The utility of biomarkers in differentiating bacterial from non-bacterial lower respiratory tract infection in hospitalized children: Difference of the diagnostic performance between acute pneumonia and bronchitis

Overview of Pediatric Procalcitonin Testing Patterns in a Tertiary Care Children's Hospital

The use of procalcitonin (PCT) has grown over the past decade with increasing reliance on the test to rule out bacterial infection. We retrospectively reviewed the medical records of children <18 years old hospitalized at a tertiary care children's hospital from 2017 to 2019 who had PCT testing performed during their admission. Of 4135 PCT levels collected on 1530 children, 982 (23.7%) were diagnostically low and 1993 (48.1%) were diagnostically elevated. Pediatric intensive care, with 6% of total hospital patients, obtained 41.4% of tests. Thirty-one (2%) patients had an average of 27 PCT levels per patient, accounting for 20% of all tests. Many children had symptoms for which testing is not indicated (eg, skin complaints). The differences in PCT testing by service, inappropriate patterns of repeat testing, and testing performed in patients for whom it is not indicated may identify targets for diagnostic stewardship.

Comparison of commercially available, rapid, point-of-care C-reactive protein assays among children with febrile illness in southwestern Uganda

In Uganda, children with febrile illness are often treated with antibiotics even though most have self-limiting, likely viral, infections. C-reactive protein (CRP) measurement can help identify those who are more likely to have a bacterial infection and therefore need antibiotic treatment. Implementation of a CRP rapid diagnostic test (RDT) at the point-of-care in resource-constrained settings with minimal laboratory infrastructure could reduce unnecessary antibiotic use. In this study, we evaluated the performance of three semi-quantitative CRP RDTs (Actim, BTNX, Duo) against a reference CRP assay requiring an electrically powered analyzer (Afinion). While both tests demonstrated substantial agreement with Afinion, Actim had slightly higher agreement than BTNX. The sensitivity was higher for the BTNX test, whereas the Actim test had a higher specificity, at cut-offs of 40 mg/L and 80 mg/L. At a cut-off of 20 mg/L, Duo demonstrated substantial agreement with the Afinion test as well. Our results demonstrate the reliability of CRP RDTs when compared to a reference standard. CRP RDTs without the need for a laboratory-based analyzer are promising tools for optimizing antibiotic use in low-resource settings.

Clinical significance of serum S100 calcium-binding protein A12 concentrations in patients with community-acquired pneumonia

OBJECTIVE

This study aimed to investigate the clinical significance of serum S100 calcium-binding protein A12 (S100A12) concentrations in patients with community-acquired pneumonia (CAP).

METHODS

This was a case-control study. We selected 120 patients with CAP treated in Xichang People's Hospital from January to June 2022 as the case group. Sixty healthy adults without a history of basic diseases were selected as the control group. The patients in the case group were divided into the low S100A12 and high S100A12 subgroups. Serum S100A12, C-reactive protein (CRP), and procalcitonin (PCT) concentrations, the leukocyte count, and other study parameters were compared.

RESULTS

Serum S100A12, CRP, and PCT concentrations and the leukocyte count were higher in the case group than in the control group. The baseline confusion, urea, respiratory rate, blood pressure, and age ≥ 65 score, baseline pneumonia severity index score, and 30-day mortality rate were higher in the high S100A12 subgroup than in the low S100A12 subgroup. Serum CRP and PCT concentrations and the leukocyte count were higher in the high S100A12 subgroup than in the low S100A12 subgroup.

CONCLUSION

Patients with high serum S100A12 concentrations have more severe CAP, a more serious inflammatory reaction, and higher 30-day mortality.

