Acute phase reactants and risk of bacterial meningitis among febrile infants and children

Bulging fontanelle in febrile infants as a predictor of bacterial meningitis

It is common practice to perform a lumbar puncture in infants presenting with fever and a bulging fontanelle in order to rule out bacterial meningitis. However, most of these infants have benign, self-limiting diseases. The objective was to determine whether there is an association between bulging fontanelle and bacterial meningitis in febrile infants. This retrospective cohort study included febrile children with a bulging fontanelle who underwent lumbar puncture at Meir Medical Center from 2005 through 2015. A total of 764 children ages 2-18 months underwent lumbar puncture during the study period. Among them, 304 had a bulging fontanelle and fever on evaluation and cerebrospinal fluid pleocytosis was found in 115 (37.8%), including 1 case of bacterial meningitis (0.3%). None of the infants described on admission as appearing well on presentation was found to have bacterial meningitis. Of the 764 children who underwent lumbar puncture, 10 infants were diagnosed with bacterial meningitis, and only one (10%) presented with a bulging fontanelle.Conclusion: The finding of a bulging fontanelle has very low sensitivity and specificity for bacterial meningitis. Most causes of a bulging fontanelle in febrile infants are self-limiting diseases. The routine approach of performing a lumbar puncture in febrile infants with a bulging fontanelle should be reconsidered. What is Known: • It is common to perform a lumbar puncture in febrile infants with a bulging fontanelle, to rule out bacterial meningitis. • However, there are only few researches regarding the relationship between bulging fontanelle and bacterial meningitis. What is New: • The finding of a bulging fontanelle has very low sensitivity and specificity for bacterial meningitis • The need for routine lumbar puncture in these cases should be reconsidered.

Plasma IP-10 as a predictor of serious bacterial infection in infants less than 4 months of age

BACKGROUND

Early diagnosis of serious bacterial infection (SBI) in young infants is a difficult problem by clinical symptoms and signs. The goal of this study is to evaluate the predictive value of plasma IP-10 levels for early diagnosis of SBI in young infants <4 months of age.

METHODS

We enrolled pediatric patients who were <4 months of age with a clinical suspicion to have SBI admitted in neonatal intensive care unit or complete nursing unit of Pediatric Department of Kaohsiung Medical University Hospital. Blood was drawn for measurement of complete blood counts, C-reactive protein (CRP) and plasma IP-10 levels and microbiological cultures were obtained at the time of admission.

RESULTS

There were 60 patients enrolled in this study. The SBI group (n = 21) have higher plasma IP-10 levels than those infants without SBI (n = 39) [median 104.8 (range 0-1457.1) versus 0 (range 0-129.3) pg ml(-1), P = 0.0161 after adjusting age]. A plasma IP-10 level >48.2 pg ml(-1) had the best diagnostic accuracy for indicating SBI {sensitivity 81.0% [95% confidence interval (CI) 71.1-90.1%]; specificity 94.9% [95% CI 65.4-87.0%]; positive likelihood ratio 15.9, negative likelihood ratio 0.2}.

CONCLUSION

In infants who were <4 months of age with suspicion of SBI, IP-10 assay might be a good predictor. Key words: chemokine, IP-10, serious bacterial infection, young infant, C-reactive protein.

Clinical features suggestive of meningitis in children: a systematic review of prospective data

CONTEXT

Clinical diagnosis of pediatric meningitis is fundamental; therefore, familiarity with evidence underscoring clinical features suggestive of meningitis is important.

OBJECTIVE

To seek evidence supporting accuracy of clinical features of pediatric bacterial meningitis.

METHODS

A review of Medline, Embase, the Cumulative Index to Nursing and Allied Health Literature, Web of Science, and PubMed was conducted for all articles of relevance. Articles contained prospective data of clinical features in children with laboratory-confirmed bacterial meningitis and in comparison groups of those without it. Two authors independently assessed quality and extracted data to calculate accuracy data of clinical features.

