Constipation may be due to weak muscles

Q: I am a 57-year-old man and have been suffering from daily constipation for four years. It started with a sudden and serious episode of constipation. I had a colonoscopy, was diagnosed with fistula-in-ano and had surgery for it.

Unfortunately, a few months later, the constipation recurred and I am now on various types of medication almost daily. I went for acupuncture and it helped for a year, but it became less effective eventually.

Recently, I was given a test called anorectal manometry and it was determined that there is minimal strength in my anal sphincter muscles.

I was referred for anorectal biofeedback therapy to strengthen my anal sphincter muscles. Unfortunately, it did not really help.

How do I improve the situation? Should I go for another fistula-in-ano operation?

A: I would like to emphasise that constipation and fistula-in-ano (FIA), also called an anal fistula, are unlikely to be related.

FIA refers to an abnormal connection between the anal skin and the inner lining of the anus (opening from which stool is discharged) and/or rectum (the last part of the large intestine that stores stool and ends in the anus).

It is most commonly due to an infection of one of several anal glands resulting in recurrent infection and discharge.

Surgery is the most effective way of treating an FIA.

Constipation, on the other hand, is not a disease but a common symptom experienced by everyone at some point in their lives.

It is attributable to a variety of causes, such as too little or too much dietary fibre, inadequate fluid intake, lack of physical activity, certain types of medication, irritable bowel syndrome or neurological diseases such as stroke and diabetes.

The colonoscopy was probably recommended in view of your constipation and your age (above 50 years old), in order to exclude more sinister causes of constipation, such as colorectal cancer.

It is likely that the FIA was detected incidentally during the evaluation of your constipation and not a result of constipation.

The subsequent surgery performed for the FIA was not meant to address your constipation per se and, thus, it is not surprising that you are still experiencing constipation.

The treatment of constipation relies on accurately identifying the underlying cause and prescribing individualised treatment.

In some patients, such as yourself, constipation can be the result of weakness or a lack of coordination of the muscles of the anus and rectum, which are responsible for the normal passage of stool.

Anorectal manometry is a useful test that measures the pressure along the anal canal and rectum, and helps doctors to identify such patients, who can benefit from anorectal biofeedback therapy.

The latter comprises a series of coordinated movements of breathing and abdominal and anal muscle contractions that a therapist teaches the patient to do. This is aided by visual and auditory feedback that allows both the therapist and patient to know if the exercises are being performed correctly.

The results of anorectal biofeedback therapy are variable and improvements do not occur overnight. They require at least six months of daily disciplined practice by the patient and regular follow-up sessions.

If you are not seeing any improvement in your constipation after anorectal biofeedback therapy, I would strongly encourage you to return to the hospital for a review by your doctor.

He will assess your symptoms in greater detail, as well as ensure that you are performing the exercises correctly.

At the same time, you should continue to moderate your intake of dietary fibre and take plenty of fluids.

Finally, your doctor should also ensure that your FIA has not returned, although this is unlikely to be related to your constipation.

Only if the FIA has returned should surgery be considered to address the FIA specifically and not the constipation.

Dr Mark Wong
Director of the pelvic floor disorder service and consultant at the department of colorectal surgery at Singapore General Hospital

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