Pain
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In knee osteoarthritis (OA), pain sensitization has been linked to a more severe symptomatology, but the prognostic implications of pain sensitivity in people undergoing conservative treatment such as physiotherapy are not established. This study aimed to prospectively investigate the association between features of pain sensitization and clinical outcome (nonresponse) after guideline-based physiotherapy in people with knee OA. Participants (n = 156) with moderate/severe knee OA were recruited from secondary care. ⋯ The model demonstrated high sensitivity (87.8%) but modest specificity (52.3%). The independent relationship between pain sensitization and nonresponse may indicate an underlying explanatory association between neuroplastic changes in nociceptive processing and the maintenance of ongoing pain and disability in knee OA pain. These preliminary results suggest that interventions targeting pain sensitization may warrant future investigation in this population.
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In humans, chronic psychological stress is associated with increased intestinal paracellular permeability and visceral hyperalgesia, which is recapitulated in the chronic intermittent water avoidance stress (WAS) rat model. However, it is unknown whether enhanced visceral pain and permeability are intrinsically linked and correlate. Treatment of rats with lubiprostone during WAS significantly reduced WAS-induced changes in intestinal epithelial paracellular permeability and visceral hyperalgesia in a subpopulation of rats. ⋯ Finally, exposure of the distal colon in control animals to Ocln siRNA in vivo revealed that knockdown of Ocln protein inversely correlated with increased paracellular permeability and enhanced visceral pain similar to the levels observed in WAS-responsive rats. These data support that Ocln plays a potentially significant role in the development of stress-induced increased colon permeability. We believe this is the first demonstration that the level of chronic stress-associated visceral hyperalgesia directly correlates with the magnitude of altered colon epithelial paracellular permeability.
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Referred and projecting pain can be observed in acute and chronic pain states. We present the case of a 69-year-old female patient with postherpetic neuralgia in dermatome Th2/3 who reported that touching the ipsilateral earlap (dermatome C2) would enhance pain and dynamic mechanical allodynia in the affected Th2/3-dermatome. ⋯ We discuss whether the observed phenomenon in combination with activation of pain-modulating areas on functional magnetic resonance imaging suggests either (1) a shift of descending pathways from inhibitory towards facilitating mode or (2) a deafferentation-induced reorganization of somatotopic maps, as the ear and the trunk are adjacent areas of the sensory homunculus. The results and a review about projection of pain in head-neck area are provided.