Comparing Single vs. Combined Cerebrospinal Fluid Parameters for Diagnosing Full-Term Neonatal Bacterial Meningitis

Meta-analysis of Cerebrospinal Fluid Cell Count and Biochemistry to Diagnose Meningitis in Infants Aged < 90 Days

OBJECTIVE

 Cerebrospinal fluid (CSF) white blood cell (WBC) count, protein, and glucose (cytochemistry) are performed to aid in the diagnosis of meningitis in young infants. However, studies have reported varying diagnostic accuracies. We assessed the diagnostic accuracy of CSF cytochemistry in infants below 90 days and determined the certainty of evidence.

STUDY DESIGN

 We searched PubMed, Embase, Cochrane Library, Ovid, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Scopus databases in August 2021. We included studies that evaluated the diagnostic accuracy of CSF cytochemistry compared with CSF culture, Gram stain, or polymerase chain reaction in neonates and young infants <90 days with suspected meningitis. We pooled data using the hierarchical summary receiver operator characteristic (ROC) model.

RESULTS

 Of the 10,720 unique records, 16 studies were eligible for meta-analysis, with a cumulative sample size of 31,695 (15 studies) for WBC, 12,936 (11 studies) for protein, and 1,120 (4 studies) for glucose. The median (Q1, Q3) specificities of WBC, protein, and glucose were 87 (82, 91), 89 (81, 94), and 91% (76, 99), respectively. The pooled sensitivities (95% confidence interval [CI]) at median specificity of WBC count, protein, and glucose were 90 (88, 92), 92 (89, 94), and 71% (54, 85), respectively. The area (95% CI) under ROC curves were 0.89 (0.87, 0.90), 0.87 (0.85, 0.88), and 0.81 (0.74, 0.88) for WBC, protein, and glucose, respectively. There was an unclear/high risk of bias and applicability concern in most studies. Overall certainty of the evidence was moderate. A bivariate model-based analysis to estimate the diagnostic accuracy at specific thresholds could not be conducted due to a paucity of data.

CONCLUSION

 CSF WBC and protein have good diagnostic accuracy for the diagnosis of meningitis in infants below 90 days of age. CSF glucose has good specificity but poor sensitivity. However, we could not identify enough studies to define an optimal threshold for the positivity of these tests.

KEY POINTS

· Median specificity of CSF leucocyte count, protein and glucose are similar in young infants.. · At median specificity, CSF leukocyte count and protein are more sensitive than glucose.. · Owing to inadequate data, bivariate modelling to suggest optimal diagnostic thresholds is not possible..

Utility of Cerebrospinal Fluid and Serum Procalcitonin for the Diagnosis of Neonatal Meningitis

OBJECTIVE

Positive CSF culture is the gold standard for the diagnosis of meningitis but it carries poor sensitivity. CSF procalcitonin (PCT) is shown to have some utility for the diagnosis of meningitis though there are limited studies in neonatal age group. We planned this study to compare CSF, serum, and CSF to serum PCT levels in neonates with confirmed, probable, and nonmeningitis groups to determine its optimal cut-off in CSF and serum for diagnosing meningitis.

STUDY DESIGN

Sixty-seven neonates who qualified for lumbar puncture were enrolled in the study. Neonates were categorized into confirmed meningitis, i.e., CSF cytochemistry and culture positive (N = 17), probable meningitis, i.e., CSF cytochemistry positive but culture negative (N = 25) and nonmeningitis, i.e., both cytochemistry and culture negative (N = 25). CSF and serum samples were stored at -80°C for PCT assay.

RESULTS

Significant difference was seen in mean of CSF PCT in neonates with confirmed (0.31 ng/mL), probable (0.22 ng/mL), and nonmeningitis (0.11 ng/mL) groups. Similarly, significant difference was observed in serum PCT levels also, though the ratio of serum to CSF PCT was comparable. At cut-off of 0.2 ng/mL, CSF PCT had sensitivity of 95.2% and specificity of 96% in the diagnosis of meningitis.

CONCLUSION

CSF PCT is more specific marker for the diagnosis of neonatal meningitis as compared with serum PCT and CSF to serum PCT ratio.

KEY POINTS

· CSF procalcitonin is a better marker than serum procalcitonin for diagnosing neonatal meningitis.. · It is better than serum procalcitonin and CSF to serum procalcitonin ratio.. · At cut-off of >0.2 ng/mL CSF procalcitonin can diagnose neonatal meningitis with 96% specificity..

