Negative Illness Perceptions are Associated With a Pronociceptive Modulation Profile and Augmented Pelvic Pain

Interplay between noxious heat sensitivity and temporal summation magnitude in patients with fibromyalgia and long-term opioid use

Introduction

In chronic pain conditions such as fibromyalgia (FM), pain amplification within the central nervous system, or "central sensitization," may contribute to the development and maintenance of chronic pain. Chronic pain treatments include opioid therapy, and opioid therapy may maladaptively increase central sensitization, particularly in patients who take opioids long-term. However, it has remained unknown how central sensitization is impacted in patients who use opioids long-term.

Methods

To investigate how long-term opioid therapy affects central sensitization, we used the validated measure of temporal summation. The temporal summation measurement consists of applying a series of noxious stimuli to a patient's skin and then calculating changes in the patient's pain rating to each stimulus. Using this measurement, we evaluated temporal summation in study participants with fibromyalgia who take opioids long-term (i.e., greater than 90 days duration; n = 24, opioid-FM). We compared opioid-FM responses to 2 control groups: participants with fibromyalgia who do not take opioids (n = 33, non-opioid FM), and healthy controls (n = 31). For the temporal summation measurement, we applied a series of 10 noxious heat stimuli (sensitivity-adjusted temperatures) to the ventral forearm (2s duration of each stimulus, applied once every 3 s). Additionally, we collected responses to standard pain and cognitive-affective questionnaires to assess pain severity and other factors.

Results and discussion

Group differences in sensitivity-adjusted stimulus temperatures were observed, with only the non-opioid FM group requiring significantly lower stimulus temperatures (The opioid-FM group also required lower temperatures, but not significantly different from the control group). However, all 3 groups exhibited similar magnitudes of temporal summation. Across combined FM groups, temporal summation negatively correlated with pain severity (r = -0.31, p = 0.021). Within the opioid-FM group, higher pain sensitivity to heat (i.e., lower sensitivity-adjusted temperatures) showed a trend relationship with higher opioid dosage (r = -0.45, p = 0.036), potentially reflective of opioid-related hyperalgesia. Our findings also indicated that heightened pain severity may skew sensitivity-adjusted temporal summation, thereby limiting its utility for measuring central sensitization. Overall, in participants taking opioids, temporal summation may be influenced by hypersensitivity to heat pain, which appeared to vary with opioid dosage.

Depression and anxiety mediate the relationship between illness representations and perceived distress in patients with chronic pain

Illness representations explain the individual's perception and processing of health-related information. In a chronic condition such as persistent pain, illness representations might influence treatment adherence and outcome. This study aims to exploratively identify illness representations of patients with chronic pain and their association to mental disorders and subjective distress. 95 participants admitted to an inpatient university clinic were included. Validated instruments were used to assess illness representations (IPQ-R), mental health disorders (PHQ-D), and subjective distress (PSQ). Sociodemographic data and scores for the instruments were first inspected descriptively. Correlation, regression, and mediator analyses were conducted. Analyses indicated that the distributions of the IPQ-R range toward higher values. In regard to mental disorders (PHQ-D) and subjective distress (PSQ), we found several significant correlations with subscales of the IPQ-R. A regression analysis showed the IPQ-R subscales personal control, emotional representation and sex (males) to be significant predictors of subjective distress measured with the PSQ (F(11,86) = 11.55, p < .001, adjusted R2 = 0.545). Depression, anxiety, and stress syndromes (PHQ-D) significantly mediated the positive association between emotional representations (IPQ-R, predictor) and subjective distress (PSQ, outcome) with a total effect of c = .005, 95% CI [.005; .129]. Illness representations play a significant role in evaluating patients' subjective distress and mental health. It is advised to incorporate illness representations into standard protocols for psychological interventions to comprehend their influence on targeted therapeutic strategies, particularly those tailored for pain management.

A novel computational technique for the quantification of temporal summation in healthy individuals

BACKGROUND

The pathophysiology of chronic musculoskeletal pain is linked to the neurophysiologic condition known as central sensitization. Developing reliable, sensitive and clinically feasible techniques for quantifying central sensitization is a timely priority for advancing the field of chronic pain diagnosis and management.