Application of Biomarkers in the Diagnostic Distinction of Bacterial and Viral Infections

Infectious diseases, which pose a great threat worldwide, have a significant impact on public health and the world economy. It contributes to increased healthcare costs, unnecessary drug-related side effects, and increased antimicrobial resistance. It is not always easy to distinguish the etiological differentiation of diseases that can develop with bacteria and viruses. Therefore, one of the biggest challenges in medicine is how to correctly distinguish between the different causes of these infections and how to manage the patient. Because bacterial and viral infections often present similar symptoms. The real decision is whether the infection is caused by bacteria or viruses and whether to treat the patient with antibiotics. There are many different methodological approaches to diagnosing infections. Biomarkers have been used in the diagnosis of diseases and other conditions for many years. Biomarkers are molecules found in blood and body fluids in measurable amounts, which can evaluate biological and pathological processes. These key indicators can provide vital information in determining disease prognosis, predicting response to treatments, adverse events and drug interactions, and identifying key risks. An effective biomarker is extremely important for the early diagnosis of various diseases. The explosion of interest in biomarker research is driving the development of new predictive, diagnostic, and prognostic products in modern medical practice. The purpose of this review is to demonstrate the use and diagnostic potential of current and investigational biomarkers in the distinction between bacterial and viral infections.

Role of procalcitonin in diagnosis of community acquired pneumonia in Children

Background

The role of serum Procalcitonin (PCT) in adults in diagnosis of Community acquired pneumonia (CAP) is well established, however, role in pediatric CAP remains controversial.

Objectives

The objective of this study was to investigate the utility of serum procalcitonin in differentiating bacterial community-acquired lower respiratory tract infection from non-bacterial respiratory infection in children; radiologically confirmed pneumonia was used as the reference. In addition, we assessed the utility of adding the PCT assay to the clinical criteria for diagnosis of pneumonia.

Study design

Subanalysis of a larger prospective,multicentriccohort study.

Participants

Children, 2 months to 59 months of age, attending paediatric OPD of 5 urban tertiary care hospitals, suffering from acute respiratory infection (ARI).

Intervention

Detailed clinical history and examination findings of enrolled children were recorded on predesigned case record form. Samples for PCT were obtained at admission and were measured centrally at the end of the study except for one site using VIDAS® B.R.A.H.M.S PCT kit (Biomerieux SA, France).

Outcomes

Sensitivity and specificity of procalcitonin for diagnosis of radiologically confirmed pneumonia.

Results

Serum Procalcitonin was measured in 370 patients; median (IQR) age of these children being 12 (7, 22) months, 235 (63.5%) were boys. The median (IQR) serum procalcitonin concentration was 0.1(0.05, 0.4) ng/mL.Sensitivity and specificity of raised PCT (> 0.5 ng/mL) for pneumonia as per any CXR abnormalities were 29.7% and87.5%,(P < 0.001) respectively. Raised PCT was also significantly associated with consolidation (34.5%,79.2%,P < 0.02)and pleural effusion(54.6%,79%,P < 001). Adding PCT to the existing clinical criteria of WHO did not improve the sensitivity for diagnosis of pneumonia. PCT was significantly higher in children with severe pneumonia.

Conclusion

Positive PCT (> 0.5 ng/mL) is significantly associated with radiographic pneumonia but not with pneumonia based on WHO criteria.However, it can act as a surrogate marker for severe pneumonia.

Association of Clinical Signs, Host Biomarkers and Etiology With Radiological Pneumonia in Bhutanese Children

Diagnosing pneumonia and identifying those requiring antibiotherapy remain challenging. Chest radiographs (CXR) are often used as the reference standard. We aimed to describe clinical characteristics, host-response biomarkers and etiology, and assess their relationship to CXR findings in children with pneumonia in Thimphu, Bhutan. Children between 2 and 59 months hospitalized with WHO-defined pneumonia were prospectively enrolled and classified into radiological endpoint and non-endpoint pneumonia. Blood and nasopharyngeal washing were collected for microbiological analyses and plasma levels of 11 host-response biomarkers were measured. Among 149 children with readable CXR, 39 (26.2%) presented with endpoint pneumonia. Identification of respiratory viruses was common, with no significant differences by radiological outcomes. No clinical sign was suggestive of radiological pneumonia, but children with radiological pneumonia presented higher erythrocyte sedimentation rate, C-reactive protein and procalcitonin. Markers of endothelial and immune activation had little accuracy for the reliable identification of radiological pneumonia.

