Megaesophagus is a condition in which the tube carrying food from mouth to stomach is too big and doesn't work properly. A normal esophagus has muscles that move the food into the stomach and help keep it there. The esophagus in an ME dog does not have these reflexes to push the food down into the stomach. With the food not reaching the stomach to cause the sensation of being full, the dog will continue to eat. As a result, the esophagus often enlarges as it dilates greatly with food. Over time, an ME dog's esophagus loses its muscle tone, becomes enlarged, and can develop pockets where food can become trapped.
Other reflexes of a normal esophagus prevent breathing during swallowing so that food and liquids cannot be inhaled into the lungs. The other danger with ME is that food moving in the wrong direction during regurgitation can enter the trachea and lungs. This results in aspiration pneumonia, which is the most common reason dogs die from this disease.
Symptoms of ME:
Regurgitation is different than vomiting. Vomiting is when the body actively pushes contents out of the stomach. Regurgitation is when food or liquid falls out of the mouth or throat.
Because food does not reach the stomach, the dog is not getting adequate nutrition.
Extreme hunger or lack of appetite
Halitosis (Bad Breath)
Aspiration pneumonia can occur when food sitting in the esophagus is inhaled into the lungs. The symptoms of aspiration pneumonia include difficulty breathing, difficulty swallowing, coughing, nasal discharge, fever, increased heart rate, weakness, lethargy, and a bluish tint to the skin.
How is ME diagnosed? The typically diagnostic work-up for megaesphagus begins with chest x-rays. X-rays may show the esophagus dilated with food and will determine whether or not there is secondary aspiration pnuemonia. In some cases, the nature of the ingested material does not allow for visualization of a dilated esophagus. If the history fits mega-esophagus, but a dilated esophagus is not seen on routine x-rays, then a contrast study can be performed, where prior to the x-ray, a radio-opaque liquid is swallowed. Since the liquid will show brightly on the x-ray, the integrity and shape of the esophagus will be clearly visualized.
A routine blood panel should also be run, consisting of a CBC, chemistry, and a thyroid profile (TSH, T4, free T4). A test for myesthenia gravis (acetyl choline receptor antibody test) should also be run.
The majority of cases of canine megaesophagus have no apparent cause. A minority of cases are caused secondary to underlying disease, typically hypothyroidism or mysthenia gravis.
What is the treatment for ME? Megaesophagus can be difficult to treat. Some puppies with congenital megaesophagus may outgrow the condition, and surgery may be possible for certain development abnormalities. However acquired cases of megaesophagus, cannot be reversed. For these dogs, treatment is essentially supportive, and may include:
Treating respiratory infections with antibiotics as soon as they occur.
Managing your dog’s eating and assuring that nutritional needs are met.
Several strategies to control the regurgitation of food are typically employed:
Feeding from an elevated position to facilitate downward movement of food. Many pet parents use a step ladder or Bailey chair to elevate their dog’s bowl.
Feeding a slurry instead of firm, wet food or crunchy kibble
Maintaining elevation of the body after eating
Esophageal tube feeding or surgical stomach tube placement for dogs that are unable to eat on their own.
Medications may be useful in some cases. Metoclopramide can help to increase muscle tone around the esophagus and stimulate contractions. Antacids can help to reduce esophageal damage, and nausea medications can reduce stomach upset.
Vinnie in a make-shift feeding station. This is actually a great idea to keep him upright during meals.
Vinnie eating in his Bailey Chair. He remains in his chair for approximately 20 minutes after meals to ensure gravity has moved the food down to his stomach.
Preventing megaesophagus comes down to removing affected individuals from breeding programs, regardless of the cause of the disease. Their siblings and parents should also be tested for the disease underlying the megaesophagus before they are allowed to continue or enter breeding programs.