THE RESPIRATORY SYSTEM. 



515 



SECONDARY LESIONS IN PULMONARY TUBERCULOSIS. 



A variety of secondary processes may be associated with the various 

 phases of pulmonary tuberculosis which we have briefly reviewed. The 

 blood-vessels in affected regions may be intact, or, as we have seen, their 

 walls may be involved in the productive and necrotic processes, with 

 thrombosis or obliteration of 

 the lumen ; or more or less ex- 

 tensive haemorrhages may oc- 

 cur. If the consolidation be 

 not complete, lung tissue, often 

 in a condition of atelectasis or 

 emphysema and with more or 

 less cellular or granular exu- 

 date, may remain between the 

 tuberculous areas. Miliary 

 tubercles may be scattered 

 among the larger consolidated 

 masses or in parts of the lung 

 otherwise free. 



In chronic forms of pul- 

 monary tuberculosis the an- 

 thracotic pigment is often con- 

 spicuous, particularly in the 

 cheesy and fibrous areas, stand- 

 ing out in masses and streaks 

 in contrast to the new or dead 

 tissue. Furthermore, there 

 may be associated with the 

 lung lesions acute exudative or 

 chronic fibrous pleuritis with 

 adhesions ; o r tuberculous 

 pleuritis of varying extent; 

 empyema and pneumothorax. 

 There is nearly always more or 

 less chronic catarrhal bronchitis 

 or broncho-pneumonia and fre- 

 quently bronchiectasia. 



Tuberculous inflammation 

 in the bronchial lymph -nodes 

 frequently accompanies and often precedes the development of pulmo- 

 nary tuberculosis. In children the tuberculous lymph-nodes often extend 

 far into the lung and may on softening give rise to cavities at a consider - 

 able distance from the hilus of the lung. 



Tuberculosis in other parts of the body is common in connection with 

 pulmonary tuberculosis. 



FIG. 296. CHRONIC PULMONARY TUBERCULOSIS 

 (CHRONIC PHTHISIS), WITH CAVITIES. 



There is much dense flbrous tissue in the upper lobe 

 surrounding and between the cavities as well as in the 

 upper portion of the lower lobe. 