Accuracy of Clinical and Cerebrospinal Fluid Indicators in the Diagnosis of Bacterial Meningitis in Infants <90 Days of Age in Luanda, Angola

BACKGROUND

The diagnosis of bacterial meningitis (BM) is problematic in young infants, as clinical features may be nonspecific or even absent. Cerebrospinal fluid (CSF) analysis usually confirms the diagnosis, but the CSF parameters can be normal also in culture-proven BM. Our objective was to identify the clinical and CSF indices, that quickly and without laboratory likely lead to the diagnosis of confirmed of probable BM in young infants in Angola.

METHODS

We conducted a prospective, observational, single-site study from February 2016 to October 2017 in the Pediatric Hospital of Luanda. All assessed infants showed symptoms and signs compatible of BM or neonatal sepsis and were <90 days of age.

RESULTS

Of the 1088 infants, 212 (19%) showed bacteria in CSF, while 88 (8%) had probable BM. Independent clinical indicators of BM were not-clear CSF, seizures, weight <2500 g and illness >7 days. In infants with BM, CSF leukocytes were >10 × 106/L in 46%, CSF glucose <25 mg/dL in 43% and CSF protein >120 mg/dL in 58%. All measured parameters were in normal range in 25% of patients. In 515 infants with normal CSF parameters, bacteria were found in 74 (14%). In these infants, illness >7 days, weight <2500 g and malnutrition increased the probability of BM.

CONCLUSIONS

Our study confirms and underlines the problems in diagnosing BM in young infants. While the CSF parameters were normal in 25% of infants, the easily recognizable unclear appearance of CSF was the single strongest predictor of BM.

A sequential guide to identify neonates with low bacterial meningitis risk: a multicenter study

Objective

To derive and validate a predictive algorithm integrating clinical and laboratory parameters to stratify a full‐term neonate's risk level of having bacterial meningitis (BM).

Methods

A multicentered dataset was categorized into derivation (689 full‐term neonates aged ≤28 days with a lumbar puncture [LP]) and external validation (383 neonates) datasets. A sequential algorithm with risk stratification for neonatal BM was constructed.

Results

In the derivation dataset, 102 neonates had BM (14.8%). Using stepwise regression analysis, fever, infection source absence, neurological manifestation, C‐reactive protein (CRP), and procalcitonin were selected as optimal predictive sets for neonatal BM and introduced to a sequential algorithm. Based on the algorithm, 96.1% of BM cases (98 of 102) were identified, and 50.7% of the neonates (349 of 689) were classified as low risk. The algorithm’s sensitivity and negative predictive value (NPV) in identifying neonates at low risk of BM were 96.2% (95% CI 91.7%–98.9%) and 98.9% (95% CI 97.6%–99.6%), respectively. In the validation dataset, sensitivity and NPV were 95.9% (95% CI 91.0%–100%) and 98.8% (95% CI 97.7%–100%).

Interpretation

The sequential algorithm can risk stratify neonates for BM with excellent predictive performance and prove helpful to clinicians in LP‐related decision‐making.

Evaluation of cerebrospinal fluid and blood parameters finding in early diagnosis and drug therapy of suspected bacterial meningitis in neonates

Background:

Whether early lumbar puncture (LP) and blood indicators are suitable as diagnostic criteria and helpful to treatment strategies for newborns remains to be solved. The study was to evaluate the value of cerebrospinal fluid (CSF) at the first LP and blood indicators at the similar time in the early diagnosis and the drug therapy of neonatal bacterial meningitis.

Materials and Methods:

We conducted a retrospective observational study of 997 infants with suspected bacterial meningitis between June 2012 and June 2018. CSF and blood parameters were evaluated by three stepwise logistic models to assess their ability: to distinguish bacterial meningitis from nonbacterial meningitis, to distinguish positive CSF culture from negative, and to distinguish Gram-positive bacteria from negative.

Results:

Of the 997 neonates, 236 (23.67%) were later diagnosed as bacterial meningitis. Of the neonates with meningitis, 54 (22.88%) had positive CSF culture results. And of neonates with positive CSF culture, 27 (50%) had Gram-positive results. One or more CSF indicators were added to the three models. Only blood hypersensitive C-reactive protein and blood lactate dehydrogenase were added to the first model, while no blood parameters was added to the other two models. The areas under the effect-time curves of the three models were 0.91 (95% confidence interval [CI]: 0.89–0.92, P < 0.001), 0.69 (95% CI: 0.63–0.75, P < 0.001), and 0.86 (95% CI: 0.74–0.94, P < 0.001), respectively.

Conclusion:

LP was irreplaceable predictor of bacterial meningitis, and comprehensive analysis of CSF indicators can predict the offending organism, which enables refinement of therapy.