Megaesophagus in Dogs

The esophagus is the first portion of the digestive tract after the mouth. In healthy animals, the esophagus pushes chewed food through to the stomach for further digestion. If something disrupts the ability of the esophagus to successfully push food through, the muscle can become stretched and weak, leading to megaesophagus.

Other symptoms that can be associated with megaesophagus depend on the underlying cause or secondary complications of the condition. Examples include:

The greatest risk associated with megaesophagus is aspiration pneumonia. When food or water is inhaled into the lungs, it can lead to life threatening infection. Frequent regurgitation and lack of esophageal muscle tone in cases of megaesophagus create a scenario where aspiration pneumonia is likely to occur since the esophagus is directly beside the breathing structures in the throat.

Megaesophagus is more common in dogs than in cats. Symptoms can be well-managed, but the risk of aspiration pneumonia is life-threatening and likely to recur. Congenital megaesophagus carries a better prognosis than the acquired form of the disease. Some breeds have a predisposition to megaesophagus.

Most causes of megaesophagus are not identified in dogs.

Regurgitation of food and liquid is the most important and common sign of megaesophagus. Regurgitation is distinct from vomiting in that it is a passive process– food and liquid simply “fall” out of the mouth, often in a tubular shape. There may be coughing or gagging, but no heaving is seen. In contrast, vomiting is an active process that involves heaving, retching, or abdominal compression.

Megaesophagus is identified through diagnostic imaging. To further diagnose the cause and potential secondary complications, veterinarians will often recommend an esophagoscopy (a scope to look into the esophagus).

Treatment is complicated and depends on the underlying cause. Potential treatments include:

• Surgery
• Medications
• Supportive care

The focus of supportive care for megaesophagus is regurgitation prevention to reduce the risk of aspiration pneumonia. It is often recommended to feed in an elevated or upright position, allowing gravity to assist in moving food and liquids into the stomach. One piece of special equipment to facilitate this is called a Bailey Chair. This chair maintains dogs in an upright position during and for a 10-15 minute post-feeding period to ensure all food has passed through the esophagus.

Other strategies involve feeding small, frequent meals, and experimenting with different food consistencies. Feeding tubes that bypass the esophagus completely are also an effective option in some cases.

Surgical intervention is sometimes successful in reducing the severity of megaesophagus, but some amount of regurgitation is likely to continue.

The most common cause of megaesophagus, myasthenia gravis, is treated with medications. Other underlying causes may also benefit from medications.

Regurgitation is likely to be a life-long complication with a need for persistent care. Megaesophagus sometimes resolves with age or treatment, but in most cases, is eventually fatal due to aspiration pneumonia. In cases where megaesophagus cannot be effectively managed, euthanasia may be the most humane option due to poor prognosis.

There is no specific prevention for megaesophagus. Its underlying causes are not contagious.

Data on prevalence of this disease in dogs are lacking, but acquired megaesophagus is more common than the congenital form.

• Surgery
• Medications
• Supportive care