Megaesophagus is a condition where there is decreased or absent motility (movement, muscular contractions) of the esophagus. The esophagus is the tube that carries food and water from the throat to the stomach. With megaesophagus, passing food all the way to the stomach becomes difficult, and the food may be regurgitated back up into the throat. This reduced motility usually results in dilation of the esophagus.
Megaesophagus may be present at birth and become apparent shortly after weaning, or it can be acquired later in life. It can be secondary to a variety of diseases that cause neuromuscular dysfunction, or it can occur as a primary disorder for which the cause is unknown (idiopathic). It may be associated with esophageal obstruction due to a foreign object, stricture or narrowing, neoplasia (cancer), compression from adjacent masses in the chest, or compression from a vascular ring anomaly (a congenital defect of the blood vessels in front of the heart).
Affected animals may have difficulty maintaining adequate nutrition due to their inability to move food into the gastrointestinal tract. They may also develop pneumonia secondary to regurgitation and aspiration of foodstuffs into the lungs.
Megaesophagus is seen in both dogs and cats; however, it is much more common in dogs. It is hereditary in the wirehaired fox terrier and miniature schnauzer. Other breeds commonly affected include the
German shepherd dog, Newfoundland, Great Dane, Irish setter, Chinese shar-pei, pug, and greyhound.
What to Watch For Regurgitation of food and water
Fever
Cough
Nasal discharge
Salivation
Sometimes difficulty swallowing
Foul odor to the breath
Weight loss
Poor body condition
Respiratory distress with severe aspiration pneumonia
Diagnosis
A thorough description of the clinical signs is very important and can often be the key to the diagnosis. It is most important that your veterinarian understands exactly what signs your pet is exhibiting at home. Diagnostic tests are necessary to confirm a diagnosis of megaesophagus. They may include:
Complete blood count (CBC)
Biochemical profile
Urinalysis
Thoracic X-rays
Acetylcholine receptor antibody titer
Antinuclear antibody (ANA) titer for immune-mediated diseases
Hormonal testing, such a an adrenal stimulation test and thyroid function tests
Blood lead level
Treatment
Treatment for megaesophagus is directed at the underlying disease or associated conditions. In the event no underlying cause is identified, symptomatic and supportive measures are recommended:
Drugs that help increase gastrointestinal motility or movement
Antibiotic and fluid therapy in cases of pneumonia secondary to megaesophagus
Home Care and Prevention
Administer any prescribed medications and feed your dog according to the instructions given to you by your veterinarian. It is critical that you follow any special feeding instructions to reduce the risk of aspiration of food or vomitus into the lungs. It is important to maintain adequate nutrition if at all possible.
Most causes of megaesophagus cannot be prevented. However, megaesophagus associated with ingestion of certain types of foreign bodies or toxins may be prevented by closely monitoring your dog's environment.
