Esophagogastroduodenoscopy
In medicine (gastroenterology), esophagogastroduodenoscopy (EGD) or upper endoscopy is a diagnostic endoscopic procedure that visualises the upper part of the gastrointestinal tract. It is considered a minimally invasive procedure since it does not require an incision into one of the major body cavities and does not require any significant recovery after the procedure (unless sedation or anesthesia has been used).
Procedure
An EGD is performed using an endoscope. This instrument is a plastic tube 8 to 12 mm in diameter and 160 cm in length that houses control cables to maneuver the tip, glass fibers to transmit light from the tip, fiberoptic cable or electronic circuits to transmit an image back to the operator, and channels through which to pass instruments, air, suction, and water to facilitate examination and biopsy or otherwise manipulate tissues from the esophagus, stomach, and duodenum. One end of the tube is attached to a control handle. The end inserted into the patient contains a lens to acquire the image, and openings of the various channels in the scope. Still photographs can be made during the procedure and later shown to the patient to help explain any findings.
Diagnostic use
In its most basic use, the endoscope is used to inspect the lining of the digestive tract. Often inspection alone suffices to diagnose a patient's problem, but biopsy is a very valuable adjunct to endoscopy. Small biopsies can be made with a pincer (biopsy forceps) that is passed through the scope and allows sampling of 1 to 3 mm pieces of tissue under direct vision. The intestinal mucosa heals quickly from such biopsies.
Problems that are amenable to diagnosis by endoscopy include those diseases where there is a visible abnormality of the gastrointestinal tract or that have a characteristic appearance on biopsy. Ulcers, tumors, bleeding blood vessels (including esophageal varices), and infections are all readily seen with endoscopy.
Biopsy allows the pathologist to render an opinion on later histologic examination of the biopsy tissue with light microscopy and/or immunohistochemistry. Biopsied material can also be tested on urease to indentify Helicobacter pylori.
Problems of gastrointestinal function are usually not well diagnosed by endoscopy since motion or secretion of the gastrointestinal tract are not easily inspected by EGD. Nonetheless, findings such as excess fluid or poor motion of gut during endoscopy can be suggestive of disorders of function. Irritable bowel syndrome and adrenalin in bleeding lesions)
- cutting off of larger pieces of tissue with a snare (e.g. polyps)
- application of cautery to tissues
- retrieval of foreign bodies that have been ingested
- tamponading bleeding esophageal varices with a balloon
Some surgical procedures can be done through the endoscope including tightening of the muscles at the end of the esophagus (the lower esophageal sphincer) and rubber band ligation of esophageal and gastric blood vessels.
