Constipation assessed on the basis of colorectal physiology

Constipation is a collective term for symptoms of different aetiologies and pathophysiologies. Our aim was to determine the prevalence of colorectal pathophysiology findings in a prospective series of patients with chronic constipation.

A total of 155 consecutive patients with chronic constipation underwent anorectal manometry, electromyography (EMG), the balloon expulsion test, colonic transit-time study, and defecography.

All investigations were completed by 134 patients (112 females) with a median age 52 (range, 17-79) years. Patients were categorized on the basis of transit time and pelvic-floor function as belonging to 1 of 4 groups: slow-transit constipation (STC) (delayed transit time but normal pelvic-floor function, n = 28), pelvic-floor dysfunction (PFD) (pelvic-floor dysfunction and normal transit time, n = 32), combined slow transit and pelvic-floor dysfunction (STC + PFD) (n = 27), and normal-transit constipation (NTC) (normal transit time and normal pelvic-floor function, n = 47). There was no difference between diagnostic groups in anal sphincter pressures. However, rectal sensitivity to balloon distension was lower (P < 0.05) in patients with delayed transit. Paradoxical puborectalis contraction (PPC) was found on EMG in 42 patients (31%). The prevalence of PPC was higher (P < 0.001) in patients with pelvic-floor dysfunction. Inability to evacuate the rectal balloon was reported by 37% of patients with pelvic-floor dysfunction and 12% of patients with normal pelvic-floor function (P < 0.001). Rectocele was the only anatomic abnormality at defecography which was associated with poor rectal emptying.

About two-thirds of our patients with constipation had objective evidence of delayed transit or pelvic-floor dysfunction. No single test could reliably identify any of the pathophysiologic subgroups of constipation.