Myocarditis. 1069 



6. Inflammation of the Heart Muscle. Myocarditis. 



(a) Acute Myocarditis. Myocarditis Acuta. 



There are two principal types of acute inflammatory 

 processes in the heart muscle, namely, the parenchymatous 

 myocarditis, which is characterized by a pathological effusion 

 that may be very slight, and by a more emphatic degeneration 

 of the muscular fibers, and secondly, purulent myocarditis, in 

 which purulent softened foci are developed in the heart muscle. 



In contrast to purulent myocarditis, the acute parenchymatous 

 myocarditis cannot be sharply distinguished from parenchymatous or 

 fatty degeneration. The essential point of differentiation is really only 

 in the pathological effusion which is absent in purulent myocarditis 

 (Kitt), but which, in parenchymatous disease, may be so inconsiderable 

 that it is only possible by means of microscopical examination to decide 

 whether the process is to be called an inflammation or a degeneration. 

 If the gross anatomical appearance of the heart muscle does not always 

 offer diagnostic information, the clinician is even less in a position to 

 decide whether and for how long a time the process in the heart muscle 

 is inflammatory or simply degenerative in nature, because both processes 

 usually develop under similar conditions and are manifested by the same 

 symptoms. It is therefore justified from a clinical point of view to 

 consider the parenchymatous degeneration, together with acute paren- 

 chymatous myocarditis. 



Nor does the consideration of acute parenchymatous and of purulent 

 inflammation in separate chapters appear justified, because clinically 

 they cannot be differentiated, and, moreover, the treatment of both 

 diseases is similar. 



Etiology. Aside from the inflammation, which, according 

 to some authors (Friedberger & Frohner, Zsehokke) develops 

 primarily in exceptional cases in horses and hunting dogs 

 owing to excessive exercise, and which probably belongs more 

 properly to acute cardiac dilatation, acute parenchjinatous 

 myocarditis is a secondary affection, which occurs especially 

 in acute infectious diseases and very rarely in certain intoxica- 

 tions. The toxins which, in the course of acute infectious 

 diseases, circulate in the blood, produce sometimes only a 

 parenchymatous degeneration or at the same time a fatty 

 degeneration of the muscular fibers, sometimes also a serous 

 or cellular infiltration of the interstitial tissue, and frequently 

 hemorrhages. This occurs especially in the septicemic diseases, 

 for instance, in hemorrhagic septicemia, in swine erysipelas, 

 anthrax, and acute glanders, while foot and mouth disease and 

 especially variola, seem to be compHcated by myocarditis only 

 in their malignant forms. An inflammation which was observed 

 by Dieekerhoff in connection with the so called Skalma and 

 which was called by him "Myocarditis septica," undoubtedly 



