on pain, anxiety, depression, and quality of life (QoL). Additionally, we investigated how these variables relate to the total number of comorbidities to gain insights into their interactions.

METHODS

A retrospective data collection was conducted during January 2016 to December 2022, involving 409 adult TMD patients. TMD patients were categorised into four groups: those without comorbidity (TMD-only) and those with comorbid migraine and/or fibromyalgia (TMD + MG, TMD + FM and TMD + MG + FM). Quantitative variables were compared among them. Linear regression was used to analyse the associations between these variables.

RESULTS

Most of study population were women (79%) with a mean age of 44.43 years. TMD + MG patients reported longer pain duration, higher pain scores and greater pain interference compared with TMD-only patients. Similarly, TMD + FM patients had higher pain intensity than patients with TMD only. Both the TMD + MG and TMD + FM groups had higher levels of anxiety, depression, and health impairment compared with patients with TMD only. Patients with all three pain conditions (TMD + MG + FM) experienced the longest pain duration, highest pain intensity, psychological distress, and impaired QoL. The result showed positive associations between pain outcomes, psychological measures, pain's impact on QoL, and the number of comorbidities and a negative association between overall health states and the number of comorbidities.

CONCLUSIONS

These findings underscore the importance of considering the presence of comorbidities and addressing physical and psychological aspects in the management of TMD patients.

Effects of monopolar pulsed-capacitive dielectric radiofrequency diathermy in patients with chronic low back pain: a randomised clinical trial

Monopolar capacitive diathermy is a physiotherapy technique that uses high-frequency currents to generate heat in deep tissues. This heat can have several therapeutic effects, especially in the treatment of chronic low back pain (CLBP), however, until now there is little evidence of this type of diathermy. The purpose was to evaluate the efficacy of a pulsed monopolar dielectric radiofrequency diathermy (PRF)-capacitive type versus simulated treatment on symptomatology of patients with CLBP. A single-blind randomised controlled trial was conducted. Sixty patients with CLBP were randomly assigned to a PRF-capacitive or a simulated treatment group. All participants received 3 sessions per week for 3 weeks. Disability, pain intensity, movement phobia, lumbar anteflexion, quality of life, and sleep quality were assessed at baseline, after treatment, and at two months. The application of 9 sessions of PRF-capacitive showed significant improvements compared to simulated therapy during the entire follow-up for disability (F = 26.99, p < 0.001), pain intensity (F = 0.550, p < 0.001), the quality of life components of physical function (F = 0.780, p < 0.001), social function (F = 0.780, p < 0.001) and mental health (F = 0.858, p = 0.003) and for sleep duration (F = 0.863, p = 0.004).

Electroencephalographic Evaluation in Fibromyalgia: A Systematic Review

Introduction. The evaluation of individuals with fibromyalgia is challenging. Electroencephalography is a promising resource for identifying physiological biomarkers in fibromyalgia, contributing to its diagnosis. Objective. To review studies involving the use of electroencephalography to evaluate individuals with fibromyalgia. Method. A systematic review of studies published in the PubMed, Lilacs, and SciELO databases from 2001 to 2020 was conducted. The keywords used were electroencephalogram, electroencephalography, and fibromyalgia. The database search complied with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) criteria. Results. A total of 136 articles were identified after a database search using the keywords "fibromyalgia" AND "electroencephalography", and 131 articles were found using the keywords "fibromyalgia" AND "electroencephalogram" (EEG). In the end, 20 articles remained after applying the exclusion criteria. The data was organized into subcategories related to the form of use, protocols, electroencephalographic findings in patients with fibromyalgia, and the EEG analysis method. Conclusion. Electroencephalography is a promising method for identifying and characterizing biomarkers for fibromyalgia.

A randomized, placebo-controlled, double-blinded mechanistic clinical trial using endotoxin to evaluate the relationship between insomnia, inflammation, and affective disturbance on pain in older adults: A protocol for the sleep and Healthy Aging Research for pain (SHARE-P) study

