Constipation

  • Medical Author:
    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Quick GuideDigestive Disorders: Constipation Myths and Facts

Digestive Disorders: Constipation Myths and Facts

Imaging studies and other tests

Colonic transit (marker) studies

Colonic transit studies are simple X-ray studies that determine how long it takes for food to travel through the intestines. For transit studies, individuals swallow capsules for one or more days. Inside the capsules are many small pieces of plastic that can be seen on X-rays. The gelatin capsules dissolve and release the plastic pieces into the small intestine. The pieces of plastic then travel (as would digesting food) through the small intestine and into the colon. After 5 or 7 days, an X-ray of the abdomen is taken and the pieces of plastic in the different parts of the colon are counted. From this count, it is possible to determine if and where there is a delay in the colon.

In non-constipated individuals, all of the plastic pieces are eliminated in the stool and none remain in the colon. When pieces are spread throughout the colon, it suggests that the muscles or nerves throughout the colon are not working, which is typical of colonic inertia. When pieces accumulate in the rectum, it suggests pelvic floor dysfunction.

Defecography

Defecography is a modification of the barium enema examination. For this procedure, a thick paste of barium is inserted into the rectum of a patient through the anus. X-rays then are taken while the patient defecates the barium. The barium clearly outlines the rectum and anus and demonstrates the changes taking place in the muscles of the pelvic floor during defecation. Thus, defecography examines the process of defecation and provides information about anatomical abnormalities of the rectum and pelvic floor muscles during defecation.

Ano-rectal motility studies

Ano-rectal motility studies, which complement defecography tests, provide an assessment of the function of the muscles and nerves of the anus and rectum. For ano-rectal motility studies, a flexible tube, approximately an eighth of an inch in diameter, is inserted through the anus and into the rectum. Sensors within the tube measure the pressures that are generated by the muscles of the anus and rectum. With the tube in place, the patient performs several simple maneuvers such as voluntarily tightening the anal muscles. Ano-rectal motility studies can help determine if the muscles of the anus and rectum are working normally. When the function of these muscles is impaired, the flow of stool is obstructed, thereby causing a condition similar to pelvic floor dysfunction.

Magnetic resonance imaging defecography

The newest test for evaluating defecation and its disorders is magnetic resonance imaging defecography and is similar to barium defecography. However, magnetic resonance imaging (MRI) is used instead of X-rays to provide images of the rectum during defecation. MRI defecography appears to be an excellent way to study defecation, but the procedure is expensive and somewhat cumbersome. As a result, it is used in only a few institutions that have a particular interest in constipation and abnormalities of defecation.

Colonic motility studies

Colonic motility studies are similar to ano-rectal motility studies in many aspects. A very long, narrow (one-eighth inch in diameter), flexible tube is inserted through the anus and passed through part or the entire colon during a procedure called colonoscopy. Sensors within the tube measure the pressures that are generated by the contractions of the colonic muscles. These contractions are the result of coordinated activity of the colonic nerves and muscles. If the activity of the nerves or muscles is abnormal, the pattern of colonic pressures will be abnormal. Colonic motility studies are most useful in defining colonic inertia. These studies are considered research tools, but they can be helpful in making decisions regarding treatment in patients with severe constipation. Continue Reading

Reviewed on 7/16/2015
References
REFERENCE:

Fauci, Anthony S., et al. Harrison's Principles of Internal Medicine. 17th ed. United States: McGraw-Hill Professional, 2011.

IMAGES:

1. Getty Images

2. iStock/MedicineNet

3. iStock

4. iStock

5. Getty Images

6. Getty Images

7. Getty Images

8. iStock

9. iStock

10. iStock

11. iStock

12. iStock

13. Getty Images

14. iStock

15. Getty Images

16. Getty Images

17. iStock

18. iStock

Subscribe to MedicineNet's Newsletters

Get the latest health and medical information delivered direct to your inbox!

By clicking Submit, I agree to the MedicineNet's Terms & Conditions & Privacy Policy and understand that I may opt out of MedicineNet's subscriptions at any time.

VIEW PATIENT COMMENTS
  • Constipation - Home Remedies and Treatments

    What kinds of treatments such as home remedies, OTC medication, or other therapies have been effective for your constipation?

    Post View 42 Comments
  • Constipation - Experience

    Has your constipation ever limited you from performing daily activities? Work? Pleasure?

    Post View 12 Comments
  • Constipation - Causes

    If known, what is the cause of or reason for your constipation? Have you found a remedy?

    Post View 7 Comments
  • Constipation - Fiber and Laxatives

    What type of fiber or laxatives have you found helpful in treating constipation?

    Post View 4 Comments
  • Constipation - Medication Causes

    What medications or drugs cause constipation or make it worse?

    Post View 1 Comment
  • Constipation - Symptoms

    What symptoms did you experience with constipation?

    Post View 5 Comments
  • Constipation - Prescription Drugs

    What prescription drugs have helped with your chronic constipation?

    Post

Health Solutions From Our Sponsors