Auscultation shows the respiratory murmur to have disappeared throughout the zone of dulness, and reveals the presence of a soft pleuritic souffle (a soft tubal souffle quite different from that of contagious pleuro-pneumonia) when pleural exudation is abundant. In septic or suppurative pleurisy fever is higher, loss of appetite more marked, wasting more rapid, and depression extreme, with, however, identical local symptoms.
Diagnosis. The diagnosis of pleural exudation presents little difficulty, because of the peculiar characters of the dulness and the pathognomonic indications obtained by auscultation. The exudation is usually unilateral, the mediastinum being very resistant and not perforated in the ox.
By passing the needle of a Pravaz’s syringe with antiseptic precautions through the intercostal space a little fluid may be drawn off and the diagnosis formed, the form and nature of the pleurisy being simultaneously established. The liquid extracted can be examined bacteriologically, and can be grown on nutritive media, or inoculated into experimental animals.
The prognosis is grave, because in the ox pleurisy is very often of a secondary character. The outlook varies, however, with the form of the pleurisy and the nature and virulence of the infecting organism.
Treatment. Treatment consists firstly in applying an energetic vesicant like antimonial ointment or liquid cantharides blister; internally diuretics such as soda bicarbonate, nitrate of potash, resin, and decoctions of pellitory, dogs’ grass, etc., may be given. If thought desirable the chest may be tapped and the pleural cavity washed out with an antiseptic solution.
CHRONIC PLEURISY.
Chronic pleurisy is frequent in aged animals, but usually assumes the form of local adhesive pleurisy. The adhesions between the lung and pleura are more or less extensive; they result from verminous broncho-pneumonia, echinococcosis, external injuries, etc. Clinically this form is of no importance, and is almost impossible to diagnose. During the development of pleural tuberculosis, on the contrary, adhesive dry pleurisy is frequent, and sometimes becomes so well marked that almost the whole of the opposing pleural surfaces may become united.
PNEUMO-THORAX.
The name pneumo-thorax is given to the condition produced by the entrance of air or gas into one of the pleural cavities.
The accident is usually produced by rupture of the parenchyma of the lung and of the pleura, a rupture which produces a communication between the alveoli or a bronchus and the corresponding pleural cavity. As soon as the rupture occurs air passes from the lung into the pleural cavity, and the lung collapses in consequence of the resilience of its elastic constituents.