Are There Sex Differences in Affective Modulation of Spinal Nociception and Pain?

Sex differences in the processing and experience of emotion exist. The present study examined whether sex differences in emotion lead to sex differences in affective modulation of pain and spinal nociception (assessed by nociceptive flexion reflex, NFR). Participants were healthy men (n = 47) and women (n = 73). Prior to affective modulation testing, electrocutaneous pain sensitivity was assessed (NFR threshold, pain threshold, pain tolerance). Affective modulation of pain and NFR was then assessed by presenting pictures that vary in emotional valence and arousal (mutilation, attack, death, neutral, families, adventure, erotica) during which suprathreshold electrocutaneous stimulations were delivered. Subjective emotional reactions were assessed after every picture, and nociceptive reactions were assessed after every suprathreshold stimulus. Results indicated women had greater pain sensitivity and also responded more negatively to attack pictures and less positively to erotic pictures. But despite these differences, affective modulation of pain/NFR was not moderated by sex: erotic pictures inhibited pain/NFR and mutilation pictures enhanced pain/NFR. Together, this implies subjective emotional experience does not completely mediate picture-evoked modulation of pain/NFR, a supposition that was further supported by exploratory analyses that demonstrated picture-evoked modulation of pain/NFR was present even after controlling for intra- and inter-individual differences in emotional reactions to pictures. Implications and limitations of these findings are discussed.     

Pain in primary erythromelalgia--a neuropathic component?

Erythromelalgia is a condition characterized by attacks of red, hot, painful extremities with relief of symptoms by cooling and aggravation by warmth. Although the main emphasis has been on pathophysiological mechanisms related to circulatory changes, recent reports have focused on an involvement of efferent small nerve fibers indicating a neuropathic component. Since the symptoms resemble those described in neuropathic pain, we wanted to investigate the possible affection of afferent nerve fibers.

Twenty-five patients with primary erythromelalgia were examined by neurological testing, neurography and quantitative sensory testing. Thresholds for heat, cold, heat-pain and cold-pain detection were compared with those of a group of 29 healthy controls. The patients had significantly higher median heat (39.5 (36.1–40.8) and cold (29.3 (27.1–30.8)-detection thresholds at the dorsal aspects of their feet compared to the controls (37.0 (35.4–37.7) and 31.2 (30.3–31.5) respectively). These findings show an impaired small fiber function inside or close to the symptomatic area in this group of erythromelalgia patients. Seven patients had brush-evoked allodynia and fourteen had punctate hyperalgesia inside or close to the symptomatic areas in their feet.

When comparing the individual results, there is a tendency to clustering of patients in two separate groups; reduced small fiber input/no hyperalgesia and normal thermal thresholds/hyperalgesia.

Our results showing an affection of afferent small nerve fibers together with the nature of the symptoms, suggest that the pain experienced by erythromelalgia patients could have a neuropathic component.     

The Effects of Self–Pain Management on the Intensity of Pain and Pain Management Methods in Arthritic Patients

The aims of this study were to investigate the effects of pain management education on the intensity of pain and frequency of utilization of pain management methods in two groups of patients with arthritis of different pathogenesis and clinical features, and to compare whether a significant difference existed between the two groups. The study was carried out between September 2007 and June 2008 on 30 female patients with gonarthrosis and 30 female patients with rheumatoid arthritis (RA) followed at the rheumatology outpatient clinic of a university hospital. Data on sociodemographic characteristics and those related with the illness were collected using a special survey. Each patient was given information about the features, causes, and treatment of the arthritis and how to cope with pain, emphasizing the importance of pain management methods. The intensity of pain and efficacy of pain management methods were assessed using the McGill Pain Questionnaire and the Pain Management Inventory at baseline and the second and sixth weeks after the education. The SPSS (v15.0) statistical package was used for statistical analysis. After education, significant improvements in pain intensity scores compared with baseline scores were observed in both groups (p < .05), and there was no significant difference between the RA and gonarthrosis groups. Among the various pain management methods, the education program led to significantly more utilization of massaging the painful area, exercising, and using complementary methods to control stress in both groups of patients, and there was no significant difference between the groups. In conclusion, the pain management education given in this study alleviated the intensity of pain and significantly increased the use of some pain management methods in both gonarthrosis and RA cases.     

