Identifying low-risk patients for bacterial meningitis in adult patients with acute meningitis

Diagnostic prediction models for bacterial meningitis in children with a suspected central nervous system infection: a systematic review and prospective validation study

OBJECTIVES

Diagnostic prediction models exist to assess the probability of bacterial meningitis (BM) in paediatric patients with suspected meningitis. To evaluate the diagnostic accuracy of these models in a broad population of children suspected of a central nervous system (CNS) infection, we performed external validation.

METHODS

We performed a systematic literature review in Medline to identify articles on the development, refinement or validation of a prediction model for BM, and validated these models in a prospective cohort of children aged 0-18 years old suspected of a CNS infection.

PRIMARY AND SECONDARY OUTCOME MEASURES

We calculated sensitivity, specificity, predictive values, the area under the receiver operating characteristic curve (AUC) and evaluated calibration of the models for diagnosis of BM.

RESULTS

In total, 23 prediction models were validated in a cohort of 450 patients suspected of a CNS infection included between 2012 and 2015. In 75 patients (17%), the final diagnosis was a CNS infection including 30 with BM (7%). AUCs ranged from 0.69 to 0.94 (median 0.83, interquartile range [IQR] 0.79-0.87) overall, from 0.74 to 0.96 (median 0.89, IQR 0.82-0.92) in children aged ≥28 days and from 0.58 to 0.91 (median 0.79, IQR 0.75-0.82) in neonates.

CONCLUSIONS

Prediction models show good to excellent test characteristics for excluding BM in children and can be of help in the diagnostic workup of paediatric patients with a suspected CNS infection, but cannot replace a thorough history, physical examination and ancillary testing.

A risk score for identifying patients at a low risk of bacterial meningitis amongst adults with cerebrospinal fluid leucocytosis and a negative gram stain result: a derivation and validation study

OBJECTIVES

We aimed to derive and validate a risk score to differentiate patients with bacterial meningitis from those with viral meningitis or encephalitis amongst patients presenting with cerebrospinal fluid (CSF) leucocytosis and a negative Gram staining result.

METHODS

We included adults with bacterial and viral meningitis or encephalitis presenting with CSF leukocyte counts of >10 per mm³ and a negative Gram staining result from cohorts in Houston, Texas (2004-2019), and the Netherlands (2012-2021). Derivation and the first validation were performed in the American patients and further validation in the Dutch patients.

RESULTS

Derivation was performed in 109 American patients with bacterial meningitis (median age, 56 years; interquartile range [IQR], 46-66 years; 46% women) and 194 with viral meningitis or encephalitis (median age, 46 years; IQR, 33-60 years; 53% women). Serum leukocyte counts of >10.0 × 10⁹/L, CSF leukocyte counts of >2000 per mm³, granulocyte counts of >1180 per mm³, protein levels of >2.2 g/L, glucose levels of <1.9 mmol/L and fever on admission were included in the risk score, which was dichotomized into 'low risk' (0 present) and 'high risk' (>0 present). The first validation showed a sensitivity of 100% (95% CI, 96.6-100) and specificity of 34.0% (95% CI, 27.4-41.2). Further validation in 262 Dutch patients with bacterial meningitis (median age, 57 years; IQR 44-70 years; 45% women) and 68 with viral meningitis (median age, 34 years; IQR, 28-45 years; 60% women) showed a sensitivity of 99.6% (95% CI, 97.9-100) and specificity of 41.2% (95% CI, 29.4-53.7).

CONCLUSIONS

Our risk score may be able to rule out bacterial meningitis amongst patients presenting with CSF leucocytosis and a negative Gram staining result. However, it needs prospective testing prior to clinical implementation.

Validation of the Bacterial Meningitis Score in adults consulting at an emergency department: a retrospective multicentric study

OBJECTIVE

The Bacterial Meningitis Score (BMS) is recommended by pediatric academic societies to rule out the diagnosis of bacterial meningitis. The aim of this study was to evaluate the performance of the BMS to identify adults at no risk for bacterial meningitis.

METHODS

We conducted a multicentric retrospective study including adults who consulted the emergency department (ED) for meningitis [cerebrospinal fluid (CSF) white blood cells ≥5/mm with a ratio of white blood cells/red blood cells <1:900) during a 4-year period. The BMS variables were: CSF positive Gram stain, CSF absolute neutrophil count ≥1000 cells/μL, CSF protein ≥80 mg/dL, peripheral blood absolute neutrophil count ≥10 000 cells/μL, and seizures. Bacterial meningitis was defined for patients who had a lumbar puncture with CSF pleocytosis and positive bacterial analysis of CSF. The primary endpoint was the sensitivity of the BMS to rule out bacterial meningitis in adults. The secondary outcome was to assess the rate of patients for whom antibiotics could have been avoided using the BMS and the diagnostic performance of procalcitonin in patients with a BMS ≥1.

