Common Characteristics
Diarrhea and abdominal cramps are the major symptoms of both irritable bowel syndrome
and colitis, but the two conditions are distinctly different diseases. Irritable bowel
syndrome, which is also called spastic colon, nervous bowel or irritable colon, is caused
by excessive spasms of the large intestine. It is much more common than colitis; indeed,
it is probably the most common abdominal complaint brought to the attention of doctors. It
usually begins during late adolescence or early adulthood and, for unknown reasons, women
are affected twice as often as men.
Colitis is a more rare and potentially serious disorder characterized by an inflammation of
the innermost lining of the colon. Sometimes the entire length of the large intestine is
involved; but more often, the inflammation occurs in the lower portion, in which case the
disease is called proctitis. Colitis tends to come and go, with alternating periods of acute
flare-ups and quiescence. In a large number of cases, the disorder progresses to ulcerative
colitis, in which the lining of the colon becomes thickened and bleeds, resulting in blood
and mucus mixed with diarrhea.
Diagnosis of Irritable Bowel
Diagnosis of the irritable bowel syndrome is often based on a review of the symptoms and a
process of elimination of other disorders. The major symptoms--abdominal cramping, gassiness,
bloating and diarrhea, sometimes alternating with constipation--are characteristic of a number
of other intestinal disorders, such as colitis, diverticulitis (the inflammation of pockets
that form in weakened segments of the intestinal wall) or cancer. The diarrhea is somewhat
distinctive in that it often occurs shortly after eating and sometimes immediately after getting
up in the morning. The excessive intestinal spasms causing this syndrome may be detected during
a barium enema--a test in which a chalky liquid substance is infused into the colon and X-ray
films are taken--or during a sigmoidoscopic examination--a test in which a hollow tube with
fiber-optics is inserted through the anus and into the colon. More often, however, these
examinations are performed to rule out other colon disorders that may produce similar symptoms;
after these other possibilities are eliminated, a presumptive diagnosis of irritable bowel
syndrome is made.
