Constipation

What is constipation?

Constipation is a symptom not a disease. The word “constipated” can mean different things to different people. It can be a feeling that the stools are too hard or that the bowels do not work regularly. Very occasionally there is a disease underlying the constipation, but most of the time the disturbance in the bowel habit is not due to a structural abnormality of the colon but is rather a functional problem (one due to a disturbance of how the bowel contracts or empties). Bowel cancer is an uncommon cause of constipation. Frequency of bowel movements varies widely in the general population. It is actually normal to pass stools between three times a day and once every three days. Stool consistency can vary between hard lumps to very loose, often depending how long the stools have been in the colon and how much water has been absorbed from them. Food usually takes an average of one to three days to be processed and up to 90% of that time is spent in the colon.

What are the possible causes of constipation?

Anatomical problems

1. Rectal Intussusception – an internal rectal prolapse, most commonly found in women. Here the defaecation process is disordered, causing patients to strain excessively, which in turn makes the prolapse worse.  

2. Rectocoele – a bulging of the rectum, most commonly found in women who have had a baby by vaginal delivery or women who have strained repeatedly because of heavy lifting or constipation. In these women the rectum bulges forward into the vagina and stool can get trapped in the bulge.

Rectal intussusception and rectocele commonly co-exist and can lead to difficulty in evacuation or emptying the rectum – a condition known as Obstructed Defaecation Syndrome (ODS).

3. Hirschsprung’s disease – this is a very rare condition where the lower part of the bowel lacks the proper nerve supply required to propel stools along. This is usually diagnosed soon after birth.

4. Megacolon or megarectum – a rare condition with a large dilated bowel.

5. Nerve disease or injury some people with major nerve problems such as a spinal cord injury, multiple sclerosis or Parkinson’s disease experience constipation.

6. Autonomic nerve problems – this is exceptionally rare with a generalised nerve problem of the bowel. This group of patients can also have bladder problems.

Functional problems

1. Medications – constipation is a side-effect of many medications e.g. painkillers such as codeine. Others include iron tablets, and some medicines used to treat heartburn, high blood pressure, depression and heart problems.

2. Pregnancy – the gut slows down during pregnancy, related to hormone levels.  

3. Following an operation – the painkillers given after surgery often cause constipation by slowing down the bowel. After an abdominal operation the abdomen may be too painful for you to want to push. Food intake may also be erratic or even non-existent. Also, some major pelvic operations can lead to damage of the pelvic nerves.

4. Eating disorders – patients who fail to eat regularly cannot expect a regular bowel action. The extreme examples of this are patients with anorexia nervosa or bulimia.

5. Lifestyle and bowel habits – people sometimes feel unable to open their bowels at their workplace. Over the years, their gastrointestinal tract gradually slows down and they become constipated.

6. Psychological disturbances – constipation is common in patients who have experienced major stressful events in their lives. This might be the death of a loved one or anything else that has led to depression or anxiety.

7. Sexual or physical abuse –patients who have been sexually or physically abused in some way in their childhood are often found to have incoordination between the rectum and anus. As the rectum contracts to expel the stool the anus contracts to retain it.

8. A fear of pain on passing a stool can lead to constipation. This pain may be the result of an anal problem such as haemorrhoids or a fissure.

There are other aspects of constipation that we do not fully understand. Women often have changes in their bowel habit which relate to their menstrual cycle. Some people get either more frequent stools or more constipated on holiday. This may be related to relief of stress or may be due to having to share toilet facilities, being away from your usual routine or a change in time zone, diet or fluid intake.

Complications of constipation

A large number of patients with constipation get abdominal bloating and discomfort. It very uncommon for the young and fit to get serious complications from constipation. However elderly or malnourished people may develop problems including:

Faecal impaction – this is a condition in which a solid ball of stool builds up in the rectum. This can present with diarrhoea as only liquid stool can make its way past the obstructing stool. It is most often seen in people who are unable to move around easily and those who are taking lots of medications.

Rectal prolapse – this means that the rectum comes down out of the back passage.

Haemorrhoids - are more common in young men than young women and constipation is less common in men. However, sitting on the toilet for long periods of time can aggravate haemorrhoids.

Stercoral perforation – this is an exceptionally rare condition where a hard stool sits in the colon for so long that it wears through the wall of the bowel and surgery becomes necessary.

What investigations are needed for constipation?

The decision to do various investigations will be based on factors such as symptoms, family history and age. Investigations may include:

Colonic investigations: These may include a colonoscopy or more rarely a barium enema.

Anorectal physiological testing: this test looks at the way the muscles and nerves of the rectum and anus are working.

Transit studies: this test gives a measure of whether or not the passage of food through the colon is slow or normal. Capsules containing tiny “markers” that show up on x-ray are ingested and then an abdominal x-ray is taken a few days later. The distribution of the markers in the colon indicate whether bowel transit is normal or slow. Normal transit of contents from the mouth to the anus is less than 72 hours for the majority of patients.

Defaecating proctogram: this involves insertion of a barium paste into the rectum, with x-rays being taken whilst the paste is subsequently evacuated from the rectum. The test shows the shape of the rectum and how it empties, including the presence of a rectocoele or internal rectal intussusception.

Dynamic MRI defaecography: A jelly is inserted into the rectum and then images are taken. These show the structure of the rectum in relation to the pelvic floor and the surrounding organs. Studies are performed at rest and then as you bear down.

What treatments are available?

1. Lifestyle

Most bowels respond best to a regular habit. About 30 minutes after eating is the most likely time for the bowel to work. This is because of the “gastro-colic reflex” which means that eating sets waves of activity in motion in the bowel. Try not to rush going to the toilet. If you have a tendency to be constipated, set aside about 10 minutes in the toilet. Find a toilet that you feel comfortable to use and where you do not feel inhibited by lack of privacy or time. Sport and exercise improve bowel habits in some people. Mr Tsavellas may refer you to a specialist bowel nurse for a formal retraining program.

2. Diet and fluids

Eating regularly and an adequate fluid intake are the best stimulants for your bowels. Skipping meals, especially breakfast, can lead to a sluggish or irregular bowel habit. If you do feel your diet is short on fibre try to use fruit and vegetables (soluble fibre) rather than cereals (insoluble fibre) as they are less bloating. Some foods e.g. prunes and figs, can act as natural laxatives. Try to drink at least eight to 10 mugs of fluid a day. Too much caffeine (coffee, tea and cola) can be dehydrating, as can too much alcohol.

3. Medications

If you are taking any medicines ask your GP or chemist if they could be adding to your constipation. If really necessary, try using a fibre supplement such as fybogel and possibly suppositories or mini-enemas to help regulate the bowels. Suppositories and enemas work by causing contraction of the rectum, softening the stool in the rectum and by causing the bowel higher up to contract. If suitable, Mr Tsavellas may suggest a trial with the Peristeen® Irrigation System (click here to see video animation).

4. Biofeedback

This is a bowel retraining programme usually run by a nurse. Advice on diet, toileting habits and access to acceptable facilities is reviewed. Patients are shown how the muscles and nerves can be retrained to coordinate and produce a satisfactory effort to empty the bowel. The therapy may involve several one-to-one sessions between the patient and nurse.

5. Surgery

This is needed in only a minority of people. There are women who may benefit from a repair of a rectocoele or intussusception. This may involve an operation known as a resection rectopexy, where the prolapsing segment of bowel is removed, followed by fixation of the rectum back into its normal position.