1042 Pericarditis. 



initial stage, is sometimes limited to portions of the pericardium 

 (pericarditis circumscripta) in whicli the vicinity of the large 

 vessels is affected preferably, less often that of the apex. In 

 the majority of cases, however, the inflammation involves the 

 entire pericardium almost uniformly (P. diffusa), although 

 also in these cases the visceral -layer usually shows more intense 

 changes. In proportion to the amount of exudate the peri- 

 cardium is more or less distended and sometimes occupies a 

 very considerable portion of the thoracic cavity. The quantity 

 of exudate varies within wide limits and may amount to 36 

 (Friedberger) and even 40 liters in horses, 18% liters (Trasbot) 

 in cattle, and % liter in dogs. The connective tissue septa of 

 the heart muscle are also infiltrated with sero-cellular exudate ; 

 if the amount of exudate is very great, compression and atrophy 

 of the heart may result. 



Finally there are evidences of stasis, such as marked full- 

 ness of the veins, passive hyperemia of the lungs and of the 

 liver, edematous infiltration, etc. 



In traumatic pericarditis of .cattle the foreign bodies are 

 not infrequently found in the exudate, either free or with one 

 end penetrating the wall of the heart. It may also occur that 

 the foreign body is not found because it has been pushed back 

 into the reticulum, or because it had rusted and crumbled; 

 in many cases it is entirely in the heart muscle, or exceptionally, 

 in a ventricle. (It is possible for an abscess to form in the 

 heart muscle and break into the pericardial aavity or into 

 one of the ventricles [Cadeac].) A traumatic origin of the 

 inflammation is suggested by the presence of a firm connective 

 tissue cord between pericardium and diaphragm, and also be- 

 tween the latter and the reticulum. This cord is either solid, 

 or it contains several cavities, either side by side or com- 

 municating with each other, and filled with purulent or ichorous 

 fluid ; in rare cases a long canal is found in the center of the 

 connective tissue cord, which connects the lumen of the 

 reticulum with the pericardial cavjty. 



Chronic pericarditis is characterized by connective tissue 

 proliferation leading either to simple thickening of the peri- 

 cardial layers (tendinous spots, Maculae albidae s. lacteae) or 

 to adhesions between them (P. fibrosa adhaesiva) ; sometimes, 

 indeed, a complete union of the pericardial layers results 

 (Concretio pericardii). In tuberculous pericarditis cheesy foci 

 may be found in varying numbers in the new connective tissue 

 which may be very copious, but this form of pericarditis occurs, 

 especially in dogs, also as a serous or hemorrhagic inflam- 

 mation. 



Symptoms. The clinical picture of traumatic pericarditis 

 is usually preceded by prolonged digestive disturbances, which, 



