Pain
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Comparative Study
Intramuscular injection of tumor necrosis factor-alpha induces muscle hyperalgesia in rats.
The role of proinflammatory cytokines in neuropathic and inflammatory pain is well established. Recent studies suggest that cytokines such as tumor necrosis factor-alpha (TNF) may also be involved in the development of muscle pain. To investigate the pathophysiology of intramuscular TNF, exogenous TNF (0.1-10 microg), formalin (9%) or vehicle was injected into the gastrocnemius or biceps brachii muscles of rats. ⋯ TNF and formalin evoked intramuscular upregulation of CGRP and NGF, whereas PGE2 was increased exclusively after TNF injection. These findings allow us to speculate that endogenous TNF may play a role in the development of muscle hyperalgesia. Targeting proinflammatory cytokines might be beneficial for the treatment of musculoskeletal pain syndromes.
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Randomized Controlled Trial Comparative Study Clinical Trial
Negative affect: effects on an evaluative measure of human pain.
Prior work indicates that exposure to fear-inducing shock inhibits finger-withdrawal to radiant heat in humans (hypoalgesia), whereas anxiety induced by threat of shock enhances reactivity (hyperalgesia; Pain 84 (2000) 65-75). Although finger-withdrawal latencies are thought to reflect changes in pain sensitivity, additional measures of pain are needed to determine whether pain perception is altered. The present study examined the impact of negative affect on visual analog scale (VAS) ratings of fixed duration thermal stimuli. ⋯ Results suggest that both negative affect manipulations reduced pain. Manipulation checks indicated that the emotion-induction treatments induced similar levels of fear but with different arousal levels. Potential mechanisms for affect induced changes in pain are discussed.
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Comparative Study
Differential effects of expressive anger regulation on chronic pain intensity in CRPS and non-CRPS limb pain patients.
Research has shown that the anger management styles of both anger-in (suppression of anger) and anger-out (direct verbal or physical expression of anger) may be associated with elevated chronic pain intensity. Only the effects of anger-out appear to be mediated by increased physiological stress responsiveness. Given the catecholamine-sensitive nature of pain mechanisms in complex regional pain syndrome (CRPS), it was hypothesized that anger-out, but not anger-in, would demonstrate a stronger relationship with chronic pain intensity in CRPS patients than in non-CRPS chronic pain patients. ⋯ The AIS main effect on MPQ-A ratings was accounted for entirely by overlap with negative affect. Results are consistent with a greater negative impact of anger-out on chronic pain intensity in conditions reflecting catecholamine-sensitive pain mechanisms, presumably due to the association between anger-out and elevated physiological stress responsiveness. These results further support previous suggestions that anger-in and anger-out may affect pain through different mechanisms.
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Case Reports
Pulsed radiofrequency treatment of the Gasserian ganglion in patients with idiopathic trigeminal neuralgia.
Pulsed radiofrequency treatment has been described as a minimal invasive alternative to radiofrequency thermocoagulation for the management of chronic pain syndromes. We present here our first five high-risk patients with idiopathic trigeminal neuralgia who were treated with pulsed radiofrequency after multidisciplinary assessment; with a mean follow-up of 19.2 months (range 10-26). ⋯ An excellent long-term effect was achieved in three of the five patients, a partial effect in one patient and a short-term effect in one patient. No neurological side effects or complications were reported.
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Attachment theory and research suggest that patterns of interpersonal relationships may be important determinants of illness behavior, care seeking, and treatment response in individuals with chronic health problems, including chronic pain. Attachment styles have been shown to be associated with psychological adjustment in the context of chronic illness, but little research has been conducted so far examining these relationships in patients with chronic pain. ⋯ Preoccupied attachment style was associated with greater than weekly pain-related visits at 12 months follow-up, even after controlling for depression, catastrophizing and pre-treatment pain-related health care utilization. The findings suggest that attachment style may be a useful construct for examining factors affecting adjustment and treatment response of patients with chronic pain.