ESCMID guideline: diagnosis and treatment of acute bacterial meningitis

Open ArchivePublished:April 07, 2016DOI:https://doi.org/10.1016/j.cmi.2016.01.007

      Keywords

      General introduction

       Motivation for guideline development

      Bacterial meningitis is a severe infectious disease of the membranes lining the brain resulting in a high mortality and morbidity throughout the world. In the past decades the epidemiology and treatment strategies for community-acquired bacterial meningitis have significantly changed [
      • McIntyre P.B.
      • O'Brien K.L.
      • Greenwood B.
      • van de Beek D.
      Effect of vaccines on bacterial meningitis worldwide.
      ,
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ,
      • van de Beek D.
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      Advances in treatment of bacterial meningitis.
      ]. First, the introduction of conjugate vaccines in Europe resulted in the virtual disappearance of Haemophilus influenzae type b, while conjugate pneumococcal and meningococcal vaccines have substantially reduced the burden of bacterial meningitis [
      • McIntyre P.B.
      • O'Brien K.L.
      • Greenwood B.
      • van de Beek D.
      Effect of vaccines on bacterial meningitis worldwide.
      ]. As a result, community-acquired bacterial meningitis has become a disease that currently affects more adults than infants, with its specific complications and treatment options. A second important development is the increasing rate of reduced susceptibility to common antimicrobial agents among strains of Streptococcus pneumoniae (pneumococcus) and Neisseria meningitidis (meningococcus). Large differences in resistance rates in Europe exist, and empiric antibiotic treatment needs to be adjusted according to regional epidemiology. Finally, several adjunctive treatments have been tested in randomized controlled trials, often with conflicting results [
      • van de Beek D.
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      Advances in treatment of bacterial meningitis.
      ]. These developments leave the physician in need of a clear practical guideline, summarizing the available evidence for diagnostic methods, and antimicrobial and adjunctive treatment in bacterial meningitis. To this end the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) promotes guidelines development in the field of infectious diseases. This guideline project was initiated by the ESCMID Study Group for Infections of the Brain (ESGIB).

       Aim of guideline

      The guideline is aimed at providing guidance in daily practice for diagnosis and treatment of community-acquired bacterial meningitis in hospitals. The conclusions of the guideline provide up-to-date scientific evidence for best medical practice. The recommendations are aimed at explicating this best medical practice and are based on available scientific evidence and the considerations of the guideline committee.
      The committee formulated ten key questions and several subquestions, which aim to address the full spectrum of current clinical dilemmas in the diagnosis and treatment of community-acquired bacterial meningitis.

       Epidemiology

      • 1.
        What are the causative microorganisms of community-acquired bacterial meningitis in specific groups (neonates, children, adults and immunocompromised patients)?

       Diagnosis

      • 2.
        What are the clinical characteristics of community-acquired bacterial meningitis, and what is their diagnostic accuracy?
      • 3.
        What is the diagnostic accuracy of algorithms in the distinction between bacterial and viral meningitis?
      • 4.
        Can we use clinical characteristics to predict the absence of intracranial abnormalities associated with increased risk of lumbar puncture?
      • 4.1.
        If lumbar puncture is delayed, should we start treatment?

       Treatment

      • 5.
        What is the optimal type, duration and method of administration of antibiotic treatment when started empirically, after the pathogen has been identified or in culture-negative patients?
      • 5.1.
        Does the addition of vancomycin or rifampicin to a third-generation cephalosporin improve outcome in pneumococcal meningitis patients in the setting of a high resistance rate of pneumococci?
      • 6.
        Does dexamethasone have a beneficial effect on death, functional outcome and hearing loss in adults and children with bacterial meningitis?
      • 6.1.
        Up to what point in time is treatment with dexamethasone indicated if antibiotics are already provided?
      • 6.2.
        Should dexamethasone be stopped if pathogens other than S. pneumoniae are identified?
      • 7.
        Do glycerol, mannitol, acetaminophen/paracetamol, hypothermia, antiepileptic drugs or hypertonic saline have a beneficial effect on death, functional outcome and hearing loss in adults and children with bacterial meningitis?
      • 8.
        Does the use of prophylactic treatment of household contacts decrease carriage or secondary cases?
      • 8.1.
        Is vaccination indicated after community-acquired (pneumococcal) meningitis?
      • 9.
        What complications occur during community-acquired bacterial meningitis, what ancillary investigations are warranted when complications occur and how should they be treated?

       Follow-up

      • 10.
        What follow-up of community-acquired bacterial meningitis patients should be provided (e.g. testing for hearing loss, neuropsychologic evaluation)?
      Meningococcal disease but also other bacterial infections can present with both meningitis and sepsis. This guideline is not aimed at the urgent recognition and treatment of sepsis patients. Therefore, if e.g. meningococcal sepsis is suspected the physician should refer to other guidelines specific for recognizing children/patients with developing shock who need acute sepsis management (e.g. NICE guidelines, https://www.nice.org.uk/guidance/cg109).

       Professional audience

      This guideline is written for all clinicians involved in diagnosis, treatment and follow-up of bacterial meningitis in adults and children with community-acquired bacterial meningitis in the context of hospital care, including infectious disease specialists, neurologists, intensive care specialists, paediatricians and microbiologists.

       Composition of guideline committee

      The initiation of the guideline project was announced at the ESGIB business meetings of 2011 and 2012 during the European Conference on Clinical Microbiology and Infectious Diseases (ECCMID). During this meeting ESGIB members were invited to join the guideline committee by approaching the guideline chairman. In composing the guideline, committee considerations were given to establish a balance in country of origin, gender and medical specialty of the guideline members. After the first meeting the guideline committee was reinforced with two additional members because their specific expertise was originally underrepresented in the committee.

       Approach of committee to guideline development

      After the guideline preparation project was granted ESCMID funding in Summer 2013, a kickoff meeting was staged in Amsterdam (October 2013) at which the key questions and subquestions were formulated and divided between guideline members. A clinical librarian and a research fellow at the chair's institute were appointed to perform the literature searches for each question. Guideline committee members received the identified literature and formulated the answers to the questions, which were discussed during a second meeting held simultaneously with the 2014 ECCMID meeting in Barcelona, Spain. During the meeting consensus was reached for most issues, and unanswered questions were identified and distributed between committee members. The research fellow and chair prepared a draft version of the guideline, which was distributed first to other guidelines members and subsequently to ESGIB members and ESCMID for comments.

       Patient participation

      For the development of a high-quality guideline, patient input is essential, as the treatment has to fulfil the demands and expectations of patients and caregivers. To incorporate these factors into the guideline, the United Kingdom–based Meningitis Research Foundation was approached to participate in the guideline development and provide comments.

       Methods of guideline development

       Literature search

      As preparation for this guideline development project, a search was performed for existing guidelines from guideline institutes (http://www.guideline.gov/, http://www.nice.org.uk/, http://www.sumsearch.org and http://www.sign.ac.uk/) and (inter)national societies for neurologists, paediatricians and infectious disease specialists. Furthermore, systematic reviews were searched in the Cochrane Library and SUMsearch. Subsequently, for all identified questions a specific search was performed in scientific publications using electronic databases PubMed, Medline and Embase (1966–2014). Additional publications were identified by cross-reference checking of identified literature. In the search hierarchy the initial aim was to identify systematic meta-analysis or meta-analyses of randomized controlled trials (RCTs). In the absence of RCTs a further search was performed for prospective controlled studies. Key questions were formulated in a PICO format (Population, Intervention, Control, Outcome) when appropriate. Search strategies were developed by a clinical librarian at the chair's institute (AMC, Amsterdam, Netherlands) for all PICO formatted questions (Appendix).

       Quality of evidence scoring

      The literature was selected by the committee members and was graded for quality on the basis of the ESCMID quality-of-evidence system (Table 1.1). The quality of used articles to substantiate the conclusions by the committee is provided with the concluding answer to each question. The scientific evidence is summarized in a conclusion, in which references to the key literature are provided.
      Table 1.1Quality of evidence
      ClassConclusions based on:
      1Evidence from at least one properly designed randomized controlled trial.
      2Evidence from at least one well-designed clinical trial, without randomization; from cohort or case–control analytic studies (preferably from >1 centre); from multiple time series; or from dramatic results of uncontrolled experiments.
      3Evidence from opinions of respected authorities, based on clinical experience, descriptive case studies.

       Strength of recommendation assessment

      On the basis of the identified literature the committee reached consensus on a recommendation for or against use of diagnostic methods or treatment. The strength of the recommendation is expressed using the ESCMID strength of recommendation system (Table 1.2) and does not link with the quality of evidence. High quality of evidence may result in marginal support for use, while low-quality evidence may result in a strong recommendation for use.
      Table 1.2Strength of recommendation
      GradeRecommendation
      AESCMID strongly supports recommendation for use.
      BESCMID moderately supports recommendation for use.
      CESCMID marginally supports recommendation for use.
      DESCMID supports recommendation against use.

       Implementation and assessment of impact

      We will disseminate and promote the guideline by publication in a peer-reviewed journal and active promotion of the guideline to all European national organizations of infectious disease specialists, intensive care specialists, neurologists, microbiologists and paediatricians. Members of the guideline committee will be asked to gather local, regional and/or national treatment guidelines from their home country (and if possible for other countries) to assess whether these have been updated to include evidence provided by the ESCMID guidelines. We aim to have at least half of the European national guidelines adapted to the ESCMID European guideline recommendations within 2 years. This will be assessed on a biannual basis and presented at the ESGIB meeting at the ECCMID.

       Revision of guideline

      Two members of the guideline committee (the chair plus one other) will give a yearly update on developments in the field of meningitis research applicable to the guideline and will assess the need for updating the guidelines. This update will be provided during the ESGIB business meeting at the ECCMID. Significant amendments or updates to the guideline will be submitted for publication. The ultimate date of updating the protocol will be 4 years after the final version is published.

       Legal status of guideline

      Guidelines do not contain legal regulations but provide evidence-based recommendations. Clinicians may strive to provide optimal care by adhering to the guideline. Because the guideline is based on general evidence of optimal care and the guideline committee's expert opinion, physicians may choose to deviate from the guideline on the basis of their professional autonomy when necessary in individual patients. Deviating from the guideline may in fact be required in specific situations. When deviating from advice provided in the guideline, it is advisable to document the considerations for doing so.

      Epidemiology of community-acquired bacterial meningitis in Europe

      Key Question 1. What are the causative microorganisms of community-acquired bacterial meningitis in specific groups (neonates, children, adults and immunocompromised patients)?
      The epidemiology of community-acquired bacterial meningitis worldwide has changed in the past decades as a result of the introduction of conjugated vaccines against H. influenzae type b, N. meningitidis serogroup C and 7-, 10- and 13-valent pneumococcal conjugate vaccines [
      • McIntyre P.B.
      • O'Brien K.L.
      • Greenwood B.
      • van de Beek D.
      Effect of vaccines on bacterial meningitis worldwide.
      ]. This resulted in a dramatic reduction of the incidence of bacterial meningitis in children [
      • Netherlands Reference Laboratory for Bacterial Meningitis (AMC/RIVM)
      Bacterial meningitis in the Netherlands annual report 2010.
      ], and currently the majority of patients are adults. The causative pathogens of bacterial meningitis depend on the age of the patient and predisposing factors.

       Bacterial meningitis in neonates

      Bacterial meningitis in the neonatal period is considered early when occurring during the first week of life and late when occurring between the second and sixth weeks [
      • Garges H.P.
      • Moody M.A.
      • Cotten C.M.
      • Smith P.B.
      • Tiffany K.F.
      • Lenfestey R.
      • et al.
      Neonatal meningitis: what is the correlation among cerebrospinal fluid cultures, blood cultures, and cerebrospinal fluid parameters?.
      ]. In early neonatal meningitis the primary mode of infection is by vertical transmission (mother to child) through the birth canal, whereas in late neonatal meningitis transmission is nosocomial or horizontal (person to person). The most common pathogens in neonatal meningitis are Streptococcus agalactiae (group B streptococcus, GBS) and Escherichia coli, causing two thirds of all cases (Table 2.1).
      Table 2.1Causative organisms of neonatal meningitis
      a Studies were performed in different time periods, with varying vaccination strategies per country.
      CountryUnited Kingdom
      • Okike I.O.
      • Johnson A.P.
      • Henderson K.L.
      • Blackburn R.M.
      • Muller-Pebody B.
      • Ladhani S.N.
      • et al.
      Incidence, etiology, and outcome of bacterial meningitis in infants aged <90 days in the United kingdom and Republic of Ireland: prospective, enhanced, national population-based surveillance.
      France
      • Gaschignard J.
      • Levy C.
      • Romain O.
      • Cohen R.
      • Bingen E.
      • Aujard Y.
      • et al.
      Neonatal bacterial meningitis: 444 cases in 7 years.
      Spain
      [Neonatal meningitis. Epidemiological study of the Grupo de Hospitales Castrillo].
      Netherlands
      • Netherlands Reference Laboratory for Bacterial Meningitis (AMC/RIVM)
      Bacterial meningitis in the Netherlands annual report 2010.
      Total
      Observation period2010–20112001–20071997–19982006–2012
      Streptococcus agalactiae1502586988565 (58%)
      Escherichia coli411231227203 (21%)
      Listeria monocytogenes1170119 (2%)
      Streptococcus pneumoniae2880339 (4%)
      Other72432214156 (16%)
      Total30244466133982
      a Studies were performed in different time periods, with varying vaccination strategies per country.
      Preventive penicillin in women colonized with S. agalactiae has been implemented as a measure to decrease the incidence of GBS meningitis in neonates following positive trials and meta-analyses [
      • Allen U.D.
      • Navas L.
      • King S.M.
      Effectiveness of intrapartum penicillin prophylaxis in preventing early-onset group B streptococcal infection: results of a meta-analysis.
      ]. Initially this was reported to result in a strong decrease in GBS neonatal disease in the 1990s [
      • Andersen J.
      • Christensen R.
      • Hertel J.
      Clinical features and epidemiology of septicaemia and meningitis in neonates due to Streptococcus agalactiae in Copenhagen County, Denmark: a 10 year survey from 1992 to 2001.
      ,
      • Schrag S.J.
      • Zywicki S.
      • Farley M.M.
      • Reingold A.L.
      • Harrison L.H.
      • Lefkowitz L.B.
      • et al.
      Group B streptococcal disease in the era of intrapartum antibiotic prophylaxis.
      ]. However, recent studies from the United Kingdom and the United States showed increased incidence rates in the 2000s [
      • Centers for Disease Control and Prevention
      Trends in perinatal group B streptococcal disease—United States, 2000–2006.
      ,
      • Lamagni T.L.
      • Keshishian C.
      • Efstratiou A.
      • Guy R.
      • Henderson K.L.
      • Broughton K.
      • et al.
      Emerging trends in the epidemiology of invasive group B streptococcal disease in England and Wales, 1991–2010.
      ]. A recent epidemiologic study from the Netherlands showed similar incidence rates of GBS meningitis over the past 25 years [
      • Bekker V.
      • Bijlsma M.W.
      • van de Beek D.
      • Kuijpers T.W.
      • van der Ende A.
      Increasing incidence and pathogen genotype redistribution of invasive group B streptococcal disease in newborns: a 25-year nationwide surveillance study in the Netherlands.
      ].
      Historically Listeria monocytogenes has been considered an important cause of neonatal meningitis [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ], but recent cohort studies and surveillance data identified L. monocytogenes in only a minority of cases. Streptococcus pneumoniae, the primary causative organism of bacterial meningitis in patients beyond the neonatal age, is only incidentally found in neonates.

       Community-acquired bacterial meningitis in children beyond neonatal age

      Historically the three main pathogens causing bacterial meningitis in children beyond the neonatal age were H. influenzae type b, N. meningitidis and S. pneumoniae. After vaccination against H. influenzae type b was introduced in the 1990s this pathogen has virtually disappeared as a major cause of bacterial meningitis in children [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ]. H. influenzae meningitis currently occurs incidentally in unvaccinated children or may be due to serotypes other than b [
      • Levy C.
      • de La Rocque F.
      • Cohen R.
      [Epidemiology of pediatric bacterial meningitis in France].
      ]. After a peak in incidence of serogroup C meningococcal meningitis in the early 2000s, several countries introduced the Men C vaccine in their vaccination programs [
      • Bijlsma M.W.
      • Brouwer M.C.
      • Spanjaard L.
      • van de Beek D.
      • van der Ende A.
      A decade of herd protection after introduction of meningococcal serogroup C conjugate vaccination.
      ,
      • Maiden M.C.
      • Ibarz-Pavon A.B.
      • Urwin R.
      • Gray S.J.
      • Andrews N.J.
      • Clarke S.C.
      • et al.
      Impact of meningococcal serogroup C conjugate vaccines on carriage and herd immunity.
      ]. This resulted in a sharp decrease in serogroup C meningococcal meningitis cases and provided long-term herd immunity [
      • Bijlsma M.W.
      • Brouwer M.C.
      • Spanjaard L.
      • van de Beek D.
      • van der Ende A.
      A decade of herd protection after introduction of meningococcal serogroup C conjugate vaccination.
      ,
      • Maiden M.C.
      • Ibarz-Pavon A.B.
      • Urwin R.
      • Gray S.J.
      • Andrews N.J.
      • Clarke S.C.
      • et al.
      Impact of meningococcal serogroup C conjugate vaccines on carriage and herd immunity.
      ]. Currently serogroup B causes most meningococcal meningitis cases in both children and adults [
      • Bijlsma M.W.
      • Bekker V.
      • Brouwer M.C.
      • Spanjaard L.
      • van de Beek D.
      • van der Ende A.
      Epidemiology of invasive meningococcal disease in the Netherlands, 1960–2012: an analysis of national surveillance data.
      ]. The incidence of meningococcal meningitis due to serogroup B has decreased in some countries in the past decade, which is probably due to stochastic variation [
      • Martin N.G.
      • Sadarangani M.
      • Pollard A.J.
      • Goldacre M.J.
      Hospital admission rates for meningitis and septicaemia caused by Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae in children in England over five decades: a population-based observational study.
      ]. Due to this decrease pneumococcal meningitis is now as common as meningococcal meningitis in children beyond the neonatal age, and reductions in incidence rates have been achieved following introduction of pneumococcal conjugated vaccines (PCVs) against 7, 11 or 13 pneumococcal serotypes [
      • Martin N.G.
      • Sadarangani M.
      • Pollard A.J.
      • Goldacre M.J.
      Hospital admission rates for meningitis and septicaemia caused by Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae in children in England over five decades: a population-based observational study.
      ].