RESULTS

Of 14 145 references initially identified, 10 met our inclusion criteria. On history, a report of bulging fontanel (likelihood ratio [LR]: 8.00 [95% confidence interval (CI): 2.4-26]), neck stiffness (7.70 [3.2-19]), seizures (outside febrile-convulsion age range) (4.40 [3.0-6.4]), or reduced feeds (2.00 [1.2-3.4]) raised concern about the presence of meningitis. On examination, jaundice (LR: 5.90 [95% CI: 1.8-19]), being toxic or moribund (5.80 [3.0-11]), meningeal signs (4.50 [2.4-8.3]), neck stiffness (4.00 [2.6-6.3]), bulging fontanel (3.50 [2.0-6.0]), Kernig sign (3.50 [2.1-5.7]), tone up (3.20 [2.2-4.5]), fever of >40°C (2.90 [1.6-5.5]), and Brudzinski sign (2.50 [1.8-3.6]) independently raised the likelihood of meningitis. The absence of meningeal signs (LR: 0.41 [95% CI: 0.30-0.57]) and an abnormal cry (0.30 [0.16-0.57]) independently lowered the likelihood of meningitis. The absence of fever did not rule out meningitis (LR: 0.70 [95% CI: 0.53-0.92]).

CONCLUSIONS

Evidence for several useful clinical features that influence the likelihood of pediatric meningitis exists. No isolated clinical feature is diagnostic, and the most accurate diagnostic combination is unclear.

Plasma IP-10 as a predictor of serious bacterial infection in infants less than 4 months of age

BACKGROUND

Early diagnosis of serious bacterial infection (SBI) in young infants is a difficult problem by clinical symptoms and signs. The goal of this study is to evaluate the predictive value of plasma IP-10 levels for early diagnosis of SBI in young infants <4 months of age.

METHODS

We enrolled pediatric patients who were <4 months of age with a clinical suspicion to have SBI admitted in neonatal intensive care unit or complete nursing unit of Pediatric Department of Kaohsiung Medical University Hospital. Blood was drawn for measurement of complete blood counts, C-reactive protein (CRP) and plasma IP-10 levels and microbiological cultures were obtained at the time of admission.

RESULTS

There were 60 patients enrolled in this study. The SBI group (n = 21) have higher plasma IP-10 levels than those infants without SBI (n = 39) [median 104.8 (range 0-1457.1) versus 0 (range 0-129.3) ng ml(-1), P = 0.0161 after adjusting age]. A plasma IP-10 level >48.2 ng ml(-1) had the best diagnostic accuracy for indicating SBI [sensitivity 81.0% [95% confidence interval (CI) 71.1-90.1%]; specificity 94.9% [95% CI 65.4-87.0%]; positive likelihood ratio 15.9, negative likelihood ratio 0.2}.

CONCLUSION

In infants who were <4 months of age with suspicion of SBI, IP-10 assay might be a good predictor.

Cerebrospinal fluid pleocytosis in children in the era of bacterial conjugate vaccines: distinguishing the child with bacterial and aseptic meningitis

Although bacterial meningitis remains an important cause of childhood morbidity and mortality, the incidence of bacterial meningitis has greatly decreased with the advent of polysaccharide-protein conjugate vaccines in the past 2 decades. Most children with cerebrospinal fluid pleocytosis have aseptic rather than bacterial meningitis, raising the possibility that some patients may be managed as outpatients. In this article, we review the changing epidemiology of bacterial meningitis as well as the available clinical decision rules that may assist the clinician in distinguishing aseptic from bacterial meningitis in patients with cerebrospinal fluid pleocytosis.

Characteristics of febrile patients with normal white blood cell counts and high C-reactive protein levels in an emergency department

