366 



LUNGS AND PLEURM. 



two walls of pleura, etc.) ; the layer of air imprisoned within the pleural 

 cavity is progressively absorbed, provided that it has not been acci- 

 dentally infected ; the collapsed and partially splenised lung progres- 

 sively 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. 



In eases of valvular pneumo-thorax with extreme oppression, attacks 

 of suffocation ^^threatening death as a consequence of excessive intra- 

 pleural pressure, disjjlacement of 

 the mediastinum towards the oppo- 

 site side, compression of the heart, 

 and functional disturbance of the 

 sound lung, it may be worth con- 

 sidering whether the attacks of 

 suffocation and threatened asphyxia 

 can be modified or removed by pre- 

 venting 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. 



Fig. 172. — Hydro-pneumo-thorax. I, Point 

 of adhesion of the pleura ; P, healthy 

 lung ; Ps, splenised lung ; E, liquid 

 or purulent exudate; C((, air cavity 

 constituting pneumo-thorax ; C, heart. 



HYDRO-PNEUMO'THORAX AND 

 PYO-PNEUMO-THORAX. 



When pneumo-thorax is set up, 

 it rarely remains simple. In th^ 

 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, 



