[Protective effect of dexamethasone and phenytoin in the treatment of experimental pneumococcal meningitis].

BACKGROUND

Pneumococcal meningitis has a high morbidity and mortality rate despite effective antibiotherapy, probably due to an exaggerated inflammatory response of the CNS. The use of dexamethasone and phenytoin reduced mortality in adults with pneumococcal meningitis.

OBJECTIVE

We sought to determine the effect of dexamethasone, phenytoin or the association of both in several inflammatory parameters in experimental bacterial meningitis.

METHODS

The study was performed using a modification of the rabbit model of Dacey and Sande. New Zealand white rabbits were intracisteranly inoculated simultaneously with heat-killed S. pneumoniae R6 dexamethasone, phenytoin or both. CSF leucocytes and concentration of proteins and lactate were determined over 6 hours, as well as the presence of brain edema.

RESULTS

Treatment with dexamethasone alone or in association with phenytoin reduced all inflammatory parameters. The administration of phenytoin alone did not prevent an increase of CSF leucocytes or protein concentration, but did prevent the development of brain edema. A trend to wards a protective effect on the lactate concentration was observed.

CONCLUSIONS

Our results gives support to the antiinflammatory effect of dexamethasone in experimental pneumococcal meningitis, and suggest that phenytoin may have also a protective effect on brain ischemia. This protective action and the prevention of brain edema could contribute, beyond its anticonvulsivant properties, to the great reduction in the mortality rate observed in some clinical studies in patients with pneumococcal meningitis.