Fever is one of the more common chief complaints of patients who visit emergency departments (ED). Many febrile patients have markedly elevated C-reactive protein (CRP) levels and normal white blood cell (WBC) counts. Most of these patients have bacterial infection and no previous underlying disease of impaired WBC functioning. We reviewed patients who visited our ED between November 2003 and July 2004. The WBC count and CRP level of patients over 18 years of age who visited the ED because of or with fever were recorded. Patients who had normal WBC count (4,000–10,000/mL) and high CRP level (> 100 mg/L) were included. The data, including gender, age and length of hospital stay, were reviewed. Underlying diseases, diagnosis of the febrile disease and final condition were recorded according to the chart. Within the study period, 54,078 patients visited our ED. Of 5,628 febrile adults, 214 (3.8%) had elevated CRP level and normal WBC count. The major cause of febrility was infection (82.24%). Most of these patients were admitted (92.99%). There were 32 patients with malignant neoplasm, nine with liver cirrhosis, 66 with diabetes mellitus and 11 with uremia. There were no significant differences in age and gender between patients with and those without neoplasm. However, a higher inhospital mortality rate and other causes of febrility were noted in patients with neoplasm. It was not rare in febrile patients who visited the ED to have a high CRP level but normal WBC count. These patients did not necessarily have an underlying malignant neoplasm or hematologic illness. Factors other than malignant neoplasm or hematologic illness may be associated with the WBC response, and CRP may be a better indicator of infection under such conditions.

Serum procalcitonin and C-reactive protein levels as markers of bacterial infection: a systematic review and meta-analysis

A meta-analysis was performed to evaluate the accuracy of determination of procalcitonin (PCT) and C-reactive protein (CRP) levels for the diagnosis of bacterial infection. The analysis included published studies that evaluated these markers for the diagnosis of bacterial infections in hospitalized patients. PCT level was more sensitive (88% [95% confidence interval [CI], 80%-93%] vs. 75% [95% CI, 62%-84%]) and more specific (81% [95% CI, 67%-90%] vs. 67% [95% CI, 56%-77%]) than CRP level for differentiating bacterial from noninfective causes of inflammation. The Q value for PCT markers was higher (0.82 vs. 0.73). The sensitivity for differentiating bacterial from viral infections was also higher for PCT markers (92% [95% CI, 86%-95%] vs. 86% [95% CI, 65%-95%]); the specificities were comparable (73% [95% CI, 42%-91%] vs. 70% [95% CI, 19%-96%]). The Q value was higher for PCT markers (0.89 vs. 0.83). PCT markers also had a higher positive likelihood ratio and lower negative likelihood ratio than did CRP markers in both groups. On the basis of this analysis, the diagnostic accuracy of PCT markers was higher than that of CRP markers among patients hospitalized for suspected bacterial infections.

Development and validation of a multivariable predictive model to distinguish bacterial from aseptic meningitis in children in the post-Haemophilus influenzae era

CONTEXT

Children with meningitis are routinely admitted to the hospital and administered broad-spectrum antibiotics pending culture results because distinguishing bacterial meningitis from aseptic meningitis is often difficult.

OBJECTIVE

To develop and validate a simple multivariable model to distinguish bacterial meningitis from aseptic meningitis in children using objective parameters available at the time of patient presentation.

DESIGN

Retrospective cohort study of all children with meningitis admitted to 1 urban children's hospital from July 1992 through June 2000, randomly divided into derivation (66%) and validation sets (34%).

PATIENTS

Six hundred ninety-six previously healthy children aged 29 days to 19 years, of whom 125 (18%) had bacterial meningitis and 571 (82%) had aseptic meningitis.

INTERVENTION

Multivariable logistic regression and recursive partitioning analyses identified the following predictors of bacterial meningitis from the derivation set: Gram stain of cerebrospinal fluid (CSF) showing bacteria, CSF protein > or =80 mg/dL, peripheral absolute neutrophil count > or =10 000 cells/mm3, seizure before or at time of presentation, and CSF absolute neutrophil count > or =1000 cells/mm3. A Bacterial Meningitis Score (BMS) was developed on the derivation set by attributing 2 points for a positive Gram stain and 1 point for each of the other variables.

MAIN OUTCOME MEASURE

The accuracy of the BMS when applied to the validation set.

RESULTS

A BMS of 0 accurately identified patients with aseptic meningitis without misclassifying any child with bacterial meningitis in the validation set. The negative predictive value of a score of 0 for bacterial meningitis was 100% (95% confidence interval: 97%-100%). A BMS > or =2 predicted bacterial meningitis with a sensitivity of 87% (95% confidence interval: 72%-96%).

CONCLUSIONS

The BMS accurately identifies children at low (BMS = 0) or high (BMS > or =2) risk of bacterial meningitis. Outpatient management may be considered for children in the low-risk group.

