Self-reported somatosensory symptoms of neuropathic pain in fibromyalgia and chronic widespread pain correlate with tender point count and pressure-pain thresholds

Knee pain during daily tasks, knee osteoarthritis severity, and widespread pain

BACKGROUND

The presence of widespread pain is easily determined and is known to increase the risk for persistent symptoms.

OBJECTIVE

The study hypothesis was that people with no or minimal knee osteoarthritis (OA) and high Western Ontario and McMaster Universities (WOMAC) Pain Scale scores would be more likely than other subgroups to report widespread pain.

DESIGN

A cross-sectional design was used.

METHODS

Data were obtained from the Multicenter Osteoarthritis Study, which includes people with or at high risk for knee OA. The inclusion criteria were met by 755 people with unilateral knee pain and 851 people with bilateral knee pain. Widespread pain was assessed with body diagrams, and radiographic Kellgren-Lawrence grades were recorded for each knee. Knee pain during daily tasks was quantified with WOMAC Pain Scale scores.

RESULTS

Compared with people who had high levels of pain and knee OA, people with a low level of pain and a high level of knee OA, and people with low levels of pain and knee OA, a higher proportion of people with a high level of knee pain and a low level of knee OA had widespread pain. This result was particularly true for people with bilateral knee pain, for whom relative risk estimates ranged from 1.7 (95% confidence interval=1.2-2.4) to 2.3 (95% confidence interval=1.6-3.3).

LIMITATIONS

The cross-sectional design was a limitation.

CONCLUSIONS

People with either no or minimal knee OA and a high level of knee pain during daily tasks are particularly likely to report widespread pain. This subgroup is likely to be at risk for not responding to knee OA treatment that focuses only on physical impairments. Assessment of widespread pain along with knee pain intensity and OA status may assist physical therapists in identifying people who may require additional treatment.

Prevalence of the fibromyalgia phenotype in patients with spine pain presenting to a tertiary care pain clinic and the potential treatment implications

OBJECTIVE

Injections for spinal pain have high failure rates, emphasizing the importance of patient selection. It is possible that detecting the presence of a fibromyalgia (FM)-like phenotype could aid in prediction, because in these individuals a peripheral injection would not address pain due to alterations in central neurotransmission. We undertook this study to test the hypothesis that patients who have spine pain meeting survey criteria for FM would be phenotypically distinct from those who do not.

METHODS

We studied 548 patients diagnosed as having primary spine pain. All patients completed validated self-report questionnaires, including the Brief Pain Inventory, the PainDETECT questionnaire, the Hospital Anxiety and Depression Scale, measures of physical function, and the FM criteria and severity scales.

RESULTS

Forty-two percent of the patients were FM positive according to the FM criteria and severity scales. Compared with FM-negative patients, FM-positive patients were more likely to be younger, unemployed, and receiving compensation for pain and to have greater pain severity and pain interference and more neuropathic pain descriptors as well as higher levels of depression and anxiety and a lower level of physical function (P < 0.002 for each comparison). Female sex, neuropathic pain, pain interference, and anxiety were independently predictive of FM status in a multivariate analysis (P < 0.01 for all variables). Receiver operating characteristic curve analysis showed a strength of association of 0.80 as measured by the cross-validated C statistic.

CONCLUSION

Using the FM criteria and severity scales, we demonstrated profound phenotypic differences in a population of patients with spine pain. Although centralized pain cannot be confirmed with a self-report instrument alone, the pathophysiology of FM may help explain a portion of the variability of responses to spine interventions.

Perception and pain thresholds for cutaneous heat and cold, and rectal distension: associations and disassociations

BACKGROUND

Hypersensitivity to somatic or visceral pain has been reported in numerous clinical conditions such as fibromyalgia or the irritable bowel syndrome, and general hypersensitivity has been proposed to be the underlying mechanism. However, cross-modal relationships especially between somatic and visceral pain have rarely been investigated even in healthy volunteers. Furthermore, psychological influences on pain have rarely been characterized across modalities.

METHODS

Sixty-one healthy participants underwent testing of perception and pain thresholds for cutaneous thermode heat and cold, as well as for rectal balloon distension. Psychological testing for anxiety, depression, and pain experience (including catastrophizing and coping) as well as cardiac interoception was performed. Measurement quality and the correlations between the different modalities were examined.

KEY RESULTS

Significant correlations existed between the perception thresholds for cold/heat (τB  = -0.28, p = 0.002) and cold/distension (τB  = -0.21, p = 0.03) and for the pain thresholds for cold/heat (r = -0.61, p < 0.001) and heat/distension (r = 0.33, p = 0.01). No association was found between pain thresholds and anxiety, depression, psychological experience with and processing of pain, or cardiac interoception. Retest reliabilities for pain measurements were satisfying after short intertrial intervals (all intraclass correlation coefficients >0.8), but less so after longer intervals. The individuals contributing to the respective correlations differ between measurements.

CONCLUSIONS & INFERENCES

Moderate associations were found for pain thresholds across modalities. The strength of the associations and their stability over time warrants further investigation and might serve to increase the understanding of conditions affecting multiple pain modalities.

