More Information on Constipation

Constipation is a common ailment in which a person has difficulty passing stool (fecal matter) from the body. It particularly affects young children and the elderly, occurring more frequently in females than in males.

Typically, there is abdominal cramping and straining while passing a very firm or hard stool. Some individuals believe that infrequency of bowel movements is the main feature of constipation; however, there is a very wide healthy range of bowel movement frequency. Generally, passing stools three times a day to three times a week is normal, as long as the bowel movements are soft and easily passed.

Constipation can occur for many reasons. Organic disease contributors to constipation, in which there is a physiological change to some tissue or organ of the body, include a number of gastrointestinal conditions, such as diverticular disease, hemorrhoids, intestinal obstructions or strictures resulting from surgery, radiation therapy, inflammatory bowel disease, and colon cancer. Other contributing conditions include stroke, neuromuscular or musculoskeletal impairment, tumours, hypothyroidism, and diabetes. Functional constipation can also result from a diet low in fibre and water, a lack of physical activity, chronic use of laxatives or enemas, or irritable bowel syndrome (wherein no organic disease is present). Medications such as narcotics, anti-depressants, iron or calcium supplements, some central nervous system drugs (psychotropics), and those that block neurotransmitters (anticholinergics) can cause constipation as well.

Symptoms/Complications

The primary function of the large intestine, also called the colon or large bowel, is to remove water from the digestive contents. The length of time during which the stool remains in the colon causes increased pressure on the bowels. Because of this, rectal pressure/fullness, bloating, and abdominal pain are common symptoms of constipation. Lumpy or hard stool, looking like either many small pellets or one solid, hard, sausage-shaped piece, occurs when not enough water and/or fibre is consumed (see Bristol Stool Chart). The backing-up in the digestive tract may also cause poor appetite, back pain, and general malaise. A sensation of incomplete evacuation is another common symptom. Most complications are due to the intense straining needed to pass stool, such as hemorrhoids, anal fissures, diverticular disease, pushing of the rectal wall out through the anus (rectal prolapse), and rectal bleeding, in the form of bright red streaks on the stool.

Diagnosis

Although some believe that as many as 30% of Canadians have constipation, researchers using specific diagnostic criteria estimate that only about 15% of Canadians actually have true functional chronic constipation. A panel of experts developed and update the main diagnostic criteria for constipation, in which two or more of the following symptoms related to bowel movement must be evident for at least 12 weeks (not necessarily consecutive) within the past 12 months:

• Straining to pass stool more than 25% of the time,
• More than 25% of stools are lumpy or hard,
• Sensation of incomplete evacuation more than 25% of the time,
• Sensation of anorectal blockage for more than 25% of the time,
• More than 25% are facilitated by manual manoeuvres (e.g., digital
• evacuation or support of the pelvic floor), and
• Fewer than 3 bowel movements per week.

If you have any abrupt changes in your bowel habits, you should contact your physician who may conduct a number of tests to rule out causes for the symptoms. The physician may need to exclude any underlying metabolic or organic disorder or a systemic illness. This process could include blood tests that might reveal abnormal levels for things like thyroid hormone, electrolytes, glucose, and other biochemical profiles. Your physician may ask you to provide a stool sample, which would then be examined for hidden (occult) blood. Colorectal screening in those persons who are older than 50 years of age who have abrupt bowel changes is recommended.

Useful diagnostic tools may include a sigmoidoscopy, which is an examination with a short instrument that allows visualization of the inside of the rectum, and a colonoscopy, which is a similar examination, but uses an instrument that reaches farther up into the colon. Less commonly, a physician may suggest a barium enema or CT scan to view the abdominal area.

The physician may also ask the patient about stool consistency and colour and a number of other questions that might reveal any signs signalling a specific gastrointestinal disorder, such as nausea or vomiting, cramping, weight loss, rectal bleeding or pain, black and tarry bloody stool (melena), or fever. During a physical examination, the physician will note the patient’s weight and overall health and nutrition status. An examination of the abdomen will be performed to look for any masses, distension, tenderness, and normal bowel sounds. Similarly, you will likely have a rectal examination, to rule out masses, and to look for anal fissures. There are also a number of specialized evacuation-specific tests, including the balloon expulsion test, anorectal manometry, defecography, and colonic transit, which are available for your physician to suggest, but which are seldom needed.

