Megaesophagus
Megaesophagus
The esophagus is the muscular tube which propels food from the mouth into the stomach. In the dog it is made up primarily of skeletal muscle. The esophagus normally has tone like other muscles in the body and is closed when it is not being used. Megaesophagus however denotes an esophageal disease where there is no tone to the esophagus and it becomes flaccid and enlarged.
What are the symptoms of megaesophagus?
Typically patients with megaesophagus will regurgitate their food. This is different from vomiting in that the food passively comes up from the esophagus versus the active abdominal compression that is involved with vomiting.
The constant regurgitation of food and liquids predisposes these patients to aspiration of stomach contents into the airways and lungs. They then develop pneumonia so coughing, lethargy, labored breathing or loss of appetite may also be among the first signs noted in these patients.
The constant regurgitation of food and liquids predisposes these patients to aspiration of stomach contents into the airways and lungs. They then develop pneumonia so coughing, lethargy, labored breathing or loss of appetite may also be among the first signs noted in these patients.
How is megaesophagus diagnosed?
Usually routine radiographs (X-rays) of the chest are enough to make a diagnosis of this esophageal disease. In some instances however, where it is not apparent on a radiograph, other studies such as fluoroscopy and/or endoscopy may be required.
What causes megaesophagus?
There are a few diseases which may be associated with megaesophagus. Diseases such as myasthenia gravis (a neuromuscular disease), Addison’s disease or hypothyroidism (endocrine diseases) or certain drugs and toxins have been associated with megaesophagus. Your veterinarian may recommend specific blood tests to look for these diseases. It is also possible that there is no underlying disease – this is called idiopathic megaesophagus. It is important to look for an underlying disease process however as addressing this may help in treatment of the megaesophagus.
How is megaesophagus treated?
If an underlying disease is identified, specific therapy to control the disease will be started. Because these patients have such poor esophageal function, changes to their diet and feeding are also necessary. Elevated feedings are used to allow gravity to aid in getting food from the mouth to the stomach. Different consistencies of food, such as meatballs or gruel, may help in these patients as well.
Patients with aspiration pneumonia may need to be more intensively managed with antibiotics or intravenous fluids.
If regurgitation is persistent or too great a risk for a particular patient, then a temporary or permanent stomach tube may be required.
Patients with aspiration pneumonia may need to be more intensively managed with antibiotics or intravenous fluids.
If regurgitation is persistent or too great a risk for a particular patient, then a temporary or permanent stomach tube may be required.
What is the prognosis for patients with megaesophagus?
Prognosis is dependent on a few factors. Young dogs with congenital megaesophagus may have improvement in the esophageal function as they mature. Older dogs however may never see a return to normal esophageal function. The prognosis in these patients depends on consistent nutritional support and how frequently they develop aspiration pneumonia. Pets that develop megaesophagus secondary to another disease may have a more favorable prognosis if the underlying problem can be successfully managed.
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