PainDETECT: a suitable screening tool for neuropathic pain in patients with painful post-traumatic trigeminal nerve injuries?

The PainDETECT questionnaire (PD-Q), originally developed and validated in a multicentre study of neuropathic pain (NeP) patients with back pain, is increasingly being applied to other pain conditions. The present study assessed whether the PD-Q would be a suitable screening tool for detecting NeP in patients with post-traumatic inferior alveolar nerve injury (IANI) and lingual nerve injury (LNI). A prospective cohort of patients with clinically diagnosed neuropathy was given the PD-Q at their clinic appointment, or it was sent to them after their consultation. Eighty-nine patients (IANI = 56, LNI = 33) were included in the study, 75 of whom suffered from painful neuropathy. Of the patients who completed the questionnaire fully (n = 56), allowing a summary score to be calculated, 34% were classified as having 'likely NeP' according to the PD-Q; 41% of patients scored in the uncertain classification range and the remaining quarter in the 'likely nociceptive' classification. There was a significant association between PD-Q scores and pain intensity levels across the sample, with those classified as likely NeP reporting high levels of pain. The results suggest that the PD-Q in its current format is not a suitable screening tool for NeP associated with IANI or LNI.

Neuropathic features of joint pain: a community-based study

OBJECTIVE

Quantitative sensory testing (QST) and questionnaire-based assessments have been used to demonstrate features of neuropathic pain in subjects with musculoskeletal pain. However, their direct relationship has not been investigated in the community. The purpose of this study was to conduct an observational study to describe the characteristics of joint pain and to examine the relationship between QST measures and the PainDETECT Questionnaire (PD-Q).

METHODS

Warm detection, heat pain, and mechanical pain thresholds as well as mechanical pain sensitivity over the sternum were determined and the PD-Q scores were calculated in a cross-sectional study of 462 participants in the Chingford Study. Comparisons were made between subjects with and those without joint pain. Logistic regression modeling was used to describe the association between neuropathic pain features, as determined by the PD-Q score, and each of the QST measures individually, adjusting for age, body mass index, and use of pain-modifying medications.

RESULTS

A total of 66.2% of the subjects reported recent joint pain, with a median average pain severity of 5 of 10. There was increased sensitivity to painful stimuli in the group with pain as compared to the pain-free group, and this persisted after stratification by pain-modifying medication use. While only 6.7% of subjects had possible neuropathic pain features and 1.9% likely neuropathic pain features according to the standard PD-Q thresholds, features of neuropathic pain were common and were present in >50% of those reporting pain of at least moderate severity. Heat pain thresholds and mechanical pain sensitivity were significantly associated with features of neuropathic pain identified using the PD-Q, with an odds ratio (OR) of 0.88 (95% confidence interval [95% CI] 0.79-0.97; P = 0.011) and an OR of 1.24 (95% CI 1.04-1.48; P = 0.018), respectively.

CONCLUSION

QST measures and the PD-Q identified features of neuropathic pain in subjects in this community-based study, with significant overlap between the findings of the two techniques.

Knee extensor strength is associated with pressure pain thresholds in adults with fibromyalgia

OBJECTIVE

Individuals with fibromyalgia (FM) have lower muscle strength and lower pressure pain thresholds (PPT). The primary aim of this study was to determine the associations between muscle strength and PPT in adults with FM to test the hypothesis that greater measures of muscle strength would be associated with greater values of PPT. Secondary aims included determining the effects of pain severity and the peak uptake of oxygen (VO2) on the associations between muscle strength and PPT.

METHODS

Knee extensor and flexor strength (N = 69) was measured in the dominant leg using a dynamometer, and PPT was assessed using an electronic algometer. Pain severity was determined using the Multidimensional Pain Inventory, and peak VO2 uptake was quantified using an electronically braked cycle ergometer.

RESULTS

Univariable linear regression analysis demonstrated a significant association between PPT (dependent variable) and isometric knee extensor (P<.001), isokinetic (60°/s) knee extensor (P = .002), and isokinetic (60°/s) knee flexor strength (P = .043). In a multiple variable linear regression analysis adjusted for age, sex, pain severity, body mass index and peak VO2 uptake, a significant association was found between PPT and isometric knee extensor strength (P = .008). In a similar multiple variable analysis, a significant association was found between PPT and isokinetic knee extensor strength (P = .044).

CONCLUSION

Greater measures of isometric and isokinetic knee extensor strength were significantly associated with greater values of PPT in both univariable and multiple variable linear regression models.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01253395.

Construct validity of an instrument to measure neuropathic pain in women with bladder pain syndrome

AIMS

To determine the construct validity of an instrument to measure neuropathic pain in women with bladder pain syndrome (BPS). Our hypothesis is that neuropathic, bladder, and bowel pain represent different constructs in women with BPS.

METHODS

Secondary planned analysis of a prospective cross-sectional study of 150 women with BPS. The relationship between neuropathic pain, urinary, and bowel symptoms was assessed.

