Pain
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Many primary care clinics are resistant to accept new patients taking prescription opioids for chronic pain. It is unclear how much of this practice is specific to individuals who may be perceived to have aberrant opioid use. This study sought to determine whether clinics are more or less willing to accept and prescribe opioids to patients depending on whether their history is more or less suggestive of aberrant opioid use by conducting an audit survey of primary care clinics in 9 states from May to July 2019. ⋯ Clinics responding differently had greater odds (odds ratio = 1.83 confidence interval [1.23-2.76]) of willingness to prescribe when the previous doctor retired than when the doctor had stopped prescribing. These findings suggest that primary care access is limited for patients taking opioids for chronic pain, and differentially further reduced for patients whose histories are suggestive of aberrant use. This denial of care could lead to unintended harms such as worsened pain or conversion to illicit substances.
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Our knowledge of the prevalence, impact, and outcomes of chronic pain in the general population is predominantly based on studies over relatively short periods of time. The aim of this study was to identify and describe trajectories of the chronic pain status over a period of 21 years. Self-reported population data (n = 1858) from 5 timepoints were analyzed. ⋯ In conclusion, chronic pain was common in the population including 6% reporting persistent CWP, although the majority persistently reported NCP. Most people had stable pain status, but some had ongoing change in pain status over time including people who improved from chronic pain. It was possible to identify clinically relevant factors, characterizing trajectories of chronic pain development, that can be useful for identifying individuals at risk and potential targets for intervention.
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Chronic pain is highly prevalent in multiple sclerosis (MS). Pain heterogeneity may contribute to poor treatment outcomes. The aim of this study was to characterize pain phenotypes distributions in persons with MS and compare pain phenotypes in terms of pain intensity, frequency of chronic overlapping pain conditions, and use and analgesic effects of different classes of pain medications. ⋯ Although NSAID use was highest among those with nociplastic pain (80%), pain relief ratings for NSAIDs were highest among those with nociceptive pain. These findings underscore the need for multidimensional assessment of pain in MS with greater emphasis on the identification of pain phenotype. An improved characterization of pain as a multifaceted condition in MS could inform therapeutic approaches.
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A large body of animal and human studies indicates that blocking peripheral calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating polypeptide (PACAP) signaling pathways may prevent migraine episodes and reduce headache frequency. To investigate whether recurring migraine episodes alter the strength of CGRP and PACAP signaling in trigeminal ganglion (TG) neurons, we compared the number of TG neurons that respond to CGRP and to PACAP (CGRP-R and PACAP-R, respectively) under normal and chronic migraine-like conditions. In a mouse model of chronic migraine, repeated nitroglycerin (NTG) administration significantly increased the number of CGRP-R and PACAP-R neurons in TG but not dorsal root ganglia. ⋯ The number of CGRP-R&PACAP-R TG neurons was also increased in a mouse model of posttraumatic headache (PTH). Interestingly, low-dose interleukin-2 treatment, which completely reverses chronic migraine-related and PTH-related behaviors in mouse models, also blocked the increase in both CGRP-R and PACAP-R TG neurons. Together, these results suggest that inhibition of both CGRP and PACAP signaling in TG neurons may be more effective in treating chronic migraine and PTH than targeting individual signaling pathways.
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During self-induced pain, a copy of the motor information from the body's own movement may help predict the painful sensation and cause downregulation of pain. This phenomenon, called sensory attenuation, enables the distinction between self-produced stimuli vs stimuli produced by others. Sensory attenuation has been shown to occur also during imagined self-produced movements, but this has not been investigated for painful sensations. ⋯ Thus, sensory attenuation did occur both in the self condition and the imagery condition. The results of this study may have clinical relevance for understanding the mechanisms involved in the elevated pain thresholds seen in patients with self-injury behavior and the low pain thresholds seen in patients with chronic pain conditions. Imagery of sensory attenuation might also be used to alleviate the pain experience for patients undergoing procedural pain.