232 Narrowing of the Esoi^liagus. 



Compression of the esophagus is frequently due to neo- 

 plasms (melanoma, struma, lymphoma, myoma) exostoses, 

 tuberculous masses in cattle, but also in dogs, tuberculous 

 mediastinal glands, purulent or tuberculous peribronchial 

 glands; sometimes also to arteries with an abnormal course 

 (Labat). All these formations may cause lateral or annular 

 compression and diminution of its lumen (Compressio oesoph- 

 agi). 



Cases of stenosis in a circumscribed place due to anomalies 

 of development are very rare (Casparini and Serres saw such 

 a case each in a foal. Smith in a one-month-old dog). 



Pathogenesis. With the exception of the congenital 

 stenosis or of cases due to spasm of the cardia, all other fonns 

 develop very slowly and the symptoms therefore rarely appear 

 suddenly or immediately after birth, or after the weaning of the 

 young when these are fed with vegetable food; but they make 

 their appearance very gradually. Since inhibition of the pas- 

 sage of morsels of food stands in direct relation to the degree of 

 obstruction, it may happen that a larger or firmer mass of food 

 becomes caught accidentally in front of the obstruction. As 

 long as arrested it will cause the symptoms of obstruction 

 of the esophagus l)y a foreign body (see page 226). The con- 

 vulsive contractions of the muscles of the esophagus, caused 

 by the arrested morsel, press the latter through the narrowed 

 place after a shorter or longer time, and deglutition is then 

 again possible. Repeated and strong efforts at deglutition made 

 voluntarily by the animal also assist in pressing the morsel 

 through the stenosed portion. 



Symptoms. The symptoms consist from the start in dis- 

 turbances of deglutition. The animals begin to feed greedily, 

 they masticate and swallow, and the mouthful first passes down 

 perfectly normally, then, however, there are strong efforts at 

 deglutition ; the morsel may finally pass into the stomach. The 

 efforts are repeated later at each act of swallowing or at each 

 meal again and again, according to the degree of stenosis and 

 to the nature of the feed, until the animal, half fed but tired 

 out, desists from feeding. During the forced attempts at degluT 

 tition, saliva, or saliva mixed with masticated food is from time 

 to time transported outwards through the mouth or nose in con- 

 sequence of antiperistalsis. Deglutition of fluids, however, is at 

 this time not at all or very little disturbed, Init if the stenosis is 

 quite marked, fluids will also cause disturbance. In some cases, 

 there is only a retarded ingestion of food accompanied for some 

 time by more or less regurgitation. 



If the stenosis increases the clinical picture of complete 

 esophageal occlusion, or more often that of dilation, gradually 

 develops. 



A considerable stenosis in ruminants leads to chronic 



