Diagnosis. The diagnosis is relatively easy when the lesion is secondary; but the difficulty (as in simple pneumo-thorax) is to identify the exact character of the primary affection.
On the other hand, pyo-pneumo-thorax and hydro-pneumo-thorax are not always complete; adhesions of very varying character may exist between the lung and the chest wall; hence it is impossible to group together all the possible symptoms.
Diagnosis is facilitated by aseptically puncturing the chest with a Pravaz’s syringe.
Prognosis. The prognosis is extremely grave even in cases of hydro-pneumo-thorax. Treatment is useless, for even allowing that the primary disease might be cured, this process of cure, after reabsorption of the transudate, would be extremely tedious, and the animals would long remain in poor condition.
Treatment. In hydro-pneumo-thorax no treatment is advisable. Nothing is gained by thoracentesis, at least at an early stage, or before the lesion causing the pneumo-thorax has closed.
In pyo-pneumo-thorax, on the contrary, the theoretical course is to evacuate the pus and completely wash out the pleural sac with lukewarm non-irritant solutions of antiseptics.
CHAPTER V.
DISEASES OF STRUCTURES ENCLOSED WITHIN THE MEDIASTINUM.
The mediastinum is a space enclosed in the median plane of the thorax by the approach of the two opposite layers of pleura. Needless to say, at those points where the layers are in apposition, the space is theoretical only. It extends from the suprasternal region to the dorsal subvertebral region, and encloses all the vessels which pass from or to the base of the heart, the trachea, the œsophagus, the pneumo-gastric, diaphragmatic and cardiac nerves, etc., as well as the pericardial sac and the heart. The organs most frequently affected are the lymphatic glands lodged in the thickness of the mediastinum, the glands placed at the entrance to the chest, the bronchial glands, and the glands situated in the posterior mediastinum.
Inflammation of the mediastinum may coincide with inflammation of the mediastinal layers of the pleura; but this can only be detected on post-mortem examination. The lesions which can be recognised during life are simple inflammation of glands, resulting from pulmonary or pleural diseases, tuberculous inflammation of glands, and the presence of cancerous tumours of the mediastinum and hypertrophy of glands due to lymphadenitis.
Simple inflammation of the lymphatic glands is secondary and consecutive to broncho-pneumonia, verminous bronchitis, infectious bronchitis, etc.