CHAPTER V. 

 DISEASES OF THE PLEURA. 



PLEURITIS. PLEURISY. 



Definition.— An inflammation of the pleura accompanied 

 by a serous, serofibrinous, hemorrhagic, or purulent exuda- 

 tion into the pleural cavity. 



Etiology. — (a) Penetrating' wounds through the thoracic 

 walls, from fractured ribs or sharp foreign bodies in the esoph- 

 agus or stomach; contusion of the thoracic walls; tumors 

 in adjacent parts; in rare cases cysts of tapeworms. These 

 conditions make possible the entrance of organisms directly 

 into the pleura, or by lowering the resistance of the pleura 

 which favors the growth of organisms that are carried to it 

 by the lymph and blood streams. These are quite numerous 

 and consist most often of the following: Bacillus bipolaris, 

 Staphylococcus pyogenes, Leptothrix buccalis, and Strepto- 

 thrix canis. 



(b) Occurs in cases of nephritis from an accumulation of 

 waste products in the blood or by bacterial toxins which are 

 carried to the pleura by the blood and produce direct irrita- 

 tion to the serous membrane. 



(c) Exposure to cold and cold dampness are common 

 predisposing factors as they reduce the general resistance to 

 infection. 



(d) Pleuritis frequently follows bronchitis and pneumonia, 

 the organisms present enter the lymph and blood streams and 

 are carried to the pleural cavity. In some cases of pneumonia 

 where abscesses develop and open into the pleural cavity a 

 purulent pleuritis is produced. 



(e) Extension of inflammation of neighboring tissues, viz: 

 Mediastinitis during the course of infectious diseases; acute 

 peritonitis; inflammation of abdominal organs. 



