Defining bacterial meningitis and other infections of the central nervous system.

OBJECTIVE: To define central nervous system infections of infants and children that occur as co-morbid or predisposing conditions of sepsis.
DESIGN: Standard pediatric infectious disease references and the pertinent literature in English were reviewed from 1960 to 2002 to ascertain the previous methods and definitions utilized in clinical studies of the epidemiology and treatment of bacterial infections of the central nervous system. An accepted definition of bacterial meningitis defined by the Infectious Disease Society of America was reviewed and adapted to the previous clinical definitions. The information was formulated into a proposed standard for definite, probable, and possible bacterial infections of the central nervous system.
RESULTS: The diagnosis of definite bacterial infection of the central nervous system, including bacterial meningitis, requires the isolation of the pathogen from the cerebrospinal fluid or other significant clinical site such as surgical tissue, an implanted device, or blood. Probable bacterial infection is defined by the association of a compatible clinical syndrome or cerebrospinal fluid changes associated with bacterial meningitis or other central nervous system infection, and confirmed as an anatomically defined infection by imaging or surgery, in association with positive blood cultures or bacterial antigen from cerebrospinal fluid. Possible bacterial meningitis may be defined as a compatible clinical syndrome with predefined cerebrospinal fluid changes in the absence of a confirmatory culture or antigen test from any site.
CONCLUSIONS: Bacterial meningitis and other central nervous system bacterial infections can be defined as definite, probable, and possible with a combination of a defining compatible clinical syndrome and an anatomic definition by surgery or imaging, coupled with isolation of the organism, bacterial antigen, or other defining molecular component of the organism.