Cricopharyngeal achalasia is characterized by inadequate relaxation of the cricopharyngeal muscle, which leads to a relative inability to swallow food or liquids. It is seen primarily as a congenital defect but is occasionally seen in adult dogs. The cause is generally unknown, but in adult animals it may be associated with acquired neuromuscular disorders. Repeated attempts to swallow are followed by gagging and regurgitation. Aspiration pneumonia is a common complication. An accurate diagnosis requires fluoroscopic evaluation of swallowing after oral administration of contrast material alone and mixed with food. Abnormal function (lack of relaxation) of the cricopharyngeal muscle results in retention of barium in the posterior pharynx.
Treatment consists of cricopharyngeal myotomy or cricopharyngeal and thyropharyngeal myectomy, which usually results in normal swallowing immediately after surgery. The success rate of surgery approaches 65%. Dogs with acquired neuromuscular disorders are less likely to respond to surgery but may respond to treatment of the underlying disease. Aspiration pneumonia should be treated aggressively if present.