Pain
-
Fibromyalgia is a common and complex long-term pain condition. Despite advancements in our understanding and treatment of fibromyalgia, patients report patchy health care provision and frustrating journeys through the health care system. To inform how best to deliver care, we undertook 2 narrative reviews examining existing evidence on (1) models of care for fibromyalgia and (2) patients' experiences, preferences, and unmet needs regarding their health care. ⋯ Positive care experiences such as being listened to and shared decision-making made patients feeling better informed, well supported, and more satisfied. There is little evidence to inform how best to organise health care for patients with fibromyalgia and ensure care is delivered in a coordinated and consistent way. These findings provide a strong rationale for developing a new model of care for fibromyalgia.
-
Cognitive impairment is one of the most common complications associated with chronic pain. Almost 20% of chronic pain patients suffer from cognitive impairment, which may substantially influence their quality of life. Levels of major excitatory neurotransmitters in the central nervous system and alterations in the glutamatergic system may influence cognitive function and the pain sensory pathway. ⋯ Ultra-high-performance liquid chromatography revealed lower levels of D-serine in the hippocampus of the spared nerve injury rats and that D-serine treatment could restore synaptic plasticity and cognitive dysfunction. The reduction of excitatory synapses was also increased by administering D-serine. These findings suggest that chronic pain has a critical effect on synaptic plasticity linked to cognitive function and may built up a new target for the development of cognitive impairment under chronic pain conditions.
-
Inhibitory interneurons in the adult spinal dorsal horn (DH) can be neurochemically classified into subpopulations that regulate distinct somatosensory modalities. Although inhibitory networks in the rodent DH undergo dramatic remodeling over the first weeks of life, little is known about the maturation of identified classes of GABAergic interneurons, or whether their role in somatosensation shifts during development. We investigated age-dependent changes in the connectivity and function of prodynorphin (DYN)-lineage neurons in the mouse DH that suppress mechanosensation and itch during adulthood. ⋯ Furthermore, inhibitory synaptic input from DYN interneurons onto PNs was weaker during the neonatal period, likely reflecting a lower number of GABAergic terminals and a reduced probability of GABA release compared to adults. Finally, spinal DYN interneurons attenuated mechanical sensitivity throughout development, but this population dampened acute nonhistaminergic itch only during adulthood. Collectively, these findings suggest that the spinal "gates" controlling sensory transmission to the brain may emerge in a modality-selective manner during early life due to the postnatal tuning of inhibitory synaptic circuits within the DH.
-
Chronic pain has far-reaching impacts on a person's life and on society more broadly. After failure or intolerance of conservative treatments, neuromodulation may be an option for a subgroup of patients. However, little is known about the patient experience of neuromodulation. ⋯ Neuromodulation should be part of an overall pain management plan that may include the need for ongoing emotional and psychosocial support. A deeper knowledge of the patient experience with neuromodulation will assist care teams in providing meaningful support to patients. The results of this study suggest that further research is needed to support neuromodulation as an option for patients living with chronic pain.
-
Physical disuse could lead to a state of chronic pain typified by complex regional pain syndrome type I due to fear of pain through movement (kinesiophobia) or inappropriate resting procedures. However, the mechanisms by which physical disuse is associated with acute/chronic pain and other pathological signs remain unresolved. We have previously reported that inflammatory signs, contractures, disuse muscle atrophy, spontaneous pain-like behaviors, and chronic widespread mechanical hyperalgesia based on central plasticity occurred after 2 weeks of cast immobilization in chronic post-cast pain (CPCP) rat model. ⋯ Furthermore, we demonstrated tactile allodynia using an optogenetic method in a transgenic rat line (W-TChR2V4), cold allodynia using the acetone test, and activation of dorsal horn neurons in the chronic phase associated with chronic mechanical hyperalgesia using c-Fos immunofluorescence. In addition, we showed that nociceptive signals in the acute phase are involved in chronic pathological pain-like behaviors by studying the effects of sciatic nerve block. Thus, we conclude that physical disuse contributes to dystrophy-like changes, spontaneous pain-like behavior, and chronic widespread pathological pain-like behaviors in CPCP rats after 2 weeks of cast immobilization.