Although adult bacterial meningitis (ABM) is rare, the outcomes can be devastating. An area of controversy concerns when to perform lumbar puncture (LP). Because of the possibility of brain herniation, it has been recommended that cerebral computed tomography (CT) be done before LP under certain clinical conditions. However, studies have suggested that performing CT before LP delays initiation of antimicrobial therapy.
In 2009, the Swedish guidelines were changed from those published in 2004 by the Infectious Diseases Society of America to exclude moderate to severe impairment of mental status and new-onset seizures as contraindications to initial LP in patients with suspected ABM. But how has this change affected time to adequate antibiotic treatment and outcomes?
To find out, researchers performed a retrospective analysis of the data from a registry of Swedish ABM patients, comparing individuals treated between 2005 and 2009 with those treated between 2010 and 2012 (n=394 and 318, respectively). Adequate antibiotic treatment was initiated an average of 1.18 hours earlier in 2010–2012 than in 2005–2009 (P<0.01). Both mortality (6.9% vs. 11.7%) and neurological sequelae (38.1% vs. 48.6%) were significantly less common among patients treated in 2010–2012 than among those treated in 2005–2009 (P<0.05). Performing CT before LP was associated with an average antibiotic-treatment delay of 1.6 hours (P<0.01).
These data suggest that a delay in only 1.5 hours before antibiotics are administered can significantly increase the rate of both mortality and neurologic sequelae.