What is gastrointestinal endoscopy?

Gastrointestinal endoscopy is a minimally invasive medical procedure that allows your veterinarian to evaluate the inside of your pet’s gastrointestinal tract without having to perform major surgery. A flexible endoscope is guided through the mouth, esophagus, stomach, and upper part of the small intestine to perform an upper gastrointestinal endoscopy. Colonoscopy is where the flexible endoscope is passed up the colon to the junction where the large intestine joins the small intestine.
A flexible endoscope is a flexible tube with a video camera attachment that is inserted either into the stomach and small intestines through the mouth or into the colon via the rectum. The endoscope permits inspection of the inside of these hollow organs. If the stomach/small intestines are being examined, the esophagus can be inspected as the endoscope is being passed into through the esophagus and into the stomach.

When is gastrointestinal endoscopy recommended?

Gastrointestinal endoscopy is usually recommended when a pet is experiencing chronic vomiting, diarrhea, weight loss, and/or reduced appetite or if there are gastrointestinal tract abnormalities identified on imaging such as ultrasound or CT.

What does gastrointestinal endoscopy allow us to see?

The endoscope allows full color images of the esophagus, stomach and the upper part of the small intestine or the colon. It allows us to assess for signs of inflammation, ulceration, swellings/masses, or narrowing within the esophagus or intestines. We can also check for foreign material that the pet may have ingested such as a bone, stick, rock, or toy. If a foreign material is found, based on its size, shape, and location most of the time it can be safely removed using the endoscope.

Is general anesthesia required to perform this procedure?

Both upper gastrointestinal tract endoscopy and colonoscopy require anesthesia in order to be safely performed. Luckily, it is still considered to be a fairly quick and minimally invasive procedure. It Is an outpatient procedure which allows the pet to go home the same day.

How does an endoscopy procedure help us reach a diagnosis?

Other than the presence of a foreign material, It is impossible to diagnose any condition by visually examining the gastrointestinal tract via endoscopy. Although identifying an abnormal or suspicious area in the gastrointestinal tract gives us valuable information, it is typically necessary to obtain a biopsy of the affected area in order to reach a diagnosis. An endoscope allows us to obtain very small pieces of tissue to submit to a veterinary pathologist for microscopic evaluation. By passing a biopsy instrument through a very small channel on the endoscope, we can collect multiple samples from the stomach and intestines to submit for evaluation. Many diseases cause changes that are only detectable by microscopic inspection of the tissue sample. Therefore, biopsies are always taken even in the absence of obvious visual abnormalities.

What type of diseases can be diagnosed with gastrointestinal endoscopy?

An endoscopic procedure can help us diagnose a foreign material in a pet’s esophagus, stomach, and upper part of their small intestine. By collecting tissue samples and submitting them for microscopic evaluation, it can also help us diagnose diseases within the gastrointestinal tract wall such as inflammatory conditions, malabsorptive conditions, and even cancer.

What are some limitations of performing an upper gastrointestinal endoscopy?

Although endoscopy can give us good visualization of the esophagus and stomach, it us unable to give us a thorough evaluation of all of the small intestine. In many cats and dogs, it is possible to pass the endoscope through the pylorus (the valve the connects the stomach and small intestines) and into a short segment of the upper duodenum (upper part of the small intestine). The size of the endoscope and the size of the pet will determine how much of the small intestines can be visually inspected and biopsied. Unfortunately, the majority of the small intestine is inaccessible to the endoscope. Typically, an abdominal ultrasound performed before the endoscopic examination will help us identify if there is an area of interest and if the endoscope may reach the area for evaluation. Another limitation of endoscopic examination is that we can only visualize the inner layer of the gastrointestinal tract. Therefore, if there is an abnormality on the outer wall or in the deeper layers of the gastrointestinal tract, we are unable to visually examine it and/or collect diagnostic biopsy samples from the lesion. In these cases, surgery is recommended in order to collect the appropriate samples.

What if the endoscopic biopsies are normal but my pet is still ill?

In many cases we are able to diagnose disease of the gastrointestinal tract using the endoscope. Since the biopsy procedure only samples the mucosa (inner layer) it is possible that we may not detect a tumor that involves only the deeper layers of the intestinal tract. In order to reach a diagnosis in these cases, full-thickness biopsies obtained through an exploratory surgery, (exploratory laparotomy) or non-invasive tests such as an MRI (Magnetic Resonance Imaging) may be required.

What steps need to be taken to prepare for gastrointestinal endoscopy?

It is imperative that the stomach and intestinal tract be empty of all food and fecal matter prior to performing an endoscopic evaluation. A 12 hour fast is required for an upper gastrointestinal endoscopy. Colonoscopy requires oral medication to be given 12-18 hours before the procedure to remove fecal material from the entire intestinal tract. Fasting for up to 24 hours is also necessary so that new fecal material does not form. On the morning of the procedure, one or more enemas are given to remove any remaining stool from the lower intestinal tract.

Are there any complications associated with this procedure?

Complications are possible but very rare. If a pet has a pre-existing ulcer present in the gastrointestinal tract this can predispose them to developing a perforation (tear) in their gastrointestinal tract either from the endoscope or due to collecting a biopsy sample. This is a very serious complication that would need to be addressed with surgery. We take special precautions to minimize the risk of perforation in the gastrointestinal tract and luckily this complication is extremely rare.