Chronic pain is prevalent in older adults. Treatment, especially with opioids, is often ineffective and poses considerable negative consequences in this population. To improve treatment, it is important to understand why older adults are at a heightened risk for developing chronic pain. Insomnia is a major modifiable risk factor for chronic pain that is ubiquitous among older adults. Insomnia can also lead to heightened systemic inflammation and affective disturbance, both of which may further exacerbate pain conditions in older adults. Endotoxin exposure can be used as an experimental model of systemic inflammation and affective disturbance. The current study aims to understand how insomnia status and endotoxin-induced changes in inflammation and affect (increased negative affect and decreased positive affect) may interact to impact pain facilitatory and inhibitory processes in older adults. Longitudinal data will also assess how pain processing, affective, and inflammatory responses to endotoxin may predict the development of pain and/or depressive symptoms. The current study is a randomized, double-blinded, placebo-controlled, mechanistic clinical trial in men and women, with and without insomnia, aged 50 years and older. Participants were randomized to either 0.8ng/kg endotoxin injection or saline placebo injection. Daily diaries were used to collect variables related to sleep, mood, and pain at two-week intervals during baseline and 3-, 6-, 9-, and 12-months post-injection. Primary outcomes during the experimental phase include conditioned pain modulation, temporal summation, and affective pain modulation ∼5.5 hours after injection. Primary outcomes for longitudinal assessments are self-reported pain intensity and depressive symptoms. The current study uses endotoxin as an experimental model for pain. In doing so, it aims to extend the current literature by: (1) including older adults, (2) investigating insomnia as a potential risk factor for chronic pain, (3) evaluating the role of endotoxin-induced affective disturbances on pain sensitivity, and (4) assessing sex differences in endotoxin-induced hyperalgesia.

Clinicaltrialsgov

NCT03256760.

Trial sponsor

NIH R01AG057750-01.

Se-[(2,2-Dimethyl-1,3-dioxolan-4-yl)methyl] 4-Chlorobenzoselenolate Attenuates Inflammatory Response, Nociception, and Affective Disorders Related to Rheumatoid Arthritis in Mice

Despite major advances, not all patients achieve rheumatoid arthritis (RA) remission, thus highlighting a pressing need for new therapeutic treatments. Given this scenario, this study sought to evaluate Se-[(2,2-dimethyl-1,3-dioxolan-4-yl)methyl] 4-chlorobenzoselenolate (Se-DMC) potential on a complete Freund's adjuvant (CFA)-induced unilateral arthritis model. The effects of Se-DMC (5 mg/kg; oral dose) and meloxicam (5 mg/kg; oral dose), both administered to animals daily for 14 days, on paw edema, mechanical sensitivity, neurobehavioral deficits (anxiogenic- and depressive-like behaviors), Na⁺/K⁺-ATPase activity, oxidative stress, and inflammation were evaluated in male Swiss mice exposed to CFA (intraplantar injection of 0.1 mL; 10 mg/mL). Se-DMC reduced the paw withdrawal threshold and CFA-induced paw edema. Histopathological results revealed the antiedematogenic potential of the compound, which was evidenced by lower quantities of dilated lymphatic vessels compared with the CFA group. Se-DMC reduced mRNA relative expression levels of tumor necrosis factor-α (TNF-α) and nuclear factor-κB (NF-κB) in the hippocampus and paw of CFA mice. The CFA-induced anxiogenic- and depressive-like behaviors were reversed by Se-DMC to the control levels in the elevated plus-maze and tail suspension tests. Se-DMC reduced the paw reactive species levels and restored the superoxide dismutase (hippocampus and paw) and Na⁺/K⁺-ATPase (hippocampus) activities previously increased by CFA. Moreover, CFA administration inhibited serum creatinine kinase activity, albeit the Se-DMC effects did not appear to involve the modulation of this enzyme and were equal to or greater than meloxicam. Se-DMC attenuates CFA-induced inflammatory response, nociception, and neurobehavioral deficits in mice.

Lower limb muscle strength and serotonin receptor gene polymorphism as factors associated in women with fibromyalgia

BACKGROUND

Fibromyalgia (FM) is a chronic pain syndrome characterized by generalized skeletal muscle chronic pain. Its etiology is not well defined, because there are several factors that may trigger it such as physical and/or emotional stresses, or a genetic susceptibility, involving serotonergic, dopaminergic and catecholaminergic paths. The objective of this study was to investigate the association between the strength of the lower limb, genetic polymorphism of the serotonin receptor gene HTR_2A in women with fibromyalgia.

METHODS

In this observational study of case-control type 48 women were evaluated who belonged to the group with FM (52 ± 12 years) and 100 women in the control group (58 ± 11 years). Socio demographic and anthropometric data were collected and peripheral blood samples for DNA extraction; genotypic analyzes were performed by means of PCR in real time by TaqMan® system. The lower limb muscle strength was assessed through the test of sitting down and standing up for 30 s. The chi-square test or Fischer Exact was used for possible associations among the variables; the t-test for independent samples was used to compare the averages among the groups; the value of significance adopted was 5%.

