Pain
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Randomized Controlled Trial Clinical Trial
Effects of low-power laser exposure on masseter muscle pain and microcirculation.
One possible cause of the reported positive treatment effect by low-power laser exposure in muscle pain conditions could be that it increases the local microcirculation. The aim of this study was therefore to investigate the immediate effects on masseter muscle blood flow by low-power laser exposure in patients with chronic orofacial pain of muscular origin in comparison to healthy individuals. Twelve patients with myofascial pain of orofacial muscles and 12 age and gender matched healthy individuals participated in the study. ⋯ The blood flow did not change significantly in the patients, but increased after active laser exposure and decreased after placebo exposure in the healthy individuals. The difference between active laser and placebo was significant. In conclusion, the results of this study do not support an effect of low-power laser exposure on masseter muscle microcirculation in patients with chronic orofacial pain of muscular origin.
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Randomized Controlled Trial Clinical Trial
Potential utility of the peripheral analgesic properties of morphine in stomatitis-related pain: a pilot study.
To determine the potential clinical utility of peripheral opioid action using a clinical model of cancer treatment-induced inflammation and pain that allowed for topical application of morphine in the damaged tissue (oral mucosa). This pilot study followed a two blocks design. Ten patients with painful oral mucositis were enrolled in the first block (dose-response relationship finding) and randomized in two groups to receive oral rinses with 15 ml of either 1 per thousand or 2 per thousand morphine solution. ⋯ During our experiment no systemically active detectable concentrations of morphine were found (GC-MS analysis). The most important side effect attributable to morphine mouthwashes was burning/itching sensation (very mild to mild intensity). Patients with painful chemoradiotherapy-induced stomatitis could be alleviated using topical morphine mouthwashes.
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Patients with fibromyalgia syndrome (FMS) report chronic pain related to abnormal sensitivity of muscles that is reflected by so-called tender points (TP). TP represent areas of abnormal mechanical pain thresholds that have only shown a minor correlation with clinical pain of FMS patients and seem to be better suited for predicting distress. Pain-related negative affect (PRNA), abnormal temporal summation of second pain (termed wind-up or WU), and abnormal WU decay are frequently present in FMS patients. ⋯ Hierarchical regression analysis demonstrated that the combination of PRNA ratings, TP count, and WU decay ratings predicted 49.7% of the variance of clinical pain in FMS. This model demonstrates independent relationships of biological and psychological factors to clinical pain and underscores the important role of abnormal peripheral and central pain mechanisms for FMS. Therefore, the combination of PRNA, TP count, and WU decay may provide an excellent measure for future clinical studies of FMS patients.
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Irritable bowel syndrome (IBS) is one of the most common gastrointestinal illnesses and is characterized by altered visceral perception. The aim of the study was to determine if local anesthetic blockade of peripheral visceral nociceptive input reduces both visceral and cutaneous secondary hyperalgesia in IBS patients. Ten women with IBS (mean age 30+/-10 years) and ten control subjects (all women) (mean age 29+/-7 years) rated pain intensity and unpleasantness to distension of the rectum (35 mmHg) and thermal stimulation (47 degrees C) of the foot before and after rectal administration of either lidocaine jelly or saline jelly in a double blind crossover design. ⋯ The results of this study support the hypothesis that local anesthetic blockade of peripheral impulse input from the rectum/colon reduces both visceral and cutaneous secondary hyperalgesia in IBS patients. The results provide further evidence that visceral hyperalgesia and secondary cutaneous hyperalgesia in IBS reflects central sensitization mechanisms that are dynamically maintained by tonic impulse input from the rectum/colon. Rectal administration of lidocaine jelly may also be a safe and effective means of reducing pain symptoms in IBS patients.
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Secondary mechanical hyperalgesia has been demonstrated in postoperative patients indicating that central sensitization occurs after surgery. However, the underlying mechanisms are unknown. Here, we studied the role of spinal N-methyl-D-aspartate and alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA)/kainate receptors for pain behaviors indicating secondary hyperalgesia caused by gastrocnemius incision in the rat. ⋯ These results indicate that spinal sensitization contributing to behaviors for secondary hyperalgesia after incision requires Ca(2+) permeable AMPA/kainate receptors. The data further demonstrate that behaviors for secondary mechanical hyperalgesia after incision can be inhibited without affecting behaviors for primary mechanical hyperalgesia and guarding. Mechanisms for central sensitization causing secondary hyperalgesia in postoperative patients may therefore be separated from spontaneous pain and hyperalgesia that arises adjacent to the area of the incision.