C-reactive protein in febrile children 1 to 36 months of age with clinically undetectable serious bacterial infection

OBJECTIVE

To determine the diagnostic properties of quantitative C-reactive protein (CRP) associated with clinically undetectable serious bacterial infection (SBI) in febrile children 1 to 36 months of age.

METHODS

Febrile children presenting to a pediatric emergency department (ED) with ages ranging from 1 to 36 months, temperatures > or =39 degrees C, and clinically undetectable source of fever were enrolled in this prospective cohort study. Demographic information, ED temperature, duration of fever, and clinical evaluation using the Yale observation scale were recorded at the time of the initial evaluation. The white blood cell count (WBC), band count, absolute neutrophil count (ANC), and CRP concentration were measured at the same time. All patients received blood cultures and either a screening urinalysis or urine culture. A chest radiograph was obtained at the discretion of the ED physician. Patients with history of using antibiotics within 1 week of their presentation to the ED were excluded. The main outcome result was the presence of laboratory or radiographically proven SBI (bacteremia, meningitis, urinary tract infection, pneumonia, septic arthritis, and osteomyelitis).

RESULTS

Seventy-seven patients were enrolled in the study. Fourteen (18%) had a SBI (6 urinary tract infection; 4 pneumonia, including 1 patient with Streptococcus pneumoniae bacteremia; and 4 occult S pneumoniae bacteremia), and 63 had no SBI. The 2 groups were indistinguishable in age, sex, ED temperature, duration of fever, and Yale observation scale. CRP concentration, WBC, and ANC were significantly different between the 2 groups. In a multivariate logistic regression analysis, only CRP remained as a predictor of SBI (Beta = 0.76, 95% confidence interval [CI]: 0.64, 0.89). Receiver-operating characteristic analysis demonstrated CRP (area under curve [AUC] 0.905, standard error [SE] 0.05, 95% CI: 0.808, 1.002) to be superior to ANC (AUC 0.805, SE 0.051, 95% CI: 0.705, 0.905) and to WBC (AUC 0.761, SE 0.068, 95% CI: 0.628, 0.895). A CRP cutoff point of 7 was determined to maximize both sensitivity and specificity (sensitivity 79%, specificity 91%, likelihood ratio 8.3, 95% CI: 3.8, 27.3). Multilevel likelihood ratios and posttest probabilities were calculated for a variety of CRP levels. A CRP concentration of <5 mg/dL effectively ruled out SBI (likelihood ratio 0.087, 95% CI: 0.02, 0.38, posttest probability of SBI 1.9%).

CONCLUSIONS

Quantitative CRP concentration is a valuable laboratory test in the evaluation of febrile young children who are at risk for occult bacteremia and SBI, with a better predictive value than the WBC or ANC.

Serum C-reactive protein in the differential diagnosis of childhood meningitis

BACKGROUND

Although determination of serum C-reactive protein (CRP) is considered one of the most useful tests for differentiating between bacterial and aseptic meningitis, its diagnostic accuracy in comparison with other laboratory parameters is yet to be further evaluated.

METHODS

A total of 192 pediatric cases, aged between 2 months and 14 years, comprising patients with bacterial meningitis (n = 66) and aseptic meningitis (n = 126), were retrospectively analyzed on the basis of data from the initial examination. The area under the best fit binormal curve of the receiver operating characteristics (Az) for CRP was determined and compared with that for several other analytic parameters, including white blood cell count and erythrocyte sedimentation rate of peripheral blood, standard cerebrospinal fluid analysis variables and the combination test (probability of acute bacterial meningitis (pABM)) derived from Hoen's model.

RESULTS

Compared with each of the other variables, the Az for serum CRP (0.97 +/- 0.02) was found to be significantly greater (P < 0.01) for all except pABM (0.99 +/- 0.01; P > 0.05). False-negative cases among the CRP test results were found to have been examined too early.

CONCLUSIONS

The diagnostic accuracy of a single CRP determination was found to be equivalent to that of the most effective combination test. Patients with meningitis in whom serum CRP values are determined at least 12 h after the onset of fever and are < 2 mg/dL are far less likely to have bacterial meningitis.

