Colonic volume in patients with functional constipation or irritable bowel syndrome determined by magnetic resonance imaging

BACKGROUND

Functional constipation (FC) and irritable bowel syndrome constipation type (IBS-C) share many similarities, and it remains unknown whether they are distinct entities or part of the same spectrum of disease. Magnetic resonance imaging (MRI) allows quantification of intraluminal fecal volume. We hypothesized that colonic volumes of patients with FC would be larger than those of patients with IBS-C, and that both patient groups would have larger colonic volumes than healthy controls (HC).

METHODS

Based on validated questionnaires, three groups of participants were classified into FC (n = 13), IBS-C (n = 10), and HC (n = 19). The colonic volume of each subject was determined by MRI. Stool consistency was described by the Bristol stool scale and colonic transit times were assessed with radiopaque makers.

KEY RESULTS

Overall, total colonic volumes were different in the three groups, HC (median 629 ml, interquartile range (IQR)(562-868)), FC (864 ml, IQR(742-940)), and IBS-C (520 ml IQR(489-593)) (p = 0.001). Patients with IBS-C had lower colonic volumes than patients with FC (p = 0.001) and HC (p = 0.019), but there was no difference between FC and HC (p = 0.10). Stool consistency was similar in the two patient groups, but patients with FC had longer colonic transit time than those with IBS-C (117.6 h versus 43.2 h, p = 0.019).

CONCLUSION

Patients with IBS-C have lower total colonic volumes and shorter colonic transit times than patients with FC. Future studies are needed to confirm that colonic volume allows objective distinction between the two conditions.

Colonic motility in patients with type 1 diabetes and gastrointestinal symptoms

BACKGROUND

Gastrointestinal (GI) symptoms are common in patients with diabetes mellitus (DM). The electromagnetic 3D-Transit system allows assessment of regional transit times and motility patterns throughout the GI tract. We aimed to compare GI transit times and detailed motility patterns of the colon in patients with DM and GI symptoms to those of healthy controls (HC). We further aimed to determine whether any abnormalities in motility were reversible by cholinergic stimulation.

METHODS

We compared 18 patients with DM with 20 HC by means of the 3D-Transit system. Patients were studied before and during oral administration of 60 mg pyridostigmine.

KEY RESULTS

Compared to HC, patients had prolonged gastric emptying (DM: 3.3 hours (interquartile range (IQR) 2.6-4.6); HC: 2.3 hours (IQR 1.7-2.7) (P < .01)), colonic transit time (DM: 52.6 hours (IQR 23.3-83.0); HC: 22.4 hours (IQR 18.9-43.6) (P = .02)), and whole gut transit time (DM: 69.4 hours (IQR 32.9-103.6); HC: 30.3 hours (IQR 25.2-49.9) (P < .01)). In addition, compared to HC, patients had prolonged transit time in the ascending colon (DM: 20.5 hours (IQR 11.0-44.0); HC: 8.0 hours (IQR 3.8-21.0) (P < .05)) and more slow retrograde movements in the colon (DM: 2 movements (IQR 1-4); HC: 1 movement (IQR 0-1) (P = .01)). In patients, pyridostigmine increased the number of bowel movements (P < .01) and reduced small intestine transit times (P < .05).

CONCLUSIONS

Patients with DM and GI symptoms have longer than normal GI transit times. This is only partly reversible by pyridostigmine. The increased number of retrograde colonic movements in patients could potentially explain the abnormally long transit time in proximal colon.