Nursing’s Role in Cancer Pain Management

Nurses have advanced practice, research, and education in the field of cancer pain management. This paper highlights the contributions nurses have made to pain science and practice through literature published in the past 3 years. Work accomplished by nurses is examined in the areas of pain assessment, pain management, intervention-based research, evidence-based practice, patient education, and palliative care. Nurses serve as advocates for empowering patients to engage in self-management of their pain, and offer education and support to patients and families at their most vulnerable times. Nurse researchers have been at the forefront of work to develop and test new instruments and approaches to measure pain, elucidate pain experiences through quantitative and qualitative methodologies, and gauge the quality of pain care for patients and its impact on their caregivers. This research has uncovered many patient, health care professional, and systemic barriers to effective pain control, and has offered feasible solutions to overcoming these barriers.     

Advances in Translational Neuropathic Research: Example of Enantioselective Pharmacokinetic–Pharmacodynamic Modeling of Ketamine-induced Pain Relief in Complex Regional Pain Syndrome

Historically, complex regional pain syndrome (CRPS) was poorly defined, which meant that scientists and clinicians faced much uncertainty in the study, diagnosis, and treatment of the syndrome. The problem could be attributed to a nonspecific diagnostic criteria, unknown pathophysiologic causes, and limited treatment options. The two forms of CRPS still are painful, debilitating disorders whose sufferers carry heavy emotional burdens. Current research has shown that CRPS I and CRPS II are distinctive processes, and the presence or absence of a partial nerve lesion distinguishes them apart. Ketamine has been the focus of various studies involving the treatment of CRPS; however, currently, there is incomplete data from evidence-based studies. The question as to why ketamine is effective in controlling the symptoms of a subset of patients with CRPS and not others remains to be answered. A possible explanation to this phenomenon is pharmacogenetic differences that may exist in different patient populations. This review summarizes important translational work recently published on the treatment of CRPS using ketamine.     

Racial Differences in Adolescents’ Answering Questions About Suicide

The present purpose was to examine racial differences in response rate and serious behavioral suicide risk based on the national Youth Risk Behavior Surveillance Survey (YRBS). Data from 15,245 adolescents (YRBS, 2011) were included. Survey items pertaining to making suicidal plans and attempting suicide were included. Significant differences in responding and content emerged, especially with regard to suicide attempts. Racial minority adolescents are at elevated risk for serious suicidal behaviors and are more likely to omit items pertaining to suicide attempts. African American adolescents rarely reported having attempted suicide, but they also frequently failed to respond to that question.     

Should Exercises be Painful or not? Effects on Clinical and Experimental Pain in Individuals with Shoulder Pain

Exercise can reduce pain, however the effect of painful versus non-painful exercises is uncertain. The primary aim of this randomized crossover study was to compare the effect of painful versus nonpainful isometric shoulder exercises on pain intensity after exercise in individuals with rotator cuff-related shoulder pain. Secondary exploratory aims were to describe the effects on pressure pain thresholds (PPTs), conditioned pain modulation (CPM) and muscle strength. On separate days, 35 individuals performed painful isometric shoulder exercises (external rotation; 20% above pain threshold), nonpainful isometric shoulder exercises (external rotation; 20% below pain threshold), and a rest condition, in randomised order. Shoulder pain intensity, PPTs, CPM, and external rotation strength were assessed before, immediately after and 45 minutes after conditions. No significant differences were observed between painful and nonpainful exercises. Visual analogue scale scores increased immediately after both painful and non-painful exercises compared with rest (P = .047, partial ƞ² = .07), but were similar to preexercise levels after 45 minutes. No changes in PPTs, CPM, or muscle strength after exercises compared with rest were observed. Painful and non-painful isometric exercises caused a moderate but short-lasting increase in shoulder pain in individuals with RCRSP. Isometric exercises had no effect on pain sensitivity and shoulder muscle strength or CPM.PerspectiveThis study evaluated for the first time in individuals with rotator cuff-related shoulder pain the effects of painful versus non-painful isometric exercises on different pain-related outcome measures. Both painful and non-painful isometric exercises caused a moderate but relatively short-lasting increase in shoulder pain in individuals with rotator cuff-related shoulder pain.Trial registration number: (ClinicalTrials.gov) NCT03675399     

Pain assessment in profound cognitive impaired children using the Checklist Pain Behavior; is item reduction valid?