Value of cerebrospinal fluid leukocyte aggregation in distinguishing the causes of meningitis in children

BACKGROUND

Current laboratory tests often cannot distinguish between bacterial and aseptic meningitis rapidly and accurately. The ability to make a prompt diagnosis has important implications for the management and outcome of children with meningitis. The observation that leukocytes aggregate in the cerebrospinal fluid (CSF) has been previously reported, and it has been advocated as a reliable method to distinguish the causes of meningitis in children.

OBJECTIVE

To investigate the utility of CSF leukocyte aggregation as a screening test to distinguish between bacterial and aseptic meningitis.

METHODS

We compared the clinical and laboratory indices of 109 prospectively enrolled patients with meningitis (67 bacterial, 23 viral, 19 undefined etiology) and evaluated the validity of the CSF leukocyte aggregation test. The predefined leukocyte aggregation scores (LAS) were compared among the types of meningitis, and correlations with other markers of inflammation were calculated.

RESULTS

The median LAS was significantly higher (P < 0.001) in the bacterial (32.1%; range, 0 to 84.1%) than in the viral (0%; range, 0 to 16.6%) or undefined (0%; range, 0 to 20.7%) groups. The optimal sensitivity of the leukocyte aggregation test, 98.5 to 92.5%, was demonstrated with LAS values of 0 to 3%. The corresponding specificity was 64.3 to 88.1%. The peripheral white blood cell (WBC) count, serum C-reactive protein, CSF WBC count, blood culture, CSF Gram stain and CSF culture were inferior to the LAS as screening tests when compared individually. The LAS was as effective as CSF protein, TNF-alpha, IL-1-beta, IL-6 and IL-8 to predict bacterial meningitis. In a logistic regression model that included routine laboratory tests, the best predictor of bacterial meningitis was the LAS (odds ratio, 1.6 to 3.7). Significant correlations were demonstrated between the LAS and CSF protein, CSF WBC count, IL-1-beta, IL-6 and IL-8. Duration of symptoms before diagnosis, pretreatment with antibiotics, HIV-1 infection status and CSF red blood cell count did not significantly alter the LAS.

CONCLUSIONS

There is no single test to diagnose the etiology of meningitis in children promptly and accurately. The finding of leukocyte aggregation in CSF might be of value as a sensitive adjunctive screening tool for the timely diagnosis of bacterial meningitis, recognizing that it has low specificity and potential practical limitations.

The C-reactive protein

C-reactive protein (CRP) was identified in 1930 and was subsequently considered to be an "acute phase protein," an early indicator of infectious or inflammatory conditions. Since its discovery, CRP has been studied as a screening device for inflammation, a marker for disease activity, and as a diagnostic adjunct. Improved methods of quantifying CRP have led to increased application to clinical medicine. In the emergency department (ED), CRP must be interpreted in the clinical context; no single value can be used to rule in or rule out a specific diagnosis. We conclude that CRP has limited utility in the ED. It may be a useful adjunct to serial examinations in equivocal presentations of appendicitis in those centers without ready access to computed tomography (CT) scan. It may be elevated with complications or treatment failures in patients with pneumonia, pancreatitis, pelvic inflammatory disease (PID), and urinary tract infections. In patients with meningitis, neonatal sepsis, and occult bacteremia, CRP is usually elevated. However, CRP has no role in diagnosing these clinical entities, and a normal CRP level should never delay antibiotic coverage.

