Flexible Sigmoidoscopy
Sigmoidoscopy is the visual examination of the inside of the rectum and
sigmoid colon, using a lighted, flexible tube connected to an eyepiece or
video screen for viewing. This device is called an endoscope. The colon (
large intestine ) is 5 to 6 feet long. During a sigmoidoscopy, only the last 1
to 2 feet of the colon is examined. This last part of the colon, just above
the rectum, is called the sigmoid colon.
Equipment
The flexible endoscope is a remarkable piece of equipment that can be directed
and moved around the bends in the lower colon and rectum. The image in the
bowel is transmitted through the endoscope to the video screen. An open
channel in the scope allows other instruments to be passed through it to take
tissue samples ( biopsies ) or to remove polyps.
Reasons for the Exam
Sigmoidoscopy is performed to diagnose the cause of certain symptoms. It is
also used as a preventative measure to detect problems at an early stage, even
before the patient recognizes the symptoms. The following are some reasons for
performing a sigmoidoscopy.
Bleeding - Rectal bleeding is very common. It often is caused by
hemorrhoids or by a small tear at the anus, called a fissure. However, more
serious problems can cause bleeding. Benign polyps can bleed. It is important
to identify and remove polyps at an early stage before they can become
cancerous. Rectal and colon cancers bleed and require immediate diagnosis and
treatment. Finally, various forms of colitis and inflammation can cause
bleeding.
Diarrhea - Persistent diarrhea should always be evaluated. There are many
causes of diarrhea and the exam is of great help in tracking down the specific
cause.
Pain - Hemorrhoids and fissures are some causes of pain around the anus or
in the rectum. Discomfort in the lower abdomen can be caused by tumors.
Diverticulousis can occur in the lower bowel. With this condition, small
pockets or sacks project from the bowel.
Detection - Colon cancer is one of the most common cancers in the country.
It is highly curable if it is found early. This cancer usually begins in the
colon as a polyp that remains benign for many years. Therefore, it is
generally advisable to have a sigmoidoscopy after age 40 or 50. If parents,
brothers, or sisters have had colon polyps or colon cancer, it is even more
critical to have this exam. The tendency to develop colon cancer and polyps
can be inherited.
The Procedure
Flexible sigmoidoscopy is usually performed on an outpatient basis. It is
performed with the patient lying on the left side with the legs drawn up. A
sheet is placed over the lower body. A finger or digital exam of the anus and
rectum is performed. Then the endoscope is gently inserted into the rectum. Air
is inflated into the bowel to expand it and allow for careful examination. The
patient usually feels a slight discomfort similar to strong gas cramps. The
endoscope is then advanced under direct vision and moved around the various
bends in the lower bowel.
It is advanced as far as possible without causing undue discomfort. When
possible, the exam is continued to 25 inches ( 60 cm ). Certain conditions,
such as diverticulosis, irritable bowel syndrome, or prior pelvic surgery may
produce discomfort when the sigmoid colon is entered by the endoscope. The
exam is stopped if this occurs. The exam usually takes 5 to 15 minutes.
Sedation is not normally required.
Summary
Sigmoidoscopy is a simple office exam which can uncover a serious medical
problem. It is one of the most useful and simple exams in medicine.
|