       Community-acquired bacterial meningitis in adults

      The majority of bacterial meningitis cases in adults is caused by S. pneumoniae (Table 2.3). After the introduction of PCVs a reduction in cases has been observed as a result of a reduction of disease due to serotypes included in the vaccine. In adults serotype replacement has also been observed, and continuous surveillance and vaccine development remains important [
      • Ardanuy C.
      • Tubau F.
      • Pallares R.
      • Calatayud L.
      • Domínguez M.A.
      • Rolo D.
      • et al.
      Epidemiology of invasive pneumococcal disease among adult patients in barcelona before and after pediatric 7-valent pneumococcal conjugate vaccine introduction, 1997–2007.
      ]. Meningococcal meningitis in adults is mostly found in adolescents and is mostly caused by serogroup B. Similar to the paediatric population, the incidence of meningococcal meningitis has declined in the past decade [
      • Bijlsma M.W.
      • Bekker V.
      • Brouwer M.C.
      • Spanjaard L.
      • van de Beek D.
      • van der Ende A.
      Epidemiology of invasive meningococcal disease in the Netherlands, 1960–2012: an analysis of national surveillance data.
      ]. L. monocytogenes is the third most common cause of meningitis in adults and is commonly associated with old age and an immunocompromised state [
      • Koopmans M.M.
      • Brouwer M.C.
      • Bijlsma M.W.
      • Bovenkerk S.
      • Keijzers W.
      • van der Ende A.
      • et al.
      Listeria monocytogenes sequence type 6 and increased rate of unfavorable outcome in meningitis: epidemiologic cohort study.
      ]. Haemophilus influenzae and Staphylococcus aureus are found in 1–2% of adult cases and are associated with specific underlying conditions such as otitis and sinusitis (H. influenzae) or endocarditis (S. aureus).
      Table 2.2Causative organisms of paediatric meningitis beyond neonatal age
      CountryFrance
      • Levy C.
      • Bingen E.
      • Aujard Y.
      • Boucherat M.
      • Floret D.
      • Gendrel D.
      • et al.
      [Surveillance network of bacterial meningitis in children, 7 years of survey in France].
      Denmark
      • Howitz M.
      • Hartvig C.A.
      • Harboe Z.B.
      • Molbak K.
      Surveillance of bacterial meningitis in children under 2 y of age in Denmark, 1997–2006.
      France
      • Bargui F.
      • D’Agostino I.
      • Mariani-Kurkdjian P.
      • Alberti C.
      • Doit C.
      • Bellier N.
      • et al.
      Factors influencing neurological outcome of children with bacterial meningitis at the emergency department.
      Netherlands
      • Netherlands Reference Laboratory for Bacterial Meningitis (AMC/RIVM)
      Bacterial meningitis in the Netherlands annual report 2010.
      Total
      Observation period2001–20071997–20061995–20042006–2012
      Neisseria meningitidis1303159353081805 (50%)
      Streptococcus pneumoniae802195353101342 (37%)
      Haemophilus influenzae7881173170 (5%)
      Other137568101302 (8%)
      Total2320418897923619
      Table 2.3Causative organisms of adult bacterial meningitis
      CountryDenmark
      • Bodilsen J.
      • Dalager-Pedersen M.
      • Schonheyder H.C.
      • Nielsen H.
      Dexamethasone treatment and prognostic factors in community-acquired bacterial meningitis: a Danish retrospective population-based cohort study.
      Turkey
      • Arda B.
      • Sipahi O.R.
      • Atalay S.
      • Ulusoy S.
      Pooled analysis of 2,408 cases of acute adult purulent meningitis from Turkey.
      United Kingdom
      • Gjini A.B.
      • Stuart J.M.
      • Lawlor D.A.
      • Cartwright K.A.
      • Christensen H.
      • Ramsay M.
      • et al.
      Changing epidemiology of bacterial meningitis among adults in England and Wales 1991–2002.
      Czech Republic
      • Dzupova O.
      • Rozsypal H.
      • Prochazka B.
      • Benes J.
      Acute bacterial meningitis in adults: predictors of outcome.
      Netherlands
      • Netherlands Reference Laboratory for Bacterial Meningitis (AMC/RIVM)
      Bacterial meningitis in the Netherlands annual report 2010.
      Total
      Observation period1998–20121994–20031997–20021997–20042006–2012
      Neisseria meningitidis42251550751711089 (27%)
      Streptococcus pneumoniae924575258210012157 (53%)
      Haemophilus influenzae3248356112 (3%)
      Listeria monocytogenes56482174154 (4%)
      Other306812435291548 (13%)
      Total172784129521615934060

       Community-acquired bacterial meningitis in immunocompromised patients

      The spectrum of causative pathogens that needs to be considered is different when the patient has certain specific medical conditions. Deficiencies of the immune system, which may be iatrogenic (e.g. use of immunosuppressive medication or splenectomy), due to diseases influencing the immune system (e.g. cancer, diabetes mellitus, alcoholism, human immunodeficiency virus (HIV) infection) or hereditary (e.g. hypogammaglobulinaemia, late complement component deficiency, common variable immunodeficiency), increase the risk of bacterial meningitis [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ]. The incidence of pneumococcal meningitis is increased in patients after splenectomy or with a hyposplenic state [
      • Adriani K.S.
      • Brouwer M.C.
      • van der Ende A.
      • van de Beek D.
      Bacterial meningitis in adults after splenectomy and hyposplenic states.
      ], chronic kidney or liver disease [
      • Cabellos C.
      • Viladrich P.F.
      • Ariza J.
      • Maiques J.M.
      • Verdaguer R.
      • Gudiol F.
      Community-acquired bacterial meningitis in cirrhotic patients.
      ], HIV infection [
      • Domingo P.
      • Suarez-Lozano I.
      • Torres F.
      • Pomar V.
      • Ribera E.
      • Galindo M.J.
      • et al.
      Bacterial meningitis in HIV-1-infected patients in the era of highly active antiretroviral therapy.
      ], alcoholism, hypogammaglobulinaemia, diabetes mellitus and patients using immunosuppressive drugs [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ]. Patients with complement system deficiencies have been identified to have a strongly increased risk of meningococcal meningitis [
      • Brouwer M.C.
      • de Gans J.
      • Heckenberg S.G.
      • Zwinderman A.H.
      • van der Poll T.
      • van de Beek D.
      Host genetic susceptibility to pneumococcal and meningococcal disease: a systematic review and meta-analysis.
      ]. Predisposing conditions associated with H. influenzae meningitis include diabetes mellitus, alcoholism, splenectomy or asplenic states, multiple myeloma and immune deficiency such as hypogammaglobulinaemia [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ]. L. monocytogenes meningitis is more often found in elderly patients (>60 years) and those with acquired immunodeficiencies, such as diabetes, cancer and use of immunosuppressive drugs [
      • Koopmans M.M.
      • Brouwer M.C.
      • Bijlsma M.W.
      • Bovenkerk S.
      • Keijzers W.
      • van der Ende A.
      • et al.
      Listeria monocytogenes sequence type 6 and increased rate of unfavorable outcome in meningitis: epidemiologic cohort study.
      ].

       Conclusions

      Tabled 1
      Level 2Most common causative pathogens in neonatal meningitis are Streptococcus agalactiae and Escherichia coli.
      Tabled 1
      Level 2Most common causative pathogens in children beyond the neonatal age are Neisseria meningitidis and Streptococcus pneumoniae.
      Tabled 1
      Level 2Most common causative pathogens in adults are Streptococcus pneumoniae and Neisseria meningitidis. Another important causative microorganism in adults is Listeria monocytogenes.

      Diagnosis of community-acquired bacterial meningitis

      Key Question 2. What are the clinical characteristics of community-acquired bacterial meningitis, and what is their diagnostic accuracy?

       Clinical characteristics in children with bacterial meningitis

       Clinical characteristics of neonatal bacterial meningitis

      Neonates with bacterial meningitis often present with nonspecific symptoms such as irritability, poor feeding, respiratory distress, pale or marble skin and hyper- or hypotonia [
      • Andersen J.
      • Christensen R.
      • Hertel J.
      Clinical features and epidemiology of septicaemia and meningitis in neonates due to Streptococcus agalactiae in Copenhagen County, Denmark: a 10 year survey from 1992 to 2001.
      ,
      • Okike I.O.
      • Johnson A.P.
      • Henderson K.L.
      • Blackburn R.M.
      • Muller-Pebody B.
      • Ladhani S.N.
      • et al.
      Incidence, etiology, and outcome of bacterial meningitis in infants aged <90 days in the United kingdom and Republic of Ireland: prospective, enhanced, national population-based surveillance.
      ,
      • Gaschignard J.
      • Levy C.
      • Romain O.
      • Cohen R.
      • Bingen E.
      • Aujard Y.
      • et al.
      Neonatal bacterial meningitis: 444 cases in 7 years.
      ,
      • Kavuncuoglu S.
      • Gursoy S.
      • Turel O.
      • Aldemir E.Y.
      • Hosaf E.
      Neonatal bacterial meningitis in Turkey: epidemiology, risk factors, and prognosis.
      ]. Fever is present in a minority (6–39%) of cases. Seizures are reported in 9–34% of cases and are more commonly reported among those with group B streptococcal (GBS) compared to E. coli meningitis. Respiratory distress or failure is frequently reported as one of the initial symptoms of neonatal meningitis [
      • Andersen J.
      • Christensen R.
      • Hertel J.
      Clinical features and epidemiology of septicaemia and meningitis in neonates due to Streptococcus agalactiae in Copenhagen County, Denmark: a 10 year survey from 1992 to 2001.
      ,
      • Okike I.O.
      • Johnson A.P.
      • Henderson K.L.
      • Blackburn R.M.
      • Muller-Pebody B.
      • Ladhani S.N.
      • et al.
      Incidence, etiology, and outcome of bacterial meningitis in infants aged <90 days in the United kingdom and Republic of Ireland: prospective, enhanced, national population-based surveillance.
      ,
      • Gaschignard J.
      • Levy C.
      • Romain O.
      • Cohen R.
      • Bingen E.
      • Aujard Y.
      • et al.
      Neonatal bacterial meningitis: 444 cases in 7 years.
      ,
      • Kavuncuoglu S.
      • Gursoy S.
      • Turel O.
      • Aldemir E.Y.
      • Hosaf E.
      Neonatal bacterial meningitis in Turkey: epidemiology, risk factors, and prognosis.
      ]. In neonates with GBS meningitis within 24 hours of birth, respiratory (72%), cardiovascular (69%) and neurologic (63%) symptoms were the predominant initial signs [
      • Andersen J.
      • Christensen R.
      • Hertel J.
      Clinical features and epidemiology of septicaemia and meningitis in neonates due to Streptococcus agalactiae in Copenhagen County, Denmark: a 10 year survey from 1992 to 2001.
      ]. Concomitant septic shock may be diagnosed in about 25% of the cases of neonatal meningitis [
      • Gaschignard J.
      • Levy C.
      • Romain O.
      • Cohen R.
      • Bingen E.
      • Aujard Y.
      • et al.
      Neonatal bacterial meningitis: 444 cases in 7 years.
      ]. The diagnosis of neonatal meningitis cannot be ruled out by clinical examination alone, and therefore a low threshold should be kept in neonates with suspected bacterial meningitis to perform a lumbar puncture. The diagnostic accuracy of clinical characteristics in assessment of neonatal meningitis is presumed to be low, although few studies have evaluated this systematically.

       Clinical characteristics of bacterial meningitis in children beyond neonatal age

      Classical signs and symptoms of bacterial meningitis consisting of fever, altered mental status and neck stiffness are less frequently present in younger infants compared to older children and adults. Typically childhood bacterial meningitis begins with fever, chills, vomiting, photophobia and severe headache (Table 3.1) [
      • Franco-Paredes C.
      • Lammoglia L.
      • Hernandez I.
      • Santos-Preciado J.I.
      Epidemiology and outcomes of bacterial meningitis in Mexican children: 10-year experience (1993–2003).
      ,
      • Vasilopoulou V.A.
      • Karanika M.
      • Theodoridou K.
      • Katsioulis A.T.
      • Theodoridou M.N.
      • Hadjichristodoulou C.S.
      Prognostic factors related to sequelae in childhood bacterial meningitis: data from a Greek meningitis registry.
      ,
      • Snaebjarnardottir K.
      • Erlendsdottir H.
      • Reynisson I.K.
      • Kristinsson K.
      • Halldórsdóttir S.
      • Hardardóttir H.
      • et al.
      Bacterial meningitis in children in Iceland, 1975–2010: a nationwide epidemiological study.
      ]. In general, the younger the patient with bacterial meningitis, the more subtle and atypical are the symptoms such as headache, photophobia, vomiting and neck stiffness [
      • Franco-Paredes C.
      • Lammoglia L.
      • Hernandez I.
      • Santos-Preciado J.I.
      Epidemiology and outcomes of bacterial meningitis in Mexican children: 10-year experience (1993–2003).
      ,
      • Snaebjarnardottir K.
      • Erlendsdottir H.
      • Reynisson I.K.
      • Kristinsson K.
      • Halldórsdóttir S.
      • Hardardóttir H.
      • et al.
      Bacterial meningitis in children in Iceland, 1975–2010: a nationwide epidemiological study.
      ]. Headache is reported in 2–9% of children with bacterial meningitis up to 1 year of age and in 75% of children older than 5 years. Fever is the most commonly reported symptom in childhood bacterial meningitis, with an occurrence rate of 92–93%. Vomiting is reported in 55–67% of children with bacterial meningitis [
      • Franco-Paredes C.
      • Lammoglia L.
      • Hernandez I.
      • Santos-Preciado J.I.
      Epidemiology and outcomes of bacterial meningitis in Mexican children: 10-year experience (1993–2003).
      ,
      • Vasilopoulou V.A.
      • Karanika M.
      • Theodoridou K.
      • Katsioulis A.T.
      • Theodoridou M.N.
      • Hadjichristodoulou C.S.
      Prognostic factors related to sequelae in childhood bacterial meningitis: data from a Greek meningitis registry.
      ,
      • Snaebjarnardottir K.
      • Erlendsdottir H.
      • Reynisson I.K.
      • Kristinsson K.
      • Halldórsdóttir S.
      • Hardardóttir H.
      • et al.
      Bacterial meningitis in children in Iceland, 1975–2010: a nationwide epidemiological study.
      ].
      Table 3.1Clinical characteristics of paediatric meningitis beyond neonatal age at presentation
      CountryGreece
      • Vasilopoulou V.A.
      • Karanika M.
      • Theodoridou K.
      • Katsioulis A.T.
      • Theodoridou M.N.
      • Hadjichristodoulou C.S.
      Prognostic factors related to sequelae in childhood bacterial meningitis: data from a Greek meningitis registry.
      United States
      • Nigrovic L.E.
      • Kuppermann N.
      • Malley R.
      Children with bacterial meningitis presenting to the emergency department during the pneumococcal conjugate vaccine era.
      Kosovo
      • Namani S.
      • Milenkovic Z.
      • Kuchar E.
      • Koci R.
      • Mehmeti M.
      Mortality from bacterial meningitis in children in Kosovo.
      France
      • Bargui F.
      • D’Agostino I.
      • Mariani-Kurkdjian P.
      • Alberti C.
      • Doit C.
      • Bellier N.
      • et al.
      Factors influencing neurological outcome of children with bacterial meningitis at the emergency department.
      Iceland
      • Snaebjarnardottir K.
      • Erlendsdottir H.
      • Reynisson I.K.
      • Kristinsson K.
      • Halldórsdóttir S.
      • Hardardóttir H.
      • et al.
      Bacterial meningitis in children in Iceland, 1975–2010: a nationwide epidemiological study.
      Observation period74–0501–0797–0295–0495–10
      No. of patients133123122789140
      Fever93%93%92%
      Vomiting58%67%
      Altered mental status13%51%25%
      Headache78%
      Neck stiffness82%40%60%
      Seizures19%10%22%25%
      Focal neurologic deficits16%11%
      Rash39%4%51%
      Seizures have been reported at hospital admission in 10–56% of children. Altered mental status was reported in 13–56% of the cases of childhood bacterial meningitis [
      • Bargui F.
      • D’Agostino I.
      • Mariani-Kurkdjian P.
      • Alberti C.
      • Doit C.
      • Bellier N.
      • et al.
      Factors influencing neurological outcome of children with bacterial meningitis at the emergency department.
      ,
      • Franco-Paredes C.
      • Lammoglia L.
      • Hernandez I.
      • Santos-Preciado J.I.
      Epidemiology and outcomes of bacterial meningitis in Mexican children: 10-year experience (1993–2003).
      ,
      • Namani S.
      • Milenkovic Z.
      • Kuchar E.
      • Koci R.
      • Mehmeti M.
      Mortality from bacterial meningitis in children in Kosovo.
      ]. Some signs or symptoms are associated with specific pathogens of childhood meningitis. Petechial and purpuric rash are usually signs of meningococcal disease, although a rash has also been described in pneumococcal meningitis [
      • Vasilopoulou V.A.
      • Karanika M.
      • Theodoridou K.
      • Katsioulis A.T.
      • Theodoridou M.N.
      • Hadjichristodoulou C.S.
      Prognostic factors related to sequelae in childhood bacterial meningitis: data from a Greek meningitis registry.
      ,
      • Nigrovic L.E.
      • Kuppermann N.
      • Malley R.
      Children with bacterial meningitis presenting to the emergency department during the pneumococcal conjugate vaccine era.
      ]. In a large study performed in Greece, 511 (61%) of 838 patients with confirmed meningococcal meningitis presented with haemorrhagic rash compared to 17 (9%) of 186 patients with meningitis due to S. pneumoniae [
      • Vasilopoulou V.A.
      • Karanika M.
      • Theodoridou K.
      • Katsioulis A.T.
      • Theodoridou M.N.
      • Hadjichristodoulou C.S.
      Prognostic factors related to sequelae in childhood bacterial meningitis: data from a Greek meningitis registry.
      ].
      Diagnostic accuracy of clinical characteristics in children with bacterial meningitis has been assessed in several studies, recently summarized in a meta-analysis [
      • Curtis S.
      • Stobart K.
      • Vandermeer B.
      • Simel D.L.
      • Klassen T.
      Clinical features suggestive of meningitis in children: a systematic review of prospective data.
      ]. Seven of 10 included studies were performed in African countries, and therefore the applicability of these data to the European situation may be limited. The meta-analysis of studies revealed sensitivities of 51% for neck stiffness, 53% for Kernig sign and 66% for Brudzinski sign for the diagnosis of bacterial meningitis, as well as poor test characteristics of other common signs and symptoms in the differentiation between bacterial and viral/aseptic or no meningitis [
      • Curtis S.
      • Stobart K.
      • Vandermeer B.
      • Simel D.L.
      • Klassen T.
      Clinical features suggestive of meningitis in children: a systematic review of prospective data.
      ]. These data indicate that clinical characteristics cannot be used to rule out bacterial meningitis [
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      • van de Beek D.
      Dilemmas in the diagnosis of acute community-acquired bacterial meningitis.
      ].

