Tuberculous meningitis

Abstract

The bacteriological examination of 172 cerebrospinal fluids has tubercule bacilli: 102 were positive by the direct microscopic examination and 70 by culture only. Thus, the use of culture media has proved itself superior to direct microscopic examination; in 40% of the cases that gave positive results by culture methods, no tubercle bacilli were revealed by the direct examination. Out of 124 specimens inoculated, 108 positive cultures were obtained on rabbit blood agar, 93 on chocolate agar medium and 81 on Loewenstein's medium. The cultural findings with various media in comparative study to determine their relative value for the primary cultivation of tubercle bacilli from cerebrospinal fluid were as follows: rabbit blood agar, 91,1%; chocolate agar, 85,3%; Loewenstein's medium, 65.3%; Petragnani's medium, 25.0%. Loewenstein's medium without glycerol and malachite green gave better results (88.2%) than with glycerol (65,3 % ). Petragnani's medium with glycerol gave 25.0%; without, 63.3%. Loewenstein's medium has proved suitable for the isolation of human strains af tubercle bacilli, but entirely unsuitable for the bovine type, as the latter failed to grow on it in primary cultures. Rabbit blood agar has given the best results for the isolation of both of them, from cerebrospinal fluid. For this reason and because of its simplicity of preparation, it is recommended for primary cultivation of tubercle bacilli from cerebrospinal fluido In the present investigation the author's researches have been undertaken to determine the relative value of various media for primary cultivation of tubercle bacilli from cerebrospinal fluid and the type of bacilli causing tuberculous meningitis in S. Paulo.Out of 124 cases from which those bacilli were isolated from cerebrospinal fluid, 16 strains were of the bovine type; these results were confirmed by cultural tests and by inoculation into the vein of a rabbit's ear. For the differenical diagnosis between eugonic and dyagonic straíns, cultures of the first generatíon on glycerol free media, were inoculated on Loewenstein's first with 5% glycerol, then without it and finally ou glycerol-potato. The last one gave the best results. This fact had already been noticed by Park and Krumwied in 1910 and by Griffith in 1934; they obtained on glycerolpotato, the most uniform results for the above mentioned diagnosis. Dysgonic, atypical strains of human tubercle bacilli were inoculated into the vein of a rabbit's ear. Only small lesions were found in the lungs and the liver. The percentage (13.2 %) for the bovine type obtained by the author is much lower than that found in other countries. The percentage found for that type in cases of meningitis in children under 10 was 14.8%. Tuberculous meningitis is more frequent in S. Paulo (Brazil) than it seems to be. It has not been exactly diagnosed clinically as we can see by the cases admitted to the Isolation Hospital "Emilio Ribas": Meningitis, 27%; Cerebrospinal Meningitis, 45%; Typhoid fever, 28%. In all these cases the diagnosis has been changed in the Hospital for Tuberculous meningitis, which the bacteriological examination confirmed, since tubercle bacilli were shown in spinal fluids by the direct microscopic examination or by culture methods. Investigations were made in 166 of these cases: 90% were from Brazilians (50.6% males and 49.4% females). ln children the highest percentage was that of girls. The percentage of children under 5 was 37.7%, of 5 to 10 years, 20.4% and of over 10, 40.9%. The percentage of children under 10 was, therefore, 58.4 %. According to the author, the above mentioned cases may be due to bovine infection, in view of the great prevalence of tuberculosis in cattle in S. Paulo, Brazil,. (about 40% of the cattle being affected, according to veterinary estimation) and because the author and A. Melo and N. Mastrofrancisco verified the presence of tubercle baeilli in raw milk