There are both commonalities and idiosyncratic features in the reaction of pain children with profound cognitive impairment (CI), and that there is no evidence to suggest that idiosyncratic behavior is more characteristic of this population than of any other population. The main objective of this study was to identify whether the 23-item version of the Checklist Pain Behavior could be reduced to 10 items. Previous research demonstrated that only these 10 items discriminated between absence and presence of pain. Second, we wanted to explore the underlying structure of these 10 selected items including its performance. Data of 477 observations in 73 children were used. All these children were video-taped while they were admitted to the Sophia Children's Hospital for surgery, twice before and five times after surgery. These video-tapes were scored by an independent observer. A visual analogue scale (VAS) by a researcher was used to assess the presence of pain. We tested whether the underlying structure was unidimensional, and whether it had differential qualities between pain and no pain, and to which degree. Using a modern psychometric method, i.e., Mokken scaling model, we unraveled the interdependency of the pain response in CI-children, in that the structure turned out to be unidimensional. In addition, these behaviors could be hierarchically ordered in terms of frequency of occurrences. Finally, these behaviors had to a high degree the potentialities to estimate the likelihood of occurrence of pain.     

Pain control in ambulatory cancer patients--can we do better?

To evaluate the degree of pain control among ambulatory cancer patients visiting the outpatient clinics of three oncology centers in south Israel, these patients were interviewed using the Brief Pain Inventory translated into Hebrew (BPI-Heb). Patients suffering from pain at least three times a week or reporting taking daily analgesics during the last two weeks were enrolled. Non-Hebrew speakers and patients too frail or ill were excluded. The study population included 218 subjects. Substantial pain was experienced by 77%, the majority was not adequately treated (81%), and 75% were undermedicated. The daily living activities of the majority of patients (64%) were moderately to severely impacted. Pain control was not associated with any of the sociodemographic or previous treatment profile variables, or by physicians' pain assessment. The physicians' and the patients' ratings of the extent to which pain interfered with the patients' activities fully agreed (+/-2) in fewer than half of the patients. Physicians estimated more severe pain levels, but underestimated its impact on everyday life. These data indicate that better pain control for ambulatory cancer patients is needed and that more information about patients' pain and its impact should be solicited. Further training of care providers is needed to improve the relief from cancer pain and the quality of life of patients.     

Does Pain Cause the Perception of Fatigue in Patients with Chronic Pain? Findings from Studies for Management of Diabetic Peripheral Neuropathic Pain with Duloxetine

A major issue in pain literature is whether an etiological association between pain, sleep, and vitality exists. We utilized data from clinical trials of duloxetine for management of diabetic peripheral neuropathic pain (DPNP) to investigate these associations. Data were pooled from 3 double-blind, randomized, placebo-controlled, 12-week trials of patients without mood disorder ( N  =  1,139). After excluding 442 patients who reported maximum vitality at baseline, experienced treatment-emergent somnolence, asthenia or fatigue, or were taking sedating concomitant medications or duloxetine 20 mg/day, 697 were included in the analysis. Efficacy measures included weekly mean scores for average daily and night pain, pain interference with sleep, and vitality. Baseline to end point mean improvements in daily and night pain, Brief Pain Inventory sleep interference, and vitality were significantly superior for duloxetine compared with placebo ( P  ≤ 0.001). Correlations between changes in daily and night pain, and sleep interference with vitality changes were −0.34, −0.32, and −0.28, respectively ( P  < 0.001). The direct effect of treatment on change in vitality was statistically significant (68%, P  = 0.010) when assessed in an indirect manner through change in sleep interference alone but not in daily or night pain solely. Path analyses suggested vitality improvement in patients with chronic pain may be secondary to improvement in pain by duloxetine. Results do not prove pain causes fatigue, but indicate in DPNP patients with fatigue that treatment of pain can improve perception of improvement in fatigue. Thus, improvement of pain may be important in the context of trying to improve fatigue in DPNP patients.     

Treating Pain in Dementia—Are We Good Enough?