       Conclusions

      Tabled 1
      Level 2Neonates with bacterial meningitis often present with nonspecific symptoms.
      Tabled 1
      Level 2In children beyond the neonatal age the most common clinical characteristics of bacterial meningitis are fever, headache, neck stiffness and vomiting. There is no clinical sign of bacterial meningitis that is present in all patients.

       Recommendation

      Tabled 1
      Grade ABacterial meningitis in children can present solely with nonspecific symptoms. Characteristic clinical signs may be absent. In all children with suspected bacterial meningitis ESCMID strongly recommends cerebrospinal fluid examination, unless contraindications for lumbar puncture are present (see section Imaging before lumbar puncture).

       Clinical characteristics in adults with bacterial meningitis

      Multiple studies have been performed on the clinical characteristics of adults with bacterial meningitis [
      • Bodilsen J.
      • Dalager-Pedersen M.
      • Schonheyder H.C.
      • Nielsen H.
      Dexamethasone treatment and prognostic factors in community-acquired bacterial meningitis: a Danish retrospective population-based cohort study.
      ,
      • van de Beek D.
      • de Gans J.
      • Spanjaard L.
      • Weisfelt M.
      • Reitsma J.B.
      • Vermeulen M.
      Clinical features and prognostic factors in adults with bacterial meningitis.
      ,
      • Dauchy F.A.
      • Gruson D.
      • Chene G.
      • Viot J.
      • Bebear C.
      • Maugein J.
      • et al.
      Prognostic factors in adult community-acquired bacterial meningitis: a 4-year retrospective study.
      ,
      • Domingo P.
      • Pomar V.
      • Benito N.
      • Coll P.
      The changing pattern of bacterial meningitis in adult patients at a large tertiary university hospital in Barcelona, Spain (1982–2010).
      ,
      • Sigurdardottir B.
      • Bjornsson O.M.
      • Jonsdottir K.E.
      • Erlendsdottir H.
      • Gudmundsson S.
      Acute bacterial meningitis in adults. A 20-year overview.
      ]. These studies have shown that headache, fever, neck stiffness and altered mental status are common signs and symptoms at admission. The classic triad of fever, neck stiffness and altered mental status, however, is reported in only 41–51% of patients (Table 3.2). A petechial rash is identified in 20–52% of patients and is indicative of meningococcal infection in over 90% of patients [
      • van de Beek D.
      • de Gans J.
      • Spanjaard L.
      • Weisfelt M.
      • Reitsma J.B.
      • Vermeulen M.
      Clinical features and prognostic factors in adults with bacterial meningitis.
      ].
      Table 3.2Presenting clinical characteristics of adults with bacterial meningitis
      CountryNetherlands
      • van de Beek D.
      • de Gans J.
      • Spanjaard L.
      • Weisfelt M.
      • Reitsma J.B.
      • Vermeulen M.
      Clinical features and prognostic factors in adults with bacterial meningitis.
      France
      • Dauchy F.A.
      • Gruson D.
      • Chene G.
      • Viot J.
      • Bebear C.
      • Maugein J.
      • et al.
      Prognostic factors in adult community-acquired bacterial meningitis: a 4-year retrospective study.
      Spain
      • Domingo P.
      • Pomar V.
      • Benito N.
      • Coll P.
      The changing pattern of bacterial meningitis in adult patients at a large tertiary university hospital in Barcelona, Spain (1982–2010).
      Iceland
      • Sigurdardottir B.
      • Bjornsson O.M.
      • Jonsdottir K.E.
      • Erlendsdottir H.
      • Gudmundsson S.
      Acute bacterial meningitis in adults. A 20-year overview.
      Denmark
      • Bodilsen J.
      • Dalager-Pedersen M.
      • Schonheyder H.C.
      • Nielsen H.
      Dexamethasone treatment and prognostic factors in community-acquired bacterial meningitis: a Danish retrospective population-based cohort study.
      Observation period1998–20022001–20041996–20101975–19941989–2010
      No. of patients69660295119172
      Headache87%87%58%
      Nausea/vomiting74%45%
      Neck stiffness83%69%82%65%
      Rash26%20%52%
      Fever (>38.0°C)77%93%95%97%87%
      Altered mental status69%30%54%66%68%
      Coma14%7%13%16%
      Focal neurologic deficits34%23%15%21%
      Triad of fever, neck stiffness and altered mental status44%41%51%45%
      Studies assessing the usefulness of neck stiffness, Kernig sign, and Brudzinski sign in the differential diagnosis of bacterial meningitis in adults have recently been summarized [
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      • van de Beek D.
      Dilemmas in the diagnosis of acute community-acquired bacterial meningitis.
      ]. These clinical findings have low diagnostic accuracy for prediction of cerebrospinal fluid (CSF) pleocytosis (sensitivity neck stiffness 31%, Brudzinski 9%, Kernig 11%), suggesting that absence of these findings cannot be used to exclude the possibility of bacterial meningitis.

       Conclusions

      Tabled 1
      Level 2In adults the most common clinical characteristics of bacterial meningitis are fever, headache, neck stiffness and altered mental status. Characteristic clinical signs and symptoms such as fever, neck stiffness, headache and altered mental status can be absent.
      Tabled 1
      Level 2The sensitivity and negative predictive value of Kernig and Brudzinski sign is low in the diagnosis of meningitis and therefore do not contribute to the diagnosis of bacterial meningitis.

       Recommendation

      Tabled 1
      Grade AIn adults with bacterial meningitis classic clinical characteristics may be absent and therefore bacterial meningitis should not be ruled out solely on the absence of classic symptoms.

       Diagnostic algorithms

      Key Question 3. What is the diagnostic accuracy of algorithms in the distinction between bacterial and viral meningitis?
      Most patients with suspected bacterial meningitis eventually receive an alternative diagnosis, which consists of viral (or aseptic) meningitis in the majority of cases with CSF pleocytosis [
      • Hasbun R.
      • Bijlsma M.
      • Brouwer M.C.
      • Khoury N.
      • Hadi C.M.
      • van der Ende A.
      • et al.
      Risk score for identifying adults with CSF pleocytosis and negative CSF Gram stain at low risk for an urgent treatable cause.
      ]. Several diagnostic algorithms have been developed to help the clinician differentiate between bacterial meningitis and viral meningitis. This could especially be helpful in patients without a positive CSF Gram stain or culture, as the diagnosis of acute bacterial meningitis can be difficult to establish or reject in these patients.
      In our literature search 311 articles were identified, of which 29 were selected on the basis of the abstract for full reading. We analysed eight algorithms that were validated in an independent cohort (Table 3.3). Studies were mostly performed in paediatric populations beyond the neonatal age. No diagnostic algorithm to differentiate neonatal meningitis from other conditions was identified.
      Table 3.3Overview of diagnostic algorithms identified by survey
      ScorePopulationItemsStudies/level of evidenceLowest reported sensitivityLowest reported specificity
      Boyer
      • Boyer D.
      • Gordon R.C.
      • Baker T.
      Lack of clinical usefulness of a positive latex agglutination test for Neisseria meningitidis/Escherichia coli antigens in the urine.
      ChildrenScore including temperature, rash, neurologic impairment/seizures or altered mental status, CSF protein, glucose and CSF WBC count, PMN count.

      If >5 points = bacterial meningitis, 3–4 = unclear, <3 = no bacterial meningitis
      5/289%88%
      Oostenbrink
      • Oostenbrink R.
      • Moons K.G.
      • Donders A.R.
      • Grobbee D.E.
      • Moll H.A.
      Prediction of bacterial meningitis in children with meningeal signs: reduction of lumbar punctures.
      ChildrenScore including duration of complaints, vomiting, meningeal irritation, cyanosis, petechiae or ecchymosis, disturbed consciousness, CRP, CSF PMN count, CSF to blood glucose ratio.

      If score is <8.5: low risk of bacterial meningitis
      5/279%50%
      Bacterial Meningitis Score
      • Nigrovic L.E.
      • Kuppermann N.
      • Malley R.
      Development and validation of a multivariable predictive model to distinguish bacterial from aseptic meningitis in children in the post–Haemophilus influenzae era.
      ChildrenItem list including CSF Gram stain, CSF protein, peripheral absolute neutrophil count, seizures before or at admission, CSF absolute neutrophil count.

      If all items are absent low risk of meningitis
      8/296%44%
      Bonsu
      • Bonsu B.K.
      • Harper M.B.
      Differentiating acute bacterial meningitis from acute viral meningitis among children with cerebrospinal fluid pleocytosis: a multivariable regression model.
      ChildrenFormula including CSF WBC count, CSF protein concentration and age.

      If score is <0.1: low risk of bacterial meningitis
      4/292%28%
      Hoen
      • Hoen B.
      • Viel J.F.
      • Paquot C.
      • Gerard A.
      • Canton P.
      Multivariate approach to differential diagnosis of acute meningitis.
      All ages, except neonatesFormula including CSF PMN count, CSF protein, blood glucose and blood WBC count.

      If score is <0.1: low risk of bacterial meningitis
      6/277%70%
      FreedmanChildrenItem list including patient's age, blood WBC count, peripheral band count, CSF glucose concentration, CSF/serum glucose ratio, CSF protein concentration, and positive CSF Gram staining.

      If all items are absent low risk of meningitis
      3/298.7%12%
      MeningitestAll ages, except neonatesItem list including WBC, CSF WBC, CSF PMN, CSF protein, and glucose CSF/blood ratio.

      If all items are absent low risk of meningitis
      2/279%51%
      Spanos
      • Spanos A.
      • Harrell Jr., F.E.
      • Durack D.T.
      Differential diagnosis of acute meningitis. An analysis of the predictive value of initial observations.
      All ages, except neonatesFormula including age, time of year, glucose ratio, and total CSF PMN count.

      Probability of meningitis calculated by nomogram
      6/289%55%
      TokudaAdultsItem list including disturbed consciousness, CSF gram stain, neutrophil count and percentage.

      If all items are absent low risk of meningitis
      2/288%88%
      De CauwerChildrenItem list including CRP, CSF neutrophil count, CSF protein and CSF glucose concentration.

      If all items are absent low risk of meningitis
      2/299%40%
      SchmidtAll ages, except neonatesItem list including CSF WBC, CSF protein and CSF lactate.

      If all items are absent low risk of meningitis
      2/259%100%
      CRP, C-reactive protein; CSF, cerebrospinal fluid; PMN, polymorphonuclear cells; WBC, white blood cells.
      None of the published diagnostic algorithms was 100% sensitive upon validation in independent cohorts, showing that every algorithm will fail to recognize a proportion of bacterial meningitis patients. An important limitation of the prediction models described is that they all differentiate between viral and acute bacterial meningitis, but in clinical practice many other causes might need to be considered. Furthermore, they only apply to the population they were tested in and cannot be used in other groups, e.g. neonates. This further limits the use of the algorithms in clinical practice.
      In individual patients with suspected acute bacterial meningitis, a prediction model could have value, but clinicians' judgement should continue to be used to estimate the risk of bacterial meningitis and whether empiric antibiotic and adjunctive therapy needs to be initiated [
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      • van de Beek D.
      Dilemmas in the diagnosis of acute community-acquired bacterial meningitis.
      ].

       Conclusion

      Tabled 1
      Level 2None of the published diagnostic algorithms was 100% sensitive upon validation in an independent cohort, indicating that bacterial meningitis patients will potentially be missed when any of the algorithms are used.

       Recommendation

      Tabled 1
      Grade CUse of diagnostic algorithms may be helpful to guide management in individual patients with suspected acute bacterial meningitis, but clinical judgement is key when considering whether to start empiric antibiotic and adjunctive therapy.

       Diagnostic accuracy of laboratory techniques in bacterial meningitis

      The diagnosis of bacterial meningitis cannot be proven without CSF examination. A positive CSF culture is diagnostic for bacterial meningitis and enables in vitro testing of the antimicrobial susceptibility patterns, after which antibiotic treatment can be optimized. Gram staining, latex agglutination, immunochromatographic antigen testing and PCR could provide additional information, especially when the CSF culture is negative. If CSF examination is not possible, serum markers of inflammation may provide a supportive role in the diagnosis of bacterial meningitis [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ].

       CSF leukocyte count, glucose, total protein and lactate levels

      Classic abnormalities of CSF composition in bacterial meningitis are a pleocytosis of mainly polymorphic leukocytes, low glucose concentration, low CSF to blood glucose ratio and elevated protein levels. In neonates, however, these abnormalities are regularly absent. A study in 146 neonates with S. agalactiae meningitis showed completely normal CSF in 6% of cases [
      • Georget-Bouquinet E.
      • Bingen E.
      • Aujard Y.
      • Levy C.
      • Cohen R.
      [Group B streptococcal meningitis’ clinical, biological and evolutive features in children].
      ]. In a large cohort of 9111 neonates in whom a lumbar puncture was performed, 95 had culture-proven meningitis, of which 10% had fewer than 3 white blood cells (WBC)/mm3 in the CSF [
      • Garges H.P.
      • Moody M.A.
      • Cotten C.M.
      • Smith P.B.
      • Tiffany K.F.
      • Lenfestey R.
      • et al.
      Neonatal meningitis: what is the correlation among cerebrospinal fluid cultures, blood cultures, and cerebrospinal fluid parameters?.
      ]. The median CSF WBC count was low (6 cells/mm3; range 0–90000/mm3, interquartile range 2–15/mm3). For culture-proven meningitis, CSF WBC counts of more than 21 cells/mm3 had a sensitivity of 79% and a specificity of 81%. CSF glucose concentrations varied from 0 to 11 mmol/L or 0 to 198 mg/dL (median, 1.1 mmol/L or 20 mg/dL), and protein concentrations varied from 0.4 to 19.6 g/L (median, 2.7 g/L); culture-proven meningitis was not diagnosed accurately by CSF glucose or by protein [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ,
      • Garges H.P.
      • Moody M.A.
      • Cotten C.M.
      • Smith P.B.
      • Tiffany K.F.
      • Lenfestey R.
      • et al.
      Neonatal meningitis: what is the correlation among cerebrospinal fluid cultures, blood cultures, and cerebrospinal fluid parameters?.
      ].
      A retrospective study assessed the value of CSF parameters for differentiating between viral and bacterial meningitis in children beyond the neonatal age and adults [
      • Spanos A.
      • Harrell Jr., F.E.
      • Durack D.T.
      Differential diagnosis of acute meningitis. An analysis of the predictive value of initial observations.
      ]. It was shown that glucose levels lower than 1.9 mmol/L, protein levels over 2.2 g/L and leukocyte count over 2000 cells/mm3 are individual predictors of bacterial meningitis [
      • Spanos A.
      • Harrell Jr., F.E.
      • Durack D.T.
      Differential diagnosis of acute meningitis. An analysis of the predictive value of initial observations.
      ]. Prospective studies showed that at least one of these predictors was present in 82–94% of patients with community-acquired bacterial meningitis [
      • van de Beek D.
      • de Gans J.
      • Spanjaard L.
      • Weisfelt M.
      • Reitsma J.B.
      • Vermeulen M.
      Clinical features and prognostic factors in adults with bacterial meningitis.
      ,
      • Heckenberg S.G.
      • Brouwer M.C.
      • van der Ende A.
      • van de Beek D.
      Adjunctive dexamethasone in adults with meningococcal meningitis.
      ]. A study of 198 children of whom 98 had bacterial meningitis revealed that lower thresholds for CSF protein level (>0.5 g/L) and a leukocyte count of >100 cells/mm3 were also strongly associated with bacterial meningitis (odds ratio 12 and 14) [
      • Dubos F.
      • Korczowski B.
      • Aygun D.A.
      • Martinot A.
      • Prat C.
      • Galetto-Lacour A.
      • et al.
      Serum procalcitonin level and other biological markers to distinguish between bacterial and aseptic meningitis in children: a European multicenter case cohort study.
      ]. A mildly elevated or normal number of leukocytes in the CSF can be found in patients with bacterial meningitis, especially in patients with concomitant septic shock [
      • Heckenberg S.G.
      • de Gans J.
      • Brouwer M.C.
      • Weisfelt M.
      • Piet J.R.
      • Spanjaard L.
      • et al.
      Clinical features, outcome, and meningococcal genotype in 258 adults with meningococcal meningitis: a prospective cohort study.
      ]. In a prospective study of 258 patients with CSF culture-proven meningococcal meningitis 19% of patients had less than 1000 cells/mm3 and five patients (1.7%) had a completely normal composition of CSF [
      • Heckenberg S.G.
      • de Gans J.
      • Brouwer M.C.
      • Weisfelt M.
      • Piet J.R.
      • Spanjaard L.
      • et al.
      Clinical features, outcome, and meningococcal genotype in 258 adults with meningococcal meningitis: a prospective cohort study.
      ]. In three of these five patients bacteria could be identified in the CSF Gram stain, which enabled the diagnosis of bacterial meningitis.
      The extent of CSF abnormalities depends on the causative microorganism [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ]. In culture-proven pneumococcal meningitis 5% of 153 patients have CSF WBC counts of <10 cells/mm3, and 17% have less than 100 cells/mm3 [
      • Ostergaard C.
      • Konradsen H.B.
      • Samuelsson S.
      Clinical presentation and prognostic factors of Streptococcus pneumoniae meningitis according to the focus of infection.
      ]. In a prospective cohort study of 62 patients with L. monocytogenes meningitis, CSF abnormalities were not typical for bacterial meningitis in 26% of cases [
      • Koopmans M.M.
      • Brouwer M.C.
      • Bijlsma M.W.
      • Bovenkerk S.
      • Keijzers W.
      • van der Ende A.
      • et al.
      Listeria monocytogenes sequence type 6 and increased rate of unfavorable outcome in meningitis: epidemiologic cohort study.
      ]. It is commonly assumed that antibiotic treatment before hospital admission modifies CSF pleocytosis, but one retrospective study in 245 children with bacterial meningitis suggested that the CSF WBC count is not greatly different between patients who have received or have not received lengthy courses of antibiotics before lumbar puncture [
      • Nigrovic L.E.
      • Malley R.
      • Macias C.G.
      • Kanegaye J.T.
      • Moro-Sutherland D.M.
      • Schremmer R.D.
      • et al.
      Effect of antibiotic pretreatment on cerebrospinal fluid profiles of children with bacterial meningitis.
      ].
      The CSF lactate concentration is a widely available, cheap and rapid diagnostic test [
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      • van de Beek D.
      Dilemmas in the diagnosis of acute community-acquired bacterial meningitis.
      ]. Two meta-analyses were performed on the diagnostic use of CSF lactate in the differentiation of bacterial meningitis vs. other types of meningitis. One included 25 studies with 1692 patients (adults and children) [
      • Huy N.T.
      • Thao N.T.
      • Diep D.T.
      • Kikuchi M.
      • Zamora J.
      • Hirayama K.
      Cerebrospinal fluid lactate concentration to distinguish bacterial from aseptic meningitis: a systemic review and meta-analysis.
      ], and the other included 31 studies with 1885 patients (adults and children) [
      • Sakushima K.
      • Hayashino Y.
      • Kawaguchi T.
      • Jackson J.L.
      • Fukuhara S.
      Diagnostic accuracy of cerebrospinal fluid lactate for differentiating bacterial meningitis from aseptic meningitis: a meta-analysis.
      ]. These meta-analyses concluded that the diagnostic accuracy of CSF lactate is better than that of CSF WBC count. In patients who received antibiotic treatment before lumbar puncture, CSF lactate concentration had a lower sensitivity (49%) compared to those not receiving antibiotic pretreatment (98%) [
      • Sakushima K.
      • Hayashino Y.
      • Kawaguchi T.
      • Jackson J.L.
      • Fukuhara S.
      Diagnostic accuracy of cerebrospinal fluid lactate for differentiating bacterial meningitis from aseptic meningitis: a meta-analysis.
      ]. CSF lactate concentration is less accurate for differentiating patients with other central nervous system diseases from meningitis, such as herpes encephalitis or seizures, as the concentrations may also be raised [
      • Buttner T.
      • Dorndorf W.
      [Viral encephalitis. Experiences with 53 patients in Middle Hessia].
      ,
      • Chow S.L.
      • Rooney Z.J.
      • Cleary M.A.
      • Clayton P.T.
      • Leonard J.V.
      The significance of elevated CSF lactate.
      ]. Therefore, the usefulness of CSF lactate concentrations in patients pretreated with antibiotics, or those with other central nervous system diseases in the differential diagnosis, is probably limited.

