Pain
-
Pain and emotional exhaustion are prevalent conditions with consequences for sickness absence. Although they often co-occur, their combined associations with sickness absence are poorly understood. This study aimed to examine the separate and combined associations of pain and emotional exhaustion with subsequent sickness absence. ⋯ A synergistic interaction effect was found for co-occurring pain and emotional exhaustion on medically certified sickness absence. The results for men were mainly similar, but less stable. In order to tackle sickness absence, special attention should be paid to the prevention and treatment of employees with co-occurring pain and emotional exhaustion.
-
Menstrual pain is the most prevalent gynecological complaint, and is usually without organic cause (termed primary dysmenorrhea, PDM). The high comorbidity in the later life of PDM with many functional pain disorders (associated with central dysfunction of pain inhibition, eg, fibromyalgia) suggests possible maladaptive functionality of pain modulatory systems already occurred in young PDM women, making them vulnerable to functional pain disorders. Periaqueductal gray (PAG) matter functions as a critical hub in the neuraxis of pain modulatory systems; therefore, we investigated the functional connectivity of PAG in PDM. ⋯ The PAG of PDM subjects exhibited adaptive/reactive hyperconnectivity with the sensorimotor cortex during painful menstruation, whereas it exhibited maladaptive hypoconnectivity with the dorsolateral prefrontal cortex and default mode network (involving the ventromedial prefrontal cortex, posterior cingulate cortex, or posterior parietal cortex) during menstruation or periovulatory phase. We propose that the maladaptive descending pain modulatory systems in PDM may underpin the central susceptibility to subsequent development of various functional disorders later in life. This hypothesis is corroborated by the growing body of evidence that hypoconnectivity between PAG and default mode network is a coterminal to many functional pain disorders.
-
Characterising the clinical course of back pain by mean pain scores over time may not adequately reflect the complexity of the clinical course of acute low back pain. We analysed pain scores over 12 weeks for 1585 patients with acute low back pain presenting to primary care to identify distinct pain trajectory groups and baseline patient characteristics associated with membership of each cluster. This was a secondary analysis of the PACE trial that evaluated paracetamol for acute low back pain. ⋯ Belief in greater risk of persistence was associated with nonrecovery, but not delayed recovery. Higher pain intensity, longer duration, and workers' compensation were associated with persistent high pain, whereas older age and increased number of episodes were associated with fluctuating pain. Identification of discrete pain trajectory groups offers the potential to better manage acute low back pain.
-
Musculoskeletal pain (MSP) is a common sequela of traumatic stress exposure. While biological factors contributing to chronic MSP after motor vehicle collision (MVC) have traditionally focused on tissue injury, increasing evidence suggests that neuro/stress/immune processes mediated by stress system activation may play a more dominant role. In a previous study, we found that genetic variants in the hypothalamic-pituitary-adrenal (HPA) axis-related gene FKBP5 influence vulnerability to persistent MSP 6 weeks after MVC. ⋯ In secondary analyses, a significant interaction between this CRHBP locus (minor allele frequency = 0.33) and time was observed (P = 0.015), with increasing effect observed over time following trauma. A significant CRHBP × FKBP5 interaction was also observed, with substantially increased MSP after MVC in those with a risk allele in both genes compared with either gene alone. The results of this study indicate that genetic variants in 2 different HPA axis genes predict chronic MSP severity following MVC and support the hypothesis that the HPA axis is involved in chronic post-MVC MSP pathogenesis.
-
Regular physical activity in healthy individuals prevents development of chronic musculoskeletal pain; however, the mechanisms underlying this exercise-induced analgesia are not well understood. Interleukin-10 (IL-10), an antiinflammatory cytokine that can reduce nociceptor sensitization, increases during regular physical activity. Since macrophages play a major role in cytokine production and are present in muscle tissue, we propose that physical activity alters macrophage phenotype to increase IL-10 and prevent chronic pain. ⋯ Blockade of IL-10 systemically or locally prevented the analgesia in physically active mice, ie, mice developed hyperalgesia. Conversely, sedentary mice pretreated systemically or locally with IL-10 had reduced hyperalgesia after repeated acid injections. Thus, these results suggest that regular physical activity increases the percentage of regulatory macrophages in muscle and that IL-10 is an essential mediator in the analgesia produced by regular physical activity.