European journal of pain : EJP
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In the context of neuropathic pain, the contribution of regeneration to the development of positive symptoms is not completely understood. Several efforts have been done to described changes in axotomized neurons, however, there is scarce data on changes occurring in intact neurons, despite experimental evidence of functional changes. To address this issue, we analysed by immunohistochemistry the presence of phosphorylated signal transducer and activator of transcription 3 (pSTAT3), an accepted marker of regeneration, within DRGs where axotomized neurons were retrogradely labelled following peripheral nerve injury. Likewise, we have characterized abnormal electrophysiological properties in intact fibres after partial nerve injury. ⋯ Positive symptoms in patients with peripheral neuropathies correlate to abnormal functioning of different subpopulations of primary afferents. Peripheral nerve damage triggers regenerating programs in the cell bodies of axotomized but also in non-axotomized nociceptors which is in turn, develop abnormal spontaneous and evoked discharges. Therefore, intact nociceptors have a significant role in the development of neuropathic pain due to their hyperexcitable peripheral terminals. Therapeutical targets should focus on inhibiting peripheral hyperexcitability in an attempt to limit peripheral and central sensitization.
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Randomized Controlled Trial
Nasopharyngeal swab-induced pain for SARS-CoV-2 screening: A randomised controlled trial of conventional and self-swabbing.
Massive screening campaigns for SARS-CoV-2 are currently carried out throughout the world, relying on reverse-transcriptase-polymerase chain reaction (RT-PCR) following nasopharyngeal swabbing performed by a healthcare professional. Yet, due to the apprehension of pain induced by nasopharyngeal probing, poor adhesion to those screening campaigns can be observed. To enhance voluntary participation and to avoid unnecessary exposition to SARS-CoV-2, self-swabbing could be proposed. To date, no data have been published concerning pain induced by conventional- or self-swabbing. Thus, the primary objective of the present study was to evaluate pain induced with the conventional swabbing method and compare it to self-swabbing. Secondary objectives focused on swabbing-induced discomfort and acceptability of the two methods. ⋯ Using the thinnest available swabs, procedural pain induced by nasopharyngeal swabbing for SARS-CoV-2 screening is very low for most subjects and should not limit voluntary participation in screening campaigns. Self-swabbing does not lead to more pain or discomfort compared to conventional swabbing, is well-accepted, and could be proposed to optimize screening campaigns, at least in healthcare professionals.
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Persistent pain during pregnancy is a significant health issue, which could be correlated with psychological distress resulting from inadequate social support. This study aims to investigate whether the relationship between poor social support and antenatal pain is mediated by psychological distress. We also aimed to examine whether social cohesion moderates the influence of psychological distress on the relationship between social support and antenatal pain. ⋯ In this study, poor social support was found to be associated with pain intensity during pregnancy, which was mediated by psychological distress and might be buffered by desirable social cohesion. This finding could potentially help healthcare providers and policy makers to understand the importance of desirable social cohesion in preventing pain among pregnant women.
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There is a broad range of evidence on optimism dampening the pain experience, as assessed by subjective self-report. Facial expression of pain conveys supplementary information about the pain experience, is an integral part of pain communication and assists psychosocial pain coping. Nevertheless, the effect of induced optimism on facial activity during pain has to our knowledge not been examined. ⋯ This study is the first to indicate that state optimism increases the facial expression of pain as a social signal for help and empathy without concomitant changes in the subjective pain experience.
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A noxious stimulus following a more intense stimulus often feels less painful than continuous noxious stimulation. This effect, known as offset analgesia (OA), may be due to descending inhibitory control, to changes in peripheral neural transmission or both. The timing and location of noxious thermal stimulation were manipulated to better understand the peripheral and central contributions to OA. ⋯ Offset analgesia (OA) is a fundamentally temporal phenomenon dependent on dynamic changes in stimulus intensity. Here we demonstrate increased OA with increased stimulus duration. This finding implies the more slowly-responding AMH-I peripheral mechanoreceptors contribute to OA. The more rapidly responding AMH-II peripheral mechanoreceptors, however, may be absent or more difficult to activate in the palm where we did not observe OA. This finding implies that the AMH-II receptors are necessary for OA. Our studies suggest methods to unravel the different peripheral and central contributions to OA.