INFLAMMATION OF THE LUNGS 55 



Diagnosis. — ^Acute catarrhal pneumonia may be confused 

 with it. The principal differential featiu-es are: (See table). 

 From pleuritis it may be distinguished by auscultation 

 and percussion. In cases complicated with pleuritis (pleuro- 

 pneumonia) differentiation may be impossible. However, 

 pleiu-itis is usually bilateral, the upper margin of the zone 

 of dulness on percussion is horizontal and the resistance 

 under the hammer pronounced. In pleuritis there is further 

 a tendency for edema to form in pendent parts of the body. 

 Cough is usually absent in pleuritis; present in pneumonia. 

 A test puncture of the thorax may be made in doubtful cases. 



Complications. — (a) Heart weakness due to cloudy swel- 

 ling. The beat is fast, arhythmic, and palpitating. The 

 pulse may be weak (thready) and rims about 76. The 

 patient is weak, may be cyanotic, superficial veins distended. 



(6) Pleiu-itis: A common complication, leading to effu- 

 sion in the chest, displacement of the heart and characteristic 

 dyspnea. (See Pleuritis.) 



(c) Gangrene of the lung: May develop during convales- 

 cence. The temperature again rises, the patient continues 

 to lose flesh and the expirium assumes a sweetish, fetid odor. 



(d) Further but less common complications are: Nephritis 

 (albumin in urine), jaundice (catarrh of duodenum), tendo- 

 vaginitis (leg swelling and lameness), founder (laminitis), 

 cerebral and meningeal symptoms. Purpura hemorrhagica 

 may occiu- during convalescence. 



Coxirse. — ^The usual com-se is typical, ending in recovery 

 in two weeks. In some cases, especially in old horses, cattle 

 and swine the course may be much shorter (larval or abortive 

 type). Death may occur suddenly during convalescence 

 from heart failure. If pleuritis complicates the pneumonia, 

 the course is much prolonged. It may lead to death, or 

 adhesions (lung to thoracic wall) may cause permanent 

 dyspnea ("heaves"). 



Chronic induration of the lungs is a common termination 

 following certain outbreaks. It is characterized by the con- 

 tinuation of the fever and dyspnea after the usual period 

 of convalescence has passed. The patient is generally left 

 short-winded. Roaring may sometimes follow an attack of 

 fibrinous pneumonia. Pericarditis is a rarer complication. 



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