ACUTE ENDOCARDITIS 85 



Etiology. (a) Occurs commonly from mild, acute attacks, 

 especially in those cases where the interstitial connective 

 tissue is primarily involved. 



(6) During the course of chronic muscular or articular 

 rheumatism in old dogs; also from chronic nephritis, tuber- 

 culosis, pericarditis, endocarditis of dogs, cats and birds. 



(c) Chronic poisoning by chemicals, toxins, etc., often 

 will produce the condition by interfering with the circulation 

 through the coronary arteries. 



Necropsy. Throughout the heart muscle appear circum- 

 scribed masses of fibrous tissue which are white in color and 

 of firm to hard consistency. They occur most conspicuously 

 near the apex of the left ventricle. The fibrous areas may be 

 quite dense, like a cicatrix, constituting the so-called " heart- 

 scar." Pigment and calcareous deposits may be present in 

 them. The affected heart wall becomes very thin in places 

 and may bulge forming a so-called aneurysm. Fatty degener- 

 ation may be present. The heart may show hypertrophy 

 with dilatation. 



ACUTE ENDOCARDITIS. 



Definition. An acute inflammation of the endocardium, 

 especially involving the part covering the valves. This con- 

 dition occurs very commonly in small animals, especially in 

 dogs and birds. 



Etiology. 1. The acute endocarditis in the majority of 

 cases results from infection, the toxins of a number of infec- 

 tious diseases irritating the endocardium. The organisms 

 (pus-producing organisms, bipolar bacillus, colon bacillus, 

 Bacterium tuberculosis, etc.), or their toxins, are the ones 

 most commonly accused. An acute, primary, infectious 

 endocarditis is observed occasionally; in the majority of 

 cases, however, it occurs secondary to other diseases, pyemia 

 and septicemia usually producing it. It develops often also 

 after abscesses, wounds on the skin, abscesses in the internal 

 organs, septic metritis, sapremia, etc. The organisms or 

 their products (toxins) are carried by the blood to the endo- 

 cardium where they become lodged, especially along the 