       CSF culture, PCR, antigen and latex agglutination tests

      A retrospective study in 875 patients in whom the diagnosis of bacterial meningitis was based on a CSF leukocyte count of >1000 WBC/mm3 or over 80% polymorphonuclear cells, CSF culture was positive in 85% of patients if not pretreated with antibiotics [
      • Bohr V.
      • Rasmussen N.
      • Hansen B.
      • Kjersem H.
      • Jessen O.
      • Johnsen N.
      • et al.
      875 cases of bacterial meningitis: diagnostic procedures and the impact of preadmission antibiotic therapy. Part III of a three-part series.
      ]. CSF culture positivity differed per causative microorganism: CSF culture was positive in 96% of H. influenzae meningitis cases compared to 87% in pneumococcal and 82% in meningococcal meningitis cases. In another retrospective study in 231 children, 82% of CSF cultures were positive [
      • Nigrovic L.E.
      • Malley R.
      • Macias C.G.
      • Kanegaye J.T.
      • Moro-Sutherland D.M.
      • Schremmer R.D.
      • et al.
      Effect of antibiotic pretreatment on cerebrospinal fluid profiles of children with bacterial meningitis.
      ]. A retrospective study from Brazil including 3973 patients showed a lower yield of CSF cultures: CSF culture was positive in 67% of patients [
      • Bryan J.P.
      • de Silva H.R.
      • Tavares A.
      • Rocha H.
      • Scheld W.M.
      Etiology and mortality of bacterial meningitis in northeastern Brazil.
      ]. The yield of CSF culture decreases when a patient is treated with antibiotics before lumbar puncture. Two large cohort studies showed a decrease in culture positivity from 66% to 62% and from 88% to 70% when the patients received antibiotics before lumbar puncture [
      • Nigrovic L.E.
      • Malley R.
      • Macias C.G.
      • Kanegaye J.T.
      • Moro-Sutherland D.M.
      • Schremmer R.D.
      • et al.
      Effect of antibiotic pretreatment on cerebrospinal fluid profiles of children with bacterial meningitis.
      ,
      • Bohr V.
      • Rasmussen N.
      • Hansen B.
      • Kjersem H.
      • Jessen O.
      • Johnsen N.
      • et al.
      875 cases of bacterial meningitis: diagnostic procedures and the impact of preadmission antibiotic therapy. Part III of a three-part series.
      ].
      The CSF Gram stain is a quick method to identify the cause of bacterial meningitis [
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      • van de Beek D.
      Dilemmas in the diagnosis of acute community-acquired bacterial meningitis.
      ]. Furthermore, the test is cheap and validated. CSF Gram stains have been shown to have incremental value when the CSF culture is negative, e.g. when a patient is treated with antibiotics before lumbar puncture [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ]. In a retrospective study of 875 patients, the Gram stain was the only positive microbiologic finding in 4% of patients [
      • Bohr V.
      • Rasmussen N.
      • Hansen B.
      • Kjersem H.
      • Jessen O.
      • Johnsen N.
      • et al.
      875 cases of bacterial meningitis: diagnostic procedures and the impact of preadmission antibiotic therapy. Part III of a three-part series.
      ]. The sensitivity of the Gram stain depends on the causative microorganism. The aggregate diagnostic yield of CSF Gram stain is 25–35% in L. monocytogenes meningitis, 50% in H. influenzae meningitis, 70–90% in meningococcal meningitis and 90% in pneumococcal meningitis [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ]. Quality and speed of performing a Gram stain depends on the hospital's infrastructure and the experience of the assessor. If these are optimal, the specificity of the Gram stain is almost 100% [
      • Dunbar S.A.
      • Eason R.A.
      • Musher D.M.
      • Clarridge III, J.E.
      Microscopic examination and broth culture of cerebrospinal fluid in diagnosis of meningitis.
      ]. The yield of the Gram stain may decrease slightly if antibiotic treatment is initiated before lumbar puncture. A Danish study in 481 children showed that the yield decreased from 56% to 52% [
      • Bohr V.
      • Hansen B.
      • Jessen O.
      • Johnsen N.
      • Kjersem H.
      • Kristensen H.S.
      • et al.
      Eight hundred and seventy-five cases of bacterial meningitis. Part I of a three-part series: clinical data, prognosis, and the role of specialised hospital departments.
      ]. In an American study of 245 children there was a similar yield whether or not antibiotic treatment had been started (63% positive with antibiotic pretreatment, 62% without pretreatment) [
      • Nigrovic L.E.
      • Malley R.
      • Macias C.G.
      • Kanegaye J.T.
      • Moro-Sutherland D.M.
      • Schremmer R.D.
      • et al.
      Effect of antibiotic pretreatment on cerebrospinal fluid profiles of children with bacterial meningitis.
      ].
      Several studies have assessed the test characteristics of PCR on CSF in the diagnosis of bacterial meningitis and reported sensitivities of 79–100% for S. pneumoniae, 91–100% for N. meningitidis and 67–100% for H. influenzae [
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      • van de Beek D.
      Dilemmas in the diagnosis of acute community-acquired bacterial meningitis.
      ]. Reported specificity was 95–100% for all microorganisms. PCR was shown to have incremental value compared to CSF culture and Gram stain [
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      • van de Beek D.
      Dilemmas in the diagnosis of acute community-acquired bacterial meningitis.
      ,
      • Corless C.E.
      • Guiver M.
      • Borrow R.
      • Edwards-Jones V.
      • Fox A.J.
      • Kaczmarski E.B.
      Simultaneous detection of Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae in suspected cases of meningitis and septicemia using real-time PCR.
      ,
      • Tzanakaki G.
      • Tsopanomichalou M.
      • Kesanopoulos K.
      • Matzourani R.
      • Sioumala M.
      • Tabaki A.
      • et al.
      Simultaneous single-tube PCR assay for the detection of Neisseria meningitidis, Haemophilus influenzae type b and Streptococcus pneumoniae.
      ]. A study in 409 bacterial meningitis patients from Burkina Faso showed 33% of patients were diagnosed by PCR only and could not be diagnosed by conventional methods [
      • Parent du Châtelet I.
      • Traore Y.
      • Gessner B.D.
      • Antignac A.
      • Naccro B.
      • Njanpop-Lafourcade B.M.
      • et al.
      Bacterial meningitis in Burkina Faso: surveillance using field-based polymerase chain reaction testing.
      ]. A study from the meningococcal reference unit in the United Kingdom showed that currently 1099 (57%) of 1925 invasive meningococcal disease patients were confirmed by PCR only [
      • Heinsbroek E.
      • Ladhani S.
      • Gray S.
      • Guiver M.
      • Kaczmarski E.
      • Borrow R.
      • et al.
      Added value of PCR-testing for confirmation of invasive meningococcal disease in England.
      ]. Similar results were shown in children with meningococcal disease in Spain, in whom 46 of 188 cases were confirmed only by PCR [
      • Munoz-Almagro C.
      • Rodriguez-Plata M.T.
      • Marin S.
      • Esteva C.
      • Esteban E.
      • Gene A.
      • et al.
      Polymerase chain reaction for diagnosis and serogrouping of meningococcal disease in children.
      ]. PCR was negative in 5% of culture-positive cases in this study. The availability of rapid CSF PCRs is variable according to country. PCR is particularly useful in patients who received intravenous antibiotic treatment before lumbar puncture, as CSF and blood cultures in these patients are often negative. PCR can be performed on both CSF and EDTA blood. A disadvantage of PCR compared to CSF culture is the lack of antimicrobial susceptibility data and subtyping of the microorganism: when detecting meningococci, only the serogroup can be determined by PCR. In children, PCR for pneumococcal DNA within blood may be positive even when the child is merely colonized and has no bacteraemia, but this varies according to the test that is used [
      • Rouphael N.
      • Steyn S.
      • Bangert M.
      • Adrian P.
      • Madhi S.A.
      • Klugman K.P.
      • et al.
      Use of 2 pneumococcal common protein real-time polymerase chain reaction assays in healthy children colonized with Streptococcus pneumoniae.
      ]. Finally, 5–26% of bacterial meningitis cases in children and adults (Table 2.2, Table 2.3) are caused by bacteria other than S. pneumoniae, N. meningitidis and H. influenzae and are therefore routinely detected by PCR. Therefore, as yet, PCR will not completely usurp CSF culture in the diagnosis of bacterial meningitis, but is a useful additional test, especially if the Gram stain is found to be negative. For suspected meningococcal disease, PCR is considered essential in the diagnosis by the European Monitoring Group on Meningococci (EMGM) [
      • Fox A.J.
      • Taha M.K.
      • Vogel U.
      Standardized nonculture techniques recommended for European reference laboratories.
      ]. Studies analysing the test characteristics of L. monocytogenes PCR in meningitis showed culture-positive CSF samples were positive by PCR as well [
      • Le Monnier A.
      • Abachin E.
      • Beretti J.L.
      • Berche P.
      • Kayal S.
      Diagnosis of Listeria monocytogenes meningoencephalitis by real-time PCR for the hly gene.
      ]. However, the incremental value of PCR in Listeria meningitis next to culture is currently unclear.
      Latex agglutination is a diagnostic method that can be used to determine rapidly the causative microorganism. The reported sensitivity of latex agglutination testing in CSF differs by the causative microorganism: for H. influenzae the reported sensitivity varies 78–100%, for S. pneumoniae 59–100% and for N. meningitidis 22–93% [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ]. In clinical practice, latex agglutination testing has offered little incremental value over other tests. In a retrospective study in 176 children with negative CSF cultures who were treated with antibiotics before lumbar puncture, no latex agglutination test was positive [
      • Nigrovic L.E.
      • Kuppermann N.
      • McAdam A.J.
      • Malley R.
      Cerebrospinal latex agglutination fails to contribute to the microbiologic diagnosis of pretreated children with meningitis.
      ]. A study of 28 patients with negative CSF cultures but with clinical and CSF characteristics of bacterial meningitis showed a sensitivity of 7% of latex agglutination tests [
      • Tarafdar K.
      • Rao S.
      • Recco R.A.
      • Zaman M.M.
      Lack of sensitivity of the latex agglutination test to detect bacterial antigen in the cerebrospinal fluid of patients with culture-negative meningitis.
      ]. A third study showed seven positive latex agglutination tests in 478 CSF samples: in all seven the pathogen had been identified by Gram stain as well [
      • Perkins M.D.
      • Mirrett S.
      • Reller L.B.
      Rapid bacterial antigen detection is not clinically useful.
      ]. The sensitivity of latex agglutination tests decreased from 60% to 9% in patients in whom treatment was started before the lumbar puncture was performed. Because of the limited value of latex agglutination, these tests are not advised in the diagnosis of bacterial meningitis when other methods are available such as Gram staining [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ].
      An immunochromatographic antigen test for the detection of S. pneumoniae in CSF has been evaluated in a study including 450 children with suspected acute bacterial meningitis [
      • Saha S.K.
      • Darmstadt G.L.
      • Yamanaka N.
      • Billal D.S.
      • Nasreen T.
      • Islam M.
      • et al.
      Rapid diagnosis of pneumococcal meningitis: implications for treatment and measuring disease burden.
      ]. The test was shown to be 100% sensitive and specific for the diagnosis of pneumococcal meningitis; the overall sensitivity of this test ranged 95–100%. Another study including 1179 CSF samples from children in Bangladesh with suspected bacterial meningitis also revealed high sensitivity (98.6%) and specificity (99.3%). CSF immunochromatography was superior to CSF culture and latex agglutination testing in this study, but a comparison to CSF Gram staining was not done [
      • Moisi J.C.
      • Saha S.K.
      • Falade A.G.
      • Njanpop-Lafourcade B.M.
      • Oundo J.
      • Zaidi A.K.
      • et al.
      Enhanced diagnosis of pneumococcal meningitis with use of the Binax NOW immunochromatographic test of Streptococcus pneumoniae antigen: a multisite study.
      ]. False-positive results have been reported in patients with meningitis due to other streptococcal species [
      • Alonso-Tarres C.
      • Cortes-Lletget C.
      • Casanova T.
      • Domenech A.
      False-positive pneumococcal antigen test in meningitis diagnosis.
      ]. Further studies in patients with negative CSF culture and Gram stain should be performed to determine whether this method has any value in addition to standard diagnostic methods.

       Serum markers of inflammation

      When differentiating between viral and bacterial meningitis, serum inflammatory markers may contribute to the diagnosis. Several retrospective studies have suggested that serum concentrations of C-reactive protein (CRP) and pro-calcitonin are highly discriminatory between paediatric bacterial and viral meningitis [
      • Dubos F.
      • Korczowski B.
      • Aygun D.A.
      • Martinot A.
      • Prat C.
      • Galetto-Lacour A.
      • et al.
      Serum procalcitonin level and other biological markers to distinguish between bacterial and aseptic meningitis in children: a European multicenter case cohort study.
      ,
      • Sormunen P.
      • Kallio M.J.
      • Kilpi T.
      • Peltola H.
      C-reactive protein is useful in distinguishing Gram stain–negative bacterial meningitis from viral meningitis in children.
      ]. The reported sensitivity in a study of 507 children with a CRP level >40 mg/L was 93% with a specificity of 100% [
      • Sormunen P.
      • Kallio M.J.
      • Kilpi T.
      • Peltola H.
      C-reactive protein is useful in distinguishing Gram stain–negative bacterial meningitis from viral meningitis in children.
      ]. A meta-analysis of several small studies including 198 children showed increased serum pro-calcitonin and CRP concentrations were associated with acute bacterial meningitis [
      • Dubos F.
      • Korczowski B.
      • Aygun D.A.
      • Martinot A.
      • Prat C.
      • Galetto-Lacour A.
      • et al.
      Serum procalcitonin level and other biological markers to distinguish between bacterial and aseptic meningitis in children: a European multicenter case cohort study.
      ]. A study in adults showed good sensitivity and specificity of procalcitonin in 105 patients with bacterial meningitis, viral meningitis or no meningitis [
      • Viallon A.
      • Zeni F.
      • Lambert C.
      • Pozzetto B.
      • Tardy B.
      • Venet C.
      • et al.
      High sensitivity and specificity of serum procalcitonin levels in adults with bacterial meningitis.
      ]. In clinical practice other bacterial infections such as sepsis and pneumonia may be included in the differential diagnosis of bacterial meningitis, and in these situations CRP and pro-calcitonin may be of little value for the diagnosis of bacterial meningitis.

