Fecal Incontinence Diagnosis

How is fecal incontinence diagnosed?
Fecal incontinence is diagnosed based on a person’s medical history, physical exam, and medical test results. In addition to a general medical history, Dr. Jones may ask the following questions:

  • When did fecal incontinence start?
  • How often does fecal incontinence occur?
  • How much stool leaks? Does the stool just streak the underwear? Does just a little bit of solid or liquid stool leak out or does complete loss of bowel control occur?
  • Does fecal incontinence involve a strong urge to have a bowel movement or does it happen without warning?
  • For people with hemorrhoids, do hemorrhoids bulge through the anus? Do the hemorrhoids pull back in by themselves, or do they have to be pushed in with a finger?
  • How does fecal incontinence affect daily life?
  • Is fecal incontinence worse after eating? Do certain foods seem to make fecal incontinence worse?
  • Can passing gas be controlled?

People may want to keep a stool diary for several weeks before their appointment so they can answer these questions. A stool diary is a chart for recording daily bowel movement details.

The person may be referred to Dr. Jones, who will perform a physical exam and may suggest one or more of the following tests:

Anal manometry uses pressure sensors and a balloon that can be inflated in the rectum to check the sensitivity and function of the rectum. Anal manometry also checks the tightness of the anal sphincter muscles around the anus.

Ultrasound uses a device, called a transducer, that bounces safe, painless sound waves off organs to create an image of their structure. An anal ultrasound is specific to the anus and rectum. The images can show the structure of the anal sphincter muscles.

MRI machines use radio waves and magnets to produce detailed pictures of the body’s internal organs and soft tissues without using x-rays. MRIs can show problems with the anal sphincter muscles. MRI is an alternative to anal ultrasound that may provide more detailed information, especially about the external anal sphincter.

Defecography is an x-ray of the area around the anus and rectum shows how well the person can hold and evacuate stool. The test also identifies structural changes in the rectum and anus such as rectocele and rectal prolapse.

Flexible sigmoidoscopy or colonoscopy tests are used to help diagnose problems causing fecal incontinence. The tests are similar, but colonoscopy is used to view the rectum and entire colon, while flexible sigmoidoscopy is used to view just the rectum and lower colon.

Anal EMG checks the health of the pelvic floor muscles and the nerves that control the muscles. Dr. Jones inserts a very thin needle electrode through the skin into the muscle. The electrode on the needle picks up the electrical activity given off by the muscles and shows it as images on a monitor or sounds through a speaker. An alternative type of anal EMG uses stainless steel plates attached to the sides of a plastic plug instead of a needle. The plug is inserted into the anal canal to measure the electrical activity of the external anal sphincter and other pelvic floor muscles. The average amount of electrical activity when the person relaxes quietly, squeezes to prevent a bowel movement, and strains to have a bowel movement shows whether there is damage to the nerves that control the external sphincter and pelvic floor muscles.