PLEURITIS 65 



falls) ; (c) from disease foci in the lung, which are in contact 

 with the pleura; (d) via blood and lymph microorganisms 

 of certain specific diseases, notably those ' which affect 

 principally the respiratory tract, 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 refrigeration . 

 (cold), overexertion, 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 metas- 

 tasis, and animal parasites (echinococcus of ox, Cysticercus 

 tenuicollis of sheep, sclerostomes in colts). 



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 

 syTuptoms are so vague that the condition is rarely recog- 

 nized clinically. In the acute form, which is at times 

 , primary, they are as follows: 



(a) First stage (congestion): The onset is sudden. The 

 patient stops eating, seems stupid, and may show pains 

 simulating mild colic. There is often a marked chiU during 

 which the temperature rises rapidly to 104° to 106° F. 

 The muscles of the thorax (intercostals) tremble. The 

 pulse is frequent (70 to 80), small and hard ("serous mem- 

 brane pulse"). The respirations are accelerated (25 to 40) 

 and of the abdominal type. If the pain is great, and the 

 diaphragm not involved, the ribs may be rolled forward 

 and held, breathing being performed by the flanks. The 

 patient may not show cough or nasal discharge. 



Percussing the thorax in this stage pains the patient 

 and causes coughing. Sometimes on palpating the inter- 

 costal spaces sensitiveness is shown, especially in the region 

 of the elbow. If the examiner's hand be laid against the 

 thorax a marked fremitus may be felt. Unless the lung is 

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