208 Pharyngitis. 



may more easily be invaded by pyogenic and other microorgan- 

 isms than those of other animals. 



Anatomical Changes. Catarrhal inflammation (pharyn- 

 gitis catarrhalis) affects the mucosa only; this appears red- 

 dened diffusely or in spots, swollen, covered with a tenacious 

 mucus; the lymph follicles and the mucous glands are swollen 

 and the submucosa tissue may be in a condition of edematous 

 infiltration. 



In severe cases the highly swollen mucosa may become ul- 

 cerated and the submucous tissue then presents a thickened, 

 gelatinous mass, containing streaky extravasations of blood, or 

 purulent infiltrations (ph. purulenta s. phlegmonosa). Sub- 

 mucous abscesses may be formed in certain places, particularly 

 in the retropharyngeal region (al)scessus retro- or peripharyn- 

 geales). These then protrude into the pharyngeal cavity, en- 

 croach upon it, or may even obliterate it completely. After the 

 opening of the abscess into the pharynx or towards the outside, 

 there may exceptionally remain a pharjnigeal fistula. After in- 

 jury of the pharynx or after malignant infection, the abscess 

 frequently contains fetid, ichorous masses, sometimes mixed 

 with remnants of food. Eetropharyngeal abscesses may also 

 be formed in consequence of suppuration of the post-pharyngeal 

 lymphatic glands. Such abscesses are formed in the horse in 

 strangles or influenza. In the dog, retropharyngeal abscess 

 often appears simultaneously with purulent parotitis. 



In some cases pseudomembranes form on the mucosa ; they 

 may consist of a deposit of exudate (ph. membranacea s. croup- 

 osa) or they may contain necrotic tissue (ph. diphtheritica). 



The tonsils are always more or less swollen, their crypts 

 filled with a thick purulent caseous, ill-smelling material. The 

 soft palate is likewise swollen ; the connective tissue between the 

 bundles of muscle fibers is infiltrated edematously. 



In pharyngitis in hogs due to the bacillus necrophorus the tonsils are much 

 swollen, dirty grayish-yellow; the crypts are filled with dry caseous material, the 

 lymph follicles in the neighborhood and in the mucosa of the pharynx in general 

 are necrotic, the surfaces coated everywhere with masses of fibrin. The necrosis 

 sometimes spreads to the surface of the tongue, while the submucous tissue of this 

 organ and of the pharynx, and likewise the muscles become infiltrated edematously. 

 The neighboring lymph glands show acute swelling. 



In chronic pharyngitis, the mucosa is thickened, particu- 

 larly on the posterior wall, and is bluish-red ; the h^llpll follicles 

 and mucous glands form nodules of the size of a lentil (ph. 

 granulosa). The muscles of the pharynx become atrophic and 

 the connective tissue proliferated (Trasbot). In horses the 

 tonsils may increase in size to form purplish masses of the size 

 of a finger (Kitt). 



Symptoms. In acute pharyngitis the ingestion of food oc- 

 curs slowly and carefully and there is difficulty in deglutition. 