Treatment

There are a number of effective ways to manage constipation through diet, exercise, physio, and medication. Diet – If your doctor has ruled out an organic cause of your constipation, an important first step to improving bowel regularity is to increase your intake of dietary fibre and fluid. Fibre helps the body form soft, bulky stool, which pass more quickly and easily through the colon. Aim for a daily intake of 20-35g of fibre. You can achieve a higher fibre intake in your daily diet by consuming 7-8 servings of vegetables and fruits, 6-7 servings of whole grains, and focusing on meals and snacks that include legumes, nuts, and seeds. A few tips to improve your fibre intake include choosing a breakfast cereal that contains at least 4-5g of fibre per serving; adding nuts and seeds to your salads, stir-fries, and yogurt; and adding beans and lentils to your soups and salads. In order to reduce the risk of bloating, abdominal discomfort, and gas, slowly increase the fibre content of your diet and evenly distribute fibre-containing foods throughout the day. Keep in mind that fibre works by drawing water into, thereby softening the stool, so if you don’t drink enough fluid, fibre can be constipating. Aim for 8 cups of fluid per day.

Exercise

Try increasing your activity level so you are exercising at least 30-60 minutes, 3 times a week. Check with your physician first to make sure this is a good plan for you. Creating a consistent routine may also help you regulate your bowel movements, as your body learns to relax at a certain time each day. Be careful not to ignore your body’s call to the toilet. Do not suppress the urge to go!

Physiotherapy

Pelvic dysfunction physiotherapy, which has helped some individuals relieve constipation, is the assessment and treatment of problems involving the pelvic region of the body by a physiotherapist who has specialized training in pelvic conditions.

Medications

Many medicines are available to treat constipation. These include suppositories, stimulants, osmotic laxatives, lubricants, and enemas. A partial list of these products are: Bulking Agents, these include fibre in many forms, including bran, psyllium, and flax; Rectal Stimulants such as enema, glycerine suppository, and Dulcolax® suppository; Osmotic Laxatives include magnesium hydroxide saline solutions such as Milk of Magnesia® and polyethylene glycol such as Pegalax®; Stimulant Laxatives such as senna, and Dulcolax® tablets. Avoid regular use of stimulant laxatives if possible, but don’t be worried if you do need to use them from time to time. Osmotic laxatives are recommended over stimulant laxatives.

Diagnostic Tests

Balloon Expulsion Test

The balloon expulsion test is performed when pelvic floor dysfunction is suspected in patients with chronic constipation or fecal incontinence who have not responded to treatment with fibre and laxatives. To perform this test, the physician inserts a small balloon in the rectum while the patient lies on his or her left side. The balloon is filled with water or air, and sometimes strung with weights. The patient is then asked to expel the balloon in privacy while expulsion time and duration is recorded. Individuals with normal pelvic floor function can expel the device faster than those with a dysfunction.

Anorectal Manometry

Anorectal manometry is one of the tests performed to determine the cause of fecal incontinence or chronic constipation. It assesses how strong the sphincter muscles are and whether or not they are able to respond during defecation and sense the need to defecate. To perform this test, the physician will insert a pressure-sensitive catheter or probe into the rectum while the patient lies on his or her left side. The probe sends signals to a machine that records the pressure exerted by the pelvic floor and sphincter muscles as they contract and relax. A balloon can also be fitted to the end of the probe, and inflated to measure the pressure, recording the rectum’s ability to defecate appropriately. Higher pressure can be found in patients with constipation while lower pressure can indicate fecal incontinence.

Defecography

While this procedure can be awkward, defecography provides valuable information about an individual’s ability to defecate and can detect the presence of pelvic floor dysfunction. A radiologist will perform this test for a patient if he or she has had unclear results during a balloon expulsion or anorectal manometry test. For this procedure, thickened barium, the consistency of soft stool, is inserted into the rectum. The patient sits on the radiolucent toilet (lets x-rays pass through without appearing on the image) and expels the stool while radiographic films or videos record the behaviour of the bowel and pelvic floor.

Colonic Transit Test

The colonic transit test is a common, non-invasive procedure used to determine the type of constipation (slow or normal transit) and to monitor patients who have had a pelvic floor dysfunction corrected. Patients swallow a capsule filled with a specific amount of tiny radiopaque markers that are visible on x-ray. A radiologist takes images of the pelvic region over a specific number of days to determine how long it takes the markers to move through the colon. If the markers move slower than normal, become stuck, or spend a particularly long time in one section of the intestine, it can indicate dysfunction or even a blockage in a specific area of the colon.

James R. Gray, MD, CCFP, ABIM, FRCPC
Gastroenterologist, Faculty of Medicine, University of British Columbia
First published in The Inside Tract® Newsletter Issue 174 - 2010 First Quarter