We searched the Cochrane Library (The Cochrane Library 2011, issue 1), Medline (1966 to March, 2012), and Embase (1974 to March, 2012) with the search terms “bacterial meningitis” or “meningitis” or “meningococcal disease” or “Neisseria meningitidis” or “pneumococcal disease” or “Streptococcus pneumoniae” in combination with the terms “diagnosis” or “diagnostic techniques” or “spinal puncture” or “cerebrospinal fluid” or “imaging”. We selected mainly articles published in the past 5 years, but
SeriesDilemmas in the diagnosis of acute community-acquired bacterial meningitis
Introduction
Acute community-acquired bacterial meningitis is a medical emergency, and patients with this disease need immediate medical assessment and treatment. Dilemmas exist in the diagnosis of patients with bacterial meningitis, because clinical findings do not always accurately identify patients with meningitis, and cerebrospinal fluid (CSF) analysis is not always diagnostic. Furthermore, in resource-poor countries with high rates of tuberculosis and HIV, and poor laboratory diagnostics, establishment of the diagnosis of bacterial meningitis can be even more difficult. In this review, we focus on dilemmas in the diagnosis of acute community-acquired bacterial meningitis in children and adults; diagnostic dilemmas in patients with nosocomial bacterial meningitis have been reviewed previously.1 We review the clinical presentation and differential diagnosis of the disease, use of lumbar puncture, and interpretation of CSF results, and draw attention to advances in diagnostic markers and the use of prediction models in the diagnosis of acute community-acquired bacterial meningitis after the neonatal period.
Section snippets
Clinical presentation
In view of the urgent need for antibiotic administration in patients with acute community-acquired bacterial meningitis, early recognition of the disease is essential. The sequence and development of signs and symptoms before hospital admission were retrospectively assessed in 448 children and adolescents with meningococcal diseases, encompassing the full range of disease from sepsis to meningitis.2 Although limited by its retrospective design, this study showed that the classic symptoms of
Differential diagnosis
The differential diagnosis of the triad of fever, headache, and stiff neck includes bacterial or viral meningitis, fungal meningitis, tuberculous meningitis, drug-induced meningitis, carcinomatous or lymphomatous meningitis, meningitis associated with inflammatory diseases (eg, systemic lupus erythematosus, sarcoidosis, Behçet's disease, or Sjögren's syndrome), cerebral abscess, and subarachnoid haemorrhage (when the body temperature is normal or only moderately raised and the onset of headache
Lumbar puncture
Because of the urgent and essential need for a lumbar puncture to obtain CSF for diagnostic studies, physicians need to establish whether cranial imaging is needed before doing a lumbar puncture to minimise the potential risks of this procedure. Patients with space-occupying intracranial lesions can present with symptoms identical to acute community-acquired bacterial meningitis or these lesions can complicate acute bacterial meningitis early in the disease course (eg, subdural empyema,
CSF examination
CSF examination is essential to establish the diagnosis of bacterial meningitis, identify the causative organism, and undertake in-vitro antibiotic susceptibility testing. Characteristic CSF findings for acute community-acquired bacterial meningitis are a polymorphonuclear pleocytosis, hypoglycorrhachia, and raised CSF protein concentrations.3, 34, 39, 40 More than 90% of cases of acute bacterial meningitis present with a CSF white cell count of more than 100 cells per μL.3 In immunocompromised
Prediction models
In patients without a positive CSF Gram stain or culture, the diagnosis of acute bacterial meningitis is often difficult to establish or reject. A combination of clinical findings with or without test results has been assessed to develop models that allow accurate prediction of the likelihood of acute bacterial meningitis compared with other possible causes (especially viral meningitis). Oostenbrink and colleagues53, 54, 55 developed a prediction model to guide decisions about the use of lumbar
Diagnostic markers
Studies have examined other markers for their diagnostic use in patients with acute bacterial meningitis (table 4); these studies have focused mainly on the differentiation of acute bacterial from viral meningitis. Determination of the CSF lactate concentration is a widely available, straightforward, cheap, and rapid diagnostic test.73, 74 Two meta-analyses, one including 25 studies with 1692 patients (adults and children)73 and the other including 31 studies with 1885 patients (adults and
Additional diagnostic dilemmas
In resource-poor settings, the differentiation between acute bacterial meningitis, cryptococcal meningitis, tuberculous meningitis, and cerebral malaria can be very difficult when patients have received prehospital antibiotic treatment.38, 75 Abnormalities in the CSF white blood cell count and CSF protein and glucose concentrations are usually less pronounced in patients with acute bacterial meningitis who are receiving antibiotics than in those who are not, and could therefore resemble CSF
Conclusions and future directions
Early recognition of acute community-acquired bacterial meningitis is essential to improve the prognosis of the disease. Clinical assessment alone is insufficient to exclude acute bacterial meningitis, and a lumbar puncture with CSF analysis is needed in all patients with suspected acute bacterial meningitis. In some cases, cranial imaging is needed before lumbar puncture to detect brain shift; in these patients, empirical antibiotic treatment should be given before imaging. Molecular
Search strategy and selection criteria
References (77)
- et al.
Clinical recognition of meningococcal disease in children and adolescents
Lancet
(2006) - et al.
Accuracy of physical signs for detecting meningitis: a hospital-based diagnostic accuracy study
Clin Neurol Neurosur
(2010) - et al.
Bacterial meningitis in children
Lancet
(2003) - et al.
Diagnosis of adult tuberculous meningitis by use of clinical and laboratory features
Lancet
(2002) - et al.
Differentiation of tuberculous meningitis from acute bacterial meningitis using simple clinical and laboratory parameters
Diagn Micrbiol Infect Dis
(2006) - et al.
Tuberculous meningitis: many questions, too few answers
Lancet Neurol
(2005) - et al.
Acute meningitis with a negative Gram's stain: clinical and management outcomes in 171 episodes
Am J Med
(1996) - et al.
Cerebral abscesses in patients with bacterial meningitis
J Infect
(2012) - et al.
Emergency diagnosis and treatment of adult meningitis
Lancet Infect Dis
(2007) - et al.
Dexamethasone treatment in childhood bacterial meningitis in Malawi: a randomised controlled trial
Lancet
(2002)