Up to 80% of nursing home residents may be experiencing pain; however, in many cases their pain is not diagnosed and/or treated. People with moderate to severe dementia may have impaired communication, and this can impact on their self-report of pain. Drug treatment should be used cautiously.

This report is adapted from paineurope 2015; Issue 1, ©Haymarket Medical Publications Ltd., and is presented with permission. paineurope is provided as a service to pain management by Mundipharma International, Ltd., and is distributed free of charge to health care professionals in Europe. Archival issues can be viewed via the Web site: www.paineurope.com, at which health professionals can find links to the original articles and request copies of the quarterly publication and access additional pain education and pain management resources.     

How Can We Best Reduce Pain Catastrophizing in Adults With Chronic Noncancer Pain? A Systematic Review and Meta-Analysis

Pain catastrophizing (PC), defined as an exaggerated negative cognitive-affective orientation toward pain, is one of the strongest psychological predictors of pain outcomes. Although regularly included as a process variable in clinical trials, there have been no comprehensive reviews of how it can be modified. Using a registered protocol (PROSPERO 2016 CRD42016042761), we searched MEDLINE, PsychINFO, EMBASE, CINAHL, and CENTRAL up to November 2016 for all randomized controlled trials measuring PC in adults with chronic noncancer pain. Two authors independently screened studies and assessed bias risk using the Cochrane tool. Quality of evidence was rated according to Grading of Recommendations Assessment, Development and Evaluation criteria. We included 79 studies (n?=?9,914), which mostly recruited participants with musculoskeletal pain and had low risk of bias. Meta-analyses (standardized mean difference) showed 9 interventions had efficacy compared with waitlist/usual care or active control, although evidence quality was often low. The best evidence (moderate-high quality) was found for cognitive-behavioral therapy, multimodal treatment, and acceptance and commitment therapy. Effects were generally of medium strength and had questionable clinical significance. When only the 8 studies targeting people with high PC were included, effects were larger and more consistent. Multimodal treatment showed the strongest effects when all studies were considered, whereas cognitive-behavioral therapy had the best evidence among targeted studies.

Immediate Changes in Neck Pain Intensity and Widespread Pressure Pain Sensitivity in Patients With Bilateral Chronic Mechanical Neck Pain: A Randomized Controlled Trial of Thoracic Thrust Manipulation vs Non–Thrust Mobilization

Objective

The purpose of this study was to compare the effects of thoracic thrust manipulation vs thoracic non–thrust mobilization in patients with bilateral chronic mechanical neck pain on pressure pain sensitivity and neck pain intensity.

Methods

Fifty-two patients (58% were female) were randomly assigned to a thoracic spine thrust manipulation group or of thoracic non–thrust mobilization group. Pressure pain thresholds (PPTs) over C5-C6 zygapophyseal joint, second metacarpal, and tibialis anterior muscle and neck pain intensity (11-point Numerical Pain Rate Scale) were collected at baseline and 10 minutes after the intervention by an assessor blinded to group allocation. Mixed-model analyses of variance (ANOVAs) were used to examine the effects of the treatment on each outcome. The primary analysis was the group * time interaction.

Results

No significant interactions were found with the mixed-model ANOVAs for any PPT (C5-C6: P > .252; second metacarpal: P > .452; tibialis anterior: P > .273): both groups exhibited similar increases in PPT (all, P < .01), but within-group and between-group effect sizes were small (standardized mean score difference [SMD] < 0.22). The ANOVA found that patients receiving thoracic spine thrust manipulation experienced a greater decrease in neck pain (between-group mean difference: 1.4; 95% confidence interval, 0.8-2.1) than did those receiving thoracic spine non–thrust mobilization (P < .001). Within-group effect sizes were large for both groups (SMD > 2.1), and between-group effect size was also large (SMD = 1.3) in favor of the manipulative group.

Conclusions

The results of this randomized clinical trial suggest that thoracic thrust manipulation and non–thrust mobilization induce similar changes in widespread PPT in individuals with mechanical neck pain; however, the changes were clinically small. We also found that thoracic thrust manipulation was more effective than thoracic non–thrust mobilization for decreasing intensity of neck pain for patients with bilateral chronic mechanical neck pain.