ADHERENT PERICARDIUM. DRY PERICARDITIS. 



Definition. Adhesion of the parietal layer of the pericardium 

 to the visceral, so as to obliterate the pericardial cavity. 



Lesions. Causes. This condition is found in all the domestic 

 animals as a result of a pericarditis in which the exudate has 

 been mainly fibrinous and little 'serous (dry pericarditis'), or 

 when the serum has been re-absorbed and the false membranes 

 covering the two pericardial layers have united. It may be par- 

 tial, confining itself to the parts near the base of the organ, 

 where the movement between the two layers is most restricted, 

 or it may be complete, the heart and entire pericardium having 

 coalesced. In partial cases the adhesions may have become 

 stretched so as to form more or less broad bands between the 

 cardiac and mediastinal layers. In other cases there is reason 

 to believe that such partial connections have broken up and be- 

 come partially absorbed, so that they have left only the thickened 

 white or milk spots on the surface of the organ. Other second- 

 ary changes are met with. The exudate may extend into the 

 mediastinum in the space between the parietal pericardium and 

 the pleura, where it may form abscess, or a fibroid hyperplasia. 

 In certain cases it becomes the seat of cretaceous deposit so that 

 cardiac calcification starts in this way. In other cases it is the 

 local manifestation of a general disorder. Thus in the horse, the 

 adhesion starts in irregular strangles, and an abscess forms and 

 finally bursts into the pericardium or pleura. In cattle and dogs 

 tuberculosis is a more common cause, and tubercles in all stages 

 (red hard nodules, caseated masses, or cretaceous collections) 

 are found in the neoplasm. A cow's heart in the New York 

 State Veterinary College museum is literally embedded in tubercle 

 several inches in thickness. This heart is enormously hyper- 

 trophied. Cancer is another cause of adhesion in dogs and cattle. 

 The investing adherent parietal layer, may limit systole and favor 

 dilatation and even hypertrophy, as in the cow's heart just 

 referred to. In other cases, by contracting in process of organi- 

 zation, it compresses the coronary arteries, lessens the blood 

 supply, unfits for exertion, and causes angina' pectoris, together 

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