Colonic sensory and motor function in irritable bowel syndrome and diverticular disease

Chapter 1 is a general introduction. Chapter 2: left-colonic motility patterns were studied in fully ambulant non-constipated IBS patients compared to healthy controls. (HAPCs) were identified. In IBS the descending colon had a decreased overall frequency of phasic contractions and motility index as compared to the sigmoid colon, whereas healthy controls did not show regional differences. In IBS the number of high amplitude propagated contractions (HAPCs) was increased and propagated more distally than did HAPCs in controls. Clustered HAPCs were more frequently observed in IBS and these were found to be related to bowel movements. Chapter 3: evaluates the effect of the 5-HT3-antagonist alosetron on left colonic motility and stool characteristics in non-constipated IBS patients and controls. Using a double-blind, randomized, crossover design and an ambulant manometry technique, motility was studied on day 7 of treatment. Alosetron increased contractile frequency in the sigmoid colon and the amplitude of contractions in the descending colon, increased the number of HAPCs in IBS and prolonged the distance of HAPC propagation. Paradoxically, stool frequency was decreased and stools became firmer during alosetron treatment. In Chapter 4 abdominal pain and HAPCs, here called high-amplitude propagated pressure waves (HAPPWs), were recorded in IBS and controls. The aim of this study was to quantify the association between pain episodes and HAPPWs, assessed by a modification of the symptom association probability (SAP). Four of the 7 IBS patients had SAP scores > 95%, meaning the association between HAPPWs and pain occurred by chance was less than 5%. A correlation was found between duration of pain and number of HAPPWs related. An association between HAPPWs and pain, recorded under physiological conditions, can be demonstrated and quantified in IBS patients. Chapter 5 evaluates colorectal periprandial tone and phasic motility in patients with asymptomatic (ADD) and symptomatic uncomplicated diverticular disease (SUDD) and controls. Rectal tone was not different between groups. In the sigmoid a trend towards a decreased volume was found in SUDD as compared to ADD. Phasic motility was increased in ADD as compared to controls and SUDD. A negative correlation between sigmoid barostat volume and phasic motility was found in SUDD only. Differences in tonic and phasic motility in the sigmoid colon indicate that not only symptoms but also motility might be a discriminating factor in SUDD and ADD. In Chapter 6 perception and compliance of the colorectal wall in ADD, SUDD and healthy controls was studied, using a dual barostat device and stepwise intermittent isobaric distensions. SUDD showed increased perception scores in the rectum as compared to controls and ADD. Increased perception in SUDD was also found in the sigmoid colon as compared to controls. No differences in perception score was found between ADD and controls. In the rectum and sigmoid compliance was comparable for all three groups. It is concluded that hyperperception can be found in SUDD but not in ADD which can not be explained by a change in wall compliance