How is Dyssynergic Defecation Diagnosed?
General Issues
The healthcare provider will begin with a history. This is when they ask you to explain your symptoms and timeline of when they started as well as any other health problems you have. They will also do an examination of the abdomen and the area around the anus and rectum. The provider will want to rule out other conditions that can cause constipation, such as disease, injury, or inflammation. Many conditions, like an anal fissure, hemorrhoid, stricture, spasm, or tenderness can be diagnosed by examination in the doctor’s office. If the healthcare provider suspects dyssynergic defecation, they may suggest one or more tests before making a definitive diagnose. Also, because many patients are unable to recall their symptoms accurately, a one-to-two-week bowel movement diary that can be kept on a mobile phone may be useful. There are several options for this type of diary, such as “constipation stool diary APP®” or “My GI Health”.
Conditions may also co-exist with dyssynergic defecation. Examples of common tests to identify other conditions include
- blood tests,
- sigmoidoscopy (examination of the inside of the sigmoid colon and rectum using a thin, flexible, lighted tube),
- and colonic transit time tests.
A colonic transit time test is a simple way to study how quickly the bowel movement moves through the colon. Capsules containing small plastic markers are swallowed and x-rays taken over several days. Transit time is measured based on the progress of the markers, which eventually pass out of the body. A newer and more comprehensive test that measures transit through the stomach, small bowel and colon, uses a swallowable capsule called the wireless motility capsule test. Slow or delayed transit time leads to infrequent bowel movements, straining, and hard BMs. But dyssynergic defecation can make bowel movement passage much more difficult regardless of whether transit time in the colon is normal or delayed.
Learn more about colonic transit test
Digital Rectal Examination
The physical and digital examination of the anal and rectal area is not only important, but is often most helpful in making a diagnosis. The physical inspection will reveal visible, abnormalities to the skin and tissue. In the digital exam, the healthcare provider will carefully insert a lubricated, gloved finger into the anus. This again is helpful to reveal possible abnormalities, including lack of sensation in the rectum. During the digital exam, the patient is asked to bear down as if having a bowel movement. This exam provides clues to the provider, as to whether or not a patient has dyssynergic defecation.
Digital rectal examination is a good screening tool for identifying dyssynergia. Despite this, not all doctors have sufficient knowledge of this useful clinical tool. This is an area of clinical medicine where improved training is needed. Research shows that rectal examination by experts can detect dyssynergic defecation in about 80% of patients.
If dyssynergic defecation is suspected after the physical examination, the healthcare provider will likely order one or more tests to confirm the suspicion. These tests can measure different functions in the colon and rectum and identify abnormal features.
Anorectal manometry is a test that measure strength or weakness of the anal muscles as well as sensation and reflex activity in the rectum. Importantly, it can identify the abnormal or dyssynergic pattern of defecation, enabling the physician to recommend a treatment called biofeedback therapy. The test is performed with the patient lying down comfortably and by placing a flexible, pencil-thick plastic probe into the rectum. It is generally well tolerated and takes about an hour. It is an essential test for a diagnosis of dyssynergic defecation.
A balloon expulsion test examines pelvic floor relaxation and opening of the anal canal. A stool-like device is placed in the rectum and, in private, the person expels it to learn how easy or difficult it is to pass a bowel movement. If unable to expel it in a timely manner, normally within one minute, dyssynergic defecation should be suspected. However, this test is most useful to rule out dyssynergia, but less useful to identify the condition.
Defecography uses a special x-ray machine to record moving images of a semi-solid paste (barium) as it passes through the rectum. This imitates passing a soft bowel movement and provides useful information about any changes to colon. However, many people are uncomfortable performing this test and it is costly.
Manometry, balloon expulsion test along with physical examination remains the preferred method of diagnosing Dyssynergic Defecation.
Evidence of Dyssynergia*
- Must demonstrate dyssynergic or obstructive pattern of defecation** with anorectal manometry, imaging, or electromyography recordings, and
- One or more of the following criteria during repeated attempts to defecate
- Inability to expel an artificial stool (50 ml water-filled balloon) within one minute
- Prolonged colonic transit time (retention of more than 5 markers) on a plain abdominal x-ray taken 120 hours after ingestion of one Sitzmark® capsule containing 24 markers
- Inability to evacuate or equal to or greater than 50% retention of barium during defecography
*Dyssynergia must be demonstrated during repeated attempts to defecate.
**Paradoxical increase in anal sphincter pressure (anal contraction); or less than 20% relaxation of the resting anal sphincter pressure; or inadequate propulsive forces.
Learn more about treatments for dyssynergic defecation
Adapted from IFFGD Publication #237 by Satish S.C. Rao, MD, PhD, FRCP(LON), AGAF, Chief, Section of Gastroenterology/Hepatology and Director, Digestive Health Center, Medical College of Georgia, Georgia Regents University, Augusta, GA.
