Difficult defecation in constipated patients and its relationship to colonic disorders

The importance in constipated subjects of having difficult defecation is poorly known. According to the Rome III criteria, constipated patients are classified as having either irritable bowel syndrome with constipation or functional constipation, depending on the presence and characteristics of abdominal pain. But, the Rome III criteria also identify another group of patients, labeled as suffering from functional anorectal disorders. Within this group, two complaints are akin to being constipated, but not labeled so: having dyssynergic defecation or inadequate defecation.

The aim of this study was to search for an association between difficult defecation and colonic transit abnormalities in constipated patients and, thus, shed some light on the definition of constipation according to the Rome III criteria.

Four hundred four consecutive patients (81% female), aged 44.9 ± 16.6 years, with a BMI of 25.5 ± 6.4 kg/m(2) (mean ± SD), suffering from chronic constipation were included in the present study. After filling out a standard Rome III questionnaire, patients were classified as suffering from an irritable bowel syndrome with constipation or functional constipation. In addition, they were classified as complaining of difficult defecation or not. Patients completed the Bristol Stool Form Scale as well as visual analogue scales for constipation, bloating, and abdominal pain. The colonic transit time was measured using radiopaque markers and analyzed according to three sites: the right colon, the left colon, and the rectosigmoid area.

Difficult defecation is more frequent in patients with irritable bowel syndrome with constipation (84%) than in patients with functional constipation (68%). It is associated with an increase in constipation and abdominal pain scores on Likert scales, and a longer oroanal transit time, due to a delay in the left part of the colon.

This study demonstrates that difficult defecation is part of a more generalized colorectal dysfunction in both irritable bowel syndrome and in functional constipation patients with an overlap of symptomatology. It also demonstrates the relative inadequacy of the Rome III criteria to describe the relationship between constipation and difficult defecation.