Pain
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Randomized Controlled Trial Comparative Study Clinical Trial
Rectal afferent function in patients with inflammatory and functional intestinal disorders.
Chronic symptoms of abdominal pain and discomfort are reported by patients with inflammatory bowel disease (IBD) and functional disorders of the gut, such as Irritable Bowel Syndrome (IBS). It has recently been suggested that transient inflammatory mucosal events may result in long-lasting sensitization of visceral afferent pathways. To determine the effect of recurring intestinal tissue irritation on lumbosacral afferent pathways, and to identify a plausible mechanism that could account for the overlap in symptomatology between IBD and IBS, we compared rectal afferent mechanisms in patients with Crohn's disease (inflammation limited to the ileum) with those observed in patients with diarrhea-predominant IBS. ⋯ These findings demonstrate that chronic ileal inflammation is associated with increased thresholds for discomfort and greatly diminished systemic autonomic reflex responses. In contrast, IBS patients show lowered thresholds for discomfort associated with increased autonomic responses. The findings in Crohn's patients may result from descending bulbospinal inhibition of sacral dorsal horn neurons in response to chronic intestinal tissue irritation.
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Randomized Controlled Trial Clinical Trial
Generalized hypervigilance in fibromyalgia: evidence of perceptual amplification.
The hypervigilance model of pain perception states that chronic pain patients have a heightened sensitivity to pain (e.g. low threshold and tolerance) because of increased attention to external stimulation and a preoccupation with pain sensations. This study tested the hypothesis that individuals with fibromyalgia, a chronic pain disorder of undetermined origin, have a generalized hypervigilant pattern of responding that extends beyond the pain domain. Twenty fibromyalgia out-patients, 20 rheumatoid arthritis (RA) patients, and 20 normal controls served as subjects. ⋯ The results of the psychological questionnaires revealed that the fibromyalgia and RA patients preferred lower levels of external stimulation than the control subjects. The outcome of this study supports the generalized hypervigilance hypothesis, suggesting that fibromyalgia patients have a perceptual style of amplification. The implications of these findings for understanding the role of biological, cognitive, and perceptual factors in pain disorders are discussed.
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Randomized Controlled Trial Clinical Trial
Successful treatment of shoulder pain syndrome due to supraspinatus tendinitis with transdermal nitroglycerin. A double blind study.
We have conducted a prospective double blind randomized and placebo controlled clinical study in 20 patients with shoulder pain syndrome caused by supraspinatus tendinitis to determine whether transdermal nitroglycerin (NTG) has analgesic action in this condition. In a randomized manner we used a 5-mg NTG (Nitroplast) patch per day over 3 days or similar placebo patches applied in the most painful area. Patients were evaluated before treatment was initiated and after 24 and 48 h. ⋯ Two patients experienced headache as a side effect 24 h after treatment was started. Patients in the NTG group remained free of symptoms when they were assessed 15 days later. We conclude that NTG is useful in the treatment of shoulder pain syndrome caused by supraspinatus tendinitis and that this treatment could be a useful approach to the management of this common disturbance and probably also in other tendon musculoskeletal disorders.
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Randomized Controlled Trial Clinical Trial
Computer-controlled lidocaine infusion for the evaluation of neuropathic pain after peripheral nerve injury.
Systemic lidocaine has been reported to be effective in treating several neuropathic pain syndromes. Few reports relate plasma lidocaine concentration to analgesia and the available studies have been complicated by labile plasma lidocaine concentrations. We used a computer-controlled infusion pump (CCIP) to target and maintain stable plasma lidocaine concentrations and study the effect of intravenous lidocaine on (1) pain scores, (2) current perception thresholds, (3) side effects, and (4) pain distribution in patients suffering from peripheral nerve injury pain. ⋯ The computer-controlled delivery of intravenous lidocaine results in relatively stable plasma concentrations which allows a more thorough evaluation of the relationship between plasma concentration and patient response. This administration methodology for intravenous lidocaine may prove to be a valuable clinical and research tool.
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Randomized Controlled Trial Clinical Trial
Topical capsaicin selectively attenuates heat pain and A delta fiber-mediated laser-evoked potentials.
Cutaneous stimulation with CO2 laser pulses activates A delta of nociceptive afferents and evokes late cerebral potentials (LEPs), the amplitude of which correlates parametrically with the perceived magnitude estimation of laser pulses. Capsaicin is known to desensitize the nociceptive terminals of C fibers. In this double-blind, vehicle-controlled experiment, we tested the hypothesis that topical capsaicin would inactivate A delta afferents and lead to an attenuation of the LEPs. ⋯ It indicated that topical capsaicin caused a definite functional and reversible inactivation of A delta nociceptive afferent transmission. The decline in the magnitude estimation of laser pulses concomitantly with the attenuation of LEP amplitudes supports the hypothesis that some A delta afferents mediate noxious heat in humans. These findings demonstrate the usefulness of LEP in the physiological evaluation of nociceptive pathways and its potential usefulness in objectively documenting the effect of pharmacological treatment on pain perception.