18 SWINE DISEASES 



Stenosis 



Stenosis, or narrowing of the esophagus, is not infre- 

 quent. This condition occurs most frequently at the 

 pharyngo-esophageal junction or at the cardiac termina- 

 tion, the cause being either extrinsic or intrinsic. 



Etiology. Among extrinsic causes may be pressure 

 from enlarged thyroids, tumors, aneurysms, or abscesses. 

 Foreign bodies, too, often produce partial obstructions 

 of the esophagus, thus causing a temporary stenosis. 

 The intrinsic causes are most frequently due to scars 

 or scar tissues that have formed as a result of injuries 

 or of diseased processes of the esophageal tissues. 

 Hyperplasia of the esophageal muscle, also, may pro- 

 duce stenosis. 



Lesions. The usual anatomical changes observed 

 in esophageal stenosis consist of cicatrized fibrous tissues. 

 The extent of the trouble varies, but as a rule it involves 

 only a small portion of the esophagus. The stenosis 

 may form a regular or irregular diminished lumen. 



Symptoms. The symptoms evidenced in esophageal 

 stenosis consist of difficult deglutition and sometimes 

 dilatation (which see), succeeded by the formation of 

 jabot, which may be observed in animals thin in flesh. 



Treatment. Surgical interference, which may or 

 may not be successful, 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 circum- 

 ference 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 



