Articles: hyperalgesia.
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Randomized Controlled Trial
The result of treatment on vestibular and general pain thresholds in women with provoked vestibulodynia.
To correlate changes in vestibular pain thresholds to general pain thresholds in a subgroup of women with provoked vestibulodynia taking part in a treatment study. ⋯ Treating provoked vestibulodynia by either topical lidocaine or electromyographic biofeedback increased vestibular pain thresholds, reduced dyspareunia, and improved bodily pain. The patients showed a general hypersensitivity to pressure pain compared with controls and in this study the hypersensitivity did not seem to be affected by treating the superficial dyspareunia.
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Complex regional pain syndromes (CRPS) have been recognized with increasing frequency in children. These disorders appear to differ markedly from those observed in adults. The International Association for the Study of Pain diagnostic criteria for CRPS were developed based on adult studies; these criteria have not been validated for children. ⋯ There was a significant correlation between mechanical dynamic allodynia and allodynia to punctate temporal summation (P<0.001). As with adult CRPS, the thermal and mechanical sensory abnormalities appear in different combinations in different patients with similar clinical presentations. In a majority of patients, the pathogenesis of pain is seemingly of central origin.
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To evaluate in patients with different types of facial pain the association between muscle tenderness and a set of characteristics, 649 consecutive outpatients with facial myogenous pain (MP), TMJ disorder, neuropathic pain (NP) and facial pain disorder (FPD) (DSM-IV) were enrolled. For each patient a psychological assessment on the Axis 1 of the DSM-IV and standardized palpation of pericranial and cervical muscles were carried out. A pericranial muscle tenderness score (PTS), a cervical muscle tenderness score (CTS) and a cumulative tenderness score (CUM, range 0-6) were calculated. ⋯ To assess associations between CUM score and patients' demographic and clinical characteristics an ordered logit model was fit and interactions between psychiatric disorders and diagnostic groups were tested. The analysis showed that, regardless of the diagnostic group, anxiety and depression independently increase the likelihood of having one point higher muscle tenderness score (OR=1.55, 95% CI: 1.13-2.12 and OR=1.56, 95% CI: 1.10-2.21, respectively). A careful screening for the presence of an underlying psychiatric disorder, either anxiety or depression, should be part of the clinical evaluation in patients suffering from facial pain.
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Chronic muscle pain is a major clinical problem that is often associated with fatigue. Conversely, chronic fatigue conditions are commonly associated with muscle pain. We tested the hypothesis that muscle fatigue enhances hyperalgesia associated with injection of acidic saline into muscle. We evaluated mechanical sensitivity of the paw (von Frey) in mice after 2 intramuscular injections of saline (20 microL; pH 4, pH 5, pH 6, pH 7.2) in a fatigue and a control group. To induce fatigue, mice were run for 2 h/day for 2 days prior to the first injection and 2 h/day for 2 days prior to the second injection. Muscle lactate, pCO(2), pO(2), creatinine kinase, phosphate, and histology were examined after the fatigue task and compared to a control group. Grip force was significantly decreased after 2 h of running indicating fatigue. The fatigue task did not induce muscle damage as there was no difference in muscle lactate, pCO(2), pO(2), creatinine kinase, phosphate, or histology. The fatigue task altered the dose-response relationship to intramuscular acidic saline injections. Mechanical hyperalgesia was observed in both fatigue and control groups after intramuscular injection of pH 4.0, but only the fatigue group after injection of pH 5. Neither the fatigue nor the control group developed hyperalgesia in response to intramuscular injection of pH 6 or pH 7.2. In conclusion, fatigue modified the susceptibility of mice to acid injection of pH 5.0 to result in mechanical hyperalgesia after 2 injections of pH 5.0. The fatigue task did not produce measurable changes in the muscle tissue suggesting a central mechanism mediating the enhancement of hyperalgesia. ⋯ These data therefore show that muscle fatigue can enhance the likelihood that one develops pain to a mild insult. Clinically, this could relate to the development of pain from such conditions as repetitive strain injury, and may relate to the interrelationship between chronic pain and fatigue.
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Neurogastroenterol. Motil. · Sep 2007
Long-term colonic hypersensitivity in adult rats induced by neonatal unpredictable vs predictable shock.
Our goal was to examine the relationship between early life trauma and the development of visceral hypersensitivity in later life in irritable bowel syndrome (IBS). Rat pups underwent neonatal conditioning: (i) paired odour-shock, where odour is a predictable shock signal, (ii) unpaired odour-shock, where odour is an unpredictable shock signal or (iii) control odour-only with odour presentations and handling without shock. At maturity, colorectal sensitivity was measured as a visceromotor behavioural response. ⋯ Adult responses to CRD were altered by infant experience with shock trauma. However, depending on the context of that early life trauma, there are major differences between the long-term effects of that early life trauma on colonic sensitivity compared to controls. These results strengthen the link between early life trauma and adult IBS, and suggest that unpredictable trauma is a critical factor for later life disorders.