Brain abscess and cerebritis

Eighteen consecutive cases of brain abscess or cerebritis seen at the Veterans Administration Wadsworth Medical Center (Los Angeles, Calif.) during 1970-1982 were analyzed. Fifteen occurred after the computerized axial tomographic (CT) scanner for diagnosis and follow-up became available in 1976. The patient population included 14 individuals with significant underlying medical problems and with a clearly identifiable contiguous or distant source. Four patients had multiple brain abscesses; the most common site of involvement in the remaining 14 patients was the parietal lobe. Microorganisms were isolated from 14 patients and included a variety of aerobic and anaerobic bacteria. Of the 27 isolates, 12 were microaerophilic species or strictly anaerobic bacteria. Therapy was most often a combination of surgical drainage and antimicrobial agents. Usually the drug regimen included penicillin and chloramphenicol and, more recently, the combination of penicillin and metronidazole. One of the two patients with brain abscess treated with antimicrobial agents alone died. Two patients with presumed bacterial cerebritis improved with chemotherapy alone. This study reaffirms the important role of anaerobes in brain abscess. The advent of the CT scanner appears to have been a valuable development in both diagnosis and monitoring of therapy, but mortality (22%) still remains relatively high. Although metronidazole will likely prove to represent a significant advance in antimicrobial therapy, surgical drainage still appears to be the mainstay of therapy for treatment of established abscesses.