Novel point-of-care biomarker combination tests to differentiate acute bacterial from viral respiratory tract infections to guide antibiotic prescribing: a systematic review

BACKGROUND

Acute respiratory tract infections (RTIs) are the most common reason to seek medical care, with many patients receiving inappropriate antibiotics. Novel testing approaches to identify aetiology at the point-of-care are required to accurately guide antibiotic treatment.

OBJECTIVE

To assess the diagnostic accuracy of biomarker combinations to rapidly differentiate between acute bacterial or viral RTI aetiology.

DATA SOURCES

MEDLINE, Embase and Web of Science databases were searched to February 2021.

STUDY ELIGIBILITY CRITERIA

Diagnostic accuracy studies comparing accuracy of point-of-care and rapid diagnostic tests in primary or secondary care, consisting of biomarker combinations, to identify bacterial or viral aetiology of RTI.

METHODS

Risk of bias was assessed using the QUADAS-2 tool. Sensitivity and specificity of tests reported by more than one study were meta-analysed using a random effects model.

RESULTS

Twenty observational studies (3514 patients) were identified. Eighteen were judged at high risk of bias. For bacterial aetiologies, sensitivity ranged from 61% to 100% and specificity from 18% to 96%. For viral aetiologies, sensitivity ranged from 59% to 97% and specificity from 74% to 100%. Studies evaluating two commercial tests were meta-analysed. For ImmunoXpert, the summary sensitivity and specificity were 85% (95% CI 75%-91%, k = 4) and 86% (95% CI 73%-93%, k = 4) for bacterial infections, and 90% (95% CI 79%-96%, k = 3) and 92% (95% CI 83%-96%, k = 3) for viral infections, respectively. FebriDx had pooled sensitivity and specificity of 84% (95% CI 75%-90%, k = 4) and 93% (95% CI 90%-95%, k = 4) for bacterial infections, and 87% (95% CI 72%-95%; k = 4) and 82% (95% CI 66%-86%, k = 4) for viral infections, respectively.

CONCLUSION

Combinations of biomarkers show potential clinical utility in discriminating the aetiology of RTIs. However, the limitations in the evidence base, due to a high proportion of studies with high risk of bias, preclude firm conclusions. Future research should be in primary care and evaluate patient outcomes and cost-effectiveness with experimental study designs.

CLINICAL TRIAL

PROSPERO registration number: CRD42020178973.

Procalcitonin Differs in Children With Infection and Children With Disease Flares in Juvenile Idiopathic Arthritis

BACKGROUND/OBJECTIVE

Patients with juvenile idiopathic arthritis (JIA) often present with signs and symptoms suggestive of serious bacterial infection (SBI). Procalcitonin (PCT) is a biomarker that is elevated in SBI. We conducted a comparative cohort study to test the hypothesis that PCT levels will differ between active JIA, quiescent JIA, and bacteremic patients and healthy controls.

METHODS

From October 2016 to May2018, consecutive children 6 months to 18 years of age with (a) active untreated JIA, (b) quiescent JIA, and (c) healthy elective presurgical candidates were recruited from clinics at a musculoskeletal specialty hospital. Juvenile idiopathic arthritis was defined according to the International League of Associations for Rheumatology criteria. Clinical data and serum samples meeting the same criteria were included from a prior study. Consecutive bacteremic patients were identified over the same period. Procalcitonin and other common measures of inflammation were measured. Descriptive statistics and univariate logistic analyses were performed.

RESULTS

Ninety-two study subjects were recruited. Erythrocyte sedimentation rate, C-reactive protein (CRP), and PCT levels were all elevated in bacteremic patients in comparison to the other groups. Erythrocyte sedimentation rate and CRP both had wide ranges that overlapped between groups; however, the PCT concentration was 0.15 μg/mL or greater in 1 of 59 patients with JIA, whereas it was 0.15 μg/mL or less in only 1 bacteremic patient.

