The journal of pain : official journal of the American Pain Society
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The objective of this article is to provide an overview of the natural history and treatment of herpes zoster, with a focus on pain management. Herpes zoster has the highest incidence of all neurological diseases, occurring annually in approximately 1 million people in the United States. A basic feature of herpes zoster is a marked increase in incidence with aging and with diseases and drugs that impair cellular immunity. Herpes zoster begins with reactivation of varicella zoster virus in dorsal root or cranial nerve ganglia, which is often accompanied by a prodrome of dermatomal pain or abnormal sensations. Varicella zoster virus spreads in the affected primary afferent nerve to the skin and produces a characteristic dermatomal maculopapular and vesicular rash and pain. Herpes zoster acute pain lowers quality of life and interferes with activities of daily living. Antiviral therapy and scheduled analgesics form the pharmacotherapeutic foundation for herpes zoster acute pain reduction. If moderate to severe herpes zoster pain is not adequately relieved by antiviral agents in combination with oral analgesic medications, then corticosteroids, anticonvulsants (eg, gabapentin or pregabalin), tricyclic antidepressants (eg, nortriptyline or desipramine), or neural blockade can be considered. ⋯ This article presents information on the clinical features and treatment of herpes zoster. This information will help clinicians diagnose and manage herpes zoster pain.
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The method of pain-evoked potentials has gained considerable acceptance over the last 3 decades regarding its objectivity, repeatability, and quantifiability. The present study explored whether the relationship between pain-evoked potentials and pain psychophysics obtained by contact heat stimuli is similar to those observed for the conventionally used laser stimulation. Evoked potentials (EPs) were recorded in response to contact heat stimuli at different body sites in 24 healthy volunteers. Stimuli at various temperatures were applied to the forearm (43 degrees C, 46 degrees C, 49 degrees C, and 52 degrees C) and leg (46 degrees C and 49 degrees C). The amplitudes of both components (N2 and P2) were strongly associated with the intensity of the applied stimuli and with subjective pain perception. Yet, regression analysis revealed pain perception and not stimulus intensity as the major contributing factor. A significant correlation was found between the forearm and the leg for both psychophysics and EPs amplitude. ⋯ Contact heat can generate readily distinguishable evoked potentials on the scalp, consistent between upper and lower limbs. Although these potentials bear positive correlation with both stimulus intensity and pain magnitude, the latter is the main contributor to the evoked brain response.
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The heat pain threshold was assessed in 32 healthy participants after a mild burn on the dorsal surface of each hand, after injection of an opioid antagonist (80 microg naloxone) or vehicle alone (0.2 mL saline) into the burnt skin of 1 hand, and after repeated painful immersion of this hand in cold water for up to 180 seconds. We hypothesized that sensitivity to heat would decrease at the burn-injured site after the immersions, due to local release of opioids into the burnt skin. Naloxone augmented cold-induced pain during the immersions in participants who tolerated the longest immersions, implying that release of endogenous opioids suppressed cold-pain. After the immersions, sensitivity to heat decreased at the burn-injured site in the immersed hand, but naloxone did not block this effect. Instead, naloxone altered sensitivity to heat in unburnt skin, implying that thermal hyperalgesia at sites of burn injury masked the modulatory effects of opioids. In particular, naloxone blocked a decrease in sensitivity to heat at an unburnt site on the contralateral hand of participants who tolerated the longest immersions, consistent with central or systemic opioid release. Naloxone reduced sensitivity to heat at unburnt sites in participants who tolerated medium-length immersions, suggesting that an increase in systemic or central opioid activity evoked thermal hyperalgesia in this group. In addition, in a small group of participants who tolerated only brief immersions, naloxone blocked decreases in sensitivity to heat at an unburnt site in the immersed hand. These findings suggest that repeated painful immersions trigger local opioid release in participants who tolerate only brief immersions, and elicit central or systemic opioid release in participants who tolerate longer immersions. ⋯ This article demonstrates that repeated immersion of the hand in painfully cold water increases opioid activity and that the increase in opioid activity exerts multiple opposing effects on sensitivity to heat. Individual differences in the response to opioids might contribute to individual differences in pain tolerance.
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Comment Letter Case Reports
Complex regional pain syndrome-a multifaceted disorder requiring multidimensional care: case study.
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Review
A review of objective pain measures for use with critical care adult patients unable to self-report.
Critically ill patients experience significant levels of pain and discomfort from multiple intrinsic and extrinsic sources while in the intensive care unit (ICU). The use of objective pain measures in nonverbal patients is an essential alternative approach for pain assessment when self-reports are unavailable. This paper provides a critical review of the psychometric properties of 6 objective pain measures that were developed to assess pain in nonverbal adult patients in the ICU. The strengths and weaknesses of these objective measures are evaluated, as well as their applicability for use with this patient population. Although 2 of the 6 objective pain measures showed good evidence of validity and reliability, none has undergone vigorous validation or has been accepted as a standardized measure. Findings from the available studies of objective pain measures provide useful information to direct future research to develop and validate clinically useful pain measures for use with critically ill patients unable to self-report. ⋯ This review provides clinicians with a summary of the psychometric properties of 6 objective pain measures and discusses their applicability for use to assess pain in critically ill adult patients unable to self-report.