OBJECTIVE

To compare the sensitivity of the Windup Ratio, a commonly employed Quantitative Sensory Testing (QST) technique, to a novel approach, the Sumsquare method, for detecting changes in experimentally induced central sensitization.

DESIGN

Individual, randomized, controlled experimental study.

METHODS

A total of 37 subjects assigned to experimental (N = 18) and control (N = 19) groups. Central sensitization was experimentally induced in the C5-C6 spinal segments using topical capsaicin (0.075%); controls received a non-sensitizing placebo (Lubriderm). Windup (temporal summation) was assessed using weighted pinpricks (MRC Systems, Heidelberg, Germany) applied within regions of secondary hyperalgesia surrounding the topical capsaicin. A train of 10 stimuli was applied at baseline, 10, 20 and 30 min post-topical application and participants provided numeric pain ratings after each pinprick application. Sumsquare and Windup Ratio outcomes were calculated using the pain rating data.

RESULTS

Sumsquare outcome was significantly increased at all time points (10, 20, 30 min) post-sensitization (p < 0.05); in contrast, no differences in Windup Ratio from baseline were observed at any time point post-sensitization (p > 0.05).

CONCLUSIONS

Sumsquare outcome offers greater sensitivity than Windup Ratio for detecting changes in experimentally induced central sensitization. These findings introduce a novel method for assessing changes in central sensitization in patients presenting with chronic musculoskeletal pain hypersensitivity.

Vulvodynia

Vulvodynia is a condition that occurs in 8-10% of women of all ages and is characterized by pain at the vulva that is present during sexual and/or non-sexual situations. Diagnosis is established through careful medical history and pelvic examination, including the cotton-swab test. The onset and maintenance of vulvodynia involves a complex interplay of peripheral and central pain mechanisms, pelvic floor muscle and autonomic dysfunction, anxiety, depression and childhood maltreatment as well as cognitive-affective, behavioural and interpersonal factors. Given the absence of empirically supported treatment guidelines, a stepwise approach of pelvic floor physical therapy and cognitive behavioural therapy as well as medical management is suggested, with surgery as the last option. Vulvodynia has a negative effect on the quality of life of women and their partners, and imposes a profound personal and societal economic burden. In addition, women with vulvodynia are more likely to report other chronic pain conditions, which further alters their quality of life. Future efforts should aim to increase girls', women's and healthcare professionals' education and awareness of vulvodynia, phenotype different subgroups of women based on biopsychosocial characteristics among more diverse samples, conduct longitudinal studies and improve clinical trial designs.

New Insights about Chronic Pelvic Pain Syndrome (CPPS)

BACKGROUND

Chronic pelvic pain syndrome (CPPS) is one of the common diseases in urology and gynecology. CPPS is a multifactorial disorder where pain may originate in any of the urogynecological, gastrointestinal, pelvic musculoskeletal, or nervous systems. The symptoms of CPPS appear to result from an interplay between psychological factors and dysfunction in the immune, neurological, and endocrine systems. The aim of this article was to present new insight about CPPS in order to raise awareness of nursing and medical staff in the identification and diagnosis of the syndrome and to promote an appropriate treatment for each woman who suffers from CPPS.

METHODS

A literature review about the factors associated with CPPS and therapeutic interventions for CPPS was conducted.

RESULTS

CPPS represents a chronic pain syndrome that combines anatomic malfunction of the pelvic floor muscles with malfunction of pain perception linked with psychological and cognitive factors.

CONCLUSIONS

The therapeutic interventions in CPPS cases should, consequently, follow a multidisciplinary approach.

Dysfunctional pain perception and modulation among torture survivors: The role of pain personification

OBJECTIVE

Individuals exposed to trauma, especially those who develop posttraumatic stress disorder (PTSD), are at a higher risk of suffering from chronic pain as well as altered pain perception and modulation. However, the underlying mechanisms of these processes are yet to be established. Recent findings have indicated that trauma survivors tend to personify chronic pain that is developed after the exposure, in a way that resonates with the traumatic experience. The aim of this study was to test whether pain personification plays a significant role in explaining the long-term links between trauma, PTSD and pain.

METHODS

This study is part of a large-scale longitudinal study on ex-prisoners of war (ex-POWs) from the 1973 Yom-Kippur war, who were followed over 35 years after the war. Fifty-nine ex-POWs who were exposed to torture and 44 matched combatants were assessed for PTSD at 18, 30, and 35 post-war. Quantitative somatosensory testing of heat-pain threshold, pain tolerance, conditioned pain modulation (CPM), and temporal summation of pain (TSP), as well as torturing personification, were assessed at 35 years after the war.

