LUMBAR PUNCTURE 



Interpretation of Results. 



157 



The discovery of Weichselbaum's diplococcus indicates that 

 the case is one of cerebro-spinal fever. The chief importance in 

 making the diagnosis (apart from the fact that it may throw light 

 upon the occurrence of several cases of meningitis within a short 

 space of time by proving the existence of an epidemic) arises from 

 the fact that the prognosis is decidedly better than in other forms 

 of meningitis. Roughly speaking, about 40 per cent, of cases 

 recover, though frequently with mental or other defects. It is in 

 these cases that repeated lumbar puncture is of therapeutic value ; 

 it should be done whenever pressure symptoms are urgent. In 

 these cases also great benefit can be obtained from vaccine treat- 

 ment or from the intraspinal injection of antimeningococcic 

 serum. The vaccine should be prepared from the patient's own 

 culture. The method is, of course, useless in very rapid cases, 

 but very good results are obtainable in the more chronic ones. 

 In some the immediate benefit resulting from each injection is 

 most marked. 



Meningitis due to the pneumococcus may arise from dissemina- 

 tion from pneumonia or other pneumonic lesion, by spreading 

 from the nasal cavity or middle ear, etc., or may be primary. 

 The examination of the exudate throws no light upon this point, 

 and the cause of the infection must be sought for on ordinary 

 clinical lines. 



Tuberculous meningitis is proved by the presence of tubercle 

 bacilli in the fluid, and is indicated by sterile cultures, absence of 

 bacteria from the stained films, and predominance of lymphocytes. 

 In these cases the fluid often undergoes a very slight coagulation, 

 delicate cobweb-like threads being observable after some hours. 

 This is in itself strong evidence of tubercle, and if the delicate 

 coagulum can be withdrawn, dried on a slide, and stained by 

 Ziehl-Neelsen's method, there is a fair chance of finding bacilU 

 entangled with it. This is not very easy to do, the best method 

 being to fish it out with a very fine piece of capillary tubing no 

 thicker than a pin. It is easy enough to pick it out with a 

 platinum needle, but almost impossible to get it off the latter on 

 to the slide. 



The other varieties of meningitis do not call for special mention. 



Th^ chief value of lumbar puncture to the surgeon is that it 

 enables him to diagnose a concomitant meningitis (indicating the 



