Megaesophagus (ME) is basically a “floppy” esophagus. The esophagus is a tube connecting the mouth to the stomach. A normal esophagus moves food to the stomach with wave-like contractions called peristalsis. An ME dog’s esophagus loses its muscle tone, becomes enlarged, and can develop pockets where food can become trapped. Since the esophagus does not function normally, food sits in the esophagus and doesn’t make its way to the stomach. This can cause malnutrition and regurgitation of vast amounts of undigested materials.
ME can be idiopathic (no known cause), or a result of a secondary disease. The most common secondary diseases causing ME are Persistent Right Aortic Arch (PRAA), which is most commonly seen in puppies and can sometimes be successfully treated with surgery, and Myasthenia Gravis (MG), which is a neuromuscular condition that can be treated with medication. Please see the links on our homepage for more information about PRAA and MG.
What are the signs and symptoms of ME?
One of the main symptoms of Megaesophagus is regurgitation. Regurgitation is different than vomiting. When a dog regurgitates, it does not usually require much effort from the dog, and the food comes out looking a lot like it went in (undigested), sometimes in a tube shape (like the esophagus). When a dog vomits, there’s a lot of effort involved. A vomiting dog will exhibit a heaving motion (the ribcage and stomach will rapidly contract multiple times) before partially or totally digested food and/or bile is expelled. A dog will also lick his lips often prior to vomiting (this is a sign of nausea). It is important to know whether your dog is regurgitating or vomiting, as it aids in diagnosis. Often, a vet will not even consider ME if he or she is told that a dog is “vomiting.”
When a dog regurgitates, some of the regurgitated material (food, water, saliva) can be inhaled into his lungs. Inhalation of foreign material into the lungs can cause another, more dangerous, symptom of Megaesophagus, Aspiration Pneumonia (AP). It is imperative that your dog be seen right away by your vet if you suspect AP. In some cases, a bout with AP is the trigger for an ME diagnosis.
Common symptoms of aspiration pneumonia in dogs include trouble breathing (heavy panting without strenuous exercise), shuddering/shaking/shivering, lack of appetite (not drinking water or eating), lack of activity (not playing), and fever. Not all of these symptoms may be present at the same time if your dog has AP. Again, if you suspect your dog has inhaled material into his or her lungs, it is our recommendation that you seek veterinary treatment.
How is Megaesophagus Diagnosed?
The most common method of diagnosis for Canine Megaesophagus is an x-ray (radiograph). Since an enlarged esophagus can be difficult to see on an x-ray, often a Barium Swallow will be done. In a Barium Swallow, the dog is fed a contrast material that makes the esophagus stand out on an x-ray. This contrast material is used regularly in humans to provide clearer x-rays.