DIGESTIVE SYSTEM 87 



cessful, depending upon the extent of the lesions and the age of the 

 animal involved, is the only treatment for esophageal stenosis. 



DILATATION 



Esophageal dilatation is less frequently met with than stenosis, 

 particularly in swine. 



Etiology. — Obstruction and stenosis of the esophagus are primary 

 causes of esophageal dilatation, but it may be the result of traction 

 from without. 



Lesions. — Dilatation usually affects the entire circumference of 

 the esophagus, although in some instances the dilatation may be lateral 

 and form a true diverticulum. In the dilated portion, the esophageal 

 walls are usually attenuated, and, in rare instances, they may be- 

 come so weak that they are easily ruptured. 



Symptoms. — The usual symptoms evidenced in an animal afflicted 

 with esophageal dilatation consist of a gradually developing tume- 

 faction or enlargement in the cervical region while the animal is 

 eating, due to the accumulation of food in the dilated portion of the 

 esophagus. The enlargement gradually subsides after eating, until 

 no enlargement is observed. 



Treatment. — The treatment of esophageal dilatation is of little 

 avail, and is primarily confined to surgical interference. 



PERFORATION 



Esophageal perforation is not very common in swine. 



Etiology. — It may be the result of erosion due to disease processes, 

 such as actinomycosis, tuberculosis, or necrobacillosis, resulting in 

 a complete destruction of portions of the esophageal walls and thus 

 permitting the contents of the esophagus to infiltrate into the sur- 

 rounding structures. 



Perforation may also result from injury due to some foreign body 

 that has been ingested and lodged in the esophagus. Weston re- 

 ported the case, in The American Veterinary Review (Vol. 40, p. 

 658), of a hog that had swallowed a piece of sharp tin, which had 

 perforated the thoracic portion of the esophagus. A sinus was 

 formed in the adjacent lung, in which a small mass of food had 

 accumulated. 



Lesiovs. — The lesions resulting from perforation of the esophagus 

 are quite variable and consist not only of the destruction of the 



