Tests and diagnosis

By Mayo Clinic Staff

Your doctor will ask questions about your condition and perform a physical exam that usually includes a visual inspection of your anus. A pin or probe may be used to examine this area for nerve damage. Normally, this touching causes your anal sphincter to contract and your anus to pucker.

Medical tests

A number of tests are available to help pinpoint the cause of fecal incontinence:

  • Digital rectal exam. Your doctor inserts a gloved and lubricated finger into your rectum to evaluate the strength of your sphincter muscles and to check for any abnormalities in the rectal area. During the exam your doctor may ask you to bear down, to check for rectal prolapse.
  • Balloon expulsion test. A small balloon is inserted into the rectum and filled with water. You are then asked to go to the toilet and expel the balloon. The length of time it takes to expel the balloon is recorded. A time of one minute or longer is usually considered a sign of a defecation disorder.
  • Anal manometry. A narrow, flexible tube is inserted into the anus and rectum. A small balloon at the tip of the tube may be expanded. This test helps measure the tightness of your anal sphincter and the sensitivity and functioning of your rectum.
  • Anorectal ultrasonography. A narrow, wand-like instrument is inserted into the anus and rectum. The instrument produces video images that allow your doctor to evaluate the structure of your sphincter.
  • Proctography. X-ray video images are made while you have a bowel movement (defecate) on a specially designed toilet. The test measures how much stool your rectum can hold and evaluates how well your body expels stool.
  • Proctosigmoidoscopy. A flexible tube is inserted into your rectum to inspect the last two feet of the colon (sigmoid) for signs of inflammation, tumors or scar tissue that may cause fecal incontinence.
  • Endorectal ultrasound. A special endoscope is inserted to look at the lower colon and to use sound waves to provide images of the anal sphincters.
  • Colonoscopy. A flexible tube is inserted into your rectum to inspect the entire colon.
  • Anal electromyography. Tiny electrodes inserted into muscles around the anus can reveal signs of nerve damage.
  • MRI. Magnetic resonance imaging (MRI) can provide clear pictures of the sphincter to determine if the muscles are intact and can also provide images during defecation.
Nov. 06, 2012