Pain
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Clinical Trial
Do nerve growth factor-related mechanisms contribute to loss of cutaneous nociception in leprosy?
While sensory loss in leprosy skin is the consequence of invasion by M. leprae of Schwann cells related to unmyelinated fibres, early loss of cutaneous pain sensation, even in the presence of nerve fibres and inflammation, is a hallmark of leprosy, and requires explanation. In normal skin, nerve growth factor (NGF) is produced by basal keratinocytes, and acts via its high affinity receptor (trk A) on nociceptor nerve fibres to increase their sensitivity, particularly in inflammation. We have therefore studied NGF- and trk A-like immunoreactivity in affected skin and mirror-site clinically-unaffected skin from patients with leprosy, and compared these with non-leprosy, control skin, following quantitative sensory testing at each site. ⋯ Keratinocyte trk A expression (which mediates an autocrine role for NGF) was increased in clinically affected and unaffected skin, suggesting a compensatory mechanism secondary to reduced NGF secretion at both sites. We conclude that decreased NGF- and SNS/PN3-immunoreactivity, and loss of intra-epidermal innervation, may be found without sensory loss on quantitative testing in clinically-unaffected skin in leprosy; this appears to be a sub-clinical change, and may explain the lack of cutaneous pain with inflammation. Sensory loss occurred with reduced sub-epidermal nerve fibres in affected skin, but these still showed trk A-staining, suggesting NGF treatment may restore pain sensation.
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Case Reports Clinical Trial
Virtual reality as an adjunctive pain control during burn wound care in adolescent patients.
For daily burn wound care procedures, opioid analgesics alone are often inadequate. Since most burn patients experience severe to excruciating pain during wound care, analgesics that can be used in addition to opioids are needed. This case report provides the first evidence that entering an immersive virtual environment can serve as a powerful adjunctive, nonpharmacologic analgesic. ⋯ He had difficulty tolerating wound care pain with traditional opioids alone and showed dramatic drops in pain ratings during VR compared to the video game (e.g. a 47 mm drop in pain intensity during wound care). We contend that VR is a uniquely attention-capturing medium capable of maximizing the amount of attention drawn away from the 'real world', allowing patients to tolerate painful procedures. These preliminary results suggest that immersive VR merits more attention as a potentially viable form of treatment for acute pain.
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparative trial of botulinum toxin type A and methylprednisolone for the treatment of myofascial pain syndrome and pain from chronic muscle spasm.
Myofascial pain syndrome (MPS) is a common illness, characterised by acute or chronic focal pain, muscle stiffness and fatigue. The pathophysiology of MPS remains unclear. Previous preliminary studies have demonstrated therapeutic efficacy of the muscle relaxant botulinum toxin type A (BTX-A) in the treatment of MPS. ⋯ At 60 days post-injection, the pain severity score for the BTX-A-treated patients was statistically significantly lower than the pain score for the steroid-treated population (2.3 vs. 4.9). Furthermore, the reduction in pain score in the BTX-A group at 60 days post-injection was greater than at 30 days (-5.5 vs. -3.9), whereas the effect of the steroid had begun to wane. These results indicate the superior efficacy of BTX-A over conventional steroid treatment in patients suffering from MPS, when combined with appropriate physiotherapy.
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Comparative Study Clinical Trial
Age-related differences in the time course of capsaicin-induced hyperalgesia.
The effect of age on hyperalgesia, one of the most common signs of injury, has not been previously examined in humans. A psychophysical study was conducted in 10 young (26.9+/-4.6 years) and 10 older (79. 0+/-5.7 years) healthy volunteers to investigate the effect of age on the development of hyperalgesia induced by topical application of capsaicin (0.1 ml, 5 mg/ml). The capsaicin patch (diameter 2 cm) was applied for 1 h. ⋯ We conclude that, given the same intensity of noxious stimulation, older adults display a similar magnitude of hyperalgesia as younger persons. However, once initiated, punctate hyperalgesia appears to resolve more slowly in older people. This finding may indicate age differences in the plasticity of spinal cord neurons following an acute injury.
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Clinical Trial
Do beliefs, coping, and catastrophizing independently predict functioning in patients with chronic pain?
Physical and psychosocial disability in patients with chronic pain have been shown to be associated with patients' pain-related beliefs, tendency to catastrophize, and pain coping strategy use. However, little is known about whether beliefs, catastrophizing, and coping strategies are independently associated with patient adjustment. Identification of specific beliefs, cognitive responses, and coping strategies strongly and independently associated with physical and psychosocial functioning would suggest the importance of targeting those variables for modification in treatment. ⋯ Belief scores significantly and independently predicted both physical disability and depression, after controlling for age, sex, pain intensity, catastrophizing, and coping. Coping scores significantly and independently predicted physical disability, but not depression, whereas catastrophizing independently predicted depression, but not physical disability. These findings suggest the importance of targeting specific pain-related beliefs and coping strategies, as well as catastrophizing, for modification in the treatment of patients with chronic pain.