Gastroduodenoscopy or GI endoscopy is endoscopy of the stomach and small intestine. GI endoscopy is a minimally invasive procedure that allows direct visualization and biopsy of the stomach and descending duodenum (the upper intestinal tract). We pass a long camera in through the mouth, through the esophagus, pass through the stomach and in to the first foot or so of the intestine. The intestines are extremely long, even in a small dog or cat, so the full length of the intestine is not visualized. GI endoscopy is only recommended in patients that have had previous testing that indicates that the diseases in question are likely to be found in these areas. Pinch biopsies can be taken in either of these tissues to evaluate the mucosa and submucosa.
There are four layers to the intestinal thickness. If one visualizes the intestine as a tube, the four layers of the tube thickness are made up from “inside” the tube to “outside” the tube by the mucosa, sub-mucosa, muscularis and serosa. The mucosa and submucosa are the layers of the intestine that are primarily involved in digestion, absorption and redistribution of nutrients. The majority of the immune monitoring of the intestinal tract is also found in these layers. Biopsies of these layers usually give our diagnosis. The muscularis layer is comprised of smooth muscles that allow contraction and relaxation for “movement” of intestinal content. The serosa is an extremely thin layer of cells that works as a wrapping or surface separation from the other abdominal organs.
GI endoscopy is usually looking for microscopic diseases that invade the mucosa and sub-mucosal layers. Initial diagnostics lead to the recommendation of GI endoscopy. This is not a test that we perform without strong supporting evidence.
GI endoscopy can be performed with rapid anesthetic recovery and patients may be discharged to their owners care, within a few hours of anesthesia. Endoscopy has a significantly reduced impact to the body of our patients. Endoscopy is performed in an effort to avoid surgery. GI endoscopy takes advantage of the mouth and throat to be able to see and take samples from tissues that are otherwise inaccessible.
Recovery of foreign objects from the stomach can be both frustrating and rewarding. Some objects are unsafe to retrieve via endoscopy (e.g. sharp objects that may further damage the esophagus with retrieval). Any patient with a gastric foreign body can be evaluated for possible endoscopic retrieval. There needs to be clear evidence of foreign material in the stomach or throat. If this is the case, some of the other initial testing (related to primary microscopic intestinal disease) becomes unnecessary. Foreign objects in the intestine cannot be removed safely with GI endoscopy. We need to be sure that anything we remove is not attached to the stomach/intestinal tissue and this is not possible for anything that has passed in to the intestine.
Foreign bodies of the esophagus or throat are a serious emergency since they often cause severe damage to the esophagus in a short period of time (hours to days) and their clinical signs (symptoms) are virtually identical to a gastric foreign body. Persistent/severe retching, uncontrolled vomiting, unable to swallow even saliva, coughing, etc., should be evaluated by a veterinarian promptly.
Appropriate case selection and pre-anesthetic work up are vital to the success or failure of endoscopic procedures.