       Blood cultures

      Blood cultures are valuable for detection of the causative organism and establish susceptibility patterns if CSF cultures are negative or unavailable, e.g. when lumbar puncture is contraindicated [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ]. The rate of blood culture positivity is different for each causative organism and is 75% of pneumococcal meningitis patients, 50–90% for H. influenzae meningitis patients and 40–60% of patients with meningococcal meningitis [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ]. The yield of blood cultures was shown to decrease by 20% if patients are treated with antibiotics before blood culture [
      • Nigrovic L.E.
      • Malley R.
      • Macias C.G.
      • Kanegaye J.T.
      • Moro-Sutherland D.M.
      • Schremmer R.D.
      • et al.
      Effect of antibiotic pretreatment on cerebrospinal fluid profiles of children with bacterial meningitis.
      ].

       Other diagnostic methods studied in bacterial meningitis

      A plethora of studies have assessed whether individual CSF chemokine, cytokine, complement factors and metabolite levels, quantitative EEG, cranial magnetic resonance imaging (MRI) or a thermogram can be useful in the diagnosis of bacterial meningitis. Few markers were replicated in independent cohorts or compared to the test characteristics of the marker to standard diagnostics tests. These studies may be valuable for pathophysiologic research but so far have not reached implementation in a clinical setting.

       Conclusions

      Tabled 1
      Level 2In neonatal meningitis, CSF leukocyte count, glucose and total protein levels are frequently within normal range or only slightly elevated.
      Tabled 1
      Level 2It has been shown that in both children and adults, classic characteristics (elevated protein levels, lowered glucose levels, CSF pleocytosis) of bacterial meningitis are present in ≥90% of patients. A completely normal CSF occurs but is very rare.
      Tabled 1
      Level 2CSF lactate concentration has a good sensitivity and specificity for differentiating bacterial from aseptic meningitis. The value of CSF lactate is limited in patients who received antibiotic pretreatment or those with other central nervous system disease in the differential diagnosis.
      Tabled 1
      Level 2CSF culture is positive in 60–90% of bacterial meningitis patients depending on the definition of bacterial meningitis. Pretreatment with antibiotics decreases the yield of CSF culture by 10–20%.
      Tabled 1
      Level 2CSF Gram stain has an excellent specificity and varying sensitivity, depending on the microorganism. The yield decreases slightly if the patient has been treated with antibiotics before lumbar puncture is performed.
      Tabled 1
      Level 2In patients with a negative CSF culture and CSF Gram stain, PCR has additive value in the identification of the pathogen.
      Tabled 1
      Level 2Latex agglutination testing has little incremental value in the diagnosis of bacterial meningitis.
      Tabled 1
      Level 2It is unclear whether immunochromatographic antigen testing has incremental value in the diagnosis of bacterial meningitis.
      Tabled 1
      Level 2In children with meningitis, elevated CRP and pro-calcitonin levels in blood are associated with bacterial infections. The diagnosis of bacterial meningitis can, however, not be made with these tests.
      Tabled 1
      Level 2In adults and children with bacterial meningitis, blood cultures are useful to isolate the causative microorganism. The yield of blood cultures decreases if the patient is pretreated with antibiotics.

       Recommendation

      Tabled 1
      Grade AIn patients with suspected bacterial meningitis, it is strongly recommended to determine CSF leukocyte count, protein and glucose concentration, and to perform CSF culture and Gram stain.
      Tabled 1
      Grade AIn patients with negative CSF cultures, the causative microorganisms can be identified by PCR and potentially by immunochromatographic antigen testing.
      Tabled 1
      Grade AIn patients with suspected bacterial meningitis, it is strongly recommended to perform blood cultures before the first dose of antibiotics is administered.
      Key Question 4. Can we use clinical characteristics to predict the absence of intracranial abnormalities associated with increased risk of lumbar puncture?

       Imaging before lumbar puncture

       Indications for cranial imaging before lumbar puncture

      Lumbar puncture is crucial in the diagnosis of bacterial meningitis to confirm the diagnosis, identify the pathogen and determine the resistance pattern to rationalize antibiotic treatment. Before the lumbar puncture is performed, the physician needs to establish whether contraindications exist. Lumbar puncture can be hazardous if brain shift is present due to space-occupying lesions [
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      • van de Beek D.
      Dilemmas in the diagnosis of acute community-acquired bacterial meningitis.
      ]. The withdrawal of CSF at the lumbar level can increase brain shift that may lead to cerebral herniation. The literature search identified 19 studies describing 74 bacterial meningitis patients in whom cerebral herniation occurred in timely association to the lumbar puncture. However, a causal relationship is difficult to establish, as brain herniation also occurs during bacterial meningitis disease course, irrespective of lumbar puncture. The risk of cerebral herniation due to lumbar puncture may be reduced by detecting conditions associated with brain shift by cranial imaging (usually computed tomography, CT), such as brain abscess, subdural empyema or large cerebral infarction [
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      • van de Beek D.
      Dilemmas in the diagnosis of acute community-acquired bacterial meningitis.
      ,
      • Hasbun R.
      • Abrahams J.
      • Jekel J.
      • Quagliarello V.J.
      Computed tomography of the head before lumbar puncture in adults with suspected meningitis.
      ]. Cranial imaging, however, was shown to lead to a substantial delay in initiation of antibiotic treatment, which is associated with poor outcome [
      • Aronin S.I.
      • Peduzzi P.
      • Quagliarello V.J.
      Community-acquired bacterial meningitis: risk stratification for adverse clinical outcome and effect of antibiotic timing.
      ,
      • Proulx N.
      • Frechette D.
      • Toye B.
      • Chan J.
      • Kravcik S.
      Delays in the administration of antibiotics are associated with mortality from adult acute bacterial meningitis.
      ]. A study in 235 adults with suspected bacterial meningitis showed that intracranial space-occupying lesions are associated with clinical characteristics [
      • Hasbun R.
      • Abrahams J.
      • Jekel J.
      • Quagliarello V.J.
      Computed tomography of the head before lumbar puncture in adults with suspected meningitis.
      ]. Therefore, clinical examination can be used to select patients at risk for lesions causing brain shift in whom CT before lumbar puncture is warranted. On the basis of the above-mentioned study, a set of criteria have been proposed to select patients for cranial imaging [
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      • van de Beek D.
      Dilemmas in the diagnosis of acute community-acquired bacterial meningitis.
      ,
      • van de Beek D.
      • de Gans J.
      • Tunkel A.R.
      • Wijdicks E.F.
      Community-acquired bacterial meningitis in adults.
      ]: focal neurologic deficits (excluding cranial nerve palsies), new-onset seizures, severely altered mental status (defined as a score on the Glasgow Coma Scale of <10) and severely immunocompromised state (e.g. in organ transplant recipients and HIV-infected patients).
      In the absence of the aforementioned features, CT is not recommended before lumbar puncture in suspected bacterial meningitis patients, as it is unlikely to provide new information on the risk of lumbar puncture–associated herniation in this patient population. In these patients, cranial imaging for other diagnostic purposes such as the detection of mastoiditis or sinusitis should be performed after the lumbar puncture.
      The studies described above were all performed in adults. We found no studies addressing this question for children in our search. The guideline committee's consensus is to use the same indications to perform CT before lumbar puncture in children (beyond the neonatal age) as in adults. For neonates, no data are available to guide daily practice on the use of ancillary investigations before lumbar puncture.
      Other contraindications for lumbar puncture, not related to space-occupying intracranial lesions, are coagulation disorders, local skin infections and need for haemodynamic stabilization before further diagnostic procedures.
      Subquestion 4.1. If lumbar puncture is delayed, should we start treatment?

       Treatment before or after lumbar puncture

      The literature search yielded two prospective and six retrospective studies evaluating the effect of timing of antibiotic treatment on outcome of bacterial meningitis [
      • Aronin S.I.
      • Peduzzi P.
      • Quagliarello V.J.
      Community-acquired bacterial meningitis: risk stratification for adverse clinical outcome and effect of antibiotic timing.
      ,
      • Proulx N.
      • Frechette D.
      • Toye B.
      • Chan J.
      • Kravcik S.
      Delays in the administration of antibiotics are associated with mortality from adult acute bacterial meningitis.
      ]. These studies showed that delayed initiation of antibiotic treatment in bacterial meningitis patients is strongly associated with death and poor outcome. The delay in treatment was often due to cranial imaging before lumbar puncture. Therefore, antibiotic treatment in patients with acute bacterial meningitis should be started as soon as possible, and the time period from entering the hospital to initiation of antibiotic treatment should not exceed 1 hour. Whenever lumbar puncture is delayed, e.g. due to cranial CT, empiric treatment must be started immediately upon clinical suspicion even if the diagnosis has not been established. In these patients, blood cultures must be drawn to before initiating antibiotics to increase the chance of identifying the causative pathogen.

       Conclusions

      Tabled 1
      Level 2The risk of cerebral herniation after lumbar puncture in patients with suspected bacterial meningitis is increased compared to normal individuals.
      Tabled 1
      Level 3Clinical characteristics can be used to identify patients with an increased risk for space-occupying lesions associated with increased risk of cerebral herniation due to lumbar puncture.
      Tabled 1
      Level 2A delay in antibiotic treatment administration is associated with poor outcome and should therefore be avoided.

       Recommendation

      Tabled 1
      Grade AIt is strongly recommended to perform cranial imaging before lumbar puncture in patients with:
      • Focal neurologic deficits (excluding cranial nerve palsies).
      • New-onset seizures.
      • Severely altered mental status (Glasgow Coma Scale score <10).
      • Severely immunocompromised state.
      In patients lacking these characteristics, cranial imaging before lumbar puncture is not recommended.
      Tabled 1
      Grade AIt is strongly recommended to start antibiotic therapy as soon as possible in acute bacterial meningitis patients. The time period until antibiotics are administered should not exceed 1 hour. Whenever lumbar puncture is delayed, e.g. due to cranial CT, empiric treatment must be started immediately on clinical suspicion, even if the diagnosis has not been established.

      Treatment of bacterial meningitis

      Key Question 5. What is the optimal type, duration and method of administration of antibiotic treatment when started empirically, after the pathogen has been identified or in culture-negative patients?

       Antibiotic treatment

       Empiric antibiotic treatment

      The choice of empiric antibiotic treatment is conditional on the age of the patient and the regional rate of decreased susceptibility to penicillin and third-generation cephalosporins of S. pneumoniae (Table 4.1). The spectrum of pathogens in neonates is considerably different to that of children beyond the neonatal age and adults, which is reflected by the empiric antibiotic treatment for this age group. When there is a risk of decreased susceptibility of S. pneumoniae, empiric treatment should include vancomycin or rifampicin. However, some experts advise the use of ceftriaxone or cefotaxime as empiric treatment instead of vancomycin or rifampicin when true resistance to third-generation cephalosporin (minimum inhibitory concentration (MIC) >2 mg/L) is not to be expected. When risk factors for an infection with L. monocytogenes are present in adults under the age of 50 years (e.g. diabetes, use of immunosuppressive drugs, cancer) or in adults over the age of 50 years, empiric antibiotic treatment should include amoxicillin or ampicillin to cover for L. monocytogenes. A recent nationwide Dutch study revealed that during a period of 6 years, four cases of L. monocytogenes occurred in adults under the age of 50 without specific risk factors (out of 259 patients aged <50 years without immunocompromised state (1.5%)) [
      • Koopmans M.M.
      • Brouwer M.C.
      • Bijlsma M.W.
      • Bovenkerk S.
      • Keijzers W.
      • van der Ende A.
      • et al.
      Listeria monocytogenes sequence type 6 and increased rate of unfavorable outcome in meningitis: epidemiologic cohort study.
      ]. If the physician wishes to cover for this rare possibility, empiric antibiotic treatment should include amoxicillin or ampicillin for all adults with bacterial meningitis.
      Table 4.1Empiric antibiotic in-hospital treatment for community-acquired bacterial meningitis
      • van de Beek D.
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      Advances in treatment of bacterial meningitis.
      Patient groupStandard treatmentIntravenous dose
      a Diabetes mellitus, use of immunosuppressive drugs, cancer and other conditions causing immunocompromise.
      Reduced Streptococcus pneumoniae antimicrobial sensitivity to penicillinS. pneumoniae susceptible to penicillin
      Neonates <1 month oldAmoxicillin/ampicillin/penicillin plus cefotaxime, or amoxicillin/ampicillin plus an aminoglycosideAge <1 week: cefotaxime 50 mg/kg q8h; ampicillin/amoxicillin 50 mg/kg q8h; gentamicin 2.5 mg/kg q12h

      Age 1–4 weeks: ampicillin 50 mg/kg q6h; cefotaxime 50mg/kg q6–8h; gentamicin 2.5 mg/kg q8h; tobramycin 2.5 mg/kg q8h; amikacin 10 mg/kg q8h
      Age 1 month to 18 yearsCefotaxime or ceftriaxone plus vancomycin or rifampicinCefotaxime or ceftriaxoneVancomycin 10–15 mg/kg q6h to achieve serum trough concentrations of 15–20 μg/mL; rifampicin 10 mg/kg q12h up to 600 mg/day; cefotaxime 75 mg/kg q6–8h; ceftriaxone 50 mg/kg q12h (maximum 2 g q12h)
      Age >18 and <50 yearsCefotaxime or ceftriaxone plus vancomycin or rifampicinCefotaxime or ceftriaxoneCeftriaxone 2 g q12h or 4 g q24h; cefotaxime 2 g q4–6 h; vancomycin 10–20 mg/kg q8–12h to achieve serum trough concentrations of 15–20 μg/mL; rifampicin 300 mg q12h
      Age >50 years, or

      Age >18 and <50 years plus risk factors for Listeria monocytogenes
      a Diabetes mellitus, use of immunosuppressive drugs, cancer and other conditions causing immunocompromise.
      Cefotaxime or ceftriaxone plus vancomycin or rifampicin plus amoxicillin/ampicillin/penicillin GCefotaxime or ceftriaxone plus amoxicillin/ampicillin/penicillin GCeftriaxone 2 g q12h or 4 g q24h; cefotaxime 2 g q4–6h; vancomycin 10–20 mg/kg q8–12h to achieve serum trough concentrations of 15–20 μg/mL; rifampicin 300 mg q12h, amoxicillin or ampicillin 2 g q4h
      a Diabetes mellitus, use of immunosuppressive drugs, cancer and other conditions causing immunocompromise.

       Specific antibiotic treatment after identification of causative microorganism

      After identification of the pathogen through culture and antibiotic susceptibility testing, the antibiotic treatment can be optimized.

       Streptococcus pneumoniae

      Streptococcus pneumoniae is currently the most common causative microorganism in adults and the second most common in children beyond the neonatal age. Reduced susceptibility to penicillin and third-generation cephalosporins of S. pneumoniae is a growing problem in Europe, although resistance rates vary considerably between countries [
      • van de Beek D.
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      Advances in treatment of bacterial meningitis.
      ]. For example, rates of reduced susceptibility to penicillin in the Netherlands, England, Denmark and Germany are <1%, while reduced susceptibility rates of 20–50% have been reported for Spain, France and Romania (data from 2011 European Centre for Disease Prevention and Control surveillance report). When S. pneumoniae has been identified and susceptibility testing is pending or not available, treatment should be based on local resistance rates (Table 4.2).
      Subquestion 5.1. Does the addition of vancomycin or rifampicin to a third-generation cephalosporin improve outcome in pneumococcal meningitis patients in the setting of a high resistance rate of pneumococci?
      Table 4.2Specific antibiotic in-hospital treatment for community-acquired bacterial meningitis
      a Recommendations must be in accordance with the results of the susceptibility testing.
      MicroorganismStandard treatmentAlternativesDuration
      Streptococcus pneumoniae
       Penicillin susceptible (MIC <0.1 μg/mL)Penicillin or amoxicillin/ampicillinCeftriaxone, cefotaxime, chloramphenicol10–14 days
       Penicillin resistant (MIC >0.1 μg/mL), third-generation cephalosporin susceptible (MIC <2 μg/mL)Ceftriaxone or cefotaximeCefepime, meropenem, moxifloxacin
      b Based on case reports.
      10–14 days
       Cephalosporin resistant (MIC ≥2 μg/mL)Vancomycin plus rifampicin, or vancomycin plus ceftriaxone or cefotaxime, or rifampicin plus ceftriaxone or cefotaxime
      c Ceftriaxone dose 2 g q12h and cefotaxime 2–3g q6h.
      Vancomycin plus moxifloxacin,
      b Based on case reports.
      linezolid
      10–14 days
      Neisseria meningitidis
       Penicillin susceptible (MIC <0.1 μg/mL)Penicillin or amoxicillin/ampicillinCeftriaxone, cefotaxime, chloramphenicol7 days
       Penicillin resistant (MIC ≥0.1 μg/mL)Ceftriaxone or cefotaximeCefipime, meropenem, ciprofloxacin or chloramphenicol7 days
      Listeria monocytogenesAmoxicillin or ampicillin, penicillin G
      d Adding an aminoglycoside can be considered.
      trimethoprim-sulfamethoxazole, moxifloxacin,
      b Based on case reports.
      meropenem, linezolid
      At least 21 days
      Haemophilus influenzae
       β-Lactamase negativeAmoxicillin or ampicillinCeftriaxone, cefotaxime or chloramphenicol7–10 days
       β-Lactamase positiveCeftriaxone or cefotaximCefepime, ciprofloxacin, chloramphenicol7–10 days
       β-Lactamase negative ampicillin resistantCeftriaxone or cefotaxime plus meropenemCiprofloxacin7–10 days
      Staphylococcus aureus
       Methicillin sensitiveFlucloxacillin, nafcillin, oxacillinVancomycin, linezolid, rifampicin,
      e Must not be used in monotherapy.
      fosfomycin,
      e Must not be used in monotherapy.
      daptomycin
      b Based on case reports.
      At least 14 days
       Methicillin resistantVancomycin
      f Addition of rifampicin can be considered.
      Trimethoprim/sulfamethoxazole, linezolid, rifampicin,
      e Must not be used in monotherapy.
      fosfomycin,
      e Must not be used in monotherapy.
      daptomycin
      At least 14 days
       Vancomycin resistant (MIC >2.0 μg/mL)Linezolid
      f Addition of rifampicin can be considered.
      Rifampicin,
      e Must not be used in monotherapy.
      fosfomycin,
      e Must not be used in monotherapy.
      daptomycin
      b Based on case reports.
      At least 14 days
      a Recommendations must be in accordance with the results of the susceptibility testing.
      b Based on case reports.
      c Ceftriaxone dose 2 g q12h and cefotaxime 2–3g q6h.
      d Adding an aminoglycoside can be considered.
      e Must not be used in monotherapy.
      f Addition of rifampicin can be considered.
      There is uncertainty regarding the benefit of adding vancomycin or rifampicin to a third-generation cephalosporin in pneumococcal meningitis patients in the setting of decreased susceptibility rates of pneumococci. We systematically evaluated the literature for studies of the efficacy of vancomycin and rifampicin in infections caused by pneumococci resistant to third-generation cephalosporins, but only animal studies were identified [
      • Suntur B.M.
      • Yurtseven T.
      • Sipahi O.R.
      • Buke C.
      • Buke M.
      Rifampicin + ceftriaxone versus vancomycin + ceftriaxone in the treatment of penicillin- and cephalosporin-resistant pneumococcal meningitis in an experimental rabbit model.
      ,
      • Lee H.
      • Song J.H.
      • Kim S.W.
      • Oh W.S.
      • Jung S.I.
      • Kiem S.
      • et al.
      Evaluation of a triple-drug combination for treatment of experimental multidrug-resistant pneumococcal meningitis.
      ,
      • Friedland I.R.
      • Paris M.
      • Ehrett S.
      • Hickey S.
      • Olsen K.
      • McCracken Jr., G.H.
      Evaluation of antimicrobial regimens for treatment of experimental penicillin- and cephalosporin-resistant pneumococcal meningitis.
      ]. These showed that ceftriaxone combined with either vancomycin or rifampicin resulted in a higher rate of CSF sterilization after 24 hours compared to monotherapy with ceftriaxone. Another animal study showed the superiority of ceftriaxone combined with either rifampicin or rifampicin and vancomycin compared to ceftriaxone combined with vancomycin. Although there is no clinical evidence for adding vancomycin or rifampicin in the setting of lower pneumococcal susceptibility rates, the committee advises addition of vancomycin or rifampicin to third-generation cephalosporins based on in vitro susceptibility patterns [
      • Erdem H.
      • Elaldi N.
      • Oztoprak N.
      • Sengoz G.
      • Ak O.
      • Kaya S.
      • et al.
      Mortality indicators in pneumococcal meningitis: therapeutic implications.
      ]. The advised duration of treatment is 10–14 days [
      • van de Beek D.
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      Advances in treatment of bacterial meningitis.
      ,
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      • van de Beek D.
      Dilemmas in the diagnosis of acute community-acquired bacterial meningitis.
      ,
      • Erdem I.
      • Hakan T.
      • Ceran N.
      • Metin F.
      • Akcay S.S.
      • Kucukercan M.
      • et al.
      Clinical features, laboratory data, management and the risk factors that affect the mortality in patients with postoperative meningitis.
      ].

