Pain thresholds in women with chronic pelvic pain.

PURPOSE OF REVIEW: To update on the latest developments in sensory changes of female patients with chronic pelvic pain (CPP). CPP is very common, but its pathophysiology is still controversial. Evaluation of pain sensitivity in painful and nonpainful areas is key to understanding the underlying peripheral vs. central contributions to the symptom. This in turn is fundamental to improving the treatment strategies. RECENT FINDINGS: We reviewed the experimental studies published over the last year on pain thresholds to different stimuli measured at both the somatic and visceral level in women with different forms of recurrent or CPP. The majority of the studies indicate a pain threshold decrease to most stimuli in skin, subcutis and muscle in painful pelvic areas, the site of referred pain from pelvic viscera, as well as a decreased pain threshold in most viscera (colon and urinary bladder). A significant threshold decrease is also found in deep somatic tissues (subcutis and muscle) outside the painful zone in the most severe cases, indicating a state of central sensitization. SUMMARY: These findings have important implications for clinical practice: pain threshold measurement in both painful and nonpainful sites could have important predictive value of the clinical evolution and response to therapy of CPP.

Sensitivity disturbances in patients with irritable bowel syndrome and fibromyalgia.

BACKGROUND: Although visceral hypersensitivity is a common feature among patients with irritable bowel syndrome (IBS), studies on somatic sensitivity have given controversial results. AIM: To assess visceral sensitivity in response to isotonic rectal distensions and somatic sensitivity at different layers of the body wall (skin, subcutis, and muscle) in patients with IBS and fibromyalgia (FM), within and outside the area of abdominal pain referral. MATERIALS AND METHODS: We studied 10 patients with IBS, 5 patients with FM, 9 patients with IBS+FM, and 9 healthy controls. Rectal distensions were performed by increasing tension at 4 g steps up to 64 g or discomfort. Pain thresholds to electrical stimulation were measured within and outside the areas of abdominal pain referral. RESULTS: Patients with IBS and IBS+FM demonstrated rectal hypersensitivity in comparison to controls. The threshold of discomfort was 44 +/- 5 g in IBS and 36 +/- 5 in IBS+FM patients, while patients with FM and healthy controls tolerated all distensions without discomfort. In the areas of pain referral, pain thresholds of all three tissues of the body wall were lower than normal in all patients groups (p < 0.001). In control areas, the pain thresholds were normal in skin, and lower than normal in subcutis and muscle in IBS (p < 0.001). FM and IBS+FM demonstrated somatic hypersensitivity at all sites (p < 0.001 vs healthy). CONCLUSION: Our observations seem to indicate that, although sharing a common hypersensitivity background, multiple mechanisms may modulate perceptual somatic and visceral responses in patients with IBS and FM.

Peripheral blood mononuclear cell beta-endorphin concentration is decreased in chronic fatigue syndrome and fibromyalgia but not in depression: preliminary report.

OBJECTIVE: The aim of this study was to examine the possible role of the immune system in the pathophysiology of chronic fatigue syndrome and fibromyalgia syndrome and in the differential diagnosis of depression by investigating changes in peripheral blood mononuclear cell levels of beta-endorphin, an endogenous opioid known to be involved in regulation of the immune system function. DESIGN: Beta-endorphin concentrations were measured by radioimmunoassay in peripheral blood mononuclear cells from healthy controls (n = 8) and patients with chronic fatigue syndrome (n = 17), fibromyalgia syndrome (n = 5), or depression (n = 10). RESULTS: Beta-endorphin concentrations were significantly lower in patients with chronic fatigue syndrome or fibromyalgia syndrome than in normal subjects and depressed patients (p <0.001 and p <0.01, respectively). They were significantly higher in depressed patients than in controls (p <0.01). CONCLUSIONS: Evaluation of peripheral blood mononuclear cell beta-endorphin concentrations could represent a diagnostic tool for chronic fatigue syndrome and fibromyalgia and help with differential diagnosis of these syndromes versus depression. The results obtained are also consistent with the hypothesis that the immune system is activated in both chronic fatigue syndrome and fibromyalgia syndrome.