Pain
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A man in his 50's with a prior traumatic brain injury and multiple psychiatric disorders developed acute pain and swelling in his left leg distal to the mid shin. These symptoms arose during an exacerbation of his post-traumatic stress disorder (PTSD). ⋯ A diagnosis of conversion disorder was technically excluded because the findings met criteria for Complex Regional Pain Syndrome (CRPS) type I. Based on recent research into the neurobiology of CRPS, PTSD and conversion disorder, we propose a supraspinal mechanism which could explain how emotional stress can produce both symptoms and signs.
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Comparative Study
Prostaglandin E2 in the midbrain periaqueductal gray produces hyperalgesia and activates pain-modulating circuitry in the rostral ventromedial medulla.
Recent years have seen significant advances in our understanding of the peripheral and spinal mechanisms through which prostaglandins contribute to nociceptive sensitization. By contrast, the possibility of a supraspinal contribution of these compounds to facilitated pain states has received relatively little attention. One possible mechanism through which prostaglandins could act supraspinally to facilitate nociception would be by recruitment of descending facilitation from brainstem pain-modulating systems. ⋯ Microinjection of PGE(2) (50 fg in 200 nl) into the PAG produced a significant decrease in paw withdrawal latency. The PGE(2) microinjection activated on-cells, RVM neurons thought to facilitate nociception, and suppressed the firing of off-cells, RVM neurons believed to have an inhibitory effect on nociception. These data demonstrate a prostaglandin-sensitive descending facilitation from the PAG, and suggest that this is mediated by on- and off-cells in the RVM.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Relative analgesic potency of fentanyl and sufentanil during intermediate-term infusions in patients after long-term opioid treatment for chronic pain.
Sufentanil, a potent mu-opioid agonist, historically has not been been given systemically to treat chronic pain. An implantable, fixed-rate osmotic pump that delivers sufentanil subcutaneously is being developed for this purpose. In that transdermal fentanyl may be a useful intermediary to estimate the appropriate sufentanil dose before implant, accurate information is needed about the relative analgesic potency of sufentanil and fentanyl during continuous infusion. ⋯ For the remaining 41 patients, target concentrations associated with adequate analgesia were achieved for both sufentanil and fentanyl. The median value for the equianalgesic concentration ratio (steady-state fentanyl infusion to steady-state sufentanil infusion) was 7.5; mean potency ratio was 7.44 (95% confidence interval 6.8-8.2). During titrated, intermediate-term infusions in patients previously treated with opioids for chronic pain, sufentanil is approximately 7.5 times as potent as fentanyl.
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Randomized Controlled Trial Comparative Study Clinical Trial
Imagery reduces children's post-operative pain.
This un-blinded experimental study investigated the effectiveness of imagery, in addition to routine analgesics, in reducing tonsillectomy and/or adenoidectomy pain and anxiety after ambulatory surgery (AS) and at home. Seventy-three children, aged 7-12, were recruited from five AS settings. Thirty-six children randomly assigned to the treatment group watched a professionally developed videotape on the use of imagery and then listened to a 30-min audio tape of imagery approximately 1 week prior to surgery (T1). ⋯ When controlling for trait anxiety, a two-way RM MANCOVA indicated no significant group differences in combined opioid and non-opioid use between the groups, or between times. Appropriately trained health care providers should use imagery to reduce post-operative pain following tonsillectomy and/or adenoidectomy in AS. Teaching parents about adequate home administration of analgesics may increase the effectiveness of imagery at home.
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Randomized Controlled Trial Comparative Study Clinical Trial
The analgesic effects that underlie patient satisfaction with treatment.
Patient satisfaction and global ratings of study medications are increasingly used as secondary outcome measures in pain clinical trials. However, little is known about the factors that underlie and contribute to these ratings. 191 patients who participated in a randomized trial of parenteral parecoxib sodium followed by oral valdecoxib for pain following laparoscopic cholecystectomy versus standard care rated their satisfaction with the overall performance of the study medications (postoperative days 1 and 7) and also provided global evaluation of the analgesics on postoperative day 7. ⋯ These results were replicated in the prediction of day 7 ratings, except that at day 7, treatment regimen also made a significant independent contribution to the prediction of satisfaction. These findings indicate that the study participants considered more than one factor when estimating their satisfaction with the study medications, and that the changes produced by the treatment (e.g. decreased pain, opioid-related symptoms) mediated, in part, the effects of treatment on treatment satisfaction.