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Irritable Bowel Syndrome
Before defining irritable bowel syndrome, it is first
necessary to understand the role of the intestine
(also known as the bowel). The intestine is a tube
shaped structure that stretches from an opening in
the stomach to the anus. It plays a major role in
digestion, a process in which food is broken down
and is absorbed (along with water) into the
bloodstream.
The small intestine takes in all of the nutrients
(healthy substances) that the body needs. The large
intestine absorbs moisture from the matter that is
Excrete means to release from the body as waste.
Irritable bowel syndrome (commonly abbreviated as
IBS) is a disorder of the intestine that is
characterized by the signs and symptoms discussed
below.
In IBS, certain parts of the
intestine can begin to spasm
or distend (widen).
FEATURED BOOK: The First Year: IBS (Irritable Bowel Syndrome): An Essential
WHAT ARE THE SIGNS AND SYMPTOMS OF
IRRITABLE BOWEL SYNDROME?
In irritable bowel syndrome, large amounts of mucus
(a thick slippery fluid) are released from the intestine
and pass through into the feces (poop). The small
and large intestines increase their movements to an
abnormal degree. Intermittent (non-continuous)
cramps and pain are felt in the belly, especially the
lower part. Swelling of the belly is also experienced
as well as excessive gas.
In addition, constipation (difficulty pooping) and diarrhea (loose watery feces) can alternate, or one can
occur and not the other, throughout the course of the syndrome. Many people with irritable bowel
syndrome feel that when they poop, they have not gotten all of it out. One may also feel an urgent need
to poop or urinate. The affected person may loose control of their ability to poop and/or pee. In general,
the symptoms of irritable bowel syndrome tend to be located below the belly button. The signs and
symptoms mentioned above are often made worse by food.
Other symptoms are observed in association with irritable bowel syndrome, but are not necessarily a
part of it. These symptoms include decreased appetite, back pain, chest pain, heartburn, acid
indigestion, tiredness, weakness, feeling faint, and feeling agitated. Other symptoms are feeling a lump
in the throat, feeling as if the throat was closing, feeling full after eating a small meal, nausea (with and
without vomiting), and pain during sex.
ARE THE SIGNS AND SYMPTOMS OF IRRITABLE BOWEL SYNDROME THE SAME FOR
EVERYONE?
No. The signs and symptoms of irritable bowel syndrome differ for each person.
WHAT CAUSES IRRITABLE BOWEL SYNDROME?
There does not seem to be a single cause of irritable bowel syndrome. Rather, this syndrome seems to
be due to a combination of emotional, behavioral, and cognitive (thinking) factors in addition to factors
related to how the body functions.
WHAT IS THE ROLE OF PSYCHOLOGICAL FACTORS IN IRRITABLE BOWEL SYNDROME?
A major component of irritable bowel syndrome is generally considered to be psychosomatic.
Psychosomatic means that psychological causes, such as emotional distress, can influence physical
functioning. Stress is known to affect the functioning of the digestive track in all people, especially those
with irritable bowel syndrome. In irritable bowel syndrome the main stressor is considered to be anxiety.
Major life stressors such as divorce, moving to a new city, the death of a loved lone, and
physical/sexual abuse can also contribute to the development of this condition. Cognitive factors such
as poor coping skills are also associated with irritable bowel syndrome.
Research has found that between 42% and 77% of patients with irritable bowel syndrome have
psychiatric diagnoses, most of which are related to anxiety (such as panic disorder) or depression.
Other common psychiatric diagnoses in people with irritable bowel syndrome are somatoform disorder
(physical disorders due to psychological causes) and hypochondriasis (an excessive concern about
one's physical health accompanied by emotional distress). By comparison, 20% of patients with other
disorders of the digestive system have psychiatric diagnoses.
It is important to keep in mind that just because psychological stressors play a role in the development of
signs or symptoms, this does not mean that those signs and symptoms are not real. Also, it is not fully
understood whether psychological problems lead to irritable bowel syndrome or if irritable bowel
syndrome leads to psychological problems. The answer may be that both are true to some extent.
There are no known physical causes of irritable bowel syndrome, such as a disease. The structure of
the intestines is not abnormal and people with this condition do not tend to lose significant amounts of
weight or have poor diets. However, some people report that the symptoms of irritable bowel syndrome
begin shortly after recovering from an infection or surgery of the digestive system. Some people also
develop signs and symptoms of irritable bowel syndrome after eating certain foods that they are
sensitive too. It should be noted that there is no one food that causes irritable bowel syndrome or that
makes the signs and symptoms worse.
WHAT IS THE ROLE OF VISCERAL HYPERALGESIA IN IRRITABLE BOWEL SYNDROME?
Visceral refers to viscera which are organs inside of the body, and typically refers to the organs inside
of the belly. Hyperalgesia refers to excessive sensitivity to painful stimuli. Thus, visceral hyperalgesia is
extreme sensitivity to painful stimuli in the internal organs, usually those of the belly. Visceral
hyperalgesia can also mean an increased awareness of the normal movements of internal organs such
as the intestines. When a small balloon is inflated in the intestine of patients with irritable bowel
syndrome, they experience pain at lower levels of balloon inflation than patients without irritable bowel
syndrome.
WHAT IS THE ROLE OF CHANGES IN THE MOVEMENT OF THE DIGESTIVE SYSTEM IN IBS?
Some scientists believe that one of the causes of irritable bowel syndrome is that the small and large
intestine are overresponsive to stimulation and move abnormally. For example, one theory is that the
colon (the major part of the large intestine) moves excessively when the body is stressed or the handling
of fluids and electrolytes in the bowels are altered in some way. Electrolytes are chemical substances
that are able to conduct electricity after they are melted or dissolved in water. However, alteration of
fluid and electrolytes is only seen in a subset of patients with irritable bowel syndrome and are not
related very well to bowel symptoms.
