Megaesophagus is an abnormality of the esophagus that can be idiopathic (unknown cause), congenital or acquired secondarily from injury or another disorder. Our focus here will be on acquired megaesophagus because dogs who are maintained at high blood serum levels of bromide MAY be at increased risk for acquired megaesophagus. Please note that there are no controlled studies that prove there is an association, however, many clinicians have noticed an increased incidence. In my opinion, knowledge is power, and knowing what to look for in the event there is really a cause and effect relationship between bromide and megaesophagus, will give you an advantage for successful treatment. Since there are no studies, the exact "high serum" level is unknown, however, in most cases serum levels were over 3.0 mg/ml.
What is megaesophagus?
When food enters the throat, it's pushed into the esophagus by movements of the tongue. The esophagus is a muscular tube that connects the throat to the stomach and is normally narrow and flat unless ingested food is moving through it. Muscular contractions within the esophagus carry food down the neck, though the thoracic cavity, past the trachea (wind pipe), heart and vena cava, which is the large vein returning all blood to the heart from the hindquarters. With megaesophagus, the esophagus is abnormally stretched far beyond it's normal collapsed state. In this condition, it is unable to move food actively toward and empty it into the stomach. Food sits in the esophagus unable to go anywhere, until a dog lowers his head at which time it spills out (regurgitation).
Symptoms of megaesophagus:
Regurgitation is a classic symptom of megaesophagus. The difference between vomiting and regurgitation is that vomiting is an active process. There is gagging, heaving and retching as the body actively tries to expel stomach contents. Regurgitation is passive. Food sits in the esophagus until it simply falls back out of the mouth at some point.
Although regurgitation is the hallmark of megaesophagus, some dogs will have coughing, gagging, nasal discharge, sneezing, excessive salivation, lethargy, weakness, loss of appetite and fever alone or in conjunction with regurgitation.
Diagnosis of megaesophagus:
A presumptive diagnosis of megaesophagus can be made based on the dog's clinical signs. Sometimes megaesophagus is obvious on plain radiographs and they should be tried before contrast (barium studies) because patients with megaesophagus have the tendency to inhale or aspirate food contents back up in their throats. If barium becomes inhaled, the body has great difficulty removing it from the lungs.
All patients with megaesophagus should be evaluated for aspiration pneumonia from inhaling regurgitated food materials. Aspiration pneumonia is a life threatening complication of megaesophagus.
Treatment of megaesophagus:
When megaesophagus is caused secondarily to something that can be treated (like high bromide levels, foreign objects lodged in the esophagus etc), the treatment is to correct the underlying condition. If the stretching of the esophagus has not persisted for too long and the underlying cause can be removed, then a dog will usually be able to live a completely normal life. Generally lowering bromide levels resolves any problems with megaesophgus.
If further treatment is necessary, the first step is to determine if the dog does better on a liquid or solid diet. The dog should eat in an elevated position and should stay in this position for 10 to 15 minutes after eating.
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Last Updated August 2009