Pain
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To inform case definition for neck/shoulder pain in epidemiological research, we compared levels of disability, patterns of association, and prognosis for pain that was limited to the neck or shoulders (LNSP) and more generalised musculoskeletal pain that involved the neck or shoulder(s) (GPNS). Baseline data on musculoskeletal pain, disability, and potential correlates were collected by questionnaire from 12,195 workers in 47 occupational groups (mostly office workers, nurses, and manual workers) in 18 countries (response rate = 70%). Continuing pain after a mean interval of 14 months was ascertained through a follow-up questionnaire in 9150 workers from 45 occupational groups. ⋯ Moreover, it showed significantly stronger associations with somatising tendency (PRR 1.6 vs 1.3) and poor mental health (PRR 1.3 vs 1.1); greater variation between the occupational groups studied (prevalence ranging from 0% to 67.6%) that correlated poorly with the variation in LNSP; and was more persistent at follow-up (72.1% vs 61.7%). Our findings highlight important epidemiological distinctions between subcategories of neck/shoulder pain. In future epidemiological research that bases case definitions on symptoms, it would be useful to distinguish pain that is localised to the neck or shoulder from more generalised pain that happens to involve the neck/shoulder region.
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Prescription opioid misuse is a major public health concern in the United States, yet little is known about national prescription patterns. We aimed to assess trends in opioid prescriptions made to children and adolescents, to their families, and to adults in the United States from 1996 to 2012. The sample was drawn from nationally representative data, the Medical Expenditure Panel Surveys. ⋯ Our main finding was that although the rates of opioid prescriptions have increased among adults in the United States, the rates have not changed among children and adolescents. Recent epidemiologic association studies have identified a strong link between increased opioid prescriptions and increased rates of opioid misuse and abuse in adults. Future studies should assess the association between adult opioid prescriptions and children or adolescent opioid misuse.
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Abnormal pain processing in the central nervous system may be related to abdominal pain in patients with Crohn's disease (CD). The purpose of this study was to investigate changes in resting-state brain activity in patients with CD in remission and its relationship with the presence of abdominal pain. Twenty-five patients with CD and with abdominal pain, 25 patients with CD and without abdominal pain, and 32 healthy subjects were scanned using a 3.0-T functional magnetic resonance imaging scanner. ⋯ In contrast, patients without abdominal pain exhibited lower ReHo values in the hippocampal/parahippocampal cortex and higher ReHo values in the dorsomedial prefrontal cortex (all P < 0.05, corrected). The ReHo values of the insula and MCC were significantly negatively correlated with daily pain scores for patients with abdominal pain (r = -0.53, P = 0.008 and r = -0.61, P = 0.002, respectively). These findings suggest that resting-state brain activities are different between remissive patients with CD with and without abdominal pain and that abnormal activities in insula and MCC are closely related to the severity of abdominal pain.
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Paresthesia-dominant and pain-dominant subgroups have been noted in carpal tunnel syndrome (CTS), a peripheral neuropathic disorder characterized by altered primary somatosensory/motor (S1/M1) physiology. We aimed to investigate whether brain morphometry dissociates these subgroups. Subjects with CTS were evaluated with nerve conduction studies, whereas symptom severity ratings were used to allocate subjects into paresthesia-dominant (CTS-paresthesia), pain-dominant (CTS-pain), and pain/paresthesia nondominant (not included in further analysis) subgroups. ⋯ Conversely, in CTS-pain subjects, contralesional S1 (r(9) = 0.62, P = 0.042) and M1 (r(9) = 0.61, P = 0.046) cortical thickness were correlated with pain severity, but not median nerve velocity or paresthesia severity. This double dissociation in somatotopically specific S1/M1 areas suggests a neuroanatomical substrate for symptom-based CTS subgroups. Such fine-grained subgrouping of CTS may lead to improved personalized therapeutic approaches, based on superior characterization of the linkage between peripheral and central neuroplasticity.
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In many patients with cancer, chemotherapy-induced severe oral ulcerative mucositis causes intractable pain, leading to delays and interruptions in therapy. However, the pain mechanism in oral ulcerative mucositis after chemotherapy has not been extensively studied. In this study, we investigated spontaneous pain and mechanical allodynia in a preclinical model of oral ulcerative mucositis after systemic administration of the chemotherapy drug 5-fluorouracil, using our proprietary pain assay system for conscious rats. 5-Fluorouracil caused leukopenia but did not induce pain-related behaviors. ⋯ In contrast, the TRPA1 antagonist HC-030031 and the N-formylmethionine receptor FPR1 antagonist Boc MLF primarily suppressed the mechanical allodynia. These results suggest that 5-fluorouracil-associated leukopenia allows excessive oral bacterial infection in the oral ulcerative region, resulting in the enhancement of spontaneous pain through continuous TRPV1 activation and cyclooxygenase pathway, and mechanical allodynia through mechanical sensitization of TRPA1 caused by neuronal effects of bacterial toxins. These distinct pain mechanisms explain the difficulties encountered with general treatments for oral ulcerative mucositis-induced pain in patients with cancer and suggest more effective approaches.