WHO IS GENERALLY AFFECTED BY IRRITABLE BOWEL SYNDROME?
Young adults (early to middle adulthood) are most affected by irritable bowel syndrome. Fifty percent of
people with irritable bowel syndrome are below age 35. Women are twice as likely to have this
syndrome than men. People of all races are affected, but Hispanics tend to be less affected than
Caucasians and African Americans. Caucasians and African Americans tend to be affected at the same
rate. Most people with this condition are otherwise healthy and have the condition for a long period of
time before seeking medical help.
HOW COMMON IS IRRITABLE BOWEL SYNDROME?
Irritable bowel syndrome is the most common disorder of the intestine. In fact, between 20 and 50% of
the patients seen by gastroenterologists (doctors that specialize in the study of the stomach and
intestine) have this syndrome. Each year, between 2.5 and 3.5 million people visit a doctor to receive
help with irritable syndrome. Between 25 and 55 million people are estimated to have this condition in
the United States. In Western countries, between 6% and 22% of the population is affected with irritable
bowel syndrome at a given time. The condition is also very common in Eastern countries such as Japan
and China.
WHAT IS THE COURSE OF IRRITABLE BOWEL SYNDROME?
The course of this syndrome is highly variable and depends on the patient. For some people, the signs
and symptoms occur only during a stressor and go away when the stressor goes away. For other
people, the signs and symptoms seem to occur randomly and without warning and may never go away
for good. For others, the signs and symptoms of irritable bowel syndrome will decrease or even
disappear for periods of time and return at a later point. One study found that more than 50% of people
with irritable bowel syndrome still experienced signs and symptoms 5 years after their initial diagnosis.
The pain in irritable bowel syndrome usually goes away when one poops or passes gas. For many
people, this syndrome continues to occur throughout life. It can lead to hospitalizations, abdominal
surgeries, and missing work three times more than people without bowel symptoms. However, irritable
bowel syndrome is not life threatening and it is not linked to cancer.
HOW DOES IRRITABLE BOWEL SYNDROME AFFECT PEOPLE?
Whereas some people find the signs and symptoms of irritable bowel syndrome only slightly annoying,
others find it to be moderate nuisance, and others are completely devastated by it.
HOW IS IRRITABLE BOWEL SYNDROME DIAGNOSED?
Irritable bowel syndrome is diagnosed by a doctor when the signs and symptoms mentioned above are
reported together. However, other diagnoses must be eliminated as causing the problem, such as
diseases that inflame the intestines, intolerance to lactose (a type of sugar present in many foods), or
dysentery (an infectious disease causing severe, bloody diarrhea). To do this, patients may have their
feces tested.
The colon (the major part of the large intestine) may be examined with a sigmoidoscopy, a procedure in
which a scope is placed in the rear end and pushed up into the colon. A barium X-ray examination may
also be done, which allows the doctor to see a picture of the intestines and other parts of the digestive
tract. In addition to these procedures, it is essential for health care professionals to obtain a detailed
history from the patient and to conduct a thorough physical examination.
WHAT ARE THE ROME CRITERIA?
The Rome criteria are a list of signs and symptoms that a team of experts agreed upon at a meeting in
Rome, Italy that should be used to diagnose irritable bowel syndrome. Here they are:
At least three months of recurring pain or discomfort in the belly that is relieved by pooping, and/or is: 1)
linked to a change in the rate at which one poops; or 2) linked to a change in the degree of firmness,
thickness, or resistance to movement or separation of the substances that make up poop. In addition, 2
or more of the following symptoms must occur on 25% of the days or occasions: 1) changes in the rate
in which one poops; 2) changes in the form of poop (for example, hard or watery poop); 3) changes in
the way that poop passes through the body (for example, feeling an urgency to poop, a strain when
pooping, or that the pooping was incomplete); 4) presence of mucus in the poop; and 5) feeling as if the
belly is swollen.
HOW IS IRRITABLE BOWEL SYNDROME TREATED?
There is no known treatment of irritable bowel syndrome that works for everyone. Rather, different
treatments work for different people. Staying away from foods that are known to make the signs and
symptoms worse is almost always a good start. Many patients report benefiting from increasing the
amount of dietary fiber (a substance in plants that cannot be digested by humans) eaten, because
dietary fiber absorbs water that is in the poop, which makes it bigger. It is easier for bigger pieces of
poop to move along the intestine and this helps relieve constipation. Some patients are recommended
by their doctor to consume large amounts of dietary fiber and to increase the amount of exercise they
do. Antidiarrhea drugs may be given briefly and are helpful in decreasing the amount of times that one
has diarrhea.
Emotional support is also helpful, since the cause is psychological and the person is experiencing pain
and discomfort. Thus, talking to a psychologist may prove helpful. Changing one's lifestyle so that
significant stressors are avoided can prove helpful. Sometimes medications are given to reduce anxiety
and/or depression. The only way to know which treatment for irritable bowel syndrome works is through
trial and error.
WHAT ELSE IS IRRITABLE BOWEL SYNDROME KNOWN AS?
Irritable bowel syndrome is also known as functional bowel syndrome, irritable colon, irritable colon
syndrome, mucous colitis, nervous colon, and spastic colon. It is commonly abbreviated as IBS.
WHO DISCOVERED IRRITABLE BOWEL SYNDROME?
Sir William Osler, a Canadian medical doctor who lived in the U.S. and England was the first to describe
this condition when he wrote about it in 1892. He named it mucous colitis.
