A colonoscopy allows a doctor to look inside the entire large intestine. The procedure allows the physician to see things such as inflamed tissue, abnormal growths and ulcers. It is most often used to look for early signs of cancer in the colon and rectum. It is also used to look for causes of unexplained changes in bowel habits and to evaluate symptoms like abdominal pain, rectal bleeding and weight loss.
The colon, or large bowel, is the last portion of your digestive tract, or gastrointestinal tract. The colon is a hollow tube that starts at the end of the small intestine and ends at the rectum and anus. The colon is about five feet long, and its primary function is to store unabsorbed food waste and absorb water and other body fluids before the waste is eliminated as stool.
EGD, or gastroscopy, formally called esophagogastroduodenoscopy, is a visual examination of the upper intestinal tract using a lighted, flexible fiberoptic or video endoscope. The upper gastrointestinal tract begins with the mouth and continues with the esophagus (food tube), which carries food to the stomach. The stomach secretes a potent acid and churns food into small particles. The food then enters the duodenum, or small bowel, where bile from the liver and digestive juices from the pancreas mix with it to help the digestive process.
ERCP enables the physician to diagnose problems in the liver, gallbladder, bile ducts and pancreas. The liver is a large organ that, among other things, makes a liquid called bile that helps with digestion. The gallbladder, a small, pear-shaped organ, stores bile until it's needed for digestion. The bile ducts are tubes that carry bile from the liver to the gallbladder and small intestine. These ducts are sometimes called the biliary tree. The pancreas, a large gland that produces chemicals, helps with digestion and hormones such as insulin.
ERCP is used primarily to diagnose and treat conditions of the bile ducts and pancreas. It combines the use of x-rays and an endoscope (a long, flexible, lighted tube). Through the endoscope, the physician can see the inside of the stomach and duodenum and can inject dyes into the ducts in the biliary tree and pancreas so they can be seen on the x-rays.
During the procedure, you will lie flat on your stomach, and the physician will pass a small plastic catheter through the scope. Through this catheter, the physician will inject a dye into the ducts to make them show up clearly on x-rays. X-rays will be taken as soon as the dye is injected.
If the test shows a gallstone or narrowing of the ducts, the physician can insert instruments into the scope to remove or relieve the obstruction. Also, a biopsy can be taken for further testing.