Pain
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The rostral ventromedial medulla (RVM) has a well-documented role in pain modulation and exerts antinociceptive and pronociceptive influences mediated by 2 distinct classes of neurons, OFF-cells and ON-cells. OFF-cells are defined by a sudden pause in firing in response to nociceptive inputs, whereas ON-cells are characterized by a "burst" of activity. Although these reflex-related changes in ON- and OFF-cell firing are critical to their pain-modulating function, the pathways mediating these responses have not been identified. ⋯ Few of these neurons expressed calcitonin gene-related peptide, suggesting that the RVM projection from PB is distinct from that to the amygdala. These data show that a substantial component of "bottom-up" nociceptive drive to RVM pain-modulating neurons is relayed through the PB. While the PB is well known as an important relay for ascending nociceptive information, its functional connection with the RVM allows the spinoparabrachial pathway to access descending control systems as part of a recurrent circuit.
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Randomized Controlled Trial
Open-label placebo treatment in chronic low back pain: a randomized controlled trial.
This randomized controlled trial was performed to investigate whether placebo effects in chronic low back pain could be harnessed ethically by adding open-label placebo (OLP) treatment to treatment as usual (TAU) for 3 weeks. Pain severity was assessed on three 0- to 10-point Numeric Rating Scales, scoring maximum pain, minimum pain, and usual pain, and a composite, primary outcome, total pain score. Our other primary outcome was back-related dysfunction, assessed on the Roland-Morris Disability Questionnaire. ⋯ Improvement in disability scores was 2.9 (1.7-4.0) in the OLP group and 0.0 (-1.1 to 1.2) in the TAU group. After being switched to OLP, the TAU group showed significant reductions in both pain (1.5, 0.8-2.3) and disability (3.4, 2.2-4.5). Our findings suggest that OLP pills presented in a positive context may be helpful in chronic low back pain.
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Millions suffer from chronic vulvar pain (ie, vulvodynia). Vulvodynia represents the intersection of 2 difficult subjects for health care professionals to tackle: sexuality and chronic pain. Those with chronic vulvar pain are often uncomfortable seeking help, and many who do so fail to receive proper diagnoses. ⋯ These patterns of findings are consistent with the literature on the multidimensional nature of vulvodynia. The VPAQ can be used for assessment, diagnosis, treatment formulation, and treatment monitoring. In addition, the VPAQ could potentially be used to promote communication between patients and providers, and point toward helpful treatment options and/or referrals.
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Breakthrough cancer pain (BTcP) is an episode of severe pain that "breaks through" a period of persistent pain at least partly controlled by a stable opioid regimen. Although mentioned in the literature decades ago, it has been only 25 years since the first effort to define and measure it. Controversy about the definition of BTcP continues despite an international effort to achieve consensus. ⋯ Given the difference in cost, transmucosal formulations should be considered in a subset of patients with BTcP, including those with pain that are not adequately controlled with an oral drug and those with distress associated with the rapid pain onset. The long-term use of opioids for BTcP remains to be clarified. Future studies should assess the potential of personalized treatment of BTcP.
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Migraine attacks are often preceded by premonitory symptoms (PS) that may be triggered pharmacologically. We investigated the incidence of PS after administration of calcitonin gene-related peptide (CGRP) or pituitary adenylate cyclase-activating peptide-38 (PACAP38) in patients with migraine without aura (MO) who reported and did not report migraine-like attacks induced by these pharmacological triggers. In addition, we investigated the association between PS and familial predisposition for migraine. ⋯ Additionally, we found no difference in PS between patients with familial predisposition of migraine (75%) and patients with no family predisposition (56%) (P = 0.101). In conclusion, CGRP did not induce PS, whereas PACAP38 induced PS in 48% of patients. However, CGRP and PACAP38 did not induce more PS in patients who developed an attack compared with those who did not develop an attack.