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The Use of Endoscopy in Dogs and Cats

Saturday, December 01, 2007

Jason Pintar, DVM, DACVIM
Internal Medicine
Garden State Veterinary Specialists

Endoscopy is a minimally invasive medical procedure that involves inserting a tube into the body to examine an organ. The equipment used can involve a simple rigid tube that the examiner looks through with the eye or a more sophisticated digital device that has a powerful light source and high resolution camera at the tip. Endoscopy can be used as a diagnostic tool by examining the inside of organs and procuring biopsies, or it can be used therapeutically such as for removing tumors or foreign material. In recent years, endoscopy has become an increasingly widespread technique for assessing veterinary patients, and in some circumstances, it has replaced older more invasive procedures and surgeries.

One of the most common endoscopic procedures used in dogs and cats is gastrointestinal (GI) endoscopy which involves examination of the digestive system. In upper GI enodscopy, or esophagogastroduodenoscopy, the veterinarian uses a long flexible tube inserted through the mouth to examine the esophagus, stomach, and first segment of small intestine (duodenum). Lower GI endoscopy or colonoscopy is used to examine the colon. The most common indication for GI endoscopy in dogs and cats is the evaluation of patients with chronic digestive disorders including vomiting, diarrhea, weight loss, or blood in the stool. In addition to examining the digestive organs, a veterinarian can also take biopsies of the stomach and intestines and sometimes even remove small tumors from the lining of these structures. Diseases including inflammatory bowel disease, certain cancers, and infections can often be diagnosed with GI endoscopy. Furthermore, dogs and cats will occasionally ingest foreign material that can get caught in the GI tract, and endoscopy can often be used instead of surgery to remove these objects.

A less common application of endoscopy in dogs and cats includes examination of the respiratory system. The trachea and smaller airways inside the lungs called bronchi can be viewed using a procedure called bronchoscopy. During a bronchoscopy, a very slender flexible endoscope is inserted through the mouth, past the larynx or voice box, and into the lower airways. This is most often used to evaluate dogs and cats with chronic coughing or difficulty breathing. Just like with GI endoscopy, samples from the airways can be obtained during bronchoscopy for further evaluation at a laboratory. Syndromes such as collapsing airways, chronic bronchitis, and tumors can all be diagnosed using bronchoscopy. Occasionally, dogs and cats will also have foreign material in their airways, and this can often be retrieved during bronchoscopy.

One other area of the respiratory system that can be evaluated with endoscopy is the nasal cavity. This procedure is called rhinoscopy, and it typically involves using a rigid fiber optic endoscope that is inserted through the nostrils. The back portion of the nose, or nasopharynx, can also be evaluated using a flexible endoscope inserted through the mouth. This procedure is most commonly used to assess dogs and cats with chronic sneezing, nasal discharge, or congestion. Because the nose and sinus cavities of dogs and cats are very complicated structures, rhinoscopy is most often combined with computed tomography (CT or CAT scan) for a more thorough evaluation.

The urinary system is the least common area to be examined with endoscopy, but the bladder and urethra can imaged in a procedure called cystoscopy. In general, most cats are too small for cystoscopy, and the procedure is limited to larger dogs. In female dogs, a rigid endoscope can be inserted into the urethra and into the bladder to evaluate for such conditions as bladder stones, bladder tumors or polyps, and some congenital anomalies. Bladder stones can sometimes be removed by passing a laser through the endoscope and pulverizing the stone in a procedure called laser lithotripsy. While cystoscopy can also be performed in male dogs, it requires a very slender flexible endoscope. Because a very narrow endoscope is needed to pass through a male dogís urethra, the resolution of the image is generally poor, and cystoscopy is less useful than in female dogs.

Endoscopy can also be used to look inside normally closed body cavities such as joints, the abdominal cavity, and the chest or thorax. While these procedures in veterinary medicine are not as advanced as in human medicine, there are some situations where they are being used more commonly. For all of these procedures, a small incision needs to be made to insert a rigid endoscope through the skin and into the cavity to be examined. In most circumstances, a second incision is made for the insertion of instruments.

One of the most common body cavities to be examined by this technique is the abdomen in a procedure called laparoscopy. During laparoscopy, the abdominal cavity is inflated with carbon dioxide to maximize visualization of the organs, and instruments can be used to manipulate the structures through a second and sometimes third incision. In dogs and cats, laparoscopy is used to evaluate the abdominal structures and to biopsy organs such as the liver, pancreas, and sometimes the intestinal tract. It allows the examiner an excellent view of these organs without having to open the abdomen surgically. Although they are not commonly performed in this country, minimally invasive surgery such as spays can also be done laparoscopically. Thorocoscopy is similar to laparoscopy but instead of examining the abdomen, the operator uses a rigid endoscope to examine the chest or thoracic cavity. Intrathoracic structures such as the lungs can be biopsied. Finally, arthroscopy is used to examine the interior of joints. In dogs, arthroscopy is used to examine for joint damage and to remove bone or cartilage fragments in patients with arthritis.

As you can see, endoscopy can be used to evaluate a multitude of medical conditions in dogs and cats. These procedures can often be performed instead of more invasive tests including surgery, and they can give a veterinarian a much better understanding of what is happening inside your dog or cat. If you have a pet with a medical condition that may require endoscopy, you should speak with your family veterinarian to discuss this option further. Your veterinarian is the best resource in discussing your petís health problems and he or she will help you decide what the best test or treatment is.

The information contained in this article is for informational purposes only and is not to be substituted for the advice of a veterinarian.

This article is for informational purposes only and should not be used as a substitute for the professional advice of your veterinarian.

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