       Neisseria meningitidis

      In the past decades, a proportional increase in meningococcal strains with reduced susceptibility to penicillin in meningococcal meningitis patients has been observed [
      • Latorre C.
      • Gene A.
      • Juncosa T.
      • Munoz C.
      • Gonzalez-Cuevas A.
      Neisseria meningitidis: evolution of penicillin resistance and phenotype in a children’s hospital in Barcelona, Spain.
      ]. A Spanish study described that up to 80% of meningococcal strains had reduced susceptibility to penicillin. The majority of patients with N. meningitidis strains of intermediate susceptibility to penicillin described in the literature responded well to penicillin therapy. However, a study in children with meningococcal meningitis described higher mortality and risk of sequelae when infected with strains with reduced susceptibility [
      • Luaces C.C.
      • Garcia Garcia J.J.
      • Roca M.J.
      • Latorre Otin C.L.
      Clinical data in children with meningococcal meningitis in a Spanish hospital.
      ].
      Therefore, patients with suspected meningococcal meningitis caused by bacterial strains that on the basis of the local epidemiology are likely to be resistant to penicillin, a third-generation cephalosporin should be provided until in vitro susceptibility testing is performed. The advised duration of treatment is 7 days [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ,
      • van de Beek D.
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      Advances in treatment of bacterial meningitis.
      ,
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      • van de Beek D.
      Dilemmas in the diagnosis of acute community-acquired bacterial meningitis.
      ].

       Listeria monocytogenes

      Linezolid, penicillin, ampicillin, gentamicin, quinolones, meropenem, chloramphenicol and vancomycin were shown to be effective against Listeria species in in vitro studies. However, there are limited clinical data to make strong recommendations for one of these agents in Listeria meningitis. Standard therapy for L. monocytogenes meningitis has been amoxicillin, ampicillin or penicillin G [
      • Tunkel A.R.
      • Hartman B.J.
      • Kaplan S.L.
      • Kaufman B.A.
      • Roos K.L.
      • Scheld W.M.
      • et al.
      Practice guidelines for the management of bacterial meningitis.
      ]. There is controversy on adding aminoglycosides to the regimen, as two retrospective series showed addition of an aminoglycoside was associated with renal failure. In these studies, however, several biases made direct comparison of treatment groups difficult. Adding aminoglycosides (gentamicin) could be considered as a treatment regimen for L. monocytogenes meningitis. Treating physicians should be cautious, however, about adding gentamicin, especially in terms of renal failure. There is no study assessing the optimal duration of the therapy in L. monocytogenes meningitis; the guideline panel recommends 21 days of therapy or longer.

       Staphylococcus aureus

      For staphylococcal meningitis, flucloxacillin, nafcillin, oxacillin or a combination therapy including fosfomycin or rifampicin are the recommended agents [
      • Brouwer M.C.
      • Tunkel A.R.
      • van de Beek D.
      Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis.
      ]. Vancomycin is recommended for methicillin-resistant staphylococcal meningitis. Linezolid may be chosen in cases of vancomycin resistance (MIC >2 μg/mL) or in cases of contraindications to vancomycin. Rifampicin could also be considered as supplementary therapy together with vancomycin or linezolid. Trimethoprim/sulfamethoxazole or daptomycin may be used as salvage therapy options, although only case reports support their use in staphylococcal meningitis. Rifampicin and fosfomycin must not be used as monotherapy to avoid the development of resistance. Although there is no study comparing the durations of therapy in staphylococcal meningitis, the guideline panel recommends at least 14 days of therapy. If staphylococci are identified as the cause of bacterial meningitis, then other sites of infections should be considered, such as endocarditis or spinal epidural abscesses, which may require surgical intervention and prolonged antibiotic therapy [
      • Brouwer M.C.
      • Keizerweerd G.D.
      • de Gans J.
      • Spanjaard L.
      • van de Beek D.
      Community acquired Staphylococcus aureus meningitis in adults.
      ].

       Culture-negative patients

      In patients with CSF suggestive of bacterial meningitis in whom the CSF culture and other tests (e.g. PCR) remain negative and the pathogen is not identified from other sites (e.g. blood culture, petechial rash culture), the committee's advice is to continue empiric treatment for a duration of at least 2 weeks. However, depending on the clinical condition of the patient, this may need to be extended.

       Duration of treatment

      The optimal duration of antibiotic treatment for bacterial meningitis has been studied in six randomized clinical trials in children. A meta-analysis of these trials concluded that there was insufficient evidence to advise a short course of antibiotics [
      • Karageorgopoulos D.E.
      • Valkimadi P.E.
      • Kapaskelis A.
      • Rafailidis P.I.
      • Falagas M.E.
      Short versus long duration of antibiotic therapy for bacterial meningitis: a meta-analysis of randomised controlled trials in children.
      ]. A large RCT showed a 5-day regimen was as effective as 10 days of antibiotics in children with bacterial meningitis who were in a stable condition after 3 days of treatment [
      • Molyneux E.
      • Nizami S.Q.
      • Saha S.
      • Huu K.T.
      • Azam M.
      • Bhutta Z.A.
      • et al.
      5 versus 10 days of treatment with ceftriaxone for bacterial meningitis in children: a double-blind randomised equivalence study.
      ]. Most of the children were resident in Malawi or Pakistan, and a large proportion had H. influenzae type b meningitis. Although there was equivalence in the short and long courses of antibiotics, the subgroups for each causative microorganism were too small to prove equivalence. Because of the substantial differences in epidemiology, clinical characteristics and comorbidity between the study population and children in the European situation, the results of this trial cannot be extrapolated to the European situation, and therefore the duration of treatment remains as advised in Table 4.2. The advised duration of treatment is based on empiric data.

       Method of administration of antibiotic treatment

      Antibiotics can be administered by continuous infusion or bolus administration (e.g. every 4 hours). Use of constant intravenous infusion of antibiotics is hypothesized to have a beneficial role in treatment of bacterial meningitis. Our literature search yielded 98 articles; six articles were relevant, consisting of three animal studies, two reviews and one RCT [
      • Pelkonen T.
      • Roine I.
      • Cruzeiro M.L.
      • Pitkaranta A.
      • Kataja M.
      • Peltola H.
      Slow initial beta-lactam infusion and oral paracetamol to treat childhood bacterial meningitis: a randomised, controlled trial.
      ]. This trial showed no significant differences between continuous and bolus administration of cefotaxime in children with bacterial meningitis. Because of the results of this trial and other concerns such as CSF pharmacokinetic/pharmacodynamic parameters (e.g. long antibiotic elimination half-life, poor bacterial growth rate) and use of dexamethasone, no recommendation for either continuous or bolus administration can be given at present.

       Conclusions

      Tabled 1
      Level 3The empiric antibiotic treatment in bacterial meningitis patients is based on expert opinion and differentiated for demographic/epidemiologic factors (age and rate of reduced antibiotic susceptibility).
      Tabled 1
      Level 3The specific antibiotic treatment in bacterial meningitis patients is based on antimicrobial susceptibility testing.
      Tabled 1
      Level 2There is insufficient evidence to support a short course of antibiotics in children and adults with bacterial meningitis in the European setting.
      Tabled 1
      Level 1There is no evidence of superiority of either continuous or bolus administration of antibiotics in bacterial meningitis patients.

       Recommendation

      Tabled 1
      Grade AThe recommended empiric treatment for bacterial meningitis patients is based on age and local resistance rates, as displayed in Table 4.1.
      Tabled 1
      Grade AThe recommended specific treatment for bacterial meningitis patients should be determined by the antibiotic susceptibility pattern, as displayed in Table 4.2.
      Tabled 1
      Grade AThe recommended treatment for bacterial meningitis patients in whom no pathogen can be cultured should be according to the empiric regimen for a minimum duration of 2 weeks.
      Tabled 1
      Grade DThe committee does not recommend a short course of antibiotics in children and adults with bacterial meningitis.
      Tabled 1
      Grade CBecause of a lack of evidence, the committee does not provide a recommendation on the use of continuous or bolus administration of antibiotics in bacterial meningitis patients.
      Key Question 6. Does dexamethasone have a beneficial effect on death, functional outcome and hearing loss in adults and children with bacterial meningitis?

       Adjunctive dexamethasone treatment

       Evidence for adjunctive dexamethasone treatment

      Experimental animal studies have shown that the outcome of bacterial meningitis is related to the severity of inflammation in the subarachnoid space [
      • Mook-Kanamori B.B.
      • Geldhoff M.
      • van der Poll T.
      • van de Beek D.
      Pathogenesis and pathophysiology of pneumococcal meningitis.
      ]. Immunomodulation of the inflammatory response with corticosteroids has been evaluated as a treatment strategy in multiple RCTs. A 2013 Cochrane review included 25 RCTs including 4121 bacterial meningitis patients [
      • Brouwer M.C.
      • McIntyre P.
      • Prasad K.
      • van de Beek D.
      Corticosteroids for acute bacterial meningitis.
      ]. The guideline update of the literature search did not identify additional RCTs that were published after the publication of this meta-analysis.
      In the Cochrane meta-analysis, corticosteroids were found to decrease overall hearing loss and neurologic sequelae, but did not reduce mortality [
      • Brouwer M.C.
      • McIntyre P.
      • Prasad K.
      • van de Beek D.
      Corticosteroids for acute bacterial meningitis.
      ]. No excess of dexamethasone-related adverse effects was observed compared to the placebo group. A subgroup analysis showed that corticosteroids reduced mortality in pneumococcal meningitis but not in meningitis due to other pathogens. Further subgroup analyses showed that use of corticosteroids was beneficial in studies performed in high-income countries with a high standard of medical care, but no effect was observed in studies performed in low-income countries.
      Only one RCT was published on the use of adjunctive corticosteroids in neonatal meningitis [
      • Brouwer M.C.
      • McIntyre P.
      • Prasad K.
      • van de Beek D.
      Corticosteroids for acute bacterial meningitis.
      ,
      • Mathur N.B.
      • Garg A.
      • Mishra T.K.
      Role of dexamethasone in neonatal meningitis: a randomized controlled trial.
      ]. This study did show a beneficial effect of corticosteroids, but it was small and treatment groups were not well balanced for patient age, culture positivity and causative microorganisms. Therefore, additional RCTs evaluating corticosteroids in neonatal meningitis need to be performed before definitive conclusions can be drawn on the role of dexamethasone treatment in neonatal meningitis. The use of dexamethasone for neonates is currently not recommended.
      Most studies included in the meta-analysis used dexamethasone; this is the most widely used corticosteroid for bacterial meningitis. The advised dexamethasone regimen in children is 0.15 mg/kg every 6 hours and in adults 10 mg every 6 hours, both for a duration of 4 days.
      Subquestion 6.1. Up to what point in time is treatment with dexamethasone indicated if antibiotics are already provided?

       Timing of dexamethasone treatment

      In the largest RCTs, dexamethasone was provided before or with the first dose of antibiotics in order to prevent the inflammatory response resulting from bacteriolysis by antibiotics [
      • de Gans J.
      • van de Beek D.
      Dexamethasone in adults with bacterial meningitis.
      ,
      • Nguyen T.H.
      • Tran T.H.
      • Thwaites G.
      • Ly V.C.
      • Dinh X.S.
      • Ho Dang T.N.
      • et al.
      Dexamethasone in Vietnamese adolescents and adults with bacterial meningitis.
      ]. Therefore, it is advised to start dexamethasone with the first dose of antibiotics [
      • van de Beek D.
      • Brouwer M.C.
      • Thwaites G.E.
      • Tunkel A.R.
      Advances in treatment of bacterial meningitis.
      ]. When dexamethasone has not been started with the first dose of antibiotics, it is unclear at what point adjunctive dexamethasone ceases to be beneficial. No RCTs have been performed that address the timing of corticosteroid therapy [
      • Brouwer M.C.
      • McIntyre P.
      • Prasad K.
      • van de Beek D.
      Corticosteroids for acute bacterial meningitis.
      ]. In experimental pneumococcal meningitis, CSF bacterial concentrations at the start of treatment seemed to be a more important factor affecting the antimicrobial-induced inflammatory response than the time when dexamethasone therapy was started [
      • Mook-Kanamori B.B.
      • Geldhoff M.
      • van der Poll T.
      • van de Beek D.
      Pathogenesis and pathophysiology of pneumococcal meningitis.
      ]. An individual patient data meta-analysis showed that dexamethasone reduced hearing loss, irrespective of whether the drug was given before or after antibiotics [
      • van de Beek D.
      • Farrar J.J.
      • de Gans J.
      • Mai N.T.
      • Molyneux E.M.
      • Peltola H.
      • et al.
      Adjunctive dexamethasone in bacterial meningitis: a meta-analysis of individual patient data.
      ].
      Because there are no data supporting a specific time, the guideline committee has reached consensus (based on expert opinion) that dexamethasone treatment can still be started up to 4 hours after initiation of antibiotic treatment.
      Subquestion 6.2. Should dexamethasone be stopped if pathogens other than S. pneumoniae are identified?

       Stopping dexamethasone after pathogen identification

      The Cochrane meta-analysis showed that adjunctive dexamethasone is effective in reducing hearing loss and neurologic sequelae in bacterial meningitis caused by all pathogens [
      • Brouwer M.C.
      • McIntyre P.
      • Prasad K.
      • van de Beek D.
      Corticosteroids for acute bacterial meningitis.
      ]. In subgroup analyses, it was shown that the effect of dexamethasone was most apparent in pneumococcal meningitis and also reduced mortality in this group. Furthermore, for H. influenzae meningitis, a strong effect on hearing loss was identified. For N. meningitidis, subgroup analysis showed no effect on any of the outcome measures. However, because the event rate (mortality, hearing loss) in meningococcal meningitis is substantially lower than in pneumococcal meningitis, no conclusions can be drawn on the efficacy of dexamethasone owing to the small number of meningococcal meningitis patients included in the meta-analysis. An implementation study showed that the use of dexamethasone is safe in meningococcal meningitis patients but that it did not significantly decrease hearing loss or death [
      • Heckenberg S.G.
      • Brouwer M.C.
      • van der Ende A.
      • van de Beek D.
      Adjunctive dexamethasone in adults with meningococcal meningitis.
      ].
      The guideline committee concludes that dexamethasone should be stopped if the patient is discovered not to have bacterial meningitis or if the bacterium causing the meningitis is a species other than H. influenzae or S. pneumoniae, although some experts advise that adjunctive treatment should be continued irrespective of the causative bacterium.

       Conclusions

      Tabled 1
      Level 1Corticosteroids significantly reduced hearing loss and neurologic sequelae but did not reduce overall mortality. Data support the use of corticosteroids in patients with bacterial meningitis beyond the neonatal age in countries with a high level of medical care. No beneficial effects of adjunctive corticosteroids have been identified in studies performed in low-income countries. The use of dexamethasone for neonates is currently not recommended.
      Tabled 1
      Level 3In the absence of scientific evidence, the committee has reached consensus that when antibiotic treatment has already been started, adjunctive dexamethasone treatment can still be started up to 4 hours after initiation of antibiotic treatment.
      Tabled 1
      Level 3In the absence of scientific evidence, the guideline committee concludes that dexamethasone should be stopped if the patient is discovered not to have bacterial meningitis or if the bacterium causing the meningitis is a species other than H. influenzae or S. pneumoniae, although some experts advise that adjunctive treatment should be continued irrespective of the causative bacterium.

