Constipation: Does Your Bowel Move Smoothly?

Causes of Constipation

In normal circumstances, food passes through the digestive tract and nutrients are absorbed along the tract. Some residual food moves to the large intestine (colon) which absorbs water from this waste and forms a soft stool. Constipation happens when stool moves too slowly through the digestive tract, so more water is absorbed from the stool, making the stool dry and hard. Consequently, the stool is more difficult to be discharged during defecation.

There are many reasons that can cause constipation, including the following lifestyle changes, medications and health conditions. 

Causes of Constipation: Lifestyles:

• Low-fiber diet
• Inadequate water intake
• Lack of exercise
• Stress
• Resisting the urge to have a bowel movement
• Changes in routine, such as eating or going to bed at different times
• Hospital environment (may due to low privacy or having to use a bedpan)

Causes of Constipation: Anorectal disease:

• Anal fissures
• Anal or colorectal cancer
• Pelvic muscle dysfunction
• Rectal prolapse (rectum protrudes from its normal position and comes out through the anus)

Causes of Constipation: Intestinal obstruction:

• Hernias
• Colorectal cancer
• Strictures, e.g Crohn’s disease

Causes of Constipation: Metabolic / endocrine conditions:

• Diabetes mellitus
• Hypothyroidism
• Hypercalcemia (high level of calcium in the body)
• Hypokalaemia (low level of potassium in the body)

Causes of Constipation: Neurological conditions:

• Spinal cord injuries, such as trauma and surgery
• Parkinson’s disease
• Multiple sclerosis
• Stroke

Causes of Constipation: Medications:

• Iron
• Opiates, e.g. morphine, codeine
• Anticholinergics like tricyclic antidepressants (TCA)
• Some antacids such as those with aluminum
• Antihypertensives, such as diuretics and calcium channel blockers

Other Causes of Constipation: 

• Pregnancy
• Irritable bowel syndrome (IBS)
• Overuse of laxatives

Signs and Symptoms of Constipation

Everyone has a unique bowel movement pattern. You are likely to suffer from constipation if you develop the following signs and symptoms:

• Infrequent bowel movements (less than 3 times a week)
• Dry, hard or lumpy stools
• Straining when passing stool
• Difficult or painful to pass
• A feeling of incomplete emptying after a bowel movement
• A feeling of a blockage in your rectum
• Bloated or discomfort
• Abdominal pain

Risk factors of Constipation

The main factors contributing to constipation are poor diet and physical inactivity. Besides, the risk can be increased by the following factors:

• Age: Older adults tend to be less physically active, a slow metabolism and less muscle contraction strength of the digestive tract contribute to a higher risk of constipation. 
• Gender: Females are found to be more likely to develop constipation than males. 
• Pregnancy: Pregnant women are at higher risk of constipation. It can be due to hormonal changes, dietary or physical activity changes, or physical changes (uterus squishes on the intestines). 
• Taking certain medications and having certain medical conditions

Complications of Constipation

Constipation on its own is not serious. However, it could be a symptom of a more serious underlying condition, such as cancer. Hence, it is recommended to make a proper diagnosis if you have chronic constipation in order to rule out other health problems and prevent possible complications:

• Hemorrhoids: Hemorrhoids are swollen veins around your anus and rectum. They can be caused by excessive straining to have a bowel movement when constipated.
• Anal fissures: Hard stools which stretch the anal area can cause tears in the lining of the anus. 
• Fecal impaction: When stools are too hard or too large, they can be stuck in the large intestine and cannot pass out the body.
• Rectal prolapse: Small amount of the rectum would push and protrude beyond the anus (outside the body).

