Pain
-
The aim of this study was to find the cut-off points on the visual analogue scale (VAS) to distinguish among mild, moderate, and severe pain, in relation to the following: pain-related interference with functioning; verbal description of the VAS scores; and latent class analysis for patients with chronic musculoskeletal pain. A total of 456 patients were included. Pain was assessed using the VAS and verbal rating scale; functioning was assessed using the domains of the Short Form (36) Health Survey (SF-36). ⋯ Latent class analysis found that a 3-class solution fitted best, resulting in the classes 0.1 to 3.8, 3.9 to 5.7, and 5.8 to 10 cm. Findings from our study agree with those of some other studies, although many other studies found different optimal cut-off point schemes. As there appear to be no universally accepted cut-off points, and in view of the low-to-moderate associations between VAS scores and functioning and between VAS and verbal rating scale scores, the correct classification of VAS scores as mild, moderate. or severe in clinical practice seems doubtful.
-
Detection of external irritants by head nociceptor neurons has deep evolutionary roots. Irritant-induced aversive behavior is a popular pain model in laboratory animals. It is used widely in the formalin model, where formaldehyde is injected into the rodent paw, eliciting quantifiable nocifensive behavior that has a direct, tissue-injury-evoked phase, and a subsequent tonic phase caused by neural maladaptation. ⋯ Using TRPA1-blocker and Trpa1(-/-) mice, we found that both TRP channels co-contribute to the formalin trigeminal pain response. These results imply TRPV4 as an important signaling molecule in irritation-evoked trigeminal pain. TRPV4-antagonistic therapies can therefore be envisioned as novel analgesics, possibly for specific targeting of trigeminal pain disorders, such as migraine, headaches, temporomandibular joint, facial, and dental pain, and irritation of trigeminally innervated surface epithelia.
-
Use of chronic opioid therapy (COT) for chronic noncancer pain has dramatically increased in the United States. Patients seek compassionate care and relief while physicians struggle to manage patients' pain effectively without doing harm. This study explores the narratives of chronic noncancer pain patients receiving chronic opioid therapy and those of their physicians to better understand the effects of COT on the doctor-patient relationship. A mixed method study was conducted that included in-depth interviews and qualitative analysis of 21 paired patients with chronic pain and their physicians in the following groups: patients, physicians, and patient-physician pairs. Findings revealed that patients' narratives focus on suffering from chronic pain, with emphasis on the role of opioid therapy for pain relief, and physicians' narratives describe the challenges of treating patients with chronic pain on COT. Results elucidate the perceptions of ideal vs difficult patients and show that divergent patterns surrounding the consequences, utility, and goals of COT can negatively affect the doctor-patient relationship. The use of paired interviews through a narrative lens in this exploratory study offers a novel and informative approach for clinical practice and research. The findings have significant implications for improving doctor-patient communication and health outcomes by encouraging shared decision making and goal-directed health care encounters for physicians and patients with chronic pain on COT. ⋯ This study found patterns of understanding pain, opioid pain medications, and the doctor-patient relationship for patients with chronic pain and their physicians using a narrative lens. Thematic findings in this exploratory study, which include a portrayal of collaborative vs conflictual relationships, suggest areas of future intervention and investigation.
-
Two-pore domain background K(+) channels (K2p or KCNK) produce hyperpolarizing currents that control cell membrane polarity and neuronal excitability throughout the nervous system. The TREK2 channel as well as the related TREK1 and TRAAK channels are mechanical-, thermal- and lipid-gated channels that share many regulatory properties. TREK2 is one of the major background channels expressed in rodent nociceptive neurons of the dorsal root ganglia that innervate the skin and deep body tissues, but its role in somatosensory perception and nociception has remained poorly understood. ⋯ TREK2 is also involved in mechanical pain perception and in osmotic pain after sensitization by prostaglandin E2. TREK2 is involved in the cold allodynia that characterizes the neuropathy commonly associated with treatments with the anticancer drug oxaliplatin. These results suggest that positive modulation of the TREK2 channel may have beneficial analgesic effects in these neuropathic conditions.