       Recommendation

      Tabled 1
      Grade AEmpiric treatment with dexamethasone is strongly recommended for all adults (10 mg qid for 4 days) and children (0.15 mg/kg qid for 4 days) with acute bacterial meningitis in the setting of high-income countries.
      Tabled 1
      Grade ATreatment with dexamethasone is strongly recommended to be initiated with the first dose of antibiotic treatment.
      Tabled 1
      Grade CIf intravenous antibiotic treatment has already been started, dexamethasone can still be administered up to 4 hours after start of the first dose of intravenous antibiotics.
      Tabled 1
      Grade BIt is recommended to stop dexamethasone if the patient is discovered not to have bacterial meningitis or if the bacterium causing the meningitis is a species other than H. influenzae or S. pneumoniae, although some experts advise that adjunctive treatment should be continued irrespective of the causative bacterium.
      Key Question 7. Do glycerol, mannitol, acetaminophen/paracetamol, hypothermia, antiepileptic drugs or hypertonic saline have a beneficial effect on death, functional outcome and hearing loss in adults and children with bacterial meningitis?

       Other adjunctive treatments

      This section considers routine use of adjunctive treatment strategies in unselected patients. In individual patients, treatment with one on the described agents may be indicated, e.g. antiepileptic drugs for patients presenting with seizures. The section Complications in bacterial meningitis during hospitalization provides details for such cases.

       Osmotic therapies

      Treatment with osmotic agents has traditionally been used in several neurologic diseases to reduce intracranial pressure. The best-studied osmotic agents in bacterial meningitis is glycerol. The literature search on glycerol in bacterial meningitis yielded 73 articles, eight of which were relevant. Five RCTs were identified, four of which were included in a 2013 Cochrane meta-analysis [
      • Wall E.C.
      • Ajdukiewicz K.M.
      • Heyderman R.S.
      • Garner P.
      Osmotic therapies added to antibiotics for acute bacterial meningitis.
      ]. One RCT in adults was stopped because of a higher mortality rate in the treatment group, one RCT in children favoured glycerol and three RCTs showed no difference. There were substantial differences between the studies regarding geography (South America, Europe or Africa), age group (adults or children) and study medication dose (maximum 100 mL/day or 300 mL/day) and duration of treatment (2 or 4 days). The study performed in Europe showed no effect. No studies were performed in neonates with bacterial meningitis. Because there is no clear benefit of glycerol, it should not be given to adults or children with bacterial meningitis.
      Other osmotic agents such as mannitol or hypertonic saline have not been studied in RCTs or comparative studies of bacterial meningitis patients. Therefore, there is insufficient evidence to guide advice on this treatment.

       Paracetamol (acetaminophen)

      Paracetamol (acetaminophen) has been considered to improve outcome by reducing the inflammatory response and decreasing fever. Observational data in bacteraemic patients showed paracetamol use was associated with improved prognosis [
      • Kuikka A.
      • Sivonen A.
      • Emelianova A.
      • Valtonen V.V.
      Prognostic factors associated with improved outcome of Escherichia coli bacteremia in a Finnish university hospital.
      ]. Our literature search identified 19 relevant articles, two of which were RCTs [
      • Pelkonen T.
      • Roine I.
      • Cruzeiro M.L.
      • Pitkaranta A.
      • Kataja M.
      • Peltola H.
      Slow initial beta-lactam infusion and oral paracetamol to treat childhood bacterial meningitis: a randomised, controlled trial.
      ,
      • Molyneux E.M.
      • Kawaza K.
      • Phiri A.
      • Chimalizeni Y.
      • Mankhambo L.
      • Schwalbe E.
      • et al.
      Glycerol and acetaminophen as adjuvant therapy did not affect the outcome of bacterial meningitis in Malawian children.
      ]. Both trials tested paracetamol in a factorial design with a second intervention. No beneficial effect was observed.

       Therapeutic hypothermia

      Therapeutic hypothermia is suggested to be neuroprotective and has been extensively studied in severe neurotrauma and postanoxic encephalopathy, with varying results. The literature search yielded one RCT and two observational studies. The RCT was stopped early because of excess mortality in the hypothermia group [
      • Mourvillier B.
      • Tubach F.
      • van de Beek D.
      • Garot D.
      • Pichon N.
      • Georges H.
      • et al.
      Induced hypothermia in severe bacterial meningitis: a randomized clinical trial.
      ]. Therefore, hypothermia is not recommended in bacterial meningitis patients.

       Antiepileptic treatment

      The literature search yielded 320 articles, none of which was relevant. No RCTs have been performed that evaluate the use of standard antiepileptic treatment in bacterial meningitis in the absence of seizures.

       Hypertonic saline

      The literature search yielded 21 articles, none of which was relevant. No RCTs have been performed that evaluate the use of hypertonic saline treatment in bacterial meningitis.

       Intracranial pressure–based treatment

      During bacterial meningitis, intracranial pressure is elevated as a result of several factors (e.g. brain swelling or hydrocephalus). Several multistep treatment strategies have been described to reduce intracranial pressure in observational studies [
      • Glimaker M.
      • Johansson B.
      • Halldorsdottir H.
      • Wanecek M.
      • Elmi-Terander A.
      • Ghatan P.H.
      • et al.
      Neuro-intensive treatment targeting intracranial hypertension improves outcome in severe bacterial meningitis: an intervention–control study.
      ,
      • Abulhasan Y.B.
      • Al-Jehani H.
      • Valiquette M.A.
      • McManus A.
      • Dolan-Cake M.
      • Ayoub O.
      • et al.
      Lumbar drainage for the treatment of severe bacterial meningitis.
      ,
      • Edberg M.
      • Furebring M.
      • Sjolin J.
      • Enblad P.
      Neurointensive care of patients with severe community-acquired meningitis.
      ] and have been suggested to improve outcome. However, no RCTs have been performed, and results varied considerably between observational studies. As the described interventions may also cause harm, further studies are needed before these treatment strategies can be advised for routine use in patients with bacterial meningitis.

       Other adjunctive treatments

      Several other adjunctive treatments were evaluated in bacterial meningitis patients.
      • Bacterial meningitis patients included in intensive care RCTs receiving activated protein C showed an increased rate of cerebral haemorrhage in the treatment group, so this treatment is therefore not recommended (and in fact is no longer available) [
        • Vincent J.L.
        • Nadel S.
        • Kutsogiannis D.J.
        • Gibney R.T.
        • Yan S.B.
        • Wyss V.L.
        • et al.
        Drotrecogin alfa (activated) in patients with severe sepsis presenting with purpura fulminans, meningitis, or meningococcal disease: a retrospective analysis of patients enrolled in recent clinical studies.
        ].
      • Intrathecal and intravenous adjuvant immunoglobulins were tested in a comparative (nonrandomized) study in children with bacterial meningitis. No significant difference was observed in outcome or death, but groups were small.
      • Adjuvant heparin was tested in a study of 15 patients with bacterial meningitis. A higher risk of bleeding and mortality was found in the treatment group, and therefore heparin is not recommended [
        • Macfarlane J.T.
        • Cleland P.G.
        • Attai E.D.
        • Greenwood B.M.
        Failure of heparin to alter the outcome of pneumococcal meningitis.
        ].

       Conclusion

      Tabled 1
      Level 1The present data do not support the use of glycerol in adults with acute bacterial meningitis. Although potential beneficial effect exists in children, no recommendation can be made because strong evidence is not available.
      Tabled 1
      Level 1Therapeutic hypothermia is associated with a higher mortality rate in bacterial meningitis patients.
      Tabled 1
      Level 1Paracetamol (acetaminophen) use in bacterial meningitis patients did not improve outcome.
      Tabled 1
      Level 3Use of mannitol, antiepileptic drugs and hypertonic saline needs further evaluation to make conclusive recommendations on its routine use in bacterial meningitis patients.
      Tabled 1
      Level 2Use of intracranial pressure/cerebral perfusion pressure monitoring and treatment needs further evaluation to make a conclusive recommendation on its use in bacterial meningitis patients.

       Recommendations

      Tabled 1
      Grade DRoutine adjuvant therapy with mannitol, acetaminophen, antiepileptic drugs or hypertonic saline is not recommended. Hypothermia and glycerol are contraindicated in bacterial meningitis.
      Tabled 1
      Grade CUse of intracranial pressure/cerebral perfusion pressure monitoring and treatment can be life-saving in selected patients but cannot be recommended as routine management because solid evidence is lacking and harm may occur.
      Tabled 1
      Grade DAdjuvant therapy with immunoglobulins, heparin and activated protein C is not recommended.

       Prophylaxis

      Key Question 8. Does the use of prophylactic treatment of household contacts decrease carriage or secondary cases?

       Prophylactic treatment of household contacts of meningococcal meningitis patients

      The risk of meningococcal disease is increased 400–800-fold in individuals in close contact with meningococcal disease, with the highest risk for household contacts [
      • Zalmanovici T.A.
      • Fraser A.
      • Gafter-Gvili A.
      • Paul M.
      • Leibovici L.
      Antibiotics for preventing meningococcal infections.
      ]. This risk may be averted by prescribing prophylactic antibiotics. Multiple studies have been performed to determine whether prophylactic antibiotics are beneficial. Our literature search yielded 258 hits, of which eight articles were relevant, including a Cochrane meta-analysis including 24 RCTs. The Cochrane analysis included 19 RCTs including 2531 participants and five cluster RCTs including 4354 participants [
      • Zalmanovici T.A.
      • Fraser A.
      • Gafter-Gvili A.
      • Paul M.
      • Leibovici L.
      Antibiotics for preventing meningococcal infections.
      ]. Ceftriaxone, rifampicin and ciprofloxacin were found to be the most effective to prevent secondary cases and to achieve eradication of N. meningitidis from the nasopharynx. Therefore, antibiotic prophylaxis should be given to all close contacts of the patient with invasive meningococcal disease to prevent secondary cases and to decrease carriage. Close contacts are defined as household members, child care centre contacts and anyone directly exposed to oral secretions.
      Ciprofloxacin provided as a single oral dose, ceftriaxone provided as a single intramuscular dose or rifampicin provided orally for 2 days are the drugs of choice and should be commenced within 24 hours of identification. Patients treated with penicillin should also receive clearance-effective antibiotics before discharge; those who have received their meningitis therapy in the form of intravenous ceftriaxone do not need additional prophylaxis.
      Subquestion 8.1. Is vaccination indicated after community-acquired (pneumococcal) meningitis?

       Vaccination of pneumococcal meningitis patients

      The risk of a recurrent episode of pneumococcal meningitis is approximately 5% [
      • Adriani K.S.
      • van de Beek D.
      • Brouwer M.C.
      • Spanjaard L.
      • de Gans J.
      Community-acquired recurrent bacterial meningitis in adults.
      ,
      • Tebruegge M.
      • Curtis N.
      Epidemiology, etiology, pathogenesis, and diagnosis of recurrent bacterial meningitis.
      ]. Of the cases of recurrent meningitis, the majority have a risk factor for meningitis such as a CSF leak due to trauma or prior surgery, or immunodeficiency such as splenectomy or hypogammaglobulinaemia. In one fourth of patients with recurrent meningitis (1% of total cases), no risk factor for recurrent meningitis can be identified [
      • Adriani K.S.
      • van de Beek D.
      • Brouwer M.C.
      • Spanjaard L.
      • de Gans J.
      Community-acquired recurrent bacterial meningitis in adults.
      ,
      • Tebruegge M.
      • Curtis N.
      Epidemiology, etiology, pathogenesis, and diagnosis of recurrent bacterial meningitis.
      ]. On the basis of the identified recurrence rate in pneumococcal meningitis patients, this population can still be considered to be at high risk, and therefore vaccination may be warranted.
      In a literature search, we did not identify RCTs or case–control studies on the vaccination of meningitis patients and recurrence of pneumococcal disease. On the basis of expert opinion, the committee recommends vaccination in all patients with pneumococcal meningitis. Along with reconstruction of the dural barrier, patients with CSF leakage should receive pneumococcal vaccination, and H. influenzae and meningococcal vaccination can be considered as well. For patients with other risk factors, such as splenectomy, hyposplenism or hypogammaglobulinaemia, other existing guidelines apply.

       Conclusion

      Tabled 1
      Level 1Prophylactic antibiotic treatment of household contacts of meningococcal meningitis patients prevents secondary cases and eradicates meningococcal carriage.
      Tabled 1
      Level 3
      • Based on the recurrence risk of 1–5% of pneumococcal meningitis, the committee sees substantial benefits in vaccination with pneumococcal vaccines after an episode of pneumococcal meningitis.
      • Vaccination with pneumococcal vaccines is deemed beneficial in bacterial meningitis patients with CSF leakage to reduce recurrences.
      • Vaccination with H. influenzae type b and a meningococcal vaccine (either serogroup C, serogroup B or quadrivalent A/C/Y/W135, depending on local epidemiology) can be considered in bacterial meningitis patients with CSF leakage.

       Recommendations

      Tabled 1
      Grade AIt is strongly recommended to treat household contacts and other close contacts of meningococcal meningitis patients with antibiotic prophylaxis consisting of ceftriaxone, ciprofloxacin or rifampicin (see Table 4.3 for dose).
      Tabled 1
      Grade BIt is recommended to vaccinate with pneumococcal vaccine patients after an episode of pneumococcal meningitis and persons with CSF leakage along with the reconstruction of the dural barrier. Additional vaccination with H. influenzae type b and N. meningitidis vaccine can be considered in patients with CSF leakage.
      Table 4.3Recommended dose of prophylactic antibiotic treatment for household contacts and other close contacts of meningococcal meningitis patients
      AntibioticDoseDuration
      RifampicinChild <3 months of age: 5 mg/kg twice a day orally2 days
      Child ≥3 months to 12 years of age: 10 mg/kg twice a day orally (max 600 mg)
      Child >12 years of age: 600 mg twice a day
      Adult: 600 mg twice a day

      Pregnancy: 600 mg twice a day—only after first 3 months of pregnancy
      CiprofloxacinAdult >16 years: 500 mg oral

      Pregnancy: Do not use
      Once
      CeftriaxoneChild <16 years: 125 mg intramuscularOnce
      Adult ≥16 years: 250 mg intramuscular
      Pregnancy: 250 mg intramuscular (first choice during pregnancy)
      Key Question 9. What complications occur during community-acquired bacterial meningitis, what ancillary investigations are warranted when complications occur and how should they be treated?

       Complications in bacterial meningitis during hospitalization

      The clinical course of bacterial meningitis can be complicated by both neurologic and systemic complications. Patients may develop a decrease in mental status, focal neurologic deficits, haemodynamic instability or respiratory insufficiency. The cause of deterioration will need to be determined by physical and neurologic investigation, and ancillary investigations may become necessary, such as laboratory investigations, cranial imaging and EEG. The frequency of complications differs between age groups and causative microorganisms. Common complications reported during neonatal meningitis are shock, convulsions and hydrocephalus (Table 4.4).
      Table 4.4Common complications of neonatal bacterial meningitis
      • Okike I.O.
      • Johnson A.P.
      • Henderson K.L.
      • Blackburn R.M.
      • Muller-Pebody B.
      • Ladhani S.N.
      • et al.
      Incidence, etiology, and outcome of bacterial meningitis in infants aged <90 days in the United kingdom and Republic of Ireland: prospective, enhanced, national population-based surveillance.
      ,
      • Gaschignard J.
      • Levy C.
      • Romain O.
      • Cohen R.
      • Bingen E.
      • Aujard Y.
      • et al.
      Neonatal bacterial meningitis: 444 cases in 7 years.
      ,
      • Kavuncuoglu S.
      • Gursoy S.
      • Turel O.
      • Aldemir E.Y.
      • Hosaf E.
      Neonatal bacterial meningitis in Turkey: epidemiology, risk factors, and prognosis.
      ComplicationFrequencyAncillary investigationsTreatment
      Seizures15–34%EEG (if not clinically evident)Antiepileptic drugs
      Hydrocephalus5–6%Transcranial ultrasound or cranial MRIExternal ventricular drain
      Sepsis24%Evaluation of other foci of infection (e.g. pneumonia, endocarditis)According to guidelines for management of sepsis
      Half of the adults with bacterial meningitis develop focal neurologic deficits during their clinical course, and one third of patients develop haemodynamic or respiratory insufficiency [
      • van de Beek D.
      • de Gans J.
      • Spanjaard L.
      • Weisfelt M.
      • Reitsma J.B.
      • Vermeulen M.
      Clinical features and prognostic factors in adults with bacterial meningitis.
      ]. The diagnostic workup in these patients can consist of cranial CT or MRI when intracranial abnormalities are suspected (in which MRI is preferred because of its superior resolution, but the availability and speed of CT are often greater), repeated lumbar puncture and EEG. However, the yield of repeated lumbar puncture is probably limited, and therefore routine repetition of lumbar puncture is not indicated [
      • Denneman L.
      • Vial-Dupuy A.
      • Gault N.
      • Wolff M.
      • van de Beek D.
      • Mourvillier B.
      Repeated lumbar puncture in adults with pneumococcal meningitis: an observational study.
      ]. When hydrocephalus or space-occupying lesions, such as subdural empyema, brain abscess or intracerebral haemorrhages, are detected on cranial imaging, neurosurgical intervention may be warranted to prevent cerebral herniation and sometimes remove the lesion. In most patients with obstructive hydrocephalus, placement of an external ventricular drain is indicated. In patients with communicating hydrocephalus who are awake and can be monitored clinically, invasive measures such as repetitive lumbar punctures or placement of an external lumbar drain can be considered but might not be necessary.
      Cerebrovascular complications occur frequently during bacterial meningitis and can consist of cerebral infarctions, subarachnoid haemorrhage, intracranial haemorrhage and venous sinus thrombosis. The development of intracerebral haemorrhage has been associated with the use of anticoagulant medication, and therefore discontinuation of this medication should be considered in bacterial meningitis patients. In patients with bacterial meningitis and venous sinus thrombosis, the guideline committee considers the increased risk of cerebral haemorrhage higher than the benefit of anticoagulants, at least during the acute phase of meningitis.

