Endoscopy in Dogs and Cats
An endoscope is a flexible fiberoptic tube that is inserted into the area that needs to be examined. This can be the nose, trachea, bronchi, esophagus, stomach, small intestine, colon or urethra. The endoscope permits viewing of the inside of these organs, and allows for biopsies or other samples to be obtained as well as providing a means of retrieving foreign objects an animal may have eaten such as toys, rocks, coins, fabric or fishhooks.
While seeing an abnormal lesion or suspicious area gives us valuable information, most cases will require that the suspicious area be biopsied to determine the diagnosis. The endoscope has a tiny channel through which a biopsy instrument can be passed. Precise biopsies can be taken of any abnormal areas. Many diseases cause changes that can only be detected by microscopic inspection of the cells. Therefore, even if the organ appears normal, biopsies are taken. In many cases, biopsy of the stomach of a vomiting dog or of the colon of a dog with diarrhea will be very helpful in determining if disease is present. In the respiratory tract, sterile fluid can be flushed in and retrieved in order to perform cultures or examine cells. The biopsy procedure only samples the lining or mucosa, so it is possible that a tumor that involves the deeper parts of the affected area will not be detected.
It is vital that the stomach and intestinal tract be empty of food and fecal matter. Withholding food and water for twelve hours is generally sufficient, but if the colon is to be examined, enemas will be required as well. Passing an endoscope is not possible or safe in a conscious dog or cat, so anesthesia is required. Most patients will require only a short-acting anesthesia to perform endoscopy.
Since the organs are viewed in real time, the result of what is seen is known immediately. However, the diagnosis is not available in many cases until the results of the pathologist’s study of the biopsies are reported or the culture completed. This will take anywhere from a day to a week depending on the location of the pathologist and whether or not special tests are required on the tissue.
Author: Dana Brooks, DVM, Diplomate ACVIM