Obstructive defecation syndrome

Sometimes constipation is caused by dysfunction in the normal rectal physiology. This can be caused by disruption of the normal pelvic anatomy by rectal or vaginal prolapse, or just poorly coordinated muscle contractions. The end result is abnormal functioning of the rectum during defecation, leading to constipation and the symptoms listed below. When this occurs, the condition is referred to as obstructive defecation syndrome.

Typical symptoms of obstructive defecation syndrome:

  • Prolonged straining on the toilet
  • Feeling of incomplete voiding after defecation
  • Feeling of needing to pass stools, but unable to do so
  • The need for evacuation of the rectum using a finger in the vagina or rectum


History-taking is important in diagnosing this form of constipation. If this condition is suspected, then a balloon expulsion test should be performed. During this investigation, a catheter is passed through the anus into the rectum and the balloon is inflated with 20-30ml of water. The patient is then asked to push the inflated balloon out into the toilet. This should normally be accomplished within one minute.

Investigations that may need to be performed include anorectal manometry and endo-anal ultrasound.


The initial treatment of this disorder is with aggressive laxative use. If this method fails, it is necessary to refer the patient for biofeedback training, when efforts are made to correct the abnormal rectal function. If there is significant structural abnormality and these measures have failed to manage the problem adequately, it may be necessary to refer the patient to a surgeon for an operation to correct the abnormality.