Megaesophagus in Dogs

Megaesophagus is a serious problem that prevents dogs from swallowing food and keeping it down. Regurgitation is one of the primary signs, so it's important to recognize the difference between this expulsion of undigested food and vomiting. Elevated feeding techniques may help manage the problem, but surgery and treatment of underlying conditions may also be required. Certain breeds are at higher risk of developing megaesophagus.

What Is Megaesophagus?

Megaesophagus, also known as dilatation of the esophagus, is the enlargement of the tube that carries food from the mouth to the stomach. Decreased esophageal motility is also associated with megaesophagus.

Symptoms of Megaesophagus in Dogs

Normally the esophagus is a smooth, thin, muscular tube lined with mucosa that gently helps food slide down into the stomach via nerve function that stimulates swallowing. In a dog that has megaesophagus, the esophagus is too wide, and the nerve function that controls motility diminishes or disappears, making it difficult for a dog to swallow food and liquid.

The most obvious sign of megaesophagus is regurgitation. This is different from vomiting because regurgitation is a passive occurrence, meaning there is no active effort by the body to expel the contents from the esophagus or stomach. Regurgitated food and liquid seem to fall out of a dog's mouth, whereas vomiting includes retching and gagging.

Dogs with megaesophagus will regurgitate food almost immediately if gravity allows it (i.e. the dog's head lowered in a normal eating position), so swallowing can be impossible. Weight and muscle loss will ensue if necessary nutrients aren't gained from food.

Bad breath is common in affected dogs because some bits of food are frequently retained in the esophagus where they begin to ferment and rot.

Rapid breathing or choking can occur if a dog aspirates (breathes) food into its lungs. During regurgitation, some food or water can enter the trachea (windpipe) instead of the esophagus, making it difficult to breathe and potentially causing aspiration pneumonia.

Causes of Megaesophagus in Dogs

Megaesophagus can either be congenital or acquired. Dogs that are born with megaesophagus have the congenital form of the disease. It is usually noted by 12 weeks of age in puppies as they are nursing or being bottle-fed.

Older dogs can develop megaesophagus, which may be secondary to another condition or have an unknown cause. Things that are known to cause acquired megaesophagus include:

• Myasthenia gravis: This is a disease that affects the nervous system, including the nerves that control the esophagus.
• Trauma: Any type of injury to the esophagus or nerves that affect the normal function of the esophagus can result in megaesophagus. This includes an obstruction, foreign body, some toxin ingestions, inflammation, excessive vomiting, and other injuries to the esophageal muscle.
• Hypothyroidism: This disease affecting the thyroid gland can also impair the motility of the esophagus muscle.
• Addison's disease: This disease affecting the adrenal gland of a dog can affect the muscle in the esophagus due to the lack of cortisol in the body.
• Dermatomyositis: Some dogs with this disease can have tissue damage and inflammation from a lack of oxygen in the blood vessels; megaesophagus can result.

Any breed of dog can be born with or develop megaesophagus, but the following breeds are more likely to be born with or develop this problem than others.

• Miniature schnauzers
• Wire-haired fox terriers
• German shepherds
• Newfoundlands
• Great Danes
• Irish setters
• Shar-peis
• Greyhounds
• Labrador retrievers

Diagnosing Megaesophagus in Dogs

Discuss symptoms with your veterinarian who will likely order X-rays to look at the placement of the trachea and esophagus in your dog. Occasionally a contrast study using barium or endoscopy will also be used.

Treatment for Megaesophagus in Dogs

If a dog develops megaesophagus as a result of Addison's or hypothyroid disease, this problem often resolves once the disease is properly managed. Dogs with other types of acquired megaesophagus and congenital megaesophagus can only manage the symptoms of the disease since there is no cure. Medications to manage the symptoms and special feeding techniques must be used in these cases.

Feeding tubes or elevated feeding techniques are necessary to allow a dog with megaesophagus to eat and drink without regurgitating. Feeding tubes are surgically placed and require regular maintenance and replacement, so elevated feeding techniques are more popular for owners of dogs with megaesophagus.

Gravity is the enemy when it comes to feeding. Dogs usually eat standing on all four legs so their esophagus is practically perpendicular to the ground. This allows food to slide out of the throat since the enlarged esophagus can't fight gravity. Eating food that is placed on a step stool or table can help reduce the effect of gravity. Another option is a special chair called a Bailey chair that positions a dog upright while it eats.

In some cases, surgery can correct megaesophagus, but it is not always a viable or successful treatment option.

Prognosis for Dogs with Megaesophagus

With proper management and treatment of underlying conditions, most dogs with either congenital or acquired megaesophagus can live healthy, happy lives.

How to Prevent Megaesophagus in Dogs

There is unfortunately no way to prevent megaesophagus in most dogs, but by knowing the warning signs, you'll be able to help your dog cope with this condition.