Related Experiment Videos
Megarectum in constipation
R N van der Plas1, M A Benninga, C R Staalman
1Department of Paediatric Gastroenterology and Nutrition, Academic Medical Center, G8-245, Meibergdreef 9, 1105 AZ Amsterdam, Netherlands. R.N.vanderplas@amc.uva.nl
Insights
Faecal impaction in constipated children is defined by rectal findings. An enlarged rectum has a rectopelvic ratio over 0.61, while megarectum involves abnormal rectal function tests.
Area of Science:
- Pediatric Gastroenterology
- Colorectal Surgery
- Functional Bowel Disorders
Background:
- Faecal impaction is common in pediatric chronic constipation.
- The terms enlarged rectum and megarectum are often used but lack clear definitions.
Purpose of the Study:
- To establish clear definitions for faecal impaction, enlarged rectum, and megarectum.
- To evaluate rectal functioning and measurements in constipated children with faecal impaction.
Main Methods:
- Radiological investigation, colonic transit time study, and anorectal manometry were performed.
- Rectal volume and rectal wall compliance were measured.
- Patients with faecal impaction were compared to controls with empty rectums.
Main Results:
- Patients showed delayed rectosigmoid transit and less rectal relaxation.
- Rectal width was greater in patients (0.68) than controls (0.52).
- Rectal wall compliance was similar between groups, but pressure-volume curves differed.
Conclusions:
- Faecal impaction is a filled rectum on digital examination.
- Enlarged rectum is defined by a rectopelvic ratio > 0.61.
- Megarectum is characterized by abnormal anorectal manometry, pressure-volume curves, or rectal compliance, with diminished rectal relaxation being an early sign.
Background:
Faecal impaction is frequently observed in children with chronic constipation. The term megarectum is often used to describe this finding.
Aim:
To evaluate rectal functioning and rectal measures in constipated children with a filled rectum, in order to define the terms faecal impaction, enlarged rectum, and megarectum.
Methods:
All children underwent radiological investigation, colonic transit time study, anorectal manometry, and rectal volume and rectal wall compliance measurements. Patients with faecal impaction were compared with controls, who had an empty rectum on digital rectal examination.
Results:
A total of 31 patients and six controls were included in the study. The mean duration of complaints was 4.2 years and all had faecal incontinence. The colonic transit times in the patients showed a distinct delay in the rectosigmoid segment. Anorectal manometry was not significantly different between patients and controls. The rectal width in patients was 0.68 and in controls 0.52 with an upper limit of 0.61. The pressure-volume curve in patients showed significant less relaxation at a distension of 50 ml. The slope of the curve (corresponding with rectal wall compliance) was comparable for patients and controls.
Conclusions:
We suggest that faecal impaction is a filled rectum found on digital rectal examination; an enlarged rectum is defined by a rectopelvic ratio greater than 0.61; and megarectum is defined in those with significant abnormalities found with anorectal manometry, pressure-volume curves, or rectal compliance investigation. A diminished relaxation of the rectum on rectal distension could be the first sign of megarectum in children with chronic constipation.