44 DISEASES OF THE LUNGS 



PULMONARY GANGRENE. 



Definition. — A decomposition of the dead lung tissue due 

 to the microorganisms of putrefaction. 



Occurrence. — Most often in horse, swine, and sheep. 



Etiology. — May result from fibrinous pneumonia, diseases 

 of the pharynx which make swallowing difficult (pharyngitis, 

 paralysis), general diseases affecting the pharynx (tetanus, 

 parturient paresis, forage poisoning) causing the food 

 swallowed to "go the wrong way;" the aspiration of foreign 

 matter (dust, sawdust, blood, pus,, grains, hair, plant 

 fibers, etc.), drenches unskilfully administered (pneumonia 

 medicantaria) especially in horses, sheep, and swine; by 

 metastasis, emboli develop from ulcerative processes in the 

 bowel, hoof matrix (gangrenous pododermatitis), and bone 

 (caries). In these instances the necrosis bacillus is active. 

 Traumatic injuries rarely cause pulmonary gangrene. 



Symptoms. — The most characteristic symptom is fetid 

 expirium. 1 There is nasal discharge of a muddy reddish- 

 brown or greenish color. The discharge, which is more 

 copious after coughing, has a fetid odor. It contains bits of 

 dead lung tissue, fat crystals, pigment, and innumerable 

 microorganisms. Under the microscope elastic fibers are 

 seen. The respirations are dyspneic especially in the 

 latter stages (toxemia). Fever is nearly always present. 

 It is usually about 104° to 105° F., and assumes an inter- 

 mittent type. In gangrene due to aspirated foreign matter," 

 the temperature may not be over 102° F. for several days. 

 The pulse is frequent, arhythmic, and thready. Chills are 

 frequent. The patient loses flesh rapidly, is weak, languid, 

 and stupid. The appetite is capricious; toward the end 

 there is diarrhea. Pregnant animals " often abort. On 

 percussion the sound is flat over the ventral and middle 

 portions of the lung. Sometimes over caverns the " cracked- 

 pot" tone is emitted. On auscultation rales and tubular 

 breathing are most often noted. 



1 If the gangrenous mass does not communicate /with a bronchus the 

 expirium may ,not be fetid. Diagnosis in these cases is very difficult or 

 impossible. 



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