Correlation of symptom criteria with perception thresholds during rectosigmoid distension in irritable bowel syndrome patients

OBJECTIVE: Due to a lack of reliable biological markers, the diagnosis of i rritable bowel syndrome (IBS) is based on symptom criteria. The possible ph ysiological correlates of these criteria are not known. Our aims were to id entify correlations of currently used IBS symptom criteria with distinct al terations in visceral perception. METHODS: Forty-two IBS patients (51% women) with a mean age of 39.5 +/- 1.4 yr, were included; 64% of patients were recruited from advertisement and 3 6% were clinic referrals. Patients completed a bowel symptom questionnaire, which included the Rome criteria and symptom severity ratings. Rectal disc omfort thresholds were evaluated in all patients and in 19 controls, using a nonbiased tracking protocol consisting of phasic rectal balloon distensio ns before (PreTh) and after (PostTh) repetitive, high-pressure sigmoid dist ensions. We assessed the effect of each Rome criteria and symptom severity on PreTh and PostTh. RESULTS: IBS symptom severity was reported as moderate in 38.1% and as seve re in 61.9% of patients. Overall, lower thresholds were observed in IBS pat ients than in controls (PreTh: 28.2 +/- 1.7 vs 36.3 +/- 2.8 mm Hg, p < 0.05 ; PostTh: 25.3 +/- 1.5 vs 34.2 +/- 2.7 mm Hg, p < 0.01). When assessing the effect of Pome criteria on rectal thresholds, we found that patients with hard/lumpy stools had lower thresholds than those without them, whereas pat ients with loose watery stools had higher thresholds than those who lacked them (both p < 0.05). The lowering of rectal discomfort thresholds after si gmoid stimulation was observed regardless of the presence or absence of any Rome criteria or symptom severity. CONCLUSION: Although a decrease in rectal discomfort thresholds after sigmo id stimulation is seen in IBS regardless of specific symptoms, baseline and postsigmoid stimulation thresholds are lower in IBS: patients with constip ation-related symptoms.