RESULTS

There was an association between the polymorphism of the HTR2A gene with FM, demonstrating that carriers of the genotype GG have 24.39 times more likely to develop the syndrome (IC95% 5.15-115.47; p = 0.01). It was observed an association between FM and the test to sit and stand up demonstrating that women with fibromyalgia have lower limb muscle strength (p = 0.01). The study showed that the white race has 3.84 times more likely to develop FM (p = 0.01).

CONCLUSION

The results of this study suggest that women of Caucasian ethnicity with GG genotype or G allele presented greater risk of developing fibromyalgia and that these patients have lower limb muscle strength compared to the control group.

Overlapping Chronic Pain Conditions: Implications for Diagnosis and Classification

There is increasing recognition that many if not most common chronic pain conditions are heterogeneous with a high degree of overlap or coprevalence of other common pain conditions along with influences from biopsychosocial factors. At present, very little attention is given to the high degree of overlap of many common pain conditions when recruiting for clinical trials. As such, many if not most patients enrolled into clinical studies are not representative of most chronic pain patients. The failure to account for the heterogeneous and overlapping nature of most common pain conditions may result in treatment responses of small effect size when these treatments are administered to patients with chronic overlapping pain conditions (COPCs) represented in the general population. In this brief review we describe the concept of COPCs and the putative mechanisms underlying COPCs. Finally, we present a series of recommendations that will advance our understanding of COPCs.

PERSPECTIVE

This brief review describes the concept of COPCs. A mechanism-based heuristic model is presented and current knowledge and evidence for COPCs are presented. Finally, a set of recommendations is provided to advance our understanding of COPCs.

Is There a Possible Neuropathic Pain Component in Knee Osteoarthritis?

Objectives

This study aims to investigate the neuropathic pain (NP) component in patients with osteoarthritis (OA) of the knee and its association with physical function, risk factors, and stages of OA.

Patients and methods

One hundred and nine patients (16 males, 93 females; mean age 62.5±8.5 years; range 44 to 81 years) diagnosed with knee OA according to the American College of Rheumatology criteria were enrolled in this study between July 2014 and June 2015. Patients were evaluated with visual analog scale for pain severity, PainDETECT questionnaire for presence and severity of neuropathic pain, Western Ontario and McMaster Universities osteoarthritis index for physical function, and the Kellgren-Lawrence system for severity of OA. Presence of the associated risk factors were also questioned.

Results

A total of 12 patients (11%) were classified as having likely NP and 23 patients (21.1%) were classified as having possible NP. PainDETECT scores were significantly correlated with the visual analog scale scores and Western Ontario and McMaster Universities osteoarthritis index pain, physical function and total scores. Patients with neuropathic pain had significantly longer symptom duration than the patients without NP. However, we found no relationship between the other risk factors and NP.

Conclusion

This study demonstrated that some of the knee OA patients had a NP component as the underlying cause of knee pain. Patients with NP had longer symptom duration, increased severity of pain, and disability. Therefore, the presence of NP component in these patients should be considered. Once it is determined, appropriate intervention strategies for NP should be incorporated in the routine treatment modalities of knee OA.

Health anxiety and depression in patients with fibromyalgia syndrome

Objectives

To investigate health anxiety and depressive symptoms in patients with fibromyalgia syndrome (FMS).

Methods

Patients with FMS and healthy control subjects were recruited. All participants completed the Health Anxiety Inventory Short Form (HAI-SF) and Beck Depression Inventory (BDI). Pain was assessed in patients with FMS using the Fibromyalgia Impact Questionnaire (FIQ) and Visual Analogue Scale (VAS).

Results

This study involved 95 patients with FMS (15 male) and 95 healthy controls (17 male). Mean ± SD HAI-SF and BDI scores were significantly higher in patients with FMS = than in controls=. HAI-SF scores were 23.50 ± 10.78 and 9.38 ± 4.24 respectively; BDI scores were 18.64 ± 10.11 and 6.21 ± 4.05 respectively. There were highly significant correlations between FIQ and HAI-SF, FIQ and BDI, and HAI-SF and BDI.

Conclusions

Patients with FMS had significantly higher HAI-SF and BDI scores than healthy controls. Psychiatric support is essential for patients with FMS. Treatment should include biological, psychological and social approaches.

