THE PNEUMOCOCCUS, PNEUMONIA, ETC, 55 



THE PNEUMOCOCCUS, PNEUMONIA, ETC. 



The pneumococcus is a very important organism, and one 

 which plays a prominent part in the production of disease. It 

 may occuf in the mouth in a healthy person; hence its recog- 

 nition in small quantities in the sputum is not of diagnostic 

 value. 



The pneumococcus is a very common cause of disease of the 

 respiratory system. It causes : 



1. Acute lobar pneumonia, of which it is the only common 

 cause. 



2. Lobular (broncho-) pneumonia. This disease may also 

 be caused by streptococci, staphylococci, diphtheria bacilli, 

 influenza bacilli, plague bacilli, tubercle bacilli, and others. 

 The pneumococcus may also occur as a secondary infection 

 in lobular pneumonia due to any of these. 



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 (strepto- 

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

 cases usually recover without resection of ribs. The bac- 

 teriological 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, bronchiectasis, etc. 



5. It is one of the common causes of bronchitis and nasal 

 catarrh. 



The most important primary lesions due to the pneit- 

 mococcus 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 acces- 

 sory sinuses of the nose. 



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

 the Streptococcus pyo genes. 



3. Brawny induration of the skin, with or without suppura- 

 tion. 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. 



5. Puerperal fever. These cases are important to recog- 

 nize, as they usually do well on vaccine treatment. 



