74 DISEASES OF THE PERICARDIUM 



Secondary Pericarditis.— This form may result from a 

 number of conditions: (a) Catarrhal pneumonia, which is 

 common in the dog and cat; simple pleuritis; endocarditis, 

 myocarditis, etc. It may also follow diseases of the medi- 

 astinal lymph glands, the ribs, sternum, and even in some 

 cases the abdominal viscera, (b) In septic processes, such 

 as suppurating wounds, puerperal septicemia, etc. (c) In 

 specific febrile diseases, such as distemper in the dog and 

 cat, pneumonia, chicken cholera, etc. 



Necropsy.— On postmortem are recognized: (a) Acute 

 fibrinous pericarditis, (b) pericarditis with effusion, and (c) 

 chronic adhesive pericarditis. 



(a) Acute Fibrinous Pericarditis.— This may be local or 

 general. In the mild form dull, rough, lusterless masses of 

 exudate cover the surface of the pericardium with a thin 

 coating of fibrin which is readily peeled off. In the more 

 severe form the exudate is more abundant, the masses of 

 organized fibrinous deposits giving the surface a rough, 

 shaggy appearance. In this form there is usually found a 

 small quantity of fluid in the meshes of the fibrin. The heart 

 muscle is not affected, except in the more severe form where 

 it will be found pale and turbid. 



(b) Pericarditis with Effusion.— This effusion may be sero- 

 fibrinous, hemorrhagic or purulent. It is most commonly 

 serofibrinous. In this case the pericardial surfaces are covered 

 with a thick fibrin and a collection of serous fluid fills the 

 pericardial sac. The hemorrhagic form is usually found in 

 acute cases which have terminated fatally following injuries, 

 etc. The pericardial sac will contain a varying quantity of 

 serous fluid mixed with blood. When pus is present the peri- 

 cardial surfaces will appear rough, occasionally eroded and 

 of grayish color. This form occurs via metastasis or from 

 internal trauma introducing infection into the pericardial sac. 



(c) Chronic Adhesive Pericarditis.— Chronic adhesive peri- 

 carditis is found occasionally on postmortem. It is char- 

 acterized by marked thickening of the membranes, with 

 adhesions between the membranes themselves, and the 

 adjacent organs. 



