Treatable cause of canine megaesophagus identified

This image shows a canine patient during a video fluoroscopic swallow study. 

Megaesophagus (ME) refers to a large, dilated esophagus with poor or no motility preventing normal passage of food and liquid into the stomach. With ingesta not reaching the stomach to produce the sensation of being full, the dog will continue to eat. As a result, the esophagus enlarges greatly.

Dogs end up not getting enough calories so they waste away. Dogs with ME also regurgitate large amounts of undigested food and some of that material can be inhaled into the lungs. This inhalation can result in aspiration pneumonia, a dangerous additional symptom that kills many affected animals.

Now, there’s help.

Researchers from the University of Missouri's College of Veterinary Medicine’s Small Animal Internal Medicine, Radiology, Surgery, and Nutrition services and Otolaryngology-Head and Neck Surgery department at the university's School of Medicine have identified a breakthrough treatment for a subpopulation of dogs with ME. They have also identified a defect of the lower esophageal sphincter (LES) as a potential treatable cause of ME.

An oral abstract of the swallowing protocol and early identification of the LES achalasia was presented on Oct. 20 at the American College of Veterinary Radiation Annual Scientific Conference in Orlando.

The LES acts as a valve between the esophagus and the stomach, opening when food and water are swallowed, then clamping tight so food doesn't come back from the stomach into the esophagus. In dogs afflicted with ME caused by an achalasia-like syndrome, the LES remains closed.

"We perform an endoscopy to first dilate the LES and then administer Botox, which paralyzes the sphincter muscles that formerly wanted to remain closed,” said Associate Professor Carol Reinero, DVM, PhD, an internal medicine specialist coordinating the efforts of the multidisciplinary team.

“While we are still evaluating this procedure, we've had dogs with remarkable clinical improvement. Additionally, when we repeat the fluoroscopic studies, we can document an open LES. The patients that show improvement can be candidates for surgery, and that surgery is potentially curative.”

Photo credit: University of Missouri College of Veterinary Medicine


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