Pain
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The personalization of neuropathic pain treatment could be improved by identifying specific sensory phenotypes (ie, specific combinations of symptoms and signs) predictive of the response to different classes of drugs. A simple and reliable phenotyping method is required for such a strategy. We investigated the utility of an algorithm for stratifying patients into clusters corresponding to specific combinations of neuropathic symptoms assessed with the Neuropathic Pain Symptom Inventory (NPSI). ⋯ Each of the 97 patients with neuropathic pain included in these studies was individually allocated to one cluster, by applying the algorithm to their baseline NPSI responses. We found significant effects of botulinum toxin A relative to placebo in clusters 2 and 3, but not in cluster 1, suggesting that this approach was, indeed, relevant. Finally, we developed and performed a preliminary validation of a web-based version of the NPSI and algorithm for the stratification of patients in both research and daily practice.
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Codeine is one of the most commonly used opioid analgesics. Significant codeine-related morbidity and mortality prompted regulatory responses, with the up-scheduling of codeine combination analgesics to prescription-only medicines implemented in Australia in February 2018. This study investigated the impact of codeine up-scheduling on the number of codeine and other (noncodeine) prescription opioid-related emergency department (ED) presentations in a large metropolitan tertiary hospital. ⋯ Noncodeine prescription opioid-related (B = -1.90, P = 0.446) and ED presentations overall (B = -118.04, P = 0.140) remained unchanged immediately post-up-scheduling, with a significant change in trend from upward to downward for noncodeine (B = -0.76; P = 0.002) and ED presentations overall (B = -19.34, P = 0.022). A significant reduction of 4.58 (B = -4.58, P = 0.009) in codeine presentations involving subsequent hospital admission immediately post-up-scheduling was found; but no immediate reduction in codeine-related suicide-related overdoses, length of inpatient stay, or re-presentations (P > 0.0125; adjusted for multiple comparisons). Restricting supply of codeine to prescription-only may have resulted in less harmful codeine-related use in the community, without a corresponding immediate decrease in other opioid-related harms.
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In complex regional pain syndrome (CRPS), hyperalgesia encompasses uninjured sites on the ipsilateral side of the body and may also include the special senses because auditory discomfort often is greater on the CRPS-affected side. To determine whether this hemilateral hyperalgesia involves the visual system, the discomfort threshold to a light-source that increased in intensity at 100 lux/second from 500 to 3600 lux was investigated for each eye, and the nasal and temporal half of each visual field, in 33 patients with CRPS and 21 pain-free controls. Recent headache history was reviewed and, in patients with CRPS, sensitivity to mechanical and thermal stimuli was assessed in all 4 limbs and on each side of the forehead. ⋯ Similarly, mechanical and thermal hyperalgesia was greater in the CRPS-affected than contralateral limb and was greater ipsilateral than contralateral to CRPS in the forehead and nonsymptomatic limbs. Ipsilateral photophobia was associated with mechanical and thermal hyperalgesia in the ipsilateral forehead but not the CRPS-affected limb. Together, these findings suggest that aberrant processing of nociceptive input in the ipsilateral trigeminal-medullary region of the brainstem contributes to visual discomfort in CRPS.
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As a rite of passage to womanhood, 2 million girls undergo female genital circumcision (FGC)-the tradition of cutting, and often removing parts of the vulva-every year. The current study is the first to focus on the connection between peripheral nerve damage and chronic neuropathic pain in women with FGC. We used mixed methods-quantitative, qualitative, and physiological-to study chronic pain in Somali-Canadian women (N = 14). ⋯ Although they report good overall health and very low pain levels on the short form of the McGill Pain Questionnaire, pressure-pain quantitative sensory testing of the vulvar region applied through vulvalgesiometers shows pain thresholds consistent with those reported by women with chronic vulvar pain. Furthermore, qualitative interviews reveal a considerable amount of often debilitating pain in daily life. These results challenge the use of assessment tools offering elicited verbal pain language and highlight the importance of culturally sensitive ways of conceptualizing, measuring, and managing pain.
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Visceral pain is a prevalent symptom of inflammatory bowel disease that can be difficult to treat. Pain and hypersensitivity are mediated by extrinsic primary afferent neurons (ExPANs) that innervate the colon. Recent studies indicate that the colon epithelium contributes to initiating ExPAN firing and nociceptive responses. ⋯ We then investigated the effect of epithelial and ExPAN inhibition in the dextran sulfate sodium model of inflammatory bowel disease. Inhibition of the colon epithelium significantly decreased dextran sulfate sodium-induced hypersensitivity and was comparable with the inhibition of ExPANs. Together, these results reveal the potential of targeting the colon epithelium for the treatment of pain.