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.