CONCLUSIONS

Our study indicates that serum erythrocyte sedimentation rate, CRP, and PCT levels are all biomarkers that can be used to distinguish SBI versus active JIA at presentation. However, PCT is the most accurate, with the least overlap between patients with infection and noninfectious inflammatory arthritis. This finding can help clinicians direct therapy.

Viral respiratory infections: a cause of community-acquired pneumonia or a predisposing factor?

PURPOSE OF REVIEW

A cause for community-acquired pneumonia (CAP) is only identified in ∼50% of cases. Nasopharyngeal PCR panels contain more viruses than previously. The problem then becomes determining the relevance of the organisms identified rather than figuring out which virus is present. This review addresses how to distinguish between viral CAP and bacterial CAP, how viral CAP predisposes to bacterial CAP and some novel antiviral treatment being conducted.

RECENT FINDINGS

The pneumonia severity index has been studied in patients with viral CAP. There are new studies using biomarkers to help determine when antimicrobial treatment is needed in CAP patients, and there is still no consensus. Newer devices are being invented in an effort to separate upper from lower respiratory organisms to make test results more relevant. Several outcome studies in patients with viral CAP are reviewed.

SUMMARY

In addition to clinical correlation, using biomarkers can be useful to distinguish viral from bacterial CAP. Outcomes in patients with a co-infection are generally worse as a viral infection may predispose someone to a bacterial pneumonia. Influenza CAP treatment may be initially accompanied with antimicrobials until a patient's diagnosis is clear (∼48-72 h). Future research is being conducted for antiviral treatment more than for influenza.

Variation in Early Inflammatory Marker Testing for Infection-Related Hospitalizations in Children

BACKGROUND AND OBJECTIVES

Inflammatory marker testing in children has been identified as a potential area of overuse. We sought to describe variation in early inflammatory marker (C-reactive protein and erythrocyte sedimentation rate) testing for infection-related hospitalizations across children's hospitals and to determine its association with length of stay (LOS), 30-day readmission rate, and cost.

METHODS

We conducted a cross-sectional study of children aged 0 to 17 years with infection-related hospitalizations using the Pediatric Health Information System. After adjusting for patient characteristics, we examined rates of inflammatory marker testing (C-reactive protein or erythrocyte sedimentation rate) during the first 2 days of hospitalization. We used k-means clustering to assign each hospital to 1 of 3 groups on the basis of similarities in adjusted diagnostic testing rates across 12 infectious conditions. Multivariable regression was used to examine the association between hospital testing group and outcomes.

RESULTS

We included 55 771 hospitalizations from 48 hospitals. In 7945 (14.3%), there was inflammatory marker testing in the first 2 days of hospitalization. We observed wide variation in inflammatory marker testing rates across hospitals and infections. Group A hospitals tended to perform more tests than group B or C hospitals (37.4% vs 18.0% vs 10.4%; P < .001) and had the longest adjusted LOS (3.2 vs 2.9 vs 2.8 days; P = .01). There was no significant difference in adjusted 30-day readmission rates or costs.

CONCLUSIONS

Inflammatory marker testing varied widely across hospitals. Hospitals with higher inflammatory testing for one infection tend to test more frequently for other infections and have longer LOS, suggesting opportunities for diagnostic stewardship.

Diagnostic accuracy of procalcitonin for bacterial pneumonia in children - a systematic review and meta-analysis

