Enlargement of the Esophagus in Dogs

An abnormal enlargement or stretching of the esophagus results in a condition called Megaesophagus. Either the nerves or muscles in the area of the enlargement do not function properly preventing food from moving to the stomach. Food can accumulate in this area and is later regurgitated. Accumulated food can sometimes get displaced into the trachea and lungs. This can lead another serious disease called aspiration pneumonia to develop.

Megaesophagus is an abnormal enlargement or stretching of the esophagus which prevents food from reaching the stomach and causing it to accumulate in the esophagus. This can cause aspiration pneumonia if it gets displaced into the lungs. 

The symptoms of Megaesophagus can be related to the enlarged throat itself, or may be related to aspiration pneumonia caused by food traveling into the trachea and lungs. Regurgitation of undigested food is more commonly seen than vomiting up of food that is partially digested. 

• Coughing
• Bad breath
• Changes in hunger levels or eating habits
• Excessive Drooling
• Increased respiratory noises
• Shortness of breath
• Vomiting or regurgitation 

Types 

Congenital megaesophagus is caused by developmental issues with the nervous system or a fetal artery remnant that partially constricts the esophagus. This variety is often diagnosed at an early age, in the first few weeks or months of life.

Acquired megaesophagus is generally diagnosed in older dogs as it is often a result of other diseases and disorders that occur most commonly in older dogs. 

Most cases of megaesophagus end up classified as idiopathic, meaning that the cause of the disorder is never found.

The majority of cases of megaesophagus get classified as idiopathic, although there are a few well-known causes. 

Congenital megaesophagus is usually diagnosed in the first few weeks or months of life, often on the introduction of solid food into the puppy’s diet. It is usually caused by either a fetal artery remnant that is partially constricting the esophagus or by developmental issues with the nervous system. Dog breeds predisposed to congenital megaesophagus:

• German Shepherd
• Greyhound
• Great Dane
• Irish Setter
• Labrador Retriever
• Miniature Schnauzers
• Newfoundland
• Shar-pei
• Wire-haired Fox Terriers

Megaesophagus can also be caused by certain diseases such as autoimmune disorders, neuromuscular diseases, Addison’s disease or tumors. Inflammation, foreign bodies in the esophagus and toxins such as lead have also been known to contribute to the development of megaesophagus. When the enlargement is determined to have one of these causes it is referred to as acquired megaesophagus. Dog breeds that may be predisposed to acquired megaesophagus:

• German Shepherd
• Golden Retrievers
• Irish Setter

Your veterinarian will want a thorough history for your pet, including diet and previously diagnosed disorders such as Addison’s disease or myasthenia gravis. He or she will determine if your dog is regurgitating undigested food or vomiting previously digested food, which will help with the diagnosis. A dog with megaesophagus is much more likely to be regurgitating than vomiting. This is usually determined by asking questions regarding the amount of time between the event and eating, as well as questions about the composition of the expelled food. 

In addition to the standard blood tests and urinalysis, your veterinarian may also order an x-ray of the abdomen and the chest to check for an enlarged esophagus. The x-ray may also reveal if air, food or liquid are trapped in the esophagus. 

A definitive diagnosis is usually made either with an x-ray or fluoroscopy after ingesting barium contrast material although a newer process called an esophagoscopy is being used more often. An esophagoscopy is a procedure in which a flexible endoscope is inserted through the mouth and into the esophagus. A device on the end of the endoscope displays magnified images to a video screen.

With acquired megaesophagus the underlying condition will need to be resolved or managed before or concurrently with treatment and management methods for the condition itself. In some cases, surgery may be needed to correct abnormalities and in extreme situations a feeding tube may be implanted.

Some puppies under 6 months old have the condition resolve spontaneously, but it is more often a case of lifelong management. Management is generally centered around preventing aspiration pneumonia from developing and ensuring that the dog gets proper nutrition. Feeding the dog with it’s upper body elevated and keeping it elevated for 15 minutes after eating is helpful to allow gravity to move the food into the stomach. Changing the consistency of the food and feeding frequent smaller meals is also beneficial. This can be accomplished by feeding the dog while it is standing on a ramp or platform, by hand while it is sitting, or using a “Bailey chair” which keeps the dog in an upright position while eating.