RESULTS

The correlation of the total neuropathic pain score with total urinary and bowel symptom scores was low to moderate (r = 0.28-0.49). The correlation of specific neuropathic pain items with bladder and bowel pain was also low to moderate (r = 0.12-0.36). Women with neuropathic pain had significantly higher scores for urinary urgency, bladder pain, abdominal pain, diarrhea, and constipation than women with non-neuropathic pain (all P < 0.0001).

CONCLUSION

Somatosensory neuropathic pain and "visceral" bladder and bowel pain represent separate but related constructs in women with BPS.

Sleep deprivation in chronic somatoform pain-effects on mood and pain regulation

Sleep deprivation was found to exert complex effects on affective dimensions and modalities of pain perception both in healthy volunteers and patients with major depression. Considering multifaceted links between mood and pain regulation in patients with chronic somatoform pain, it is intriguing to study sleep deprivation effects for the first time in this group of patients. Twenty patients with a somatoform pain disorder according to ICD-10 diagnostic criteria were sleep-deprived for one night, followed by one recovery night. Clinical pain complaints (visual analog scale), detection- and pain thresholds (temperature and pressure) as well as mood states (Profile of Mood States) were assessed on the day prior to the experiment, on the day after sleep deprivation and on the day after recovery sleep. We found a discrepancy between significantly increased clinical pain complaints and unaltered experimental pain perception after sleep deprivation. Only the clinical pain complaints, but not the experimental pain thresholds were correlated with tiredness-associated symptoms. Total mood disturbances decreased and feelings of depression and anger improved significantly after sleep deprivation. However, these changes were not correlated with a change in clinical pain perception. We conclude that sleep deprivation may generally change the reagibility of the limbic system, but mood processing and pain processing may be affected in an opposite way reflecting neurobiological differences between emotional regulation and interoceptive pain processing.

Association of neuropathic pain with bladder, bowel and catastrophizing symptoms in women with bladder pain syndrome

PURPOSE

In this study we determined if there is an association of neuropathic pain with urinary, bowel and catastrophizing symptoms in women with bladder pain syndrome.

MATERIALS AND METHODS

Female patients with a diagnosis of bladder pain syndrome completed validated questionnaires to assess neuropathic pain, urinary and bowel symptoms, quality of life and pain catastrophizing. Women were dichotomized into neuropathic pain and nonneuropathic pain groups. Urinary and bowel symptoms, pain catastrophizing and quality of life scores were compared between the 2 groups using parametric and nonparametric tests.

RESULTS

Of 150 women with bladder pain syndrome 40 (27%) had features of neuropathic pain while 110 (73%) did not. Women with features of neuropathic pain had significantly worse urinary urgency (mean ± SD 3.1 ± 3.1 vs 2.1 ± 1.7, p <0.001), bladder pain (3.0 ± 1.1 vs 2.0 ± 1.3, p <0.001), bowel pain (8.8 ± 4.0 vs 5.3 ± 3.6, p <0.001), diarrhea (7.8 ± 6.1 vs 4.1 ± 4.3, p <0.001), quality of life (12.2 ± 5.5 vs 9.8 ± 3.8, p <0.001) and higher pain catastrophizing (32.2 ± 12.4 vs 23.1 ± 14.3, p <0.001) scores than those without neuropathic pain.

CONCLUSIONS

In women with bladder pain syndrome the presence of neuropathic pain is significantly associated with the severity of bladder and bowel pain, urinary urgency and diarrhea. Women with features of neuropathic pain also have worse pain catastrophizing and quality of life than those without features of neuropathic pain.

Tactile perceptual processes and their relationship to medically unexplained symptoms and health anxiety

OBJECTIVE

The Somatic Signal Detection Task (SSDT; Lloyd, Manson, Brown and Poliakoff, 2008) is an innovative paradigm to study perceptual processes related to physical symptoms. It allows examining touch illusions as a laboratory analog of medically unexplained symptoms (MUS) according to the cognitive model of MUS proposed by Brown (2004). The present study compared psychopathologic measures of MUS and health anxiety with SSDT parameters. Furthermore, we aimed to define a reliable measurement of tactile perception threshold.

METHODS

67 participants of a student population reported whether they detected tactile stimuli at their fingertip which were presented in half of the test trials. An additional brief visual stimulus was displayed with a probability of 50%. The rate of false-positive perceptions of the tactile stimulus in its absence, response bias, tactile sensitivity, and tactile perception thresholds was recorded. Questionnaires were used to assess MUS and health anxiety.

RESULTS

The visual stimulus led to a more liberal response criterion (i.e., the tendency to report tactile perceptions irrespective of whether a stimulus was presented or not) and a non-significant increase in tactile sensitivity. The false-alarm rate when reporting the tactile stimulus was correlated with MUS (r=.26). Tactile perception thresholds were measured reliably (r(tt)=.84).

CONCLUSION

Some of the SSDT parameters, especially the response criterion (c), were related to self-report-measures of MUS and health anxiety. Previous SSDT results were replicated and extended. Further SSDT studies with clinical samples are needed.