Treatment of bacterial meningitis: an overview of Cochrane systematic reviews.

BACKGROUND: Acute bacterial meningitis (ABM) is a rapidly developing acute inflammation of leptomeninges and underlying subarachnoid cerebrospinal fluid (CSF). ABM is caused by bacteria and has a case fatality rate of 20-30%. Most prevalent causes of ABM are Neisseria meningitis, Streptococcus pneumoniae and Haemophilus influenzae. The aim of this paper is to summarize the main findings from Cochrane systematic reviews that have considered the evidence for treatments of ABM.

METHODS: We searched the Cochrane Library (issue 1, 2007) for relevant reviews using 'meningitis' as a search term. The titles of all the search results were examined to select reviews on treatment of ABM. The full text of each of the selected reviews was studied to summarize the evidence available in Cochrane systematic reviews.

RESULTS: We found three Cochrane reviews that focused specifically on the treatment of ABM, addressing empiric antibiotic therapy, fluid therapy and effects of adjuvant corticosteroids respectively. No statistically significant difference was found between third generation cephalosporins and conventional antibiotics in the combined endpoint of death or deafness (risk difference (RD) -1%, 95% CI -4% to +2%). However, culture positivity of CSF at 10-48 h was significantly higher in the conventional antibiotic group and diarrhoea was significantly more common in the cephalosporin group. When third generation cephalosporins are not available, ampicillin-chloramphenicol combination may be used as an alternative empiric treatment, however both resistance pattern as well as availability should be considered while prescribing empiric therapy of community acquired ABM. The fluid therapy review found too few studies to provide any robust conclusion. In settings with high mortality rates and where patients present late, use of intravenous maintenance fluids seems preferable to a restricted fluid intake. The efficacy of adjuvant corticosteroids varied between high- and low-income countries suggesting greater mortality reduction in high-income countries (RR 0.74, 95% CI 0.52-1.05) than in low-income countries (RR 0.87, 95% CI 0.72-1.05) and a beneficial effect on severe hearing loss in high-income countries (RR 0.32, 95% CI 0.18-0.57), whereas, sparse data in low-income countries (RR 1.04, 95% CI 0.66-1.63). A four-day regimen of dexamethasone should be given preferably before or with the first dose of antibiotics for cases of ABM from high-income countries.

CONCLUSION: In presence of sensitive organisms, third generation cephalosporins and conventional antibiotics lead to similar outcomes. More studies are needed to determine the antimicrobial resistance pattern against various antibiotics in rural and remote areas of developing as well as developed countries. To assess the effectiveness of either restricting or maintenance fluids in populations where patients present early and on death and disability when mortality rates are low, large trials should be conducted. More trials are needed to assess the use of adjuvant dexamethasone for ABM in low-income countries.