The authors investigated 103 consecutive Thai patients (29M, 74F, age 50+20) with chronic idiopathic constipation (symptom duration; median 5yr, range 0.25-45 yr) as defined by Rome II criteria using colonic transit test, anorectal manometry, and balloon expulsion tests. Constipation symptoms were evaluated by a questionnaire.
Results: There were 30,14,11, and 48 patients who fulfilled the criteria of anorectal dysfunction, colonic inertia, anorectal
dysfunction plus colonic inertia, and the normal transit constipation, respectively. The proportion of female gender in the normal transit constipation group (F:M=37:11) was significantly greater than the anorectal dysfunction group (16:14,p<0.05%). Patients with colonic inertia and colonic inertia plus anorectal dysfunction had a higher prevalence of infrequent bowel movement compaired to anorectal dysfunction and normal transit constipation (p<0.001). The prevalence of straining, hard stool, incomplete evacuation, sense of anal obstruction, and use of manual maneuver to facilitate defecation, were not different among the constipation subgroups (p>0.05).
Conclusions: Prevalence of pathophysiologic conditions associated with idiopathic constipation in Thai patients are
similar to Western countries.29%,13%, and 11% of Thai patients with idiopathic constipation were associated with
anorectal dysfunction, colonic inertia, and anorectal dysfunction plus colonic inertia, respectively. Among the 6 constipation
symptoms defined by Rome II criteria, only infrequent bowel movements was associated with delayed colonic transit.

Keywords: Constipation, Anorectal dysfunction, Colonic inertia, Constipation symptoms