Is stool output from the rectum expected in a patient with a diverting loop sigmoid colostomy?

Stool Output from Rectum with Diverting Loop Sigmoid Colostomy

No, a patient with a properly functioning diverting loop sigmoid colostomy should NOT have stool coming out of the rectum—the colostomy is designed to completely divert the fecal stream away from the distal colon and rectum. 1, 2

Understanding Loop Colostomy Function

A loop sigmoid colostomy is specifically constructed to achieve total fecal diversion when properly created:

• The loop ostomy is created by bringing a continuous piece of intestine through the abdominal wall and opening the anterior wall, resulting in two intestinal openings side by side within the same skin aperture. 1

• The proximal end (which drains stool) is made dominant (Brooked), while the defunctionalized distal end is diminutive. 1

• Research definitively demonstrates that loop colostomies constructed over a rod and matured immediately totally divert the fecal stream—barium studies in 23 patients showed no passage of contrast into the distal limb even after 24 hours or after bowel preparation. 2

What Should Come from the Rectum

The only expected output from the rectum in a patient with a functioning diverting loop sigmoid colostomy is mucus, NOT stool:

• The defunctionalized distal segment (including the rectum) continues to produce mucus from the intestinal lining 1

• This mucus discharge is normal and expected 1

• Any actual stool output from the rectum indicates the colostomy is NOT adequately diverting 2

Clinical Implications of Stool Per Rectum

If stool is coming from the rectum, this represents a failure of diversion and requires immediate evaluation:

• The colostomy may not be properly constructed or matured 2

• There may be technical issues with how the loop was created 3

• The proximal limb may not be adequately dominant 1

This is particularly critical because loop colostomies are often created to protect distal anastomoses, allow healing of rectal injuries, or manage severe conditions like radiation proctitis—all situations where complete fecal diversion is essential for treatment success. 4, 5

Expected Normal Colostomy Output

The stool should come ONLY from the colostomy, with these characteristics:

• Normal colostomy output is typically formed stool occurring once daily 6, 7

• Colostomy appliances usually require changing once every 6-7 days due to the formed consistency 6, 7

• Output volume should be proportional to intake, with concerning output being greater than 1.5 L/day 6, 7