Pain
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Meta Analysis
Endogenous pain modulation in chronic orofacial pain: a systematic review and meta-analysis.
Abnormal endogenous pain modulation was suggested as a potential mechanism for chronic pain, ie, increased pain facilitation and/or impaired pain inhibition underlying symptoms manifestation. Endogenous pain modulation function can be tested using psychophysical methods such as temporal summation of pain (TSP) and conditioned pain modulation (CPM), which assess pain facilitation and inhibition, respectively. Several studies have investigated endogenous pain modulation function in patients with nonparoxysmal orofacial pain (OFP) and reported mixed results. ⋯ Sensitivity analyses did not affect the overall estimate for TSP; for CPM, the overall estimate became significant if specific random-effect models were used or if the most influential study was removed. Publication bias was not present for TSP studies, whereas it substantially influenced CPM's overall estimate. These results suggest increased pain facilitation and trend for pain inhibition impairment in patients with nonparoxysmal OFP.
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Approximately one-third of individuals with sickle cell disease (SCD) develop chronic pain. This debilitating pain is inadequately treated because the underlying mechanisms driving the pain are poorly understood. In addition to persistent pain, patients with SCD are also in a tonically proinflammatory state. ⋯ Inhibition of chemokine receptor 2 (CCR2), but not CCR4, alleviated the behavioral mechanical and cold hypersensitivity in SCD. Furthermore, acute CCR2 blockade reversed both the behavioral and the in vitro responsiveness of sensory neurons to an agonist of TRPV1, a neuronal ion channel previously implicated in SCD pain. These results provide insight into the immune-mediated regulation of hypersensitivity in SCD and could inform future development of analgesics or therapeutic measures to prevent chronic pain.
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Randomized Controlled Trial
Early workplace dialogue in physiotherapy practice improved work ability at 1-year follow-up-WorkUp, a randomised controlled trial in primary care.
Workplace involvement in rehabilitation for patients with musculoskeletal pain may improve work ability. Convergence Dialogue Meeting (CDM) is a model aimed at helping the patient, the care giver, and the employer to support work ability and return-to-work. Our aim was to study the effect on work ability when adding a workplace dialogue according to CDM in physiotherapy practice for patients with pain in ordinary primary care. ⋯ Work ability was reached by significantly more patients in the intervention group (108/127, 85%) compared with the reference group (127/171, 74%) (P = 0.02). The intervention increased the odds of having work ability at 1-year follow-up, also after adjustment for baseline health-related quality of life (odds ratio 1.85, confidence interval 1.01-3.38). We conclude that an early workplace dialogue in addition to structured physiotherapy improved work ability significantly.
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The latent sensitization model of chronic pain reveals that recovery from some types of long-term hyperalgesia is an altered state in which nociceptive sensitization persists but is suppressed by the ongoing activity of analgesic receptors such as μ-opioid receptors (MORs). To determine whether these MORs are the ones present in nociceptive afferents, we bred mice expressing Cre-recombinase under the Nav1.8 channel promoter (Nav1.8cre) with MOR-floxed mice (flMOR). These Nav1.8cre/flMOR mice had reduced MOR expression in primary afferents, as revealed by quantitative PCR, in situ hybridization, and immunofluorescence colocalization with the neuropeptide calcitonin gene-related peptide. ⋯ Naltrexone also reinstated swelling of the hind paw in flMOR mice and female Nav1.8cre/flMOR mice, but not male Nav1.8cre/flMOR mice. The MOR agonist DAMGO inhibited substance P release in flMOR mice but not Nav1.8cre/flMOR mice, demonstrating a loss of MOR function at the central terminals of primary afferents. We conclude that MORs in nociceptive afferents mediate an ongoing suppression of hyperalgesia to produce remission from chronic pain.
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Despite increasing rates of prescription opioid (PO) misuse in adults 50 years of age and older, little research has investigated such misuse in this population. This work aimed to examine sources of misused opioid medication in adults 50 years and older, with comparisons to younger groups. Data were from the 2009 to 2014 National Survey on Drug Use and Health surveys. ⋯ Across those 50 years and older, use of purchases, physician, or multiple sources were associated with elevated POUD symptom prevalence. Older adults, particularly those 65 years and older, use a different pattern of PO sources than adolescents or younger adults, and those using physician sources have elevated POUD symptoms. Physicians are a key avenue for older adults to obtain opioids for misuse, highlighting the potential role of clinicians in limiting such misuse.