RESULTS

Of 930 patients with meningitis, 626 were included in the analysis, and 27 (4.3%) were diagnosed with bacterial meningitis. A total of 384/626 (61.3%) patients had a BMS = 0, and none presented bacterial meningitis. BMS sensitivity was 100% [95% confidence interval (CI), 87.2-100%], and its negative predictive values were 100% (95% CI, 98.8-100%).

CONCLUSION

Among patients with a diagnosis of meningitis in ED, a BMS of 0 may safely rule out bacterial meningitis.

Systematic review and validation of diagnostic prediction models in patients suspected of meningitis

OBJECTIVES

Diagnostic prediction models have been developed to assess the likelihood of bacterial meningitis (BM) in patients presented with suspected central nervous system (CNS) infection. External validation in patients suspected of meningitis is essential to determine the diagnostic accuracy of these models.

METHODS

We prospectively included patients who underwent a lumbar puncture for suspected CNS infection. After a systematic review of the literature, we applied identified models for BM to our cohort. We calculated sensitivity, specificity, predictive values, area under the curve (AUC) and, if possible, we evaluated the calibration of the models.

RESULTS

From 2012-2015 we included 363 episodes. In 89 (24%) episodes, the patient received a final diagnosis of a CNS infection, of whom 27 had BM. Seventeen prediction models for BM were identified. Sensitivity of these models ranged from 37% to 100%. Specificity of these models ranged from 44% to 99%. The cerebrospinal fluid model of Oostenbrink reached the highest AUC of 0.95 (95% CI 0.91-0.997). Calibration showed over- or underestimation in all models.

CONCLUSION

None of the existing models performed well enough to recommend as routine use in individual patient management. Future research should focus on differences between diagnostic accuracy of the prediction models and physician's therapeutic decisions.

Proposal for a New Score-Based Approach To Improve Efficiency of Diagnostic Laboratory Workflow for Acute Bacterial Meningitis in Adults

Microbiological tests on cerebrospinal fluid (CSF) utilize a common urgent-care procedure that does not take into account the chemical and cytological characteristics of the CSF, resulting sometimes in an unnecessary use of human and diagnostic resources. The aim of this study was to retrospectively validate a simple scoring system (bacterial meningitis-Careggi score [BM-CASCO]) based on blood and CSF sample chemical/cytological parameters for evaluating the probability of acute bacterial meningitis (ABM) in adults. BM-CASCO (range, 0 to 6) was defined by the following parameters: CSF cell count, CSF protein levels, CSF lactate levels, CSF glucose-to-serum glucose ratio, and peripheral neutrophil count. BM-CASCO was retrospectively calculated for 784 cases of suspected ABM in adult subjects observed during a four-and-a-half-year-period (2010 to 2014) at the emergency department (ED) of a large tertiary-care teaching hospital in Italy. Among the 28 confirmed ABM cases (3.5%), Streptococcus pneumoniae was the most frequent cause (16 cases). All ABM cases showed a BM-CASCO value of ≥3. Most negative cases (591/756) exhibited a BM-CASCO value of ≤1, which was adopted in our laboratory as a cutoff to not proceed with urgent microbiological analysis of CSF in cases of suspected ABM in adults. During a subsequent 1-year follow-up, the introduction of the BM-CASCO in the diagnostic workflow of ABM in adults resulted in a significant decrease in unnecessary microbiological analysis, with no false negatives. In conclusion, BM-CASCO appears to be an accurate and simple scoring system for optimization of the microbiological diagnostic workflow of ABM in adults.

The UK joint specialist societies guideline on the diagnosis and management of acute meningitis and meningococcal sepsis in immunocompetent adults

Bacterial meningitis and meningococcal sepsis are rare conditions with high case fatality rates. Early recognition and prompt treatment saves lives. In 1999 the British Infection Society produced a consensus statement for the management of immunocompetent adults with meningitis and meningococcal sepsis. Since 1999 there have been many changes. We therefore set out to produce revised guidelines which provide a standardised evidence-based approach to the management of acute community acquired meningitis and meningococcal sepsis in adults. A working party consisting of infectious diseases physicians, neurologists, acute physicians, intensivists, microbiologists, public health experts and patient group representatives was formed. Key questions were identified and the literature reviewed. All recommendations were graded and agreed upon by the working party. The guidelines, which for the first time include viral meningitis, are written in accordance with the AGREE 2 tool and recommendations graded according to the GRADE system. Main changes from the original statement include the indications for pre-hospital antibiotics, timing of the lumbar puncture and the indications for neuroimaging. The list of investigations has been updated and more emphasis is placed on molecular diagnosis. Approaches to both antibiotic and steroid therapy have been revised. Several recommendations have been given regarding the follow-up of patients.