RESULTS

Sequential mediation analyses revealed that the associations between torture and heat pain threshold, as well as pain tolerance were mediated by PTSD at several time-points (-1.43<indirect effect < 1.47). Torturing personification significantly mediated the associations between torture, PTSD, CPM and TSP (-0.16 < indirect effect).

CONCLUSIONS

These findings point to the effect of trauma on the subjective orientation towards bodily signals as a key factor in dysfunctional pain modulation.

How Does Myofascial Physical Therapy Attenuate Pain in Chronic Pelvic Pain Syndrome?

Background

Chronic pelvic pain syndrome (CPPS) is a multifactorial disorder comprising structural and functional muscular abnormalities, a dysfunctional pain system, and psychological distress. Myofascial physical Therapy (MPT) that is targeted at improving pelvic muscle functioning is considered a first line nonpharmacological treatment for CPPS, although the precise mechanisms that lead to symptoms alleviation have not yet been elucidated.

Purpose

This longitudinal study aimed to examine the local and systemic effects of MPT intervention, including biopsychophysiological processes, among CPPS patients.

Methods

The study included 50 CPPS women. Morphologic assessment of the levator ani and quantitative sensory testing of the pain system were applied alongside with evaluation of pain-related psychological factors using designated questionnaires. All measures were evaluated both before and after MPT in 39 patients. The long-term effects of MPT were evaluated by clinical pain reports obtained at 3 and 9 months following MPT that were compared with a nontreated group of 11 untreated CPPS women.

Results

Along with an improvement in the clinical pain intensity (p = 0.001) and sensitivity to experimental pain tests (p = 0.001) following MPT, the results also indicate that MPT has anatomical, psychological, and social therapeutic effects (p = 0.04; p = 0.001; p = 0.01, respectively). Furthermore, clinical pain evaluation at 3 and 9 months after MPT revealed a significant improvement in women who received treatment (p = 0.001).

Conclusions

The findings of this pilot study suggest multisystemic (direct and indirect anatomical, neurophysiological, and psychological) effects of MPT on the multifactorial pain disorder of CPPS and therefore place MPT as a mechanism-based intervention.

Sedentary behaviour facilitates conditioned pain modulation in middle-aged and older adults with persistent musculoskeletal pain: a cross-sectional investigation

Introduction:

Higher physical activity (PA) and lower sedentary behaviour (SB) levels have demonstrated beneficial effects on temporal summation (TS) and conditioned pain modulation (CPM) in healthy adults. This cross-sectional study investigated the relationships between PA and SB and TS/CPM responses in individuals with chronic musculoskeletal pain.

Methods:

Sixty-seven middle-aged and older adults with chronic musculoskeletal pain were recruited from the community. Questionnaires measuring demographics, pain, and psychological measures were completed. Physical activity/SB levels were measured using the International Physical Activity Questionnaire—short form and Sedentary Behaviour Questionnaire, respectively. Semmes monofilament was used to assess mechanical TS (MTS) at the most symptomatic (MTS-S) and a reference region (MTS-R); change in the pain scores (baseline-10th application) was used for analysis. Conditioned pain modulation procedure involved suprathreshold pressure pain threshold (PPT-pain4) administered before and after (CPM30sec, CPM60sec, and CPM90sec) conditioning stimulus (2 minutes; ∼12°C cold bath immersion). For analysis, PPT-pain4 (%) change scores were used.

Results:

PPT-pain4 (%) change scores at CPM30sec and CPM60sec demonstrated significant weak positive correlations with SB levels and weak negative correlations with PA measures. After adjusting for confounding variables, a significant positive association was found between SB (h/d) and PPT-pain4 (%) change scores at CPM30sec and CPM60sec. No significant associations between MTS and PA/SB measures.

Conclusion:

Sedentariness is associated with higher pain inhibitory capacity in people with chronic musculoskeletal pain. The observed relationship may be characteristic of a protective (sedentary) behaviour to enhance pain modulatory mechanism. Prospective longitudinal studies using objective PA/SB measures are required to validate the observed relationship in a larger sample size.