The diagnosis of pneumo-thorax, and even of its varieties, does not, however, enable one to form a prognosis; the important point is to ascertain the original cause.
Treatment. It may be said of pneumo-thorax that no treatment exists, and that the position is one of expectancy. In fact, we possess no means of directly dealing with such diseases as echinococcosis, tuberculosis, or emphysema. For this reason it is best as a rule to advise slaughter. Nevertheless, when the condition is due simply to pulmonary echinococcosis of a discrete character, there is some chance that after several months the animal may recover spontaneously. The communicating orifice becomes closed by reparative processes (cicatricial contraction, the formation of a false membrane, limited adhesion between the two walls of pleura, etc.); the layer of air imprisoned within the pleural cavity is progressively absorbed, provided that it has not been accidentally infected; the collapsed and partially splenised lung progressively regains its function under the inspiratory efforts, and after some months complete recovery may occur. This termination cannot always be confidently predicted, because complications may arise at any moment; under no circumstances can complete recovery be anticipated when the primary disease is tuberculous.
Fig. 172.—Hydro-pneumo-thorax. I, Point of adhesion of the pleura; P, healthy lung; Ps, splenised lung; E, liquid or purulent exudate; Ca, air cavity constituting pneumo-thorax; C, heart.
In cases of valvular pneumo-thorax with extreme oppression, attacks of suffocation threatening death as a consequence of excessive intra-pleural pressure, displacement of the mediastinum towards the opposite side, compression of the heart, and functional disturbance of the sound lung, it may be worth considering whether the attacks of suffocation and threatened asphyxia can be modified or removed by preventing the excess of intra-pleural pressure. By simply passing a stout hollow needle through one of the intercostal spaces, the intra-pleural pressure may be reduced to that of the external atmosphere, and the effects of compression removed. This, however, is a last resort, and has no permanent effect.
HYDRO-PNEUMO-THORAX AND PYO-PNEUMO-THORAX.
When pneumo-thorax is set up, it rarely remains simple. In the great majority of cases the pleura becomes infected, either directly, by the lesion which has determined the pneumo-thorax (tubercle, superficial abscess, actinomycotic lesion, etc.), or secondarily, by the penetration of germs from the air or from the bronchus (echinococcosis, emphysema). Simple pneumo-thorax then becomes converted into hydro-pneumo-thorax or pyo-pneumo-thorax, according to circumstances—that is to say, whether the exudation into the pleural cavity is of a simple character or is of the nature of pus.
Symptoms. Hydro-pneumo-thorax is characterised by the signs common to true pneumo-thorax, which constitutes the primary lesion, viz., sudden difficulty in breathing, exaggerated unilateral resonance, amphoric souffle accompanied by a sound like that of drops of water falling into a metallic vessel, and by the signs of secondary exudative pleurisy, viz., moderate fever, dulness over the lower zones of the chest, limited above by a horizontal line, slight splashing sound, and a soft distant pleuritic souffle.
All the secondary symptoms—loss of appetite, suppressed rumination, sighing, accelerated pulse, etc.—are found in a more or less accentuated form.
In pyo-pneumo-thorax fever is more marked, while the signs noted on auscultation and percussion are identical, and are accompanied by digestive disturbance and marked œdema of the wall of the chest, which can be seen or detected by palpation.