The journal of pain : official journal of the American Pain Society
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We recently showed that during acute muscle pain, C-tactile (CT) fibers mediate allodynia in healthy human subjects. In this study, we pursued the following questions: Do CTs contribute to allodynia observed in delayed onset muscle soreness (DOMS)? Is CT-mediated allodynia reproducible in a clinical pain state? In 30 healthy subjects, DOMS was induced in anterior compartment muscles of the leg by repeated eccentric contractions. DOMS was confirmed by mapping the emergence of tender points (decreased pressure pain thresholds). Furthermore, we measured pressure pain thresholds in a clinical subject who presented with activity-triggered heel pain but no resting pain. Cutaneous vibration (sinusoidal; 200 Hz-200 μm)--an otherwise innocuous stimulus--was applied to anterolateral leg before exercise, during DOMS, and following recovery from DOMS. The peripheral origin of allodynia was determined by employing conduction blocks of unmyelinated (intradermal anesthesia) and myelinated (nerve compression) fibers. In DOMS state, there was no resting pain, but vibration reproducibly evoked pain (allodynia). The blockade of cutaneous C fibers abolished this effect, whereas it persisted during blockade of myelinated fibers. In the clinical subject, without exposure to eccentric exercise, vibration (and brushing) produced a cognate expression of CT-mediated allodynia. These observations attest to a broader role of CTs in pain processing. ⋯ This is the first study to demonstrate the contribution of CT fibers to mechanical allodynia in exercise-induced as well as pathological pain states. These findings are of clinical significance, given the crippling effect of sensory impairments on the performance of competing athletes and patients with chronic pain and neurological disorders.
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Contemporary medical education is inadequate to prepare medical students to competently assess and design care plans for patients with acute and chronic pain. The time devoted to pain education in most medical school curricula is brief and not integrated into case-based clinical experiences, and it is frequently nonexistent during clinical clerkships. Medical student pain curricula have been proposed for over 30 years and are commonly agreed upon, though rarely implemented. As a consequence of poor undergraduate pain education, postgraduate trainees and practicing physicians struggle with both competency and practice satisfaction; their patients are similarly dissatisfied. At the University of Washington School of Medicine, a committee of multidisciplinary pain experts has, between 2009 and 2011, successfully introduced a 4-year integrated pain curriculum that increases required pain education teaching time from 6 to 25 hours, and clinical elective pain courses from 177 to 318 hours. It is expected that increased didactic and case-based multidisciplinary clinical training will increase knowledge and competency in biopsychosocial measurement-based pain narrative and risk assessment, improve understanding of persistent pain as a chronic complex condition, and expand the role of patient-centered interprofessional treatment for medical students, residents, and fellows, leading to better prepared practicing physicians. ⋯ Strategies for improving multidisciplinary pain education at the University of Washington School of Medicine are described and the preliminary results demonstrated.