Point-of-care cerebrospinal fluid Gram stain for the management of acute meningitis in adults: a retrospective observational study

Tomohiro Taniguchi,Masashi Narita,Sanefumi Tsuha,Soichi Shiiki

doi:10.1186/s12941-020-00404-9

Abstract

BackgroundGram stain of cerebrospinal fluid (CSF) is widely used in the diagnosis of acute meningitis, however, it is often conducted in the laboratory, as only some hospitals have access to point-of-care Gram stain (PCGS). The purpose of this study was to demonstrate the clinical impact and utility of PCGS in diagnosing and treating both bacterial and aseptic meningitis in adults.MethodsThis was a hospital-based, retrospective observational study at a referral center in Okinawa, Japan. We reviewed the records of all patients aged 15 years or older who were admitted to the Division of Infectious Diseases between 1995 and 2015 and finally diagnosed with bacterial (n = 34) or aseptic meningitis (n = 97). For bacterial meningitis, we compared the treatments that were actually selected based on PCGS with simulated treatments that would have been based on the Japanese guidelines. For aseptic meningitis, we compared the rates of antibiotic use between real cases where PCGS was available and real cases where it was not.ResultsPCGS was the most precise predictor for differentiating between bacterial and aseptic meningitis (sensitivity 91.2%, specificity 98.9%), being superior in this regard to medical histories, vital signs and physical examinations, and laboratory data available in the emergency room (ER). In bacterial meningitis, PCGS reduced the frequency of meropenem use (1/34 = 3.0%) compared with simulated cases in which PCGS was not available (19/34 = 55.9%) (p< 0.001). In aseptic meningitis cases, the rate of antibiotic administration was lower when PCGS was used (38/97 = 39.2%) than when it was not (45/74 = 60.8%) (p = 0.006).ConclusionsPCGS of CSF distinguishes between bacterial and aseptic meningitis more accurately than other predictors available in the ER. Patients with bacterial meningitis are more likely to receive narrower-spectrum antimicrobials when PCGS is used than when it is not. PCGS of CSF thus can potentially suppress the empiric use of antimicrobials for aseptic meningitis.

Highlights

Gram stain of cerebrospinal fluid (CSF) is widely used in the diagnosis of acute meningitis, it is often conducted in the laboratory, as only some hospitals have access to point-of-care Gram stain (PCGS)
We evaluated whether PCGS can discriminate between bacterial and aseptic meningitis, whether the selection of targeted therapies based on PCGS results as opposed to reliance on the Japanese guidelines alone can suppress broad-spectrum antimicrobial use for bacterial meningitis, and whether PCGS as opposed to no Gram stain findings can limit the use of empiric antibiotics for aseptic meningitis
Adolescent and adult patients who are diagnosed with bacterial or aseptic meningitis are admitted to the Division of Infectious Diseases, while patients with meningitis related to surgical interventions such as ventricular peritoneal shunt infection are admitted to the Division of Neurosurgery and patients with encephalitis are admitted to the Division of Neurology

Summary

Introduction

Gram stain of cerebrospinal fluid (CSF) is widely used in the diagnosis of acute meningitis, it is often conducted in the laboratory, as only some hospitals have access to point-of-care Gram stain (PCGS). Rapid diagnosis of bacterial meningitis and early antimicrobial treatment are essential for a favorable outcome [1,2,3], and empiric broad-spectrum antibiotics should be given as soon as possible to patients with suspected bacterial meningitis. There is no single laboratory test that adequately discriminates between bacterial and aseptic meningitis [7, 8]. Due to this diagnostic uncertainty, most patients with aseptic meningitis are unnecessarily treated with broad-spectrum antibiotics [3]. At institutions where Gram staining is not available around the clock, empiric antibiotics are started in 60.8% (45/74) of aseptic meningitis cases in adults [11]

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