CONSTIPATION
by Dr Kieran Moriarty, Bolton General Hospital
What is a normal bowel habit ?
People vary a lot in how often they open their bowels - usually between
three times a day and three times a week in the U.K. A stool should be solid,
but moist and easy to pass.
What does the bowel do ?
Receives food and liquid we eat and drink. Absorbs most of the nutrients
from food and drink into the blood-stream. Secretes fluid from the body into
the gut. Propels its contents from the stomach down the length of the bowel to
the back passage (anus). Excretes waste material as stool.
What is constipation ?
A person is constipated when fewer than 3 bowel actions happen in a week, or
if there is often a need to strain to pass a stool. Constipation is not a
disease. Occasionally, however, it can be a symptom of underlying disease.
Constipation is hardly ever harmful. You won’t become ‘poisoned’
or ‘dirty’ if your bowels don’t open.
How does constipation trouble people ?
You may feel uncomfortable or distended (bloated) in the abdomen, or feel a
sense of fullness above the back passage. Straining can lead to piles which may
appear at the anus or bleed. Women may find intercourse uncomfortable if the
bowel is very full.
What causes the usual types of constipation ?
Diet - usually a lack of fibre (roughage) in the diet.
Bad bowel habits - most people have an urge to go to the toilet once
or twice a day. This often happens after a meal. If this urge is ignored, the
stool dries out and becomes hard. The next bowel movement may then be difficult
or painful.
Unco-ordinated straining. Some people do not strain effectively
and/or fail to relax the muscles around the back passage when they strain.
Constipation can be made worse by: dehydration: low fluid levels in the body
inactivity emotional upsets a painful anal condition such as piles shift work
poor toilet facilities.
What conditions can cause constipation ?
Constipation can be caused by: obstruction to the bowels by scarring,
inflammation or tumours pregnancy underactive thyroid gland altered function in
the nerves or muscles controlling bowel movement such as in the irritable bowel
syndrome (see separate DDF leaflet).
Which medicines cause constipation ?
It is common to become constipated without realising that it is due to the
medicines you are taking, eg: antacids which contain aluminium or calcium taken
for indigestion iron tablets (sometimes) some pain-killers such as codeine
cough medicines which also contain codeine ‘nerve’ treatments - some
antidepressant drugs - certain tranquillisers drugs given to affect muscle
function such as some given for abdominal pain, bladder relaxation or
parkinsonism.
What is fibre and how does it help ?
Fibre is found not only in the tough fibrous part of fruit and vegetables,
particularly in the stalk and on the outside of fruits, seeds or grains (bran
is the outer covering of wheat grains), but also in soft parts of fruit and
vegetables that are not digested by the small intestine. Much of the food we
eat is digested in the stomach and small intestine, but fibre is not digested
and passes to the large intestine (colon). Here it:
- acts like blotting paper, drawing water into the stool
- increases the number of bacteria in the colon.
Both these effects make the stool larger, softer and easier to pass.
How can you increase the fibre in your diet ?
The easiest way to improve your diet is to eat brown, wholemeal bread and
plenty of fresh fruit and vegetables. If this is insufficient, a good way to
further increase fibre is to sprinkle one or two tablespoons of bran on
breakfast cereal. A dietitian can advise you and several books about high fibre
diets are available at book stores.
What should you do if your bowels are not regular ?
Always try to go to the toilet as soon as you feel the urge. Try to do this
as a routine, eg. as soon as you get up, or after breakfast. Drink at least 4
pints of fluid daily. Eat an adequate amount of fibre in your diet. Be as
active as possible even if you have a disability. Avoid laxatives. Eat
regularly. Ensure good toilet facilities at home and work.
When you should see your doctor ?
If constipation is not responding to the simple treatments outlined and is
causing you trouble. Sudden or gradual changes in bowel habit, occurring for no
obvious reason in people aged approximately forty years or more, should be
reported to the doctor (especially if there is rectal bleeding or new abdominal
symptoms such as pain or distension).
Will I need any tests for constipation ?
Probably not, although your doctor may want to take a blood sample to make
sure your thyroid gland is working properly.
If your constipation is very bad, your doctor may wish to check whether the
colon is normal by arranging:
- a barium enema X-Ray (this involves the insertion into the rectum of a
harmless material which shows up on an X-ray, allowing the doctor to see any
abnormalities) or
- a flexible sigmoidoscopy or colonoscopy (inserting a flexible telescope so
the doctor can see the whole of the colon).
Tests are sometimes done to check the function of the muscles around the
back passage.
If you suddenly become constipated for no reason, you should see your doctor
promptly.
Are laxatives harmful ?
Constipation is usually improved by a proper diet, and drugs are therefore
not needed. Occasional use of a suitable laxative is harmless, but regular use
may make you dependent on it.
Stimulant laxatives, such as senna and cascara, cause changes in the colon
if used regularly for many years but can be useful every now and then for a
short time.
Laxatives cause gripey abdominal pains if used in large doses.
Which laxatives can I use ?
A few people will need to take laxatives regularly, but this should only be
done on your doctor’s advice. The best types are:
Bulk laxatives - concentrated fibre preparations are helpful for
those who find it hard to change their diet. These include: - bran - ispaghula
husk - methylcellulose - sterculia The above preparations should always be
taken with plenty of water.
Stimulant laxatives - Bisacodyl, Senna.
Osmotic laxatives - mineral salts (eg. magnesium sulphate/Epsom
salts, magnesium citrate, magnesium hydroxide) - retain water in the bowel. The
stool is then softened.
Lactulose, lactitol or sorbitol-sugars which humans can’t
digest. They act a bit like fibre and a bit like an osmotic laxative.
Suppositories inserted into the rectum which soften the stool and
stimulate bowel action.
Enemas - a few people, especially those with severe nerve damage in
the spine, have to use enemas. With any laxative, it is important to keep up a
good fluid intake with extra drinks if necessary.
Are other treatments available ?
Special tests may show that straining is unco-ordinated. Such people may be
helped by training to effectively contract their abdominal muscles and relax
those around the back passage. This training can be supplemented by a device
which enables a person to tell if their muscle is relaxed (biofeedback), but
such a device is often not necessary. This treatment is, at present, limited to
a few centres, but is likely to become more generally available.
If constipation is associated with emotional problems, counselling or
similar treatment may help.
A few sufferers require surgical treatment, but this is reserved for those
with a definite abnormality of the large intestine.
Summary
- A tendency to constipation should usually be managed by: developing regular
bowel habits a good intake of fibre and fluids exercise. Bulk-forming or
osmotic laxatives are preferable to stimulant laxatives which should be taken
regularly only under medical supervision. Very severe constipation (which tends
to occur in younger women despite the measures described above) may need
specialist help.
- If you are constipated, this does NOT mean that bodily wastes are being
absorbed and damaging your health.
- Sudden or gradual changes in bowel habit, occurring for no obvious reason
in people aged approximately forty years or more, should be reported to the
doctor (especially if there is rectal bleeding or new abdominal symptoms such
as pain or distension).
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