Performance of thirteen clinical rules to distinguish bacterial and presumed viral meningitis in Vietnamese children

Background and Purpose

Successful outcomes from bacterial meningitis require rapid antibiotic treatment; however, unnecessary treatment of viral meningitis may lead to increased toxicities and expense. Thus, improved diagnostics are required to maximize treatment and minimize side effects and cost. Thirteen clinical decision rules have been reported to identify bacterial from viral meningitis. However, few rules have been tested and compared in a single study, while several rules are yet to be tested by independent researchers or in pediatric populations. Thus, simultaneous test and comparison of these rules are required to enable clinicians to select an optimal diagnostic rule for bacterial meningitis in settings and populations similar to ours.

Methods

A retrospective cross-sectional study was conducted at the Infectious Department of Pediatric Hospital Number 1, Ho Chi Minh City, Vietnam. The performance of the clinical rules was evaluated by area under a receiver operating characteristic curve (ROC-AUC) using the method of DeLong and McNemar test for specificity comparison.

Results

Our study included 129 patients, of whom 80 had bacterial meningitis and 49 had presumed viral meningitis. Spanos's rule had the highest AUC at 0.938 but was not significantly greater than other rules. No rule provided 100% sensitivity with a specificity higher than 50%. Based on our calculation of theoretical sensitivity and specificity, we suggest that a perfect rule requires at least four independent variables that posses both sensitivity and specificity higher than 85–90%.

Conclusions

No clinical decision rules provided an acceptable specificity (>50%) with 100% sensitivity when applying our data set in children. More studies in Vietnam and developing countries are required to develop and/or validate clinical rules and more very good biomarkers are required to develop such a perfect rule.

Application of a prediction rule to discriminate between aseptic and bacterial meningitis in adults

INTRODUCTION

Differentiating between aseptic and bacterial meningitis presents a difficult diagnostic challenge. Accurately ruling out bacterial meningitis may reduce unnecessary hospitalization, patient morbidity, and utilization of resources. This study applies a prediction rule previously developed in the pediatric population to an adult cohort.

METHODS

We performed a retrospective chart review of all patients admitted to an urban community hospital in the United States between 1994 and 2007.

RESULTS

One hundred eleven patients met the inclusion criteria. Twenty-two (20%) had bacterial meningitis and 89 (80%) had aseptic meningitis. The prediction rule generated a negative predictive value of 100% and a sensitivity of 100%, successfully ruling out all patients with aseptic meningitis.

CONCLUSIONS

The prediction rule, previously validated in a pediatric population, was accurate in ruling out bacterial meningitis in an adult cohort. Prospective validation in an adult population is warranted.

Early diagnosis model for meningitis supports public health decision making

OBJECTIVE

To develop a predictive model for rapid differential diagnosis of meningitis and meningococcal septicaemia to support public health decisions on chemoprophylaxis for contacts.

METHODS

Prospective study of suspected cases of acute meningitis and meningococcal septicaemia admitted to hospitals in the South West, West Midlands and London Regions of England from July 2008 to June 2009. Epidemiological, clinical and laboratory variables on admission were recorded. Logistic regression was used to derive a predictive model.

RESULTS

Of the 719 suspect cases reported, 385 confirmed cases were included in analysis. Peripheral blood polymorphonuclear count of >16 × 10(9)/l, serum C-reactive protein of >100 mg/l and haemorrhagic rash were strongly and independently associated with diagnosis of bacterial meningitis and meningococcal septicaemia. Using a simple scoring system, the presence of any one of these factors gave a probability of >95% in predicting the final diagnosis.

CONCLUSION

We have developed a model using laboratory and clinical factors, but not dependent on availability of CSF, for differentiating acute bacterial from viral meningitis within a few hours of admission to hospital. This scoring system is recommended in public health management of suspected cases of meningitis and meningococcal septicaemia to inform decisions on chemoprophylaxis.

Lymphocytic hypophysitis accompanied by aseptic meningitis mimics subacute meningoencephalitis

A 66-year-old man was admitted to our hospital with muscle pain, fatigue and appetite loss that had lasted for a month. The patient was somnolent and had nuchal stiffness with a high fever. Cerebrospinal fluid (CSF) tests demonstrated lymphocytic pleocytosis with a decreased CSF-blood glucose ratio. The tests for tuberculous, fungal and carcinomatous meningitis and herpetic meningoencephalitis were negative. Endocrinological exams showed hypopituitarism and diabetes insipidus. A pituitary MRI showed an enlargement of the pituitary stalk. A diagnosis of lymphocytic hypophysitis with aseptic meningitis was made after the exclusion of secondary hypophysitis. Lymphocytic hypophysitis with aseptic meningitis can mimic subacute meningoencephalitis.