Pain
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Review
The prevalence of neuropathic pain is high after treatment for breast cancer: a systematic review.
Pain is common, but often poorly managed after breast cancer treatment. Screening questionnaires and the Neuropathic Pain Special Interest Group (NeuPSIG) criteria are 2 clinical approaches used to determine whether pain has neuropathic components, which may enable better pain management. The aims of this review were (1) to synthesise data from the literature on neuropathic pain prevalence in women after breast cancer treatment; (2) to investigate whether the prevalence of neuropathic pain differed between studies using screening questionnaires and the NeuPSIG criteria. ⋯ Among all participants treated for early-stage breast cancer, pooled prevalence estimates (95% confidence interval) ranged between 14.2% (8.3-21.4) and 27.2% (24.7-88.4) for studies using screening questionnaires; studies using NeuPSIG criteria reported prevalence rates from 24.1% to 31.3%. Among those who reported pain after treatment, the pooled prevalence estimate (95% confidence interval) of neuropathic pain from screening questionnaires ranged from 32.6% (24.2-41.6) to 58.2% (24.7-88.4); studies using NeuPSIG criteria reported prevalence rates from 29.5% to 57.1%. These prevalence estimates are higher than those reported for other types of cancer, and emphasise the need to assess the contribution of neuropathic pain after breast cancer treatment.
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Pain catastrophizing is a significant risk factor for patients with knee osteoarthritis (KOA) and thus is a target for many psychological interventions for pain. This study examined if interventions targeting sleep found to be effective in improving sleep in KOA also reduce pain catastrophizing measured as a trait through the pain catastrophizing scale and measured as a daytime and nocturnal state through daily diaries. Secondary analyses were conducted on data collected as part of a randomized controlled trial assessing the effectiveness of cognitive behavioral therapy for insomnia in patients with KOA at 5 different time points: pretreatment, midtreatment and posttreatment and at 3- and 6-month follow-up. ⋯ Multilevel modeling revealed that both intervention groups showed a significant reduction pretreatment to posttreatment in all 3 measures of pain catastrophizing and maintained stable levels through the 6-month follow-up. Increased sleep continuity early in treatment (pretreatment to midtreatment), but not reductions in pain, was associated with a reduction in trait and nocturnal catastrophizing later in treatment (midtreatment to posttreatment). These results suggest that short interventions focusing on sleep can significantly reduce pain catastrophizing even in a clinical population with low baseline levels of catastrophizing, possibly through improving sleep continuity.
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Neurofibromatosis type 1 (NF1), a genetic disorder linked to inactivating mutations or a homozygous deletion of the Nf1 gene, is characterized by tumorigenesis, cognitive dysfunction, seizures, migraine, and pain. Omic studies on human NF1 tissues identified an increase in the expression of collapsin response mediator protein 2 (CRMP2), a cytosolic protein reported to regulate the trafficking and activity of presynaptic N-type voltage-gated calcium (Cav2.2) channels. Because neurofibromin, the protein product of the Nf1 gene, binds to and inhibits CRMP2, the neurofibromin-CRMP2 signaling cascade will likely affect Ca channel activity and regulate nociceptive neurotransmission and in vivo responses to noxious stimulation. ⋯ Stimulus-evoked release of calcitonin gene-related peptide from lumbar spinal cord slices was inhibited by t-CNRP1. Intrathecal administration of t-CNRP1 was antinociceptive in experimental models of inflammatory, postsurgical, and neuropathic pain. Our results demonstrate the utility of t-CNRP1 to inhibit CRMP2 protein-protein interactions for the potential treatment of pain.
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More than half of individuals experiencing major thermal burn injury (MThBI) receive an autologous skin graft (autograft), in which skin is removed from a healthy "donor" site and transplanted to the burn site. Persistent pain and itch at the graft site are major causes of suffering and disability in MThBI survivors. African Americans have a higher risk of MThBI, and in other clinical settings African Americans experience a greater burden of pain and itch relative to European Americans. ⋯ In adjusted linear mixed models, African Americans experienced a slower rate of pain resolution in the acute phase of recovery (β = -0.05 vs -0.08 NRS points per day, P < 0.001), which resulted in a higher pain severity in the persistent phase of recovery (NRS mean difference = 1.21, 95% confidence interval [0.12-2.29]), although not statistically significant after correction for multiple comparisons. African Americans also experience greater itch severity in 6 weeks to 12 months after burn injury compared with European Americans (NRS mean difference = 1.86 [0.80-2.93]), which results from a faster rate of itch development in African Americans in the acute recovery phase after burn injury. Future studies may improve outcomes in African Americans and lead to new pathogenic insights that benefit all burn injury survivors.
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We know little about the individual pain experience of patients recovering from surgery in the first weeks after hospital discharge. Here, we examine individual differences in the day-to-day experience after 2 major surgeries: lower limb total major joint arthroplasty (TJA) and cesarean delivery (CD). Fifty-five TJA patients and 157 CD patients were recruited to complete questionnaires and record their daily pain experiences after surgery. ⋯ These data add meaningfully to our understanding of recovery from pain after surgery by extending the period of frequent observations a few days after surgery to a 2-month period. These high time resolution data suggest that there is a typical experience of pain resolution after surgery, but that meaningful subpopulations of experience may exist. They also indicate that a transition occurs within 1 month after surgery from 1 pattern of change in pain over time to another.