Tuesday, May 11, 2010
What is Megaesophagus?
So what is Congenital Megaesophagus in dogs? Basically, it is loss of motility of the esophagus, which is a tube of smooth muscle that connects the mouth to the stomach. If you are interested in some fancy, medical description - I found the below actual description online:
"The esophagus is the tube connecting the throat to the stomach. When food is perceived in the esophagus, a neurologic reflex causing sequential muscle contraction and relaxation leads to rapid transport of the food into the stomach, like an elevator going down. Other reflexes prevent breathing during this swallowing process to protect the lungs from aspiration. When these reflexes are interrupted such as by disease in the esophageal tissue or nerve disease, the esophagus loses its ability to transport food. Instead the esophagus loses all tone and dilates. Also, the reflex protecting the lung is disrupted and aspiration pneumonia commonly follows."
Sidney has Congenital Megaesophagus. In Sidney's case the condition was present from birth and presumably there is a genetic basis or it is a birth/developmental defect. The other form is called Acquired Megaesophagus, which happens to dogs later in life. I've read there are two treatable conditions that can lead to Acquired Megaesophagus - hypothyroidism and myasthenia gravis, both of which Sid does not have.
There is no answer to why Congenital Megaesophagus exists or what causes it, if so, we don't know what it is. There are some causes such as a Vascular Ring Anomaly, which Sid didn't have so I don't know much about it - but all the info on this is on the Yahoo Support Site.
The main causes of death are malnutrition and aspiration pneumonia. The malnutrition results from the food never getting to the small intestine for absorption. The aspiration pneumonia results from inhaling small amounts of the regurgitated 'stuff.' Sidney had Aspiration Pneumonia once already - but seems to have recovered well. This is the scariest part of the condition for us.
General recommendations are to have the dog sit in a vertical position for 30 minutes after each meal, to feed multiple small meals and make the meals in the consistency of gruel. Some people feed meatballs to their dogs if they aren't chewers, but my lab will chew anything he sees, so we went for the gruel route.
Basically - the disease/condition affects everything he eats. He cannot have any solid food, treats, etc. And what he does have he must stay vertical for 30 minutes. Fun training a lab puppy with no treats and stopping him from eating sticks and mud outside!!