Physiology of refractory chronic constipation

OBJECTIVE: Investigators suggest three distinct pathophysiologies for patie nts with constipation symptoms: 1) slow colon transit, 2) irritable bowel s yndrome (IBS), and 3) pelvic floor dysfunction (PFD). Our aim was to determ ine the prevalence of the three types of constipation pathophysiology, the degree of overlap, and what interactions exist between pathophysiologies. METHODS: Constipated patients refractory to fiber (n = 131) underwent regio nal colon transit studies, anorectal manometry/EMG, measurement of rectal c ompliance, and rectal sensory testing. Correlations were performed examinin g interactions between the above measures. RESULTS: Visceral hypersensitivity (typical of IBS) was found in 58%, slow colonic transit in 47%, PFD in 59%, and no physiological abnormalities were detected in 24%. Slow transit and visceral hypersensitivity overlapped in half of each group. PFD physiology was found in approximately half of each of the subgroups. There was no correlation between PFD physiology and recto sigmoid transit, total colon transit, or any other physiology. There were n o correlations between slow transit and visceral hypersensitivity. Visceral hypersensitivity did correlate with increased rectal compliance, suggestiv e of increased accommodation reflexes in IBS. CONCLUSIONS: At a tertiary center, slow transit physiology and visceral hyp ersensitivity typical of IBS are equally common and overlap heavily in cons tipated patients. PFD physiology does not correlate with slower rectosigmoi d colon transit, and is seen equally in all subgroups. No abnormalities wer e found in 24% of patients. We therefore identify four subgroups in constip ation: IBS, slow transit, both, and neither. (Am J Gastroenterol 1999;94:60 9-615. (C) 1999 by Am. Cell. of Gastroenterology).