48 DISEASES OF THE LUNGS 



sucklings), or secondary to primary abscess (abscess within 

 hoof, abscess following castration). It is rarely due to 

 fibrinous pneumonia, but may follow catarrhal pneumonia 

 due to foreign matter entering the bronchi, especially 

 medicines. 



Symptoms. — Pulmonary abscess usually follows an attack 

 of pneumonia with delayed resolution. The temperature 

 again rises, the pulse becomes rapid and weak, and the patient 

 shows a purulent nasal discharge. On percussion a flat area 

 may be determined; on auscultation rales and tubular 

 breathing. If complicated with gangrene the expirium is 

 often fetid. The course of the fever is very atypical showing 

 marked variations from day to day. At times the tempera- 

 ture may drop to almost normal, to rise again next day. 



Course. — Usually death in seven to ten days. Isolated 

 abscesses may become encapsulated or break into a bronchus 

 and be discharged. Diagnosis in these instances is difficult. 

 Death may result from pyemia or more commonly from 

 serofibrinous or purulent pleuritis. 



Diagnosis. — ^A copious nasal discharge \vhich is largely 

 made up of pus is the chief clinical feature which distinguishes 

 it from pulmonary gangrene. 



Treatment. — Usually of little avail. In man well defined, 

 superficial abscesses are surgically treated by opening and 

 draining. The use of antiseptics as inhalations (bichlorid, 

 1 per mille, as a spray) or intratracheal injections are sug- 

 gested. 



CHRONIC ALVEOLAR EMPHYSEMA. 



Definition. — Chronic alveolar emphysema is a permanent 

 overdistention of the alveoli with an increased amount of 

 air present in the lung. The walls of the alveoli become 

 anemic and atrophic. 



Occurrence. — ^Most common in horses, especially old, 

 hard-worked individuals. It is a common cause of so-called 

 "heaves" or "broken wind." 



Etiology. — (a) Continued severe exercise (hard pulling, 

 fast driving, high jumping). This causes repeated physio- 

 logical dyspnea inducing overdistention at inspiration and 



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