Unselected brain imaging in suspected meningitis delays lumbar puncture, can prolong hospitalisation and may increase antibiotic costs - a pilot study

Abstract

Background: Antibiotics reduce mortality in bacterial meningitis; a lumbar puncture (LP) will demonstrate that many patients with suspected meningitis do not need them; but delays reduce chances of culture, particularly if N8 h. Guidelines advise a LP without brain imaging unless specific features are present. Objective: We assessed the duration of hospitalisation and inpatient costs incurred with delays in LP in a Northwest of England teaching hospital. Methods: We screened the cerebrospinal fluid (CSF) database to identify patients with suspected meningitis over 3 months (07–09/ 2010). Data were recorded from clinical case notes; costs were calculated with established datasets and the British national formulary. Results: 142 patients were screened; 35 had a suspected CNS infection; 10 had a CNS infection proven: 3 bacterial meningitis; 4 aseptic meningitis and 3 viral encephalitis. Brain imaging delayed the LP for 19 (54%), (11.08 vs 5.29 hrs, p= 0.10); ten (53%) did not need imaging. 11 (42%) of those given antibiotics before the LP were delayed N8 h. For patients with aseptic meningitis and those who had a CNS infection excluded, without prior antibiotics, the delay in LP increased duration of hospitalisation (r=0.94, p=0.02 and r=0.96, p=0.01 respectively). Overall there was no trend with LP delays and antibiotic cost. However, 4 patients had antibiotics continued despite negative cultures; 2 of whom had the LP delayed N8 h, with an antibiotic cost of £215.96. Conclusion: Inappropriate brain imaging often delayed the LP; in patients who did not need antibiotics this led to longer hospitalisation.