Psychological screening/phenotyping as predictors for spinal cord stimulation

Spinal cord stimulation (SCS) is becoming a widely used treatment for a number of pain conditions and is frequently considered as a pain management option when conservative or less invasive techniques have proven to be ineffective. Potential indications for SCS include complex regional pain syndrome (CRPS), postherpetic neuralgia, traumatic nerve injury, failed back surgery syndrome, refractory angina pectoris, peripheral vascular disease, neuropathic pain, and visceral pain (Guttman et al. Pain Pract. 9:308-11, 2009). While research on SCS is in its infancy, it is clear that substantial variation exists in the degree of benefit obtained from SCS, and the procedure does not come without risks; thus focused patient selection is becoming very important. Psychological characteristics play an important role in shaping individual differences in the pain experience and may influence responses to SCS, as well as a variety of other pain treatments (Doleys Neurosurg Focus 21:E1, 2006). In addition to psychological assessment, quantitative sensory testing (QST) procedures offer another valuable resource in forecasting who may benefit most from SCS and may also shed light on mechanisms underlying the individual characteristics promoting the effectiveness of such procedures (Eisenberg et al. Pain Pract. 6:161-165, 2006). Here, we present a brief overview of recent studies examining these factors in their relationship with SCS outcomes.

Neuropathic pain symptoms on the modified painDETECT correlate with signs of central sensitization in knee osteoarthritis

OBJECTIVE

Clinical tools are needed to identify and target a neuropathic-like phenotype, which may be associated with central sensitization (CS), in osteoarthritis (OA). The modified painDETECT questionnaire (mPD-Q) has face and content validity for identifying neuropathic-like symptoms in knee OA. To further validate the mPD-Q, this study assessed the unknown relationship between mPD-Q scores and signs of CS on quantitative sensory testing (QST) in knee OA.

DESIGN

36 Individuals were recruited with chronic, symptomatic, knee OA without other pain/neurological conditions. Reference QST data were obtained from 18 controls/32 eligible knees, enabling identification of sensory abnormalities/CS among case knees. A standardized questionnaire assessed psychological factors (depressive symptoms and pain catastrophizing), and for individual knees, mPD-Q and pain intensity scores. A standardized/comprehensive QST protocol was conducted for each knee. QST signs of CS were defined as: mechanical hyperalgesia and/or enhanced temporal summation and/or allodynia. The relationship between the presence of CS (yes/no) and a pre-selected mPD-Q score (≤12 or >12), by knees, was assessed using generalized estimating equations.

RESULTS

Among 57 eligible case knees, 45.6% had ≥1 sign of CS. Controlling for age, knees with higher mPD-Q scores (>12.0) had higher odds of having QST signs of CS (adjusted odds ratio (OR) = 5.6; 95% confidence interval (CI), 1.3-22.9). This relationship was unaffected by controlling for depression and pain intensity, but was attenuated by pain catastrophizing.

CONCLUSIONS

Among painful OA knees, higher mPD-Q scores were associated with greater odds of having signs of CS. Thus, the mPD-Q may aid the identification of CS in people with chronic knee OA.

Psychological treatment for pain among cancer patients by rational-emotive behavior therapy--efficacy in both India and Iran

The aim of the present study is to find out the influence of rational-emotive behavior therapy (REBT) on pain intensity among cancer patients in India and Iran. The study followed a quasi-experimental, pre-post test, carried out with a sample of 88 cancer patients, aged 21-52 years, referred to the Baharat cancer hospital of Mysore in India and Shahidzade hospital of Behbahan in Iran. They were randomly assigned to the experimental (n=India 21; Iran 22) and control (n=India 22; Iran 23) groups. Pain was measured with the McGill Pain Questionnaire- MPQ (1975), the intervention by REBT has given to the experimental group for 45 days (ten sessions) and at the end of intervention, the pain of patients was again evaluated. Concerning to hypothesis of the study, two independent sample T test and three ways mixed ANOVA is used to analyze the data. Results showed that the experimental group in post test had less pain than the control group, but there were no statistically significant differences between Indian and Iranian patients in pain perception. With respect the outcome of study, it has realized that REBT can be used in hospitals and other psychological clinics to reduce the pain of cancer patients.

