Duration of symptoms and outcome in bacterial meningitis: an analysis of causation and the implications of a delay in diagnosis.

The prompt diagnosis and therapy of bacterial meningitis remain enduring clinical challenges, for no physician would knowingly delay appropriate therapy. However, whether a delay in the initiation of antimicrobials in fact causes a worse outcome is a separate and tangential question. In clinical medicine a treatment decision involves a bedside estimate of the risk and potential severity of illness balanced against the benefits and adverse effects of therapy. For severe infections, the inexorable damage of untreated disease is presumed, and antimicrobials properly are given without hesitation. In contrast the methodical weighing of evidence regarding the issue of causation is for the purpose of characterizing biologic phenomena. Although legal and medical implications may be contained in such an analysis, its relevance to any particular clinical case is only retrospective. To judge responsibly the strength of a causative link, all available scientific evidence must be analyzed by established criteria. Such as analysis suggests that any connection between a delay in the treatment of bacterial meningitis and outcome depends on the presenting clinical pattern. If the presentation is that of a nonspecific illness with general symptoms, then a short delay of < 3 to 5 days does not appear to alter the risk of sequelae or death. In the case of fulminant meningitis a delay in initiating therapy seems unconnected to outcome. Finally for patients with a history of clinically overt meningitis, an inappropriate delay in commencing therapy incrementally increases the risk of permanent injury.