The appropriate scope for the particular procedure is inserted into the body through a natural opening or small incision. A light source and camera are connected to the scope, and the image from inside the body is displayed on a screen. Many scopes have slender channels that water, air, or suction is delivered through when needed to help the doctor see inside the body, and another channel for a biopsy instrument (armed with tiny jaws) that takes samples. These channels are also used for instruments that reach inside the body to remove foreign objects or to perform other tasks.
All types of endoscopy require skill and experience to perform and interpret.
Endoscopy of the upper and lower gastrointestinal tract (upper GI endoscopy and colonoscopy)
Endoscopy of the gastrointestinal tract allows examination of the interior of the esophagus, stomach, and intestines. Many people are familiar with colonoscopy, which is endoscopy of the colon (large intestine). For this procedure, the large intestine is entered rectally. The patient’s colon must be cleaned out before colonoscopy is performed, which involves the use of enemas, laxative-type solutions, or both. For upper GI endoscopy, the instrument is passed through the mouth, down the esophagus, into the stomach, and then into the small intestine. The only preparation generally required is an overnight fast. In this procedure, the endoscope can usually only reach the first section of the small intestine, called the duodenum.
Although the procedure is not painful, it does require anesthesia; otherwise animals would never allow the procedure to be done! Anesthetizing an animal also makes it possible for the doctor to place a tube in the trachea (windpipe) to prevent material from the GI tract entering the lungs. There is generally no discomfort after the procedure.
When would a pet need this? There are a variety of situations in which these procedures may be recommended. Pets who have GI symptoms, such as vomiting, diarrhea, blood in their stool, poor appetite, or weight loss, may have endoscopy for examination and biopsy of the GI tract. Pets who have swallowed an object that becomes lodged in the esophagus, stomach, or intestines may have the object removed by endoscopy rather than surgery, as long as the object is within reach of the endoscope. For pets who can’t or won’t eat on their own for a period of time, endoscopy can be used to place a feeding tube in the stomach. This may sound intimidating, but is actually a convenient and minimally invasive way to allow pet owners to feed and medicate their ill pets without a struggle.
Endoscopy can also be used to diagnose and treat animals who have a stricture, or narrowing, in the esophagus, usually as a result of scar formation due to previous esophageal inflammation or trauma. For example, imagine a dog who swallows a bone that then becomes lodged in the esophagus. Due to pressure and injury from the bone, the esophagus can be severely ulcerated. When the ulcer heals, a scar can form, closing off the passage. Using endoscopy, the passage can be opened by with specialized balloons that dilate the narrowed area.
Who usually performs this? Internal medicine specialists, who receive endoscopy instruction during their training, generally perform GI endoscopy. Gastroenterology falls within the province of internal medicine and internists have advanced training and knowledge not only in the performance of endoscopy, but also in the interpretation and treatment of the results. Endoscopy equipment can be purchased easily, and it is important to ensure that the doctor performing endoscopy on your pet is fully qualified. For example, it takes education and experience to develop the ability to pass the endoscope from the stomach into the intestine, especially in small animals. Untrained individuals may only examine the stomach, thus missing critical diagnostic information. It also takes skill to get useful biopsy samples, which requires knowledge of proper biopsy technique and the ability to maneuver the endoscope in very tight spaces. Unfortunately, inadequate biopsies can lead to misdiagnosis.
In many ways performing endoscopy, which involves the simultaneous manipulation of multiple knobs and buttons, is similar to playing a musical instrument. I first thought of this analogy during my residency, while watching a talented endoscopist in action. As I observed her, I was often reminded of a skilled musician. Endoscopy takes training and then lots of practice to master.
What are the risks? Upper GI endoscopy and colonoscopy require general anesthesia in animals. General anesthesia carries certain risks that vary with the overall health of the patient. Usually the risk is quite low. The procedure itself also carries certain risks, depending on the specific situation, and you should discuss this with your doctor. The GI tract can be perforated during the procedure, requiring surgical repair. For most animals, this risk is very low.
Louise Murray DVM DACVIM
www.drlouise.com
