CHAPTER XXVI 



MIOROCOCCUS INTRACELLULARIS MENINGITIDIS (MENINGOCOCCUS) 

 AND EPIDEMIC CEEEBBOSPINAL MENINGITIS 



INFECTIOUS processes in the meninges may be caused by many 

 different microorganisms. 



Meningitis may be primary or secondary. Secondary meningitis 

 may often occur during the course of pneumonia, when pneumococci, 

 carried to the meninges by the blood stream, give rise to a usually 

 fatal form of the disease. More rarely a similar process may occur 

 as a secondary manifestation of typhoid fever or influenza. Menin- 

 gitis may also result secondarily by direct extension from sup- 

 purative lesions about the skull, such as those occurring in diseases 

 of the middle ear or frontal sinuses or after compound fractures. In 

 such cases the invading organisms are usually staphylococci, strepto- 

 cocci, or pneumococci. 



Isolated cases of meningeal infection with B. coli, B. para- 

 typhosus, Bacillus pestis, and Bacillus mallei have been reported- 

 A frequent more chronic form of the disease is caused by Bacillus 

 tuberculosis. 



Primary acute meningeal infection, however, is due chiefly to 

 two microorganisms, Micrococcus intracellularis meningitidis, and 

 the pneumococcus. 



A tabulation of the comparative frequency with which the vari- 

 ous microorganisms are found in the meninges has been attempted 

 by Marschal. 1 This author estimates that about 69.2 per cent of all 

 acute cases are due to the meningococcus, 20,8 per cent to Diplo- 

 coccus pneumonias, and the remaining 10 per cent to the other bac- 

 teria mentioned. 



The cases caused by the pneumococcus and the other less frequent 

 incitants usually occur sporadically. When the disease occurs in 

 epidemic form, it is almost always due to the meningococcus. 



1 Marschal, Diss. Strassburg, 1901, Quoted from Weichselbaum, in Kollc und 

 Wassermann, ' ' Handbuch. ' ' 



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