Dr.
Bader Faiyaz Zuberi
Consultant Gastroenterogist & Hepatologist,
Assistant Professor
Dow University of Health Sciences, Karachi, Pakistan
Colonoscopy is an endoscopic procedure to directly examine the interior of the large intestine (large bowel) from the rectum to the terminal ileum using a colonoscope (Figure 1). The procedure takes approximately 30–60 minutes and is usually performed as an outpatient. Diagnostic colonoscopy is recommended for alterations in bowel habits, occult or frank blood in the stool, unexplained anemia, and as a screening procedure for colon cancer.
The
colon must be completely clean for colonoscopy to be thorough and safe. Patients
may be placed on a liquid diet for 1–2 days before the examination and
administered oral laxatives and/or enemas to clear the colon. Patients are asked
to arrive at the endoscopy suite about 1–2 hours prior to the procedure and
should be accompanied by a responsible adult to transport them home. The patient
is registered and a medical history is documented. Then, a needle/catheter is
inserted into a vein for intravenous access (allowing for fluid and sedative
administration).
The videocamera on the colonoscope transmits images of the inside of the colon
to a monitor. Multiple monitors in the endoscopy suite can allow for multiple
examiner viewing. After the sedation is administered the physician usually
performs a digital rectal exam after which the colonoscope is inserted into the
rectum. The colonoscope is advanced to the cecum (Figure 2 A-C). During the
exam, air may be introduced into the colon to improve visibility. The physician
may take biopsies or remove polyps during the procedure using instruments passed
through the endoscope. The tissue samples are sent to a laboratory for analysis.
If there is bleeding in the colon the physician has a variety of instruments at
his disposal to treat bleeding. There is no pain involved with these procedures.
On completion of the examination, patients remain in
the recovery area for 1–2 hours until the effects of the medication wear off.
The physician will inform the patient about the results of the colonoscopy and
provide additional information as needed. Patients are discharged with
instructions to have limited activity for the remainder of the day. Walking may
help relieve bloatedness or gas.
Colonoscopy is safe and effective when performed by professionals with
appropriate training and experience. Complications are rare (1:10,000).
Complications may include bleeding from a biopsy site or perforation (a tear in
the bowel wall). Symptoms of abdominal pain, distention, nausea, vomiting,
chills, fever or rectal bleeding should be reported to the physician.