Should dexamethasone be part of routine therapy of bacterial meningitis in industrialised countries?

Abstract

Two issues are clear from the data available regarding the current place of dexamethasone in routine management of suspected bacterial meningitis in industrialised countries. First, there is now good evidence of benefit from adjunctive dexamethasone therapy which is not confined to Hib meningitis, but in the case of pneumococcal meningitis probably requires that dexamethasone is given with or before, rather than after, parenteral antibiotics. In meningococcal meningitis, statistically significant benefit has not been demonstrated for any outcome, even in meta-analyses, but the point estimate is in the direction of benefit and failure to demonstrate an effect is more likely to be due to limited power from low event rates rather than no benefit; certainly there is no evidence of a detrimental effect. Most culture-negative cases of presumptive bacterial meningitis outside the neonatal period are likely to be due to one of the above 3 organisms. In the neonatal period or in some settings in developing countries, the spectrum of organisms is very different and extrapolation of these findings cannot be assumed. Second, the suggestion that dexamethasone is not applicable to certain subgroups in industrialised countries (such as cases not treated with cefuroxime, or some other sub-optimal therapy, or cases treated with vancomycin) (5) or that benefit only applies to hearing loss or Hib cases, either do not stand up to scrutiny or are not answerable from available data. What does this mean for clinical practice? The results of randomised controlled trials may not readily translate to clinical practice, particularly with respect to early commencement of steroids. The Sydney data show that in a representative developed country population with good access to services, after controlling for other prognostic variables, early corticosteroid therapy is associated with improved outcome. These data also show that deferred lumbar puncture is frequent and so criteria requiring presumptive identification of an organism are not practical to guide dexamethasone use, indeed those patients in whom lumbar puncture is deferred are more likely to have severe disease. This experience is an important addition to the findings from clinical trials of dexamethasone in pneumococcal meningitis in industrialised countries (5,6) as it demonstrates that adjunctive steroid therapy is beneficial in a 'real world' situation. In addition, the prospect of clinical trials in children, already limited by small case numbers, will be further reduced when the use of the conjugate pneumococcal vaccines is widespread. In Canada, a trend to decreasing use of corticosteroids was noted between 1991 and 1999, probably reflecting conflicting evidence. (16). Unless clear protocols are in place, the commencement of steroids before or with antibiotics will be difficult to implement in emergency situations, as illustrated by the data from Sydney.