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Megaesophagus (Esophageal Dilation)

What is megaesophagus?
This condition results from dilation or increase in the volume of the esophagus or gullet which connects the mouth with the stomach. There is also an inability of the esophagus to contract and push the swallowed food into the stomach. The food accumulates in the gullet and this results in vomiting, or more correctly, regurgitation of the meal, a variable time after the dog has eaten. Fluids will usually run down into the stomach, but in some cases, these can be regurgitated some time after drinking.

Pertinent Anatomy
The esophagus is a long muscular tube that connects the mouth to the stomach (illustration right - esophagus as it passes through the chest cavity - red structure labeld E).
The purpose of the esophagus is to transport swallowed food and water to the stomach. To do this, the esophagus normally uses a squeezing movement behind the food (peristalsis) to propel the material into the stomach within seconds after it is swallowed.
After swallowing, the normal esophagus is empty and resembles a collapsed hose.

Are some breeds more prone?The condition is not uncommon in dogs and appears to be congenital in some. There appears to be a familial predisposition in German Shepherds, Great Danes and Irish Setters. Some forms of the condition appear to be truly congenital (present from birth) and these will be evident shortly after weaning. Due to its variety of causes megaesophagus can occur in dogs of any age.What are the signs?Frequent vomiting (regurgitation) after eating, together with a failure to thrive, are the main signs. Because of the frequent regurgitation the animal often has a chronic pneumonia. This will result in coughing and sometimes a mucopurulent nasal discharge. Feeding difficulties may be observed.What are the causes?The congenital form may or may not be hereditary. Other causes can include central nervous system disorders as well as neuromuscular diseases, such as myasthenia gravis and systemic lupus erythematosis.Inflammation of the esophagus from whatever cause can also result in this unfortunate condition.Damage following an esophageal obstruction, for example, a bone in the throat, can result in megaesophagus due to damage to the gullet.What is the diagnosis?The condition can often be suspected on the symptoms, particularly if it is noted that there is improvement if the dog is fed with the head in a raised position. Once a tentative diagnosis has been made it is usual to undertake fairly exhaustive laboratory and diagnostic procedures including x-rays, endoscopy, barium swallows, etc.What is the treatment?This involves careful management. Your veterinarian will give you instructions regarding feeding in an upright position, either with the food bowel raised on a stool or on steps. Sometimes antibiotics and other drugs are prescribed on a long term basis in order to minimize complications such as pneumonia. Repeat x-rays and other tests are frequently necessary.Will treatment cure my dog?The condition is frequently incurable although careful management will allow the dog to lead a relatively normal life. This can be expensive both in terms of time and money. Your veterinarian will be more than happy to discuss all these aspects with you.Megaoesophagus in puppies that has been present from birth sometimes resolves as the puppy reaches adulthood. Unfortunately, this cannot be guaranteed.