Guided imagery in people with fibromyalgia: A randomized controlled trial of effects on pain, functional status and self-efficacy

Studies on the effects of guided imagery in patients with fibromyalgia show varying results. This randomized controlled trial ( n = 65) aims to give more insight into the effects on pain, functional status, and self-efficacy. Daily pain was assessed with a pain diary using a Visual Analogue Scale. Functional status and self-efficacy were measured at pretest, posttest, and follow-up using the Fibromyalgia Impact Questionnaire and the Chronic Pain Self-Efficacy Scale. No effects of guided imagery could be established. Explanations for the diverging results between studies might be found in the content of the exercises, length of the intervention period, and background of participants.

Does past pain influence current pain: biological and psychosocial models of sex differences

Previous studies have generally indicated sizeable sex differences for both laboratory pain reactivity and clinical pain reports. Numerous biological and psychosocial models have been invoked to account for these findings, but the laboratory and clinical findings have generally been examined in isolation. This paper reviews data which show a relationship between past clinical pain experiences and current responses to experimentally induced pain. Individuals with a greater pain history tend to show lower pain tolerance. Since women often have high pain experience levels and lower pain tolerance, one might ask whether the two factors are related. We review several models, based upon concepts of neonatal differences in pain reactivity, hypervigilance following early pain experiences, and concepts of peripheral and central sensitization or plasticity which might help to bridge the gap between clinical and experimental findings.

Pain persists in DAS28 rheumatoid arthritis remission but not in ACR/EULAR remission: a longitudinal observational study

INTRODUCTION

Disease remission has become a feasible goal for most rheumatoid arthritis (RA) patients; however, patient-reported symptoms, such as pain, may persist despite remission. We assessed the prevalence of pain in RA patients in remission according to the Disease Activity Score (DAS28-CRP4) and the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) remission criteria.

METHODS

Data were analyzed from RA patients in the Brigham Rheumatoid Arthritis Sequential Study with data at baseline and 1 year. DAS28 remission was defined as DAS28-CRP4 <2.6. The ACR/EULAR remission criteria included (a) one or more swollen joints, (b) one or more tender joints, (c) C-reactive protein ≤1 mg/dl, and (d) patient global assessment score ≤1. Pain severity was measured by using the pain score from the Multi-Dimensional Health Assessment Questionnaire (MDHAQ). The associations between baseline clinical predictors and MDHAQ pain at baseline and 1 year were assessed by using multivariable linear regression.

RESULTS

Among the 865 patients with data at baseline and 1 year, 157 (18.2%) met DAS28-CRP4 remission criteria at both time points. Thirty-seven (4.3%) met the ACR/EULAR remission criteria at baseline and 1 year. The prevalence of clinically significant pain (MDHAQ pain ≥4) at baseline ranged from 11.9% among patients meeting DAS28-CRP4 remission criteria to none among patients meeting ACR/EULAR remission criteria. Patient global assessment, MDHAQ function, MDHAQ fatigue, MDHAQ sleep, and arthritis self-efficacy were significantly associated with MDHAQ pain in cross-sectional (P ≤ 0.0005) and longitudinal analyses (P ≤ 0.03). Low swollen-joint counts were associated with high MDHAQ pain in longitudinal analyses (P = 0.02) but not cross-sectional analyses. Other measures of inflammatory disease activity and joint damage were not significantly associated with MDHAQ pain at baseline or at 1 year.

CONCLUSIONS

Clinically significant pain continues among a substantial proportion of patients in DAS28 remission but not among those in ACR/EULAR remission. Among patients in DAS28 remission, patient global assessment, disability, fatigue, sleep problems, and self-efficacy are strongly associated with pain severity at baseline and 1 year, whereas inflammatory disease activity and joint damage are not significantly associated with elevated pain severity at either baseline or 1 year.

Neuropathic pain symptoms in a community knee OA cohort

OBJECTIVE

A neuropathic pain (NP) questionnaire may facilitate the identification of a neuropathic component to osteoarthritis (OA) pain. An existing questionnaire, the painDETECT, was modified for use in knee OA and administered to measure the prevalence and correlates of NP symptoms among adults with this condition.

METHOD

Sensibility of the modified painDETECT (mPD-Q) was assessed in 20 OA subjects followed by mail administration in an established knee OA cohort. NP symptoms were defined using a previously established, painDETECT cut-point. Correlates of NP symptoms, including OA severity (Western Ontario and McMaster Universities Osteoarthritis Index, Von Korff Chronic Pain Grade pain subscale score), psychological factors (Centre for Epidemiological Studies Depression Scale, Pain Catastrophizing Scale), and concomitant medical conditions, were evaluated using logistic regression. Construct validity of the mPD-Q was evaluated through co-administration with another NP questionnaire (S-LANSS).

