Increased colon transit time and faecal load in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a bowel disorder involving abdominal pain or discomfort along with irregularity of stool form and passage frequency. The pathophysiology is poorly understood and seems to be multifactorial. Investigations of possible causes of IBS have included only a few colonic transit studies and no simultaneous determination of the colonic faecal content.

To compare colon transit time and faecal load between IBS-patients and healthy control subjects.

The study included 140 patients with IBS, with a mean age of 50.0 years. The control group comprised 44 healthy persons with a mean age of 43.4 years, who were selected at random from the National Civil Register. Both the patient group and the control group underwent a marker study to measure colon transit time (CTT) and to calculate a faecal loading score. The patient group underwent treatment with a combined prokinetic regime, after which their CTT and faecal loading were reassessed. Analyses were performed to compare measurements between the control group and the patient group before and after treatment.

Compared to healthy controls, IBS-patients exhibited a significantly prolonged mean CTT (45.48 h vs 24.75 h, P = 0.0002) and significantly greater mean faecal loading scores in all colonic segments (P < 0.001). Among IBS patients, we found no significant differences between the 48 h and 96 h radiographs. Among patients exhibiting increased CTT and faecal loading, approximately half exhibited a palpable mass in the right iliac fossa. After intervention with a prokinetic treatment, the mean CTT among IBS patients was reduced from 45.48 h to 34.50 h (P = 0.091), with the post-treatment CTT not significantly differing from the CTT among control subjects (P = 0.095). The faecal loading score among IBS patients did not significantly differ before and after treatment (P = 0.442). The post-treatment faecal loading score in IBS patients remained significantly higher compared to that in controls (5.3 vs 4.3, P = 0.014). After treatment, half of the IBS-patients were relieved of bloating, while the majority no longer experienced abdominal pain and achieved a daily consistent stool.

IBS-patients exhibited prolonged CTT and heavier faecal loading. These assessments may aid in diagnosis. Faecal retention may contribute to IBS symptoms, which can be treated using a prokinetic regime.