Endoscopy - contd.
In small animals, endoscopy is performed under general anesthesia with a flexible, fiberoptic endoscope. The endoscope is attached to a light source, and a lens allows visualization of the areas being examined. It is often hooked up to a video camera so that the examination can be recorded. The endoscope has small channels through which biopsy forceps or retrieving instruments can be passed. Water and air can be sent through separate channels to keep the viewing area clean, and to allow for distension of the portions of the gastrointestinal tract as they are examined. Rigid endoscopes are also available, and can be very useful for evaluation of the esophagus and the lower parts of the intestinal tract. Prior to endoscopy, initial diagnostics usually include a thorough physical examination, bloodwork, and x-rays. Fecal examinations for parasites, stool cultures, and abdominal ultrasound are additional tests that may need to be considered prior to endoscopy.
Once the patient is anesthetized, the endoscope is passed into the mouth and then into the esophagus, stomach, and small intestine for the examination of the upper part or the gastrointestinal tract. Each area is carefully inspected for abnormalities that are apparent to the naked eye. Biopsies are taken from areas that appear abnormal, but also from areas that look normal since, in many cases, diseases are found on biopsy in tissues that look normal on endoscopy.
For colonoscopy, the endoscope is passed into the anus, then into the rectum, and up into the colon. The entire length of the colon can be examined, all the way to the point where the small intestine empties into the large intestine. In some circumstances, it is possible to pass the endoscope into the ileum, the last part of the small intestine, allowing for evaluation of that portion of the intestinal tract as well. If colonoscopy is done along with examination of the upper part of the gastrointestinal tract, this part of the procedure is done last.