RESULTS

The mPD-Q had face and content validity. Of 259 eligible cohort members, 171 (66%) completed the questionnaire; 28% had NP symptoms on the mPD-Q (19% among those without neurological conditions). Independent correlates of NP symptoms were: pain intensity (adjusted odds ratio [OR]=2.1 per 10 unit increase, P<0.0001), the presence of referred back/hip pain (adjusted OR=2.9, P=0.024), number of painful joints (OR=1.2, P=0.20) and one or more self-reported neurological condition (OR=3.0, P=0.026).

CONCLUSIONS

Among older adults with chronic symptomatic knee OA, over one-quarter had NP symptoms localized to their knees using the mPD-Q. The mPD-Q may facilitate the identification of a neuropathic component to pain in adults with knee OA who may benefit from further evaluation and/or treatment for NP.

Random forests classification analysis for the assessment of diagnostic skill

Mechanisms are needed to assess learning in the context of graduate medical education. In general, research in this regard is focused on the individual learner. At the level of the group, learning assessment can also inform practice-based learning and may provide the foundation for whole systems improvement. The authors present the results of a random forests classification analysis of the diagnostic skill of rheumatology trainees as compared with rheumatology attendings. A random forests classification analysis is a novel statistical approach that captures the strength of alignment of thinking between student and teacher. It accomplishes this by providing information about the strength and correlation of multiple variables.

Sleep disorders and their association with laboratory pain sensitivity in temporomandibular joint disorder

STUDY OBJECTIVES

We characterized sleep disorder rates in temporomandibular joint disorder (TMD) and evaluated possible associations between sleep disorders and laboratory measures of pain sensitivity.

DESIGN

Research diagnostic examinations were conducted, followed by two consecutive overnight polysomnographic studies with morning and evening assessments of pain threshold.

SETTING

Orofacial pain clinic and inpatient sleep research facility.

PARTICIPANTS

Fifty-three patients meeting research diagnostic criteria for myofascial TMD.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

We determined sleep disorder diagnostic rates and conducted algometric measures of pressure pain threshold on the masseter and forearm. Heat pain threshold was measured on the forearm; 75% met self-report criteria for sleep bruxism, but only 17% met PSG criteria for active sleep bruxism. Two or more sleep disorders were diagnosed in 43% of patients. Insomnia disorder (36%) and sleep apnea (28.4%) demonstrated the highest frequencies. Primary insomnia (PI) (26%) comprised the largest subcategory of insomnia. Even after controlling for multiple potential confounds, PI was associated with reduced mechanical and thermal pain thresholds at all sites (P < 0.05). Conversely, the respiratory disturbance index was associated with increased mechanical pain thresholds on the forearm (P < 0.05).

CONCLUSIONS

High rates of PI and sleep apnea highlight the need to refer TMD patients complaining of sleep disturbance for polysomnographic evaluation. The association of PI and hyperalgesia at a nonorofacial site suggests that PI may be linked with central sensitivity and could play an etiologic role in idiopathic pain disorders. The association between sleep disordered breathing and hypoalgesia requires further study and may provide novel insight into the complex interactions between sleep and pain-regulatory processes.

Individual differences in opioid efficacy for chronic noncancer pain

OBJECTIVE

Over a decade ago, Jamison noted the lack of studies that identify patient profiles or specific groups that might be best suited for opioid treatment of chronic noncancer pain.

METHODS

This paper reviews the studies that provide evidence for individual differences in opioid analgesia for chronic noncancer pain.

RESULTS

What we have found is that few investigations have addressed these important aspects of pain treatment. The most consistent finding is that depression and anxiety are associated with increased risk for drug abuse and decreased opioid efficacy.

DISCUSSION

The question remains whether the psychologic disorders antedated the pain condition or whether the experience of chronic pain exerts psychologic pressures that cause changes in behavior and psychologic processes. Additionally, the overall pattern suggests that younger age is predictive of opioid abuse and greater opioid efficacy. We also present a brief review of biologic mechanisms that support individual differences on opioid analgesia.

Latest developments in the assessment and management of chronic musculoskeletal pain syndromes in children

PURPOSE OF REVIEW

As many as 25% of new patients in pediatric rheumatology clinics present with idiopathic chronic pain and recent data suggest the prevalence of these conditions is increasing. Knowledge of the latest developments in assessment and treatment is critical for providing optimal clinical care. This review summarizes advances published in the past year forwarding our understanding of chronic musculoskeletal pain syndromes in children.

