Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.
Colitis means inflammation of the colon. The colon, also
known as the large intestine or large bowel,
constitutes the last part of the digestive tract. The colon is a long, muscular
tube that receives undigested food from the small intestine. It removes water
from the undigested food, stores the undigested food, and then eliminates it from the body through
bowel movements. The rectum is the last part of the colon adjacent to the anus. The common symptoms of colitis include:
ischemic colitis (such as blockage of an artery in
the colon by a blood
clot. If the blood clot
interrupts the flow of blood to a segment of the colon, the result is
inflammation of that segment and, sometimes, even death [gangrene] of the
segment)
Crohn's disease and ulcerative colitis (two related
conditions that are caused by abnormalities of the body's immune system in which the body is inappropriately making antibodies and
chemicals that attack the colon). Crohn's disease and ulcerative colitis are
also referred to as
inflammatory bowel disease (IBD).
Infectious, radiation, ischemic, ulcerative, and Crohn's colitis all have
visible abnormalities of the inner lining of the colon. These abnormalities
include edema (swelling of the lining),
redness, bleeding from the lining with gentle rubbing (friability), and ulcers.
These abnormalities can be seen during either colonoscopy (examination of the
entire colon using a long flexible viewing tube) or flexible sigmoidoscopy
(examination of the rectum and the sigmoid colon - the segment of the colon closest to the rectum).
Edema and inflammation of the colon's lining interferes
with the absorption of water from the undigested food, and the unabsorbed water
exits the rectum as diarrhea. Pus and fluid also are secreted into the colon and
add to the diarrhea. The redness, bleeding from the lining with gentle rubbing
(friability), and ulcerations in the lining of the colon contribute to rectal
bleeding.
What diseases are not colitis?
Individuals with irritable bowel syndrome (IBS) do not have
colitis, even though this condition is sometimes referred to as having "spastic colitis."
These individuals may have symptoms that mimic colitis such as diarrhea, abdominal
pain, and mucous in stool. Nevertheless, there is no inflammation of the colon
(not even microscopic colitis) in patients with IBS. The cause of symptoms in
IBS is not clearly known; it may be caused by either abnormal motility (abnormal
contractions) of the intestinal muscles or abnormally sensitive nerves in the
intestines (visceral hypersensitivity).
What is microscopic colitis?
Microscopic colitis refers to inflammation of the colon
that is only visible when the colon's lining is examined under a microscope. The
appearance of the inner colon lining in microscopic colitis is normal by visual
inspection during colonoscopy or flexible sigmoidoscopy. The diagnosis of
microscopic colitis is made when a doctor, while performing colonoscopy or
flexible sigmoidoscopy, takes biopsies (small samples of tissue) of the normal-appearing lining, and
then
examines the biopsies under a microscope.
There are two types of microscopic colitis: 1) lymphocytic colitis and
2) collagenous colitis.
In lymphocytic colitis, there is an accumulation of
lymphocytes (a type of white blood cell) within the lining of the colon.
In collagenous colitis, there is an
additional layer of collagen (scar tissue) just
below the lining.
Some experts believe that lymphocytic colitis and
collagenous colitis represent different stages of the same disease.
The inflammation and the collagen probably interfere with absorption of water
from the colon, and cause the diarrhea.
Abdominal pain is pain in the belly and can be acute or chronic. Causes include inflammation, distention of an organ, and loss of the blood supply to an organ. Abdominal pain can reflect a major problem with one of the organs in the abdomen such as the appendix, gallbladder, large and small intestine, pancreas, liver, colon, duodenum, and spleen.
Diarrhea is a change is the frequency and looseness of bowel movements. Cramping, abdominal pain, and the sensation of rectal urgency are all symptoms of diarrhea. Absorbents and anti-motility medications are used to treat diarrhea.
Inflammation of the inner lining of the colon is referred to as colitis. Symptoms of the inflammation of the colon lining include diarrhea, pain, and blood in the stool. There are several causes of colitis including infection, ischemia of the colon, inflammatory bowel disease (Crohn's disease, Ulcerative colitis, or microscopic colitis). Treatment depends on the cause of the colitis.
Digestion is the complex process of turning food you eat into the energy you need to survive. The digestive process also involves creating waste to be eliminated, and is made of a series of muscles that coordinate the movement of food.
Colonoscopy is a procedure that enables an examiner (usually a gastroenterologist) to evaluate the inside of the colon (large intestine or large bowel). The colonoscope is a four foot long, flexible tube about the thickness of a finger with a camera and a source of light at its tip. The tip of the colonoscope is inserted into the anus and then is advanced slowly, under visual control, into the rectum and through the colon usually as far as the cecum, which is the first part of the colon.
Why is colonoscopy done?
Colonoscopy may be done for a variety of reasons. Most often it is done to investigate the cause of
blood in the stool,
abdominal pain, diarrhea, a change in bowel habit, or an abnormality found on colonic
X-rays or a computerized tomographic (CT) scan. Individuals with previous history of polyps or colon cancer and certain individuals with a family history of some types of non-colonic cancers or co...