Irritable bowel syndrome (IBS) is
a mixture of abdominal symptoms for which there's no apparent cause.
Symptoms include constipation,
diarrhoea, bloating and abdominal pain.
It's the most common condition
seen by gastroenterologists, and some estimates suggest that as many as one in
five adults in the UK have IBS at any one time.
The bowel and IBS
Your bowel, or gut, extends from
your stomach to your anus. It is made up of the small intestine and the large
intestine. Their job is to process food from the stomach.
Other names for IBS
Irritable colon.
Spastic colon.
Mucous colitis.
These names are misleading
because IBS is not limited to the colon.
The small intestine absorbs nutrients
from food and passes undigested food into the large intestine. In the large
intestine, or colon, this waste product is processed into faeces.
The normal bowel moves food along
the intestines through muscular contractions, known as propulsion. There are
also areas of hold-up, known as segmentation.
This combination of propulsion
and segmentation is called peristalsis. You are completely unaware of it when it is working normally.
The control of peristalsis is
complex. The best way to regard IBS is as a loss of coordination of these
muscular contractions.
In addition, there's evidence
that people with irritable bowel syndrome have increased sensitivity within the
gut to external stimuli, such as stress.
This means IBS is often the
outcome of a complex interaction between psychological and physical factors.
A disorder of the digestive
system can affect the gut anywhere from the mouth to the anus, which accounts
for the diversity of symptoms seen in IBS.
What causes irritable
bowel syndrome?
How common is IBS?
IBS is more common in women.
In the UK about 13 per cent of
women and 5 per cent of men have IBS.
We don't know what causes IBS.
About half of people with IBS
date the start of their symptoms to a major life event – such as change of
house or job, or bereavement. This suggests that there may be a psychological
trigger for IBS.
About 10 to 20 per cent of people
will date the start of their symptoms to an acute gastroenteritis (inflammation
of the stomach that causes vomiting and diarrhoea).
In the remainder of cases, the
trigger factor remains unidentified.
Abnormalities in peristalsis can
often be seen in close relatives of people with IBS, although without symptoms.
This suggests a trigger sets off the condition in susceptible people.
Nerve-signalling chemicals,
particularly serotonin, appear to have an important role.
What are the symptoms
of IBS?
IBS and cancer
Although IBS can be a distressing
condition, it never causes bowel cancer or bowel damage.
IBS symptoms can start at any
age, but they are most common in late teenage years or early adulthood.
The four most common symptoms
are:
constipation
abdominal pain
bloating that usually subsides
overnight and returns the following day
diarrhoea
you may experience problems in
only one part of the gut or in several, and symptoms can change over time
your
symptoms will depend on which parts of the gut are involved.
Oesophagus (takes food from mouth to stomach)
A sensation like a golf ball in
the throat between meals, but does not interfere with swallowing.
Heartburn – burning pain often
felt behind the breastbone.
Painful swallowing (odynophagia),
but without hold-up of food.
Sticking of food (dysphagia) –
this requires investigation.
Stomach
Non-ulcer dyspepsia (symptoms
suggestive of a stomach or duodenal ulcer, but which has not been confirmed on
investigation).
Feeling full after small meals.
This may reach the stage of not being able to finish a meal.
Abdominal bloating after meals.
Small bowel
Increased gurgling noises which
may be loud enough to cause social embarrassment (borborygmi).
Severe abdominal bloating and
generalised abdominal tenderness associated with bloating.
Large bowel
Right-sided abdominal pain,
either low or tucked up under the right ribs. Does not always get better after
passing a stool.
Pain tucked up under the left
ribs (splenic flexure syndrome). When the pain is bad, it may enter the left
armpit.
Variable and erratic bowel habits
alternating from constipation to diarrhoea.
Flatulence (excess wind).
Increased gastro-colic reflex.
This is an awakening of the childhood reflex where food in the stomach
stimulates colonic activity, resulting in the need to pass a stool.
Severe, short stabbing pains in
the rectum, called proctalgia fugax.
Feeling of incomplete emptying of
bowels.
Loss of mucus from the rectum
(back passage).
Other symptoms
Headaches.
In women, left-sided abdominal
pain pain during sex.
Passing urine more often.
Fatigue and tiredness.
Sleep disturbance.
Loss of appetite.
Nausea.
Depressive symptoms in about a
third of patients.
Anxiety and stress-related
symptoms, which may interact with gut symptoms.
When should I see a
doctor?
Because irritable bowel syndrome
can mimic so many other intestinal disorders, you should see your doctor if you
identify any of the following symptoms.
Difficulty in swallowing when
food gets stuck.
Indigestion-type pain that wakes
you up at night.
Abdominal bloating that does not
get better overnight.
Significant and unexplained
weight loss.
Bleeding from the back passage.
Chronic, painless diarrhoea.
This list is not comprehensive.
If there are other symptoms, you should seek further advice.
In general, first-time symptoms
of IBS in a person over the age of 40 should be assessed by a doctor.
How is irritable bowel
syndrome diagnosed?
There is no single blood test,
X-ray or scan that will diagnose IBS.
The diagnosis is often made on
the basis that typical symptoms are present, particularly in younger people who
have had at least six months of change in bowel habit, abdominal pain and
bloating.
Symptoms, such as pain relieved
by opening your bowels and those made worse by eating and passing mucus from
the rectum, will help to confirm that you are suffering from IBS.
Blood tests may be taken to
exclude other conditions, and occasionally further investigations are
performed.
As people with IBS get older,
more investigations are performed to ensure the diagnosis is correct –
especially if there's:
unexplained weight loss
abdominal or rectal masses
(unexplained lumps felt by your doctor in the tummy or back passage)
rectal bleeding
anaemia
a family history of bowel or
ovarian cancer
being aged over 60 with a change
in bowel habit lasting over 6 weeks.
These may include:
gastroscopy – examination of the
oesophagus, stomach and small intestine with a camera on the end of a long thin
tube (endoscope).
ultrasound
barium studies – a salt that
shows up in X-rays of the stomach and intestines.
colonoscopy – examination of the
large intestine with an endoscope.
Is there anything I can do to
prevent IBS?
Since the cause of IBS is
unknown, it's not possible to reliably prevent symptoms.
The following
strategies can help your digestive system and so may improve the condition.
Drink lots of water, preferably
two litres a day.
A high-fibre diet improves
digestion. The amount of fibre must be increased gradually to allow the stomach
to get used to it.
Avoid food or beverages that make
the symptoms worse. Coffee and milk are frequent offenders.
It may be helpful to keep a diary
in which you note down the foods that seem to upset your stomach.
Avoid strong spices and foods
that give you wind.
Avoid large meals, but eat
regularly.
Limit your alcohol intake.
What else can improve IBS?
Physical activity and exercise
can improve digestion and reduce stress.
Heat treatment with hot packs,
hot-water bottles or electric blankets may relieve stomach pain.
Try to reduce the amount of
stress in your life. You might like to experiment with some of the different
relaxation techniques, such as meditation.
Try to keep things in
perspective: excessive worrying about digestive problems could lead to social
and psychological problems.
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