Evaluation of the selection of cerebrospinal fluid testing in suspected meningitis and encephalitis

Approach to acute encephalitis in the intensive care unit

PURPOSE OF REVIEW

Recent years have seen a dramatic increase in the identification of autoimmune encephalitis (AE) and the emergence of new causes of infectious encephalitis (IE). However, management of these patients remains challenging, with many requiring care in intensive care units. Here, we describe recent advances in the diagnosis and management of acute encephalitis.

RECENT FINDINGS

Advances in the identification of clinical presentations, neuroimaging biomarkers, and electroencephalogram patterns have enabled more rapid diagnosis of encephalitis. Newer modalities such as meningitis/encephalitis multiplex PCR panels, metagenomic next-generation sequencing, and phage display-based assays are being evaluated in an effort to improve detection of autoantibodies and pathogens. Specific advances in the treatment of AE include establishment of a systematic approach to first-line therapies and the development of newer second-line modalities. The role of immunomodulation and its applications in IE are actively being investigated. In the ICU, particular attention to status epilepticus, cerebral edema, and dysautonomia may improve outcomes.

SUMMARY

Substantial diagnostic delays still occur, with many cases left without an identified etiology. Antiviral therapies remain scarce, and optimal treatment regimens for AE still need to be clarified. Nevertheless, our understanding of diagnostic and therapeutic approaches to encephalitis is rapidly evolving.

An Electronic Health Record Intervention to Limit Viral Testing of Cerebrospinal Fluid

Meningitis and encephalitis are neurologic emergencies that require immediate management and current guidelines recommend empiric treatment with broad-spectrum antimicrobials. Cerebrospinal fluid (CSF) testing algorithms are heterogeneous and largely institution-specific, reflecting a lack of consensus on how to effectively identify CSF pathogens while conserving resources and avoiding false positives. Moreover, many lumbar punctures (LPs) performed in the inpatient setting are done for noninfectious workups, such as evaluation for leptomeningeal metastasis. As such, tailoring CSF testing to clinical context has been a focus of multiple prior reports and several healthcare systems have focused on efforts to limit low-yield diagnostic testing when a positive result is unlikely. To curb ordering viral PCRs when pre-test probability is low, some peer institutions have implemented pleocytosis criteria for virus-specific polymerase chain reaction (PCR) tests from CSF. In this report, we retrospectively analyzed the diagnostic testing of CSF from patients who had an LP while admitted to a single, large academic medical center and found that many cases of Herpes Simplex Virus (HSV) meningoencephalitis were diagnosed by non-neurologists. The rate of positive virus-specific PCR tests was very low, and tests were frequently ordered in duplicate with a multiplexed meningitis/encephalitis PCR panel (M/E panel, BioFire, Salt Lake City, UT). We designed and implemented a systems-level intervention to promote a revised stepwise testing algorithm that minimizes unnecessary tests. This intervention led to a significant reduction in the number of low-yield virus-specific PCR tests ordered without implementing a policy of cancelling virus-specific PCRs.

Rational Use of Microbiological Tests in the Diagnosis of Central Nervous System Infections Using Restrictive Criteria: a Retrospective Study

Microbiological testing in general and in the setting of central nervous system (CNS) infection in particular are often excessive, leading to superfluous laboratory work and costs. In this regard, restrictive criteria, named Reller criteria, have been developed to reduce unnecessary CSF herpes simplex virus 1 (HSV-1) PCR testing when suspecting encephalitis.

FilmArray® Meningoencephalitis panel in the diagnosis of central nervous system infections: stewardship and cost analysis in a paediatric hospital in Chile

BACKGROUND

Central nervous system (CNS) infection has been an ongoing concern in paediatrics. The FilmArray® Meningoencephalitis (FAME) panel has greater sensitivity in identifying the aetiology of CNS infections. This study's objective was to compare the aetiological identification and hospitalization costs among patients with suspected CNS infection before and after the use of FAME.

METHODS

An analytical observational study was carried out using a retrospective cohort for the pre-intervention (pre-FAME use) period and a prospective cohort for the post-intervention (post-FAME use) period in children with suspected CNS infection.

RESULTS

A total of 409 CSF samples were analysed, 297 pre-intervention and 112 post-intervention. In the pre-intervention period, a total of 85.5% of patients required hospitalization, and in the post-intervention period 92.7% required hospitalization (p < 0.05). Median of ICU days was significantly lower in the post-intervention period than it was in the pre-intervention period. The overall positivity was 9.4 and 26.8%, respectively (p < 0.001). At ages 6 months and below, we found an increase in overall positivity from 2.6 to 28.1%, along with an increased detection of viral agents, S. agalactiae, S. pneumoniae, and N. meningitidis. The use of this diagnostic technology saved between $2916 and $12,240 USD in the cost of ICU bed-days. FAME use provided the opportunity for more accurate aetiological diagnosis of the infections and thus the provision of adequate appropriate treatment.

CONCLUSIONS

The cost/benefit ratio between FAME cost and ICU bed-day cost savings is favourable. Implementation of FAME in Chilean public hospitals saves public resources and improves the accuracy of aetiological diagnosis.