Meningitis cerebrospinal fluid values

Powderly WG, Cloud GA, Dismukes WE, Saag MS. Measurement of cryptococcal antigen in serum and cerebrospinal fluid Value in the management of AIDS-associated cryptococcal meningitis. Clin Infect Dis 1994 18 789-792. 

L2. Leib, S. L., Boscacci, R., Gratzl, O., and Zimmerli, W., Predictive value of cerebrospinal fluid (CSF) lactate level versus CSF/blood glucose ratio for the diagnosis of bacterial meningitis following neurosurgery. Clini. Infect. Dis. 29, 69-74 (1999). 

Cerebrospinal Fluid PeniciUin does not readily enter the CSF but penetrates more easily with meningeal inflammation. The concentration attained usuaUy reaches 5% of the value in plasma and thus is therapeutically effective against susceptible microorganisms. Penicilhn and other organic acids are secreted rapidly from the CSF into the bloodstream by an active transport process. In uremia, other organic acids compete with penicillin for secretion the drug occasionally reaches toxic CNS concentrations that can produce convulsions. 

Pneumococcal isolates with a minimal inhibitory concentration for penicillin G of greater than 2 pg/mL are highly resistant. Such strains are not killed by the concentrations of penicillin G or ampicillin that can be achieved in the cerebrospinal fluid. Nafcillin would be of value in a purulent meningitis suspected to be due to staphylococci but has minimal activity against penicillin-resistant pneumococci. Cefotaxime and ceftriaxone (not listed) are the most active cephalosporins against penicillin-resistant pneumococci, and the addition of vancomycin or rifampin is recommended in the case of highly resistant strains. As mentioned above, cefopera-zone does not readily cross the blood-brain barrier. The answer is (C). 

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