RURAL VETERINARY SECRETS 27 



PLEURITIS 



Pleuritis is an inflammation of the pleura. It is nearly always 

 a secondary condition in animals. 



Pleuritis affects all animals, but principally the horse. In the 

 horse it is usually a symptom of infectious fibrinous pneumonia ; 

 in the ox of tuberculosis, contagious pleuropneumonia and hem- 

 orrhagic septicemia, and in swine most frequently of so-called swine 

 plague. Pleuritis, however, may occur unattended by pneumonia, 

 as is frequently observed in horses. 



Pleuritis in animals is always due to infection. Cold, which 

 was believed to be the most potent etiological factor, is now con- 

 sidered merely predisposing (pleuritis in sheep following shearing; 

 exposure of horses to cold wind and rain). The micro-organisms 

 which produce pleuritis are many. Rarely is pleuritis a primary 

 disease — it is most commonly seen in practice accompanying dis- 

 eases of the lungs (pleuropneumonia). The micro-organisms caus- 

 ing pleuritis may enter as follows : (1) Through penerating thoracic 

 wounds ; (2) through deep contusions on the chest wall, especially 

 if rib fractures be present (kicks, blows, falls) ; (3) from disease foci 

 in the lung, which are in contact with the pleura; (4) via blood 

 and lymph micro-organisms of certain specific diseases ; notably 

 those which affect principally the respiratory tract. The latter may 

 also invade the pleura and cause inflammation thereof (influenza, 

 fibrinous pneumonia, swine plague, hemorrhagic septicemia, acute 

 rheumatism). It may happen that the dominant lesions are in the 

 pleura, in which case primary pleuritis is spoken of (pleurisy of 

 the horse without pneumonia). 



As predisposing factors may be mentioned: Chilling (cold), 

 over-exertion, long railway transports, and acute diseases of the 

 respiratory tract (laryngitis). Subacute and chronic pleuritis may 

 accompany tuberculosis, glanders, contagious pleuropneumonia of 

 the ox, tumors (spread of sarcoma or carcinoma via contiguity of 

 tissue), or metastasis, and animal parasites. 



SYMPTOMS 



Depending upon whether it is acute or chronic, primary or 

 secondary, the symptoms of pleuritis will vary greatly. In mild 

 circumscribed and in chronic pleuritis the symptoms are so vague 

 that the condition is rarely recognized clinically. In the acute form, 

 which is at times primary, they are as follows : 



