[Bacterial meningitis - diagnosis and treatment]

OBJECTIVE: To present new concepts on diagnosis and treatment of bacterial meningitis regarding etiologic agents, pathophysiology and options about antimicrobial, antiinflammatory and supportive therapy. METHODS: Bibliographic review from MEDLINE data including articles published during the last ten years. One classic article published before this period and chapters of textbooks on infectious diseases were also included. RESULTS: Initial empirical antibiotic therapy is chosen according to probable etiologic agents for the age group. In the CSF microbiological analysis, the gram stains can reveal bacteria in 50% to 80% of the cases and the culture in nearly 85%. The tests for detection of bacterial antigens are useful for the diagnosis but they present low sensitivity. The most common agents during the neonatal period continue to be E. coli, Streptococcus B and L. monocytogenes. Beyond this period, the incidence of meningitis by Haemophilus influenzae b had a significant decrease after the introduction of conjugate vaccines. However, S. pneumoniae and N. meningitidis continue to be frequent agents. Currently, the thirdgeneration cephalosporins, ceftriaxone or cefotaxime, are the antibiotic therapy of choice. They are used with ampicillin up to two months of life and alone beyond this age. Dexamethasone has showed to be effective in reducing the inflammatory response and the sequelae, mainly the auditory sequelae. The fluid restriction doesn't offer advantages in the supportive care. CONCLUSIONS: Early diagnosis and prompt treatment are related to good outcome. The new insights on pathophysiology, the new antibiotics and the increasing bacterial resistance have determined changes in treatment.