Colonoscopy

A colonoscopy is an examination of the lower part of the gastrointestinal tract, which is called the colon or large intestine (bowel). Colonoscopy is a safe procedure that provides information other tests may not be able to give. Patients who require colonoscopy often have questions and concerns about the procedure.

Colonoscopy is performed by an endoscopist, who is a physician with special training in endoscopy procedures. The colonoscope is inserted into the anus and advanced through the entire colon (to the caecum) and possibly a short distance into the small intestine . The procedure generally takes between twenty minutes and one hour.

REASONS FOR COLONOSCOPY

  • As a screening exam for colon cancer in anyone over age 60
  • Blood in the stool or rectal bleeding
  • Dark/black stools
  • Persistent diarrhoea
  • Iron deficiency anaemia (a decrease in blood count due to loss of iron)
  • Significant, unexplained weight loss, accompanied by gastrointestinal symptoms
  • A family history of colon cancer
  • A history of previous colon polyps or colon cancer
  • Surveillance in people with ulcerative colitis
  • For the medical management of chronic inflammatory bowel disease
  • Chronic, unexplained abdominal pain.

PREPARATION

The endoscopy unit will provide specific instructions about how to prepare for the examination. The instructions are designed to maximize safety during and after the examination, minimize possible complications, and allow the endoscopist to fully view the colon.

The inside lining of the colon must be cleaned of stool to permit the endoscopist to complete a thorough examination. This is accomplished by restricting what is eaten and by using strong laxatives.

What to eat

As a general rule, patients should not eat any solid food for at least one day before the examination. Only clear liquids (such as juices, squash, water) are recommended.

WHAT TO EXPECT

The doctor will start an intravenous line (insert a needle into a vein in the hand or arm) to administer medications. The intravenous line insertion feels like a pin prick, similar to having blood drawn. The vital signs (blood pressure, heart rate, and blood oxygen level) will be monitored before, during, and after the examination. The monitoring is not painful. Some patients will be given oxygen during the examination.

THE PROCEDURE

The colonoscopy will be performed while the patient lies on their left side. Medications will be administered through the intravenous line. Most endoscopy units use a combination of a sedative (to help patients relax), and a narcotic (to prevent discomfort). Many people sleep during the examination while others are very relaxed, comfortable, and generally not aware of the examination.

The colonoscope is a flexible tube, approximately the size of the index finger. It has a lens and a light source that allows the endoscopist to look into the scope or at a TV monitor. The image on the TV monitor is magnified many times so the endoscopist can see small changes in tissue.

The endoscope contains channels that allow the endoscopist to obtain biopsies (small pieces of tissue), remove polyps and to introduce or withdraw fluid or air. Polyps are extra growths of tissue that can range in size from the tip of a pen to several inches (doctors measure them in millimeters and centimeters). Most polyps are benign (not cancerous) but can become cancerous if allowed to grow for a long time. As a result, they are usually removed so they can be analyzed. This does not hurt since the lining of the colon does not sense pain.

Air is introduced through the scope to open up the colon so that the scope can be moved forward and to allow the endoscopist to see. Patients may experience a feeling of bloating or gas cramps from the air as it distends the colon. Try not to be embarrassed about releasing the air through the rectum; patients should let their physician know if they are uncomfortable

RECOVERY

After the colonoscopy, the patient will be observed until the effects of the sedative medication are gone. The most common discomfort after colonoscopy is a feeling of bloating and gas cramps. Patients may also feel groggy from the sedation medications. Patients should not return to work that day. Most patients are able to eat a regular diet after the examination.

COMPLICATIONS

Colonoscopy is a safe procedure and complications are rare, but can occur:

  • Bleeding can occur from biopsies or the removal of polyps, but it is usually minimal and stops quickly or can be controlled.
  • The colonoscope can cause a tear or hole in the tissue being examined, which is a serious problem, but, fortunately, very uncommon.
  • Adverse reactions to the medications used to sedate you are possible. The endoscopy team will ask about previous medication allergies or reactions and about health problems such as heart, lung, kidney, or liver disease.

The following symptoms should be reported immediately:

  • Severe abdominal pain (not just gas cramps)
  • A firm, distended abdomen
  • Vomiting
  • Fever
  • Rectal bleeding (greater than a few tablespoons).