Severity of Fecal Incontinence: Symptoms and Pathophysiologic Abnormalities

Abstract

Purpose: Fecal incontinence (FI), a disorder receiving increasing recognition, is actually common with a reported prevalence of 1.5-11% in the population. The relationship of symptoms of FI to physiologic abnormalities is not well-defined. Many patients who suffer from FI also suffer from urinary incontinence (UI). Aims: To determine the relationship of clinical symptoms of FI to pathophysiologic abnormalities on anorectal manometry (ARM) and to the presence of urinary incontinence. Methods: 101 patients with FI referred for ARM between Jan 2008 to Feb 2009 filled out the Rome III questionnaires for FI, the Bristol stool form scale (grading stool caliber from 1= hard stools to 7= watery stools), and the International Consultation on Urinary Incontinence Questionnaire (ICIQ). ARM included water perfused anorectal manometry, anal EMG, and balloon expulsion. Results: Amount of leakage for FI episodes was related to several physiologic abnormalities: as the FI leakage increased from small to moderate to large, the resting anal sphincter pressure decreased (71±5 vs. 58±4 vs. 44±4 mmHg, p=0.004,respectively) and the volitional anal sphincter contractile response decreased (98±9 vs. 68±7 vs. 59±17 mmHg, p=0.01, respectively), and the sensory threshold increased (22±1 vs. 23±1 vs. 30±4 ml, p=0.01, respectively). The type of FI leakage (liquid/mucus vs. stool only vs. liquid/mucus and stool) was not significantly associated with abnormalities on ARM. Both frequency of FI episodes ≥1 day/month and a large amount of leakage were associated with a higher Bristol stool form scale (p=0.002 and p=0.02, respectively). Low volitional contractile response was associated with both frequency of FI (p=0.02) and amount of leakage (p=0.03). Interestingly, paradoxical contraction of the external anal sphincter on EMG and prolonged balloon expulsion (≥60 seconds), which suggest dyssynergic defecation, were present in 44/101 (44%) and 22/101 (22%) patients, respectively. 58 of the 101 patients with FI also had UI: stress and urge UI were seen in 41 and 38 patients, respectively. Conclusion: Clinical characterization of the severity of FI, especially amount of leakage, is associated with pathophysiologic abnormalities found on ARM. An abnormally low volitional contractile response was associated with both frequency of fecal incontinence and amount of leakage. Some patients with FI had evidence of dyssynergic defecation which may suggest overflow incontinence and might suggest a different treatment plan. In some patients with FI, urinary incontinence is also associated with fecal incontinence.