Is it expected for a patient to have stool from the rectum if they have a diverting loop sigmoid colostomy (diverting loop sigmoid colostomy)?

Stool from Rectum with Diverting Loop Sigmoid Colostomy

It is not expected for a patient to have stool from the rectum if they have a properly functioning diverting loop sigmoid colostomy, as the purpose of this procedure is to completely divert the fecal stream away from the distal bowel segment. 1

Understanding Loop Sigmoid Colostomy Function

A diverting loop sigmoid colostomy is designed to interrupt the normal fecal passage through the colon by creating a temporary opening (stoma) in the sigmoid colon. When properly constructed:

• The proximal limb of the loop brings stool out through the abdominal wall
• The distal limb (leading to the rectum) should remain inactive
• Complete diversion prevents fecal matter from reaching the rectum 2

Research has specifically examined this question, with a retrospective study showing that properly constructed loop stomas provide adequate diversion without spillage into the nonfunctional limb 1. When CT scans with oral contrast were performed on patients with loop ostomies, no evidence of contrast was found in the distal limb in any of the examined cases.

Potential Causes of Rectal Output Despite Colostomy

If stool is observed from the rectum despite a diverting colostomy, several possibilities should be considered:

1. Incomplete diversion: The colostomy may not be completely diverting, which can occur if:

   • The supporting rod was removed too early
   • The loop was not adequately mobilized during surgery
   • Technical issues with stoma creation 2

2. Mucus discharge: What appears to be stool may actually be mucus produced by the rectal mucosa, which is normal and expected

   • Mucus production continues in the defunctionalized segment
   • This can sometimes be confused with stool passage

3. Residual stool: Material that was present in the distal segment before the colostomy was created may be gradually expelled

Clinical Implications and Management

For patients with a diverting loop sigmoid colostomy who report stool from the rectum:

• Perform a digital rectal examination to confirm the presence of actual stool versus mucus
• Consider a limited proctosigmoidoscopy to assess the distal segment
• If true fecal diversion failure is confirmed, surgical revision may be necessary

The World Society of Emergency Surgery guidelines note that a properly constructed loop sigmoid colostomy should provide complete fecal diversion 3. This is particularly important in cases where the colostomy was created to protect a distal anastomosis or to manage rectal injuries 4.

Special Considerations

For patients with inflammatory bowel disease who have a diverting colostomy, specialized interdisciplinary care is essential, as noted in the Journal of Crohn's and Colitis guidelines 3. These patients may require additional monitoring for complications specific to their underlying condition.

In summary, while mucus discharge from the rectum is expected, actual stool passage suggests inadequate diversion and warrants clinical evaluation to determine if surgical revision is necessary.