RECENT FINDINGS

Research has recently focused on the impairment associated with chronic pain syndromes in children, issues impacting the diagnosis of these conditions, and the efficacy of pharmacological and psychosocial treatments. No diagnostic criteria have been developed for specific chronic pain syndromes in children; however, data from several studies substantiate the need for thorough assessment of the child and family in multiple domains. In addition, studies have expanded both pharmacologic and psychosocial treatment options for children with these syndromes.

SUMMARY

Despite a growing body of research on chronic pain syndromes in children, there are no established standards of care. Data continues to support an interdisciplinary approach for effectively assessing and managing these conditions.

Activity limitations in the lower extremities in patients with osteoarthritis: the modifying effects of illness perceptions and mental health

OBJECTIVES

Using the International Classification of Functioning, Disability and Health as framework, we evaluated modifying effects of illness perceptions and mental health on the association between impairments in body structures and functions due to osteoarthritis (OA) and limitation in activities in the lower extremities.

METHODS

Self-reported limitation in activities was assessed by the Western Ontario and McMaster Universities OA index (WOMAC) function subscale in 316 patients with knee or hip pain or evidence of OA on knee or hip radiographs. Body structures and functions were evaluated during clinical and radiological assessments. Illness perceptions and mental health were assessed with the revised Illness Perception Questionnaire (IPQ-R) and the mental component summary score of the RAND 36-item Health Survey, respectively. For each patient an expected WOMAC function score was calculated, using an equation based on a multivariate model of the association of body structures and functions with limitation in activities.

RESULTS

The median (interquartile) self-reported WOMAC function score was 22.2 (9.6-43.5). Ninety-one patients reported more and 120 patients reported less limitation in activities than expected. Patients with lumbar spine degeneration, physical or exercise therapy and high IPQ-R identity, consequences and chronic timeline scores had an increased risk to report more limitation in activities than the expected range. Low IPQ-R identity, consequences and emotional representation scores and better mental health were associated with reporting less limitation in activities than the expected range.

CONCLUSION

Illness perceptions and mental health modify the association between self-reported limitation in activities and calculated limitation in activities based on impairments in body structures and functions due to OA.

Effects of guided imagery on outcomes of pain, functional status, and self-efficacy in persons diagnosed with fibromyalgia

OBJECTIVES

(1) To investigate the effects of a 6-week intervention of guided imagery on pain level, functional status, and self-efficacy in persons with fibromyalgia (FM); and (2) to explore the dose-response effect of imagery use on outcomes.

DESIGN

Longitudinal, prospective, two-group, randomized, controlled clinical trial.

SETTING AND SUBJECTS

The sample included 48 persons with FM recruited from physicians' offices and clinics in the mid-Atlantic region.

INTERVENTION

Participants randomized to Guided Imagery (GI) plus Usual Care intervention group received a set of three audiotaped guided imagery scripts and were instructed to use at least one tape daily for 6 weeks and report weekly frequency of use (dosage). Participants assigned to the Usual Care alone group submitted weekly report forms on usual care.

MEASURES

All participants completed the Short-Form McGill Pain Questionnaire (SF-MPQ), Arthritis Self- Efficacy Scale (ASES), and Fibromyalgia Impact Questionnaire (FIQ), at baseline, 6, and 10 weeks, and submitted frequency of use report forms.

RESULTS

FIQ scores decreased over time in the GI group compared to the Usual Care group (p = 0.03). Ratings of self-efficacy for managing pain (p = 0.03) and other symptoms of FM also increased significantly over time (p = < 0.01) in the GI group compared to the Usual Care group. Pain as measured by the SF-MPQ did not change over time or by group. Imagery dosage was not significant.

CONCLUSIONS

This study demonstrated the effectiveness of guided imagery in improving functional status and sense of self-efficacy for managing pain and other symptoms of FM. However, participants' reports of pain did not change. Further studies investigating the effects of mind-body interventions as adjunctive self-care modalities are warranted in the fibromyalgia patient population.