       Conclusion

      Tabled 1
      Level 2Neurologic and systemic complications occur in a large proportion of children and adults with bacterial meningitis. In patients with neurologic deterioration, cranial imaging (MRI or CT) is often indicated, and repeated lumbar puncture and EEG may be indicated in selected cases.
      Tabled 1
      Level 3Bacterial meningitis complicated by hydrocephalus, subdural empyema and brain abscess may require neurosurgical intervention.

       Recommendations

      Tabled 1
      Grade AAs neurologic and systemic complications frequently occur during bacterial meningitis, physicians should be alert for recognition of these complications, perform ancillary investigations upon deterioration and initiate specific treatment when required (Table 4.4, Table 4.5).
      Table 4.5Common complications of bacterial meningitis in adults
      • Bodilsen J.
      • Schonheyder H.C.
      • Nielsen H.
      Hydrocephalus is a rare outcome in community-acquired bacterial meningitis in adults: a retrospective analysis.
      ,
      • Bodilsen J.
      • Dalager-Pedersen M.
      • Schonheyder H.C.
      • Nielsen H.
      Stroke in community-acquired bacterial meningitis: a Danish population-based study.
      ,
      • Mook-Kanamori B.B.
      • Fritz D.
      • Brouwer M.C.
      • van der Ende A.
      • van de Beek D.
      Intracerebral hemorrhages in adults with community associated bacterial meningitis in adults: should we reconsider anticoagulant therapy?.
      ,
      • Schut E.S.
      • Lucas M.J.
      • Brouwer M.C.
      • Vergouwen M.D.
      • van der Ende A.
      • van de Beek D.
      Cerebral infarction in adults with bacterial meningitis.
      ,
      • Zoons E.
      • Weisfelt M.
      • de Gans J.
      • Spanjaard L.
      • Koelman J.H.
      • Reitsma J.B.
      • et al.
      Seizures in adults with bacterial meningitis.
      ,
      • Jim K.K.
      • Brouwer M.C.
      • van der Ende A.
      • van de Beek D.
      Subdural empyema in bacterial meningitis.
      ,
      • Jim K.K.
      • Brouwer M.C.
      • van der Ende A.
      • van de Beek D.
      Cerebral abscesses in patients with bacterial meningitis.
      ComplicationFrequencyAncillary investigationsTreatment
      Seizures17%Cranial CT or MRI; EEG if not clinically evidentAntiepileptic drugs
      Hydrocephalus3–5%Cranial CT or MRIExternal ventricular drain if clinically relevant
      Ischaemic stroke14–25%Cranial CT or MRINo specific treatment
      Haemorrhagic stroke3%Cranial CT or MRIConsider neurosurgical intervention
      Subdural empyema3%Cranial CT or MRIConsider neurosurgical intervention
      Brain abscess2%Cranial CT or MRIConsider neurosurgical intervention
      Sinus thrombosis1%Cranial CT or MRINo proven therapy
      Severe sepsis15%Evaluation of other foci of infection (e.g. pneumonia, endocarditis)According to guidelines for the management of sepsis
      • Dellinger R.P.
      • Levy M.M.
      • Rhodes A.
      • Annane D.
      • Gerlach H.
      • Opal S.M.
      • et al.
      Surviving sepsis campaign: international guidelines for management of severe sepsis and septic shock: 2012.
      including fluid replacement, ICU admission and monitoring
      Hearing loss17–22%Otoacoustic emission/hearing evaluationCochlear implant
      CT, computed tomography; ICU, intensive care unit; MRI, magnetic resonance imaging.

      Follow-up care of bacterial meningitis patients

      Key Question 10. What follow-up of community-acquired bacterial meningitis patients should be provided (e.g. testing for hearing loss, neuropsychological evaluation)?
      It is estimated that one third of patients surviving an episode of bacterial meningitis will have persisting complaints. A systematic review has been performed on the sequelae of bacterial meningitis in children, including 18183 patients surviving bacterial meningitis included in 132 studies [
      • Edmond K.
      • Dieye Y.
      • Griffiths U.K.
      • Fleming J.
      • Ba O.
      • Diallo N.
      • et al.
      Prospective cohort study of disabling sequelae and quality of life in children with bacterial meningitis in urban Senegal.
      ]. In this review, the most common cause of meningitis was H. influenzae type b, followed by S. pneumoniae (20%) and N. meningitidis (16%); other bacteria were identified in 12% of patients. Median follow-up was 24 months. The most common severe sequelae were hearing loss (34%), seizures (13%), motor deficits (12%), cognitive defects (9%), hydrocephalus (7%) and visual loss (6%) [
      • Edmond K.
      • Dieye Y.
      • Griffiths U.K.
      • Fleming J.
      • Ba O.
      • Diallo N.
      • et al.
      Prospective cohort study of disabling sequelae and quality of life in children with bacterial meningitis in urban Senegal.
      ]. One in five children had multiple sequelae.
      Common sequelae in adults are neurologic deficits due to cerebral infarctions, hearing loss and cognitive slowness. It is important to recognize patients in whom neuropsychologic investigation is indicated upon discharge from the hospital. Patients, family members and caregivers should be informed about the potential sequelae and when to contact their physician.

       Hearing loss

      Bacterial meningitis is the most common cause of acquired hearing loss in children [
      • Fortnum H.
      • Davis A.
      Hearing impairment in children after bacterial meningitis: incidence and resource implications.
      ], and hearing loss also occurs in neonates and adults after bacterial meningitis [
      • Heckenberg S.G.
      • Brouwer M.C.
      • van der Ende A.
      • Hensen E.F.
      • van de Beek D.
      Hearing loss in adults surviving pneumococcal meningitis is associated with otitis and pneumococcal serotype.
      ]. An estimated 5–35% of patients with bacterial meningitis develop sensorineural hearing loss, and 4% of patients have severe bilateral hearing loss. In a study on hearing loss in pneumococcal meningitis survivors, including patients with no clinical suspicion of hearing loss, 54% of patients had audiometric evidence of hearing loss [
      • Worsoe L.
      • Caye-Thomasen P.
      • Brandt C.T.
      • Thomsen J.
      • Ostergaard C.
      Factors associated with the occurrence of hearing loss after pneumococcal meningitis.
      ]. Hearing loss may be present at admission or may develop during the course of the disease. Especially in young children, it may go undetected for a period of time. This can negatively influence the speech development of these children. A cochlear implant can prevent this when placed in a timely fashion. If implantation is delayed, cochlear fibrosis and calcification may occur, limiting the function of the implant.
      Because of the necessity to quickly identify hearing loss in both children and adults with bacterial meningitis, hearing evaluation should be performed during admission. In children, otoacoustic emission can be used as a screening test. If the otoacoustic emission test fails, children need to be referred to a centre with audiologic expertise for further hearing evaluation using brain stem–evoked response audiometry or speech tone audiometry, depending on the patient's age. In adults, speech tone audiometry has to be performed during admission. In patients with no hearing loss during the initial hospitalization, follow-up testing may be indicated, as hearing loss may become apparent 6–12 months after the meningitis episode. In patients with over 30 dB hearing loss or progressive hearing loss over time, contrast-enhanced MRI, repeated hearing evaluation and consultation with a cochlear implantation specialist are indicated.

       Neuropsychologic sequelae

      Neuropsychologic sequelae in children often consist of failure to learn in school and poor development of cognitive abilities for their age. A follow-up study on the short- and long-term impacts of pneumococcal meningitis among 102 Bangladeshi children aged 2–59 months found high rates of cognitive delay that affected their ability to learn, language development and social relationships [
      • Saha S.K.
      • Khan N.Z.
      • Ahmed A.S.
      • Amin M.R.
      • Hanif M.
      • Mahbub M.
      • et al.
      Neurodevelopmental sequelae in pneumococcal meningitis cases in Bangladesh: a comprehensive follow-up study.
      ]. Half of the patients were followed for 30–40 days after discharge and the other half for 6–24 months after discharge; in both groups, 41% of the patients had significant deficits in cognitive development. Two other studies reported cognitive impairment at discharge in 13% of children after pneumococcal meningitis [
      • King B.A.
      • Richmond P.
      Pneumococcal meningitis in Western Australian children: epidemiology, microbiology and outcome.
      ,
      • Ispahani P.
      • Slack R.C.
      • Donald F.E.
      • Weston V.C.
      • Rutter N.
      Twenty year surveillance of invasive pneumococcal disease in Nottingham: serogroups responsible and implications for immunisation.
      ]. IQ scores are also reported to be lower in young patients after bacterial meningitis compared to controls. A full-scale IQ score of <85 is reported in 10–36% of patients after pneumococcal meningitis. Learning problems were found in 10–20% of children, and 12–33% of children had to repeat school years or required referral to a special-needs school after pneumococcal meningitis in one Dutch follow-up study [
      • Koomen I.
      • Grobbee D.E.
      • Roord J.J.
      • Jennekens-Schinkel A.
      • van der Lei H.D.
      • Kraak M.A.
      • et al.
      Prediction of academic and behavioural limitations in school-age survivors of bacterial meningitis.
      ].
      In a Dutch study including 155 adult survivors of bacterial meningitis and 72 healthy controls, neuropsychologic examination revealed that 32% had cognitive defects compared to 6% in the control group. The most apparent defect was cognitive slowness [
      • Hoogman M.
      • van de Beek D.
      • Weisfelt M.
      • de Gans J.
      • Schmand B.
      Cognitive outcome in adults after bacterial meningitis.
      ]. A follow-up study in the same population 9 years after bacterial meningitis found that psychologic functioning and quality of life had returned to normal on a group level, but some cognitive slowness persisted on an individual level [
      • Schmand B.
      • de Bruin E.
      • de Gans J.
      • van de Beek D.
      Cognitive functioning and quality of life nine years after bacterial meningitis.
      ]. A German study comparing 59 patients with bacterial meningitis and 30 controls showed that 37% of bacterial meningitis patients had short-term memory and working memory problems.
      Neuropsychologic examination is not routinely indicated in bacterial meningitis patients. Patients should be informed about the nature and frequency of cognitive disorders after bacterial meningitis (difficulty with concentration, cognitive slowness, memory deficits). If cognitive defects are suspected, neuropsychologic examination should be performed and referral to a (neuro)psychologist/rehabilitation physician may be indicated. Simple neuropsychologic tests may suffice (e.g. the Montreal Cognitive Assessment test, MoCA) for screening in experienced hands.

       Conclusion

      Tabled 1
      Level 2Sequelae occur in a substantial proportion of children and adults with bacterial meningitis and most frequently consist of hearing loss, neuropsychologic defects and focal neurologic deficits.
      Tabled 1
      Level 2Hearing loss needs to be detected early during the disease course to facilitate effective cochlear implantation in the case of severe hearing loss.

       Recommendations

      Tabled 1
      Grade AIn children with bacterial meningitis, testing for hearing loss should be performed during admission (otoacoustic emission). In adults with bacterial meningitis, testing for hearing loss should be performed during admission. In the case of hearing loss, patients should be referred to an ear–nose–throat specialist in a medical centre performing cochlear implants.
      Tabled 1
      Grade BRoutine neuropsychologic examination is not recommended. If cognitive defects occur, neuropsychologic examination should be performed, and referral to a (neuro)psychologist/rehabilitation physician may be indicated.

      Acknowledgement

      We thank L. Glennie, Meningitis Research Foundation , Bristol, UK, for her input.

      Transparency declaration

      Funded by a grant of the European Clinical Microbiology and Infectious Disease Society (ESCMID) . All authors report no conflicts of interest relevant to this article.

      Appendix.

       Search strategies

        1.

        What is the diagnostic accuracy of algorithms in the distinction between bacterial and viral meningitis?

      • 1
        exp Meningitis, Bacterial/
      • 2
        Bacterial Meningiti*.ti,ab.
      • 3
        ((bacterial or meningococcal or pneumococcal or Neisseria or meningitides or Streptococcus or pneumoniae or Haemophilus or Hib or influenzae or Listeria or monocytogenes or Escherichia or coli or agalactiae or pyogenes or Staphylococcus or aureus or Cryptococcus or neoformans) adj5 meningiti*).ti,ab.
      • 4
        or/1-3
      • 5
        (rule$ or model$ or (decision adj5 (support or rule$)) or logistic model$ or (“Stratification” or “Discrimination” or “Discriminate” or “c-statistic” or “c statistic” or “Area under the curve” or “AUC” or “Calibration” or “Indices” or “Algorithm” or “Multivariable”)).tw. or exp algorithms/
      • 6
        4 and 5
      • 7
        exp Meningitis, Viral/
      • 8
        ((virus or viral) adj5 meningitis).tw.
      • 9
        exp Enterovirus/
      • 10
        exp Enterovirus Infections/
      • 11
        enterovir$.tw.
      • 12
        exp Virus Diseases/
      • 13
        Meningitis/
      • 14
        12 and 13
      • 15
        7 or 8 or 9 or 10 or 11 or 14
      • 16
        4 and 15
      • 17
        5 and 16
      • 18
        exp “sensitivity and specificity”/ or exp “mass screening”/ or “reference values”/ or “false positive reactions”/ or “false negative reactions”/ or specificit$.tw. or screening.tw. or false positive$.tw. or false negative$.tw. or accuracy.tw. or predictive value$.tw. or reference value$.tw. or roc$.tw. or likelihood ratio$.tw.
      • 19
        16 and 18
      • 20
        17 or 19
        2.

        Can we use clinical characteristics to predict the absence of intracranial abnormalities associated with increased risk of lumbar puncture?

      • 1
        exp Meningitis, Bacterial/
      • 2
        Bacterial Meningiti*.ti,ab.
      • 3
        ((bacterial or meningococcal or pneumococcal or Neisseria or meningitides or Streptococcus or pneumoniae or Haemophilus or Hib or influenzae or Listeria or monocytogenes or Escherichia or coli or agalactiae or pyogenes or Staphylococcus or aureus or Cryptococcus or neoformans) adj5 meningiti*).ti,ab.
      • 4
        or/1-3
      • 5
        Spinal Puncture/
      • 6
        ((lumbar or spinal) adj3 (puncture or tap)).tw.
      • 7
        exp Cerebrospinal Fluid/
      • 8
        spinal fluid.tw.
      • 9
        cerebrospinal fluid.tw.
      • 10
        CSF.tw.
      • 11
        or/5-10
      • 12
        4 and 11
      • 13
        (ae or de or co).fs.
      • 14
        (safe or safety or side-effect* or undesirable effect* or treatment emergent or tolerability or toxicity or adrs or (adverse adj2 (effect or effects or reaction or reactions or event or events or outcome or outcomes))).ti,ab.
      • 15
        13 or 14
      • 16
        12 and 15
      • 17
        (CT adj3 (cine or scan* or x?ray* or xray*)).ab,ti.
      • 18
        (CT or MDCT).ti.
      • 19
        ((electron?beam* or comput* or axial) adj3 tomography).ab,ti.
      • 20
        tomodensitometry.ab,ti.
      • 21
        exp Tomography, X-Ray Computed/
      • 22
        or/17-21
      • 23
        16 and 22
        3.

        Does dexamethasone have a beneficial effect on death, functional outcome and hearing loss in adults and children with bacterial meningitis?

      • 1
        exp Meningitis/
      • 2
        meningit*.tw.
      • 3
        exp Neisseria meningitidis/
      • 4
        exp Haemophilus influenzae/
      • 5
        Streptococcus pneumoniae/
      • 6
        (“N. meningitidis” or “H. influenzae” or “S. pneumoniae”).tw.
      • 7
        (“neisseria meningitidis” or “haemophilus influenzae” or “streptococcus pneumoniae”).tw.
      • 8
        or/1-7
      • 9
        exp Adrenal Cortex Hormones/
      • 10
        corticosteroid*.tw,nm.
      • 11
        glucocorticoid*.tw,nm.
      • 12
        exp Steroids/
      • 13
        steroid*.tw,nm.
      • 14
        exp Dexamethasone/
      • 15
        (dexamethasone* or hydrocortisone* or prednisolone* or methylprednisolone*).tw,nm.
      • 16
        or/9-15
      • 17
        8 and 16
        4.

        Do glycerol, mannitol, acetominophen, hypothermia, antiepileptic drugs or hypertonic saline have a beneficial effect on death, functional outcome and hearing loss in adults and children with bacterial meningitis?

      • 1
        exp Meningitis/
      • 2
        meningit*.tw.
      • 3
        exp Neisseria meningitidis/
      • 4
        exp Haemophilus influenzae/
      • 5
        Streptococcus pneumoniae/
      • 6
        (“N. meningitidis” or “H. influenzae” or “S. pneumoniae”).tw.
      • 7
        (“neisseria meningitidis” or “haemophilus influenzae” or “streptococcus pneumoniae”).tw.
      • 8
        or/1-7
      • 9
        medline.tw.
      • 10
        systematic review.tw.
      • 11
        meta-analysis.pt.
      • 12
        intervention$.ti.
      • 13
        9 or 10 or 11 or 12
      • 14
        8 and 13
        5.

        Does the use of prophylactic treatment of household contact decrease carriage or secondary cases?

      • 1
        ((exp “Meningitis, Bacterial”/ or bacterial meningitis*.ti,ab. or pneumococcal meningitis*.ti,ab. or meningococcal meningitis*.ti,ab. or staphylococcal meningitis*.ti,ab. or nosocomial meningitis*.ti,ab. or hospital acquired meningitis*.ti,ab. or e coli meningitis*.ti,ab. or escherichia coli meningitis*.ti,ab. or neonatal meningitis*.ti,ab.) and (exp “Anti-Bacterial Agents”/ or antibiotic*.ti,ab. or antimicrobial*.ti,ab.) and Humans/) not (tuberc* or anthra*).ti. not (case reports or editorial).pt.
      • 2
        limit 1 to ed=20110101-20140301

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