Background: In suspected acute bacterial meningitis (ABM), cerebral computerized tomography (CT) is recommended before lumbar puncture (LP) if mental impairment. Despite guideline emphasis on early treatment, performing CT prior to LP implies a risk of delayed treatment and unfavorable outcome. Therefore, Swedish guidelines were revised in 2009, deleting impaired mental status as a contraindication for LP without prior CT scan. The aim of the present study was to evaluate the guideline revision.
Methods: The Swedish quality registry for community-acquired ABM was analyzed retrospectively. Door-to-antibiotic time and outcome were compared among patients treated 2005-2009 (n=394) and 2010-2012 (n=318). The effect of different LP-CT sequences was analyzed during 2008-2012.
Results: Adequate treatment was started 1.2 hours earlier, and significantly more patients were treated <2 hours from admission 2010-2012 than 2005-2009. Compared with CT before LP, immediate LP resulted in 1.6 hours earlier treatment, significant increase in door-to-antibiotic times of <1 and <2 hours, and a favorable outcome. In 2010-2012, mortality was lower (6.9% vs 11.7%) and the risk of sequelae at follow-up decreased (38% vs 49%) in comparison with 2005-2009. Treatment delay resulted in a significantly increased risk for fatal outcome, with a relative increase in mortality of 12.6% per hour of delay.
Conclusions: The deletion of impaired mental status as contraindication for prompt LP and LP without prior CT scan are associated with significantly earlier treatment and a favorable outcome. A revision of current international guidelines should be considered.
Keywords: bacterial meningitis; guidelines; lumbar puncture; outcome; time to treatment.
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