At wits' end with chronic constipation

Q: My sister, who is in her early 40s, has had chronic constipation since she was quite young.

She goes to the toilet every day but the stool is hard, which causes tears in her rectal walls at times.

When she is in pain, she uses suppositories (medication in the form of a solid bullet that is inserted into the anus) as well as ointment.

As recommended by her doctor, she takes a laxative every night, although it does not always help.

She drinks plenty of water, takes a fibre supplement with a little cranberry juice at night and, sometimes, salt water in the morning.

She eats vegetables and fruit such as pitted prunes, avocados, bananas and papayas regularly.

She walks for at least 20 to 30 minutes a day.

With such a diet, she has another problem: she feels bloated and nauseated. She reckons this is because of excessive gas in her gut.

She is at her wits' end and I would be very grateful if you can shed some light on her problem.

A: The meaning of the word "constipation" varies among different people, with some referring to hard stool and others meaning infrequent bowel movements.

It is generally accepted that chronic constipation is having fewer than three bowel movements a week on a regular basis.

There may be accompanying symptoms of hard stool, excessive straining and the feeling of incomplete evacuation of stool.

There are many causes of constipation, including primary colonic diseases as well as medical conditions, that can affect the function of the bowel.

Some colonic conditions that can cause constipation include cancer and diverticular disease, which is when weak spots in the colon wall bulge to form pouches that can become inflamed.

Numerous medical conditions, including Parkinson's disease and conditions affecting the thyroid hormones, calcium levels and potassium levels in the blood, may also predispose a person to constipation.

In your sister's case, a colonoscopy should first be performed to rule out a colonic cause of constipation.

Medical conditions, such as those mentioned above, should also be excluded.

In addition, medication such as calcium and iron supplements, opiates (such as morphine and codeine) and drugs used in the treatment of depression and anxiety disorders are known to cause constipation, and should be stopped if they are not necessary.

FUNCTIONAL CONSTIPATION

Constipation that does not have a physical or biochemical (hormone and electrolyte that helps carry electrical signals between cells) cause is known as functional constipation.

Slow transit constipation is one cause of functional constipation. It essentially means that the colon is sluggish. This is caused by abnormalities of the nerves supplying the large intestine, leading to decreased colonic motility (movements).

It sounds like your sister may have functional constipation, complicated by the development of an anal fissure (tear in the inner lining of the anus) caused by chronic straining.

Treatment of functional constipation is usually not required if the symptoms are mild.

General measures, such as increasing the intake of fibre and fluids, as well as increasing physical activity, may help.

It must be cautioned that intake of excessive fibre can actually worsen constipation and cause abdominal bloating as gas is produced by colonic bacteria during the breakdown of fibre.

In particular, beans and vegetables such as cabbage, broccoli and cauliflower contain fibre and sugar that are harder for the body to digest and can lead to excessive bloating.

WHEN MEDICAL THERAPY FAILS

With worsening symptoms, such as abdominal bloating and straining when defaecating, treatment may be required.

This usually takes the form of various types of laxatives. The type and amount of laxatives required are titrated to the needs of the individual patient.

Biofeedback, which teaches patients how to coordinate and optimise the use of their pelvic floor muscles and anal sphincter muscles to improve defaecation, has also been used in the treatment of slow transit constipation, with varying degrees of success.

In a small percentage of patients, symptoms remain severe despite maximal doses of medical therapy.

Surgery may then be required.

This may result in the removal of the colon or the formation of an ileostomy. This is an opening in the abdominal wall, through which the small intestine empties its contents into an external bag.

In some countries, the insertion of a nerve stimulator has recently been introduced with some success. However, this is not currently practised widely in Singapore.

With frequent straining, a chronic anal fissure can sometimes develop.

The accompanying symptoms are usually anal pain and bleeding.

Treatment of an anal fissure includes stool softeners, painkillers and medication to help the muscles around the anus to relax, so that the tear has an opportunity to heal.

Treatment of underlying constipation is important in encouraging the healing of the fissure and to prevent future recurrence.

Most fissures will heal with these measures.

In rare instances, surgery may be required for the treatment of chronic anal fissures resistant to medical therapy.

DR TAN WAH SIEW
Consultant at the department of colorectal surgery at Singapore General Hospital


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