Repeated sound stress enhances inflammatory pain in the rat

While it is well established that acute stress can produce antinociception, a phenomenon referred to as stress-induced analgesia, repeated exposure to stress can have the opposite effect. Since, chronic pain syndromes, such as fibromyalgia and rheumatoid arthritis, may be triggered and/or exacerbated by chronic stress, we have evaluated the effect of repeated stress on mechanical nociceptive threshold and inflammatory hyperalgesia. Using the Randall-Selitto paw pressure test to quantify nociceptive threshold in the rat, we found that repeated non-habituating sound stress enhanced the mechanical hyperalgesia induced by the potent inflammatory mediator, bradykinin, which, in normal rats, produces hyperalgesia indirectly by stimulating the release of prostaglandin E2 from sympathetic nerve terminals. Hyperalgesia induced by the direct-acting inflammatory mediator, prostaglandin E2 as well as the baseline nociceptive threshold, were not affected. Adrenal medullectomy or denervation, reversed the effect of sound stress. In sound stressed animals, bradykinin-hyperalgesia had a more rapid latency to onset and was no longer inhibited by sympathectomy, compatible with a direct effect of bradykinin on primary afferent nociceptors. In addition, implants of epinephrine restored bradykinin-hyperalgesia in sympathectomized non-stressed rats, lending further support to the suggestion that increased plasma levels of epinephrine can sensitize primary afferents to bradykinin. These results suggest that stress-induced enhancement of inflammatory hyperalgesia is associated with a change in mechanism by which bradykinin induces hyperalgesia, from being sympathetically mediated to being sympathetically independent. This sympathetic-independent enhancement of mechanical hyperalgesia is mediated by the stress-induced release of epinephrine from the adrenal medulla.

[Psychosomatic aspects in the diagnosis and treatment of fibromyalgia]

The fibromyalgia syndrome (FMS) is a chronic pain condition of the musculoskeletal system defined by criteria of the American College of Rheumatology in 1990. Despite this definition, etiology and pathogenesis of FMS are still unknown, and consequently the therapy aims mainly at relieving symptoms. The favourite hypothesis is a multietiological concept including genetic, central nervous, muscular, and psychological issues. This article focuses on current psychological aspects as to etiology, process of chronification, and therapy of FMS. Regarding etiology there are diverging hypotheses rather than a general agreement, e.g. specific personality traits, traumatic events, psychodynamic explanations on the basis of a depressive conflict, or the subsumption under somatoform disorders. However, psychological aspects are evident to influence the course and treatment of FMS. In the chronification process behavioural aspects like avoidance behaviour with subsequent physical impairment, attitudes towards subjective theories of illness and therapeutic options, social factors like effects on work, interpersonal conditioning, and coping strategies play an important role. Therapeutic options of FMS comprise exercise, drugs, and psychotherapy. An integrated approach combining these options, a sustainable doctor-patient relationship, and a continuous support of the patient seem to be beneficial.

Psychoeducational interventions in rheumatic diseases: a review of papers published from September 2001 to August 2002

A large number of psychoeducational intervention studies have been developed for use with patients with rheumatic disease. The interventions vary considerably in the components they include and in the extent of the benefits they find. Recent meta-analyses of studies in rheumatoid arthritis (RA) report moderate short-term benefits, but it remains necessary to further examine which components are most important in bringing about change. A significant recent development in psychoeducational interventions is the move toward a generic intervention-the Chronic Disease Self-Management Program (CDSMP). A randomized controlled trial of this program has been performed, but statistical analysis for arthritis have not been reported separately.

Vagal modulation of nociception is mediated by adrenomedullary epinephrine in the rat

Vagal afferent activity modulates mechanical nociceptive threshold and inflammatory mediator-induced hyperalgesia, effects that are mediated by the adrenal medulla. To evaluate the role of epinephrine, the major hormone released from the adrenal medulla, the beta2-adrenergic receptor antagonist ICI 118,551 was chronically administered to vagotomized rats and epinephrine to normal rats. In vagotomized rats, chronic administration of ICI 118,551 markedly attenuated vagotomy-induced enhancement of bradykinin hyperalgesia but had no effect on nociceptive threshold. In normal rats, chronic epinephrine had the opposite effect, enhancing bradykinin hyperalgesia. Like vagotomy-, epinephrine-induced enhancement of hyperalgesia developed slowly, taking 14 days to reach its peak. Vagotomy induced a chronic elevation in plasma concentrations of epinephrine. We suggest that ongoing activity in vagal afferents inhibits the release of epinephrine from the adrenal medulla. Chronically elevated levels of epinephrine, occurring after vagotomy, desensitize peripheral beta2-adrenergic receptors and lead to enhancement of bradykinin hyperalgesia. The ability of prolonged elevated plasma levels of epinephrine to sensitize bradykinin receptors could contribute to chronic generalized pain syndromes.