Articles: pain-clinics.
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Reg Anesth Pain Med · Mar 2016
Multicenter Study Clinical TrialA Longitudinal Study to Evaluate Pregnancy-Induced Endogenous Analgesia and Pain Modulation.
The phenomenon of pregnancy-induced analgesia has been demonstrated in animal models but less consistently in human studies. This study aimed to assess endogenous pain modulation, evaluating inhibitory and excitatory pain pathways, over the course of pregnancy and postpartum. ⋯ This is the first study to assess CPM and mTS changes in pregnancy and postpartum. Endogenous pain modulation evaluating both inhibitory and excitatory pain pathways did not significantly change during pregnancy or postpartum. Future studies are required to determine the magnitude and clinical significance of pregnancy-induced analgesia.
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Methadone administration has increased in pediatric clinical settings. This review is an attempt to ascertain an equianalgesic dose ratio for methadone in the pediatric population using standard adult dose conversion guidelines. ⋯ Opioid conversion to methadone is commonly practiced at our institution; however, dosing was significantly lower compared to adult conversion ratios, and more than 40 percent of children were undermedicated. The majority of children in this study received opioids for sedation while intubated and ventilated; therefore, safe and efficacious pediatric methadone conversion rates remain unclear. Prospective studies are needed.
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Emerging evidence associates chronic pain syndrome, such as fibromyalgia, with endogenous pain modulatory system dysfunction, leading to an impaired descending pain inhibition. In this study, using resting-state functional magnetic resonance imaging (fMRI), we aimed at seeking possible functional connectivity changes of the periaqueductal gray (PAG), a brainstem area that belongs to the endogenous pain modulatory system, in patients with fibromyalgia. ⋯ Our fMRI study showing abnormal resting state functional connectivity of the PAG suggests that patients with fibromyalgia have an endogenous pain modulatory system dysfunction, possibly causing an impaired descending pain inhibition. This abnormal PAG functioning might underlay the chronic pain these patients suffer from.
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Clinical studies show that chronic pain can spread to adjacent or even distant body regions in some patients. However, little is known about how this happens. In this study, we found that partial infraorbital nerve transection (p-IONX) in MRL/MPJ mice induced not only marked and long-lasting orofacial thermal hyperalgesia but also thermal hyperalgesia from day 3 postoperatively (PO) and tactile allodynia from day 7 PO in bilateral hind paws. ⋯ In addition, microglial activation after p-IONX transmitted caudally from the Vc in the medulla to lumber dorsal horn in a time-dependent manner. Inhibition of microglial activation by minocycline at early but not late stage after p-IONX postponed and attenuated pain sensitization in the hind paw. These results indicate that neuropathic pain after p-IONX in MRL/MPJ mice spreads from the orofacial region to distant somatic regions and that a rostral-caudal transmission of central sensitization in the spinal cord is involved in the spreading process of pain hypersensitivity.