Diagnosis of Constipation

Constipation is usually diagnosed by symptoms and medical history. If the cause of constipation cannot be identified, additional tests might be required to diagnose constipation, such as:

• Digital rectal exam (DRE): Your physician would insert a gloved and lubricated finger into your rectum to check for any abnormalities.
• Blood tests: Blood samples may be taken to check for blood count, electrolytes, and thyroid function.
• Colonoscopy: It is used to examine the entire colon by inserting a long and flexible tube with a small camera inside. 
• Sigmoidoscopy: Your doctor will insert a thin and flexible tube with a light camera to examine the rectum through the nearest part of the colon (sigmoid colon). 
• Anorectal manometry: Your doctor will insert a flexible tube with a balloon tip attached to the end into your rectum. When the tube is inside, the balloon will be inflated and slowly pulled out. This test is used to check how well your sphincter muscles work to control your bowel movements. 
• Barium enema: During this test, a fluid called barium is inserted into your rectum using a lubricated enema tube. Barium helps show the images of the colon, rectum, and anus on an X-ray, in order to find out any abnormalities (e.g. strictures or obstruction). 
• Colorectal transit study: In the test, you will need to take capsules containing small markers visible on X-ray. After a few days, you will receive several abdominal X-rays to monitor the movement of the markers through the colon. It is used to see how well food moves through your colon. 

Prevention and Home remedies for Constipation

Home remedies are typically the best cure for constipation. By changing your diet and lifestyle, most cases of constipation can be resolved. Constipation home remedies include:

• Dietary: Fiber plays an important role in constipation. There are 2 types of fiber: soluble and insoluble. Soluble fiber helps wet and soften stools, while insoluble fiber increases the bulkiness of the stools. Therefore, both forms of fiber make stools easier to pass. A diet with 25-35 grams of fiber daily is commonly recommended. Fiber-rich foods include raw fruits and vegetables, whole grains, beans, and bran cereal. Avoid foods that are high in fat (low-fiber), such as cheese and milk.
• Exercise regularly: Exercise stimulates the muscles in the gastrointestinal tract to aid bowel movements. 
• Increase water intake: By drinking plenty of water, it can prevent dehydration in the colon and hence keep your stool soft and easy to pass. Besides, try to limit your consumption of caffeinated beverages and alcohol because they can make you dehydrated.
• Fiber supplements: Fiber supplementation along with plenty of water can be added to your diet if necessary. 
• Do not delay the urge to have a bowel movement: Delaying the urge can make your stools harder to pass.

Treatments of Constipation

Most often, constipation can be improved by home remedies. Though some medications (e.g. laxatives) are available over-the-counter, they should only be considered when dietary and lifestyle changes fail to improve constipation. Besides, they should be used for short periods only. Consult your doctor or pharmacist before using any medications. 

Laxatives: Constipation Cure:

• Bulk laxatives: Bulk (or called bulk-forming) laxatives are used to form soft and bulky stools so that they can pass more easily through the intestines. They must be taken with plenty of fluid and may take a few days to act. A common example is metamucil® (ispaghula husk). 
• Stimulant laxatives: They are used to increase intestinal motility by stimulating the contraction of intestinal muscles. Examples include senna and bisacodyl. 
• Emollient laxatives (stool softeners): Stool softeners, like docusate, are used to moisten and soften the stools so they are easier to pass. 
• Osmotic laxatives: Osmotic laxatives help draw fluid into the bowel and soften stools to facilitate bowel movement. These laxatives include macrogol (Forlax®) and glycerin suppository. 

Other medications to relieve constipation:

When laxatives do not help with the condition, the following medications might be prescribed by your doctor: 

• Prucalopride (selective 5-HT4 receptor agonists): Prucalopride is a drug used to stimulate intestinal motility.
• Linaclotide (guanylate cyclase–C receptor agonist): It works by increasing fluid in your intestines and speeding up bowel movements.  

Other treatments to cure constipation:

• Surgery: Surgery is rarely needed to treat constipation. If your constipation is caused by structural problems, such as intestinal obstruction or intestine stricture, surgical removal of part of the colon might be an option. 
• Biofeedback: This is a type of physical therapy that can train your pelvic muscle. The physical therapist will lead you through different exercises in order to help you retrain the movement and coordination of your pelvic floor.

This article was medically reviewed by Dr. Ernest Han Fai Li. Dr. Li is a specialist in gastroenterology and hepatology practicing at the Central Gastroenterology & Hepatology Center currently. Dr. Li served in the public hospital for 12 years after his graduation from the Chinese University of Hong Kong in 2004. At the same time, Dr. Li is a medical consultant to the Hong Kong Fire Service Officers Association, a medical advisor to the Board of Chung Shak-Hei (Cheung Chau) Home for the Aged and the chairperson of the District 303 Lions Club Organ Donation Committee.