C-reactive protein and bacterial meningitis: a meta-analysis

The aim of the study was to review published articles on the diagnostic accuracy of C-reactive protein (CRP) tests with cerebrospinal fluid and serum in diagnosing bacterial meningitis. The literature from 1980 and onwards was searched using the electronic databases of MEDLINE, and we used summary receiver operating characteristic curve analyses (SROCs) to describe central tendencies and examine possible sources of inter-study variability in the results. We included data from 35 studies of both children and adults: 21 in which CRP had been measured in cerebrospinal fluid, 10 in which CRP had been measured in serum, and 4 in which it had been measured in both cerebrospinal fluid and serum. The odds ratio for bacterial meningitis versus aseptic meningitis for a positive CRP test with cerebrospinal fluid was estimated at 241 (95% confidence interval [CI]: 59-980), and the central tendencies for the true-positive fraction (sensitivity) and the false-positive fraction (1-specificity) were estimated at 0.94 and 0.06, respectively. The corresponding figures for a CRP test with serum were 150 (95% CI: 44-509), 0.92 and 0.08, respectively. Regression analyses including variables coding for study design features, inclusion of neonatal patients, geographical region, or use of a quantitative biochemical method did not indicate statistically significant contributions to inter-study variances in the log odds ratios. For values of the true- and the false-positive fractions of 0.92-0.94 and 0.06-0.08, respectively, the post-test probability of not having bacterial meningitis given a negative test is very high (> or = 97%), in the range of a pre-test probability (prevalence of bacterial meningitis) from 10 to 30%, whereas the post-test probability of bacterial meningitis given a positive test is considerably lower. Hence, only a negative test is highly informative in a typical clinical setting. This, as well as the absence of analyses to show if CRP tests contribute independent diagnostic information, relatively to the information held in the traditionally used clinical and biochemical variables, makes it difficult to conclude on the clinical usefulness of CRP tests in the management of patients suspected of having bacterial meningitis.

Clinical applications of C-reactive protein in pediatrics

The body of literature concerning studies of the applications of CRP measurement in the pediatric population continues to grow. Based on current data serial CRP measurements appear to be most useful for monitoring patient response to therapy after the primary diagnosis of invasive infectious or inflammatory diseases, for monitoring patients after major surgical procedures and those with serious burns. Monitoring CRP over time may be used to assess for recrudescent disease, a secondary process or ineffective therapy. In addition CRP appears to be suited to most applications for which the ESR is used but offers many advantages. At present there are no objective outcome-based clinical trial data to justify using CRP values alone, whether elevated or normal, as a basis for management decisions regarding instituting or withholding antimicrobial therapy, or its early discontinuance for patients suspected of having neonatal sepsis, meningitis, bacteremia or pneumonia, regardless of immune status. In addition, because of significant inconsistencies among studies for which CRP has been applied to differential diagnosis of bacterial vs. viral diseases, including meningitis, acute otitis media and lower respiratory tract infection, we cannot recommend it for this purpose. Data do not support a role for CRP in differential diagnosis of acute appendicitis or for localizing urinary tract infections.

Acute phase proteins in serum and cerebrospinal fluid in the course of bacterial meningitis

We carried out estimations of the following acute phase proteins: C-reactive protein (CRP), alpha-1-antitrypsin (AAT), alpha-1-acid glycoprotein (AAG), alpha-2-ceruloplasmin (CER), and alpha-2-haptoglobin (HPT) in serum and in cerebrospinal fluid (CSF) in patients with bacterial meningitis (BM, n = 30) and viral meningitis (VM, n = 30). We have shown that determinations of concentrations of AAG and CRP in serum and CER in CSF are useful in differentiation between BM and VM. The diagnostic power of these three tests (the areas under their ROC curves equal 0.942, 0.929, and 0.931, respectively) is bigger, though statistically not significantly, than that of traditional parameters of BM in CSF, i.e., total protein concentration and white blood cell count. Determination of AAG, CRP, and AAT in serum is a valuable monitoring marker in the course of BM treatment. Convenience of serum sampling constitutes an advantage over traditional BM parameters in CSF.

Urgent full blood count in children over 3 months of age with bacterial meningitis

Children with bacterial meningitis often have a full blood count (FBC) measured urgently on admission. We investigated whether urgent FBC gave results that aided immediate management or predicted outcome in children with meningitis. FBCs were measured on admission during 190 episodes of bacterial meningitis in children admitted between 1984 and 1991. Significant anaemia was found in seven children, but immediate transfusion was only necessary in the three subjects who were in the Paediatric Intensive Care Unit (PICU). A white blood count of less than 5 x 10(9) L-1 was significantly associated with death (P < 0.02), but a Glasgow Coma Score of less than 8 predicted death more accurately (positive predictive value of 40%). FBC yielded immediately useful information only in the 15% of children who were admitted to PICU. Conscious level was a better predictor of outcome than FBC. We recommend that urgent FBC should be performed in children with meningitis admitted to a PICU; in other children with meningitis FBC can be analysed during normal laboratory hours.