RT Journal Article
SR Electronic
T1 Paradoxical sphincter contraction is rarely indicative of anismus
JF Gut
JO Gut
FD BMJ Publishing Group Ltd and British Society of Gastroenterology
SP 258
OP 262
DO 10.1136/gut.41.2.258
VO 41
IS 2
A1 W A Voderholzer
A1 D A Neuhaus
A1 A G Klauser
A1 K Tzavella
A1 S A Müller-Lissner
A1 N E Schindlbeck
YR 1997
UL http://gut.bmj.com/content/41/2/258.abstract
AB Background—Anismus is thought to be a cause of chronic constipation by producing outlet obstruction. The underlying mechanism is paradoxical contraction of the anal sphincter or puborectalis muscle. However, paradoxical sphincter contraction (PSC) also occurs in healthy controls, so anismus may be diagnosed too often because it may be based on a non-specific finding related to untoward conditions during the anorectal examination. Aims—To investigate the pathophysiological importance of PSC found at anorectal manometry in constipated patients and in patients with stool incontinence. Methods—Digital rectal examination and anorectal manometry were performed in 102 chronically constipated patients, 102 patients with stool incontinence, and in 18 controls without anorectal disease. In 120 of the 222 subjects defaecography was also performed. Paradoxical sphincter contraction was defined as a sustained increase in sphincter pressure during straining. Anismus was assumed when PSC was present on anorectal manometry and digital rectal examination and the anorectal angle did not widen on defaecography. Results—Manometric PSC occurred about twice as often in constipated patients as in incontinent patients (41.2% versus 25.5%, p<0.017) and its prevalence was similar in incontinent patients and controls (25.5% versus 22.2%). Oroanal or rectosigmoid transit times in constipated patients with and without PSC did not differ significantly (total 64.6 (8.9) hours versus 54.2 (8.1) hours; rectosigmoid 14.9 (2.4) hours versus 13.8 (2.5) hours). Conclusions—Paradoxical sphincter contraction is a common finding in healthy controls as well as in patients with chronic constipation and stool incontinence. Hence, PSC is primarily a laboratory artefact and true anismus is rare.