50 CLINICAL BACTERIOLOGY AND HEMATOLOGY 



3. Pleurisy, either the serous, fibrinous, or purulent varieties, 

 and especially in children. It is important to notice that the 

 prognosis of empyema is better when the disease is due solely 

 to the pneumococcus than when other organisms (streptococci, 

 staphylococci, tubercle bacilli, etc.) are present, and such cases 

 usually recover without resection of ribs. The bacteriological 

 examination of the pus from a pleural cavity may thus lead to 

 results important as to prognosis and treatment. 



4. The pneumococcus may occur as a secondary infection in 

 almost any disease of the lung ; for instance, in the walls of a 

 phthisical vomica. 



The most important primary lesions due to the pneumococcus 

 outside the respiratory system are : 



1. Otitis media (of which it is a very common cause), empyema 

 of the antrum, and of the frontal and other accessory sinuses of 

 the nose. 



2. Erysipelas, which is usually due to another organism, the 

 Streptococcus pyogenes. 



3. Brawny induration of the skin, with or without suppuration. 

 This is uncommon, but I have seen several cases. 



4. Suppuration in any region, especially in infants, in whom it 

 is probably the most common pyogenic organism. 



Pneumococci may escape into the blood from any of these 

 lesions, and may appear in that fluid when there is no obvious 

 primary lesion from which it could have gained access. The 

 most common results are : 



1. Septicemia. 



2. Ulcerative endocarditis. Many other bacteria may cause this 

 disease. 



3. Meningitis. Pneumococcal meningitis may also be due to 

 direct spread from the middle ear. 



4. Arthritis. 



5. Peritonitis. 



The prognosis in these latter affections is on the whole slightly 

 better if they are due to the pneumococcus than if caused by 

 other organisms, except in the case of meningitis, which is usually 

 fatal in a few days. 



In actual practice we have most commonly to search for the 

 pneumococcus in sputum, pus, and blood. In the latter case 

 cultural methods are usually necessary, and we shall defer its 

 consideration for the present. 