Objective: The predictive role of procalcitonin for childhood bacterial pneumonia, a leading cause of death, is unclear. We aimed to evaluate the diagnostic accuracy of procalcitonin for childhood bacterial pneumonia.Methods: Major bibliographic databases were searched from inception through September 2019 using pre-defined index terms, including 'procalcitonin,' 'pneumonia' and 'children'. The study is reported according to Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies. Meta-analyses of the diagnostic accuracy and odds ratio of procalcitonin for bacterial pneumonia were conducted along with subgroup analyses for different cut-offs of procalcitonin. The Quality Assessment of Diagnostic Accuracy Studies 2 instrument was used to assess the methodologic quality of eligible studies.Results: Twenty-five studies (with 2,864 patients) showed that procalcitonin for bacterial pneumonia had an overall sensitivity of 0.64 (95% confidence interval: 0.53-0.74), specificity of 0.72 (95% confidence interval: 0.64-0.79), positive likelihood ratio of 2.3 (95% confidence interval: 1.8-3.0) and negative likelihood ratio of 0.50 (95% confidence interval: 0.38-0.66), and Area Under the Receiver Operating Characteristics of 0.74 (95% confidence interval: 0.70-0.78). Using a cut-off of 0.5 ng/ml, Procalcitonin had a sensitivity of 0.68 (95% confidence interval: 0.50-0.82), specificity of 0.60 (95% confidence interval: 0.47-0.72), and Area Under the Receiver Operating Characteristics of 0.68 (95% confidence interval: 0.64-0.72). Using a cut-off of 2 ng/ml, procalcitonin had a sensitivity of 0.59 (95% confidence interval: 0.40-0.76), specificity of 0.71 (95% confidence interval: 0.58-0.81), and AUROC curve of 0.71 (95% confidence interval: 0.67-0.75). Elevated procalcitonin was not associated with increased odds of bacterial pneumonia (odds ratio: 1.36, 95% confidence interval: 0.81-1.92, p = .18). Quality assessment found minimal concerns for bias or applicability.Conclusions: Given the moderate diagnostic accuracy of procalcitonin for bacterial pneumonia, we recommend that procalcitonin be used in conjunction with other findings for management and disposition of children with pneumonia.

Blood biomarkers differentiating viral versus bacterial pneumonia aetiology: a literature review

Background and objectives

The goal of this literature review is to compare current studies regarding the accuracy of different serum markers in differentiating viral from bacterial pneumonia in the pediatric population with what is employed in the medical settings at present. Currently there is still a lack of significant research, that would give us evaluation on biomarkers benefits towards getting a definite diagnosis of pneumonia. Finding out the potential of biomarkers to differentiate between viral and bacterial pneumonia is also important because knowing the exact pathogen would prevent irrational use of antibiotics. At present, irrational, broad-spectrum antibiotic use and increasing antibiotic resistance in microorganisms are still one of the greatest challenges in clinical settings. The use of biomarkers in clinical practice would not only facilitate accurate diagnosis, but would also help to reduce the amount of antibiotics overuse.

Materials and methods

Literature search conducted on Medline and Google Scholar using a combination of terms. Articles that were in English and within ten years of the search date were manually sorted according to inclusion and exclusion criteria. Results: Initial search returned n = 13,408. After activating filters, n = 140 were identified of which n = 12 included for literature review.

Conclusions

Rise or drop in the concentration of a single marker is not accurate enough for predicting viral/bacterial community acquired pneumonia. This is because there is overlapping to a varying extent depending on the marker cut-off values, detection methods, analyses, the desired specificity, and sensitivity. Furthermore, the presence of mixed infection makes almost all markers suboptimal to be used universally. New markers such as MxA1 and HMGB1 gave promising results. However, to replicate a similar testing condition in a clinical environment may not be practical. Another approach is to make use of more than one marker and combine with clinical signs and symptoms. This may not be cost-effective in many clinical settings; nevertheless, in many studies, marker combination greatly improved the predictive power.

Increased procalcitonin level is a risk factor for prolonged fever in children with Mycoplasma pneumonia

PURPOSE

Macrolide-resistant Mycoplasma pneumoniae pneumonia (MPP) is characterized by prolonged fever and radiological progression despite macrolide treatment. Few studies have examined serum procalcitonin (PCT) level in children with MPP. We aimed to investigate the association of acute inflammation markers including PCT with clinical parameters in children with MPP.

METHODS

A total of 147 children were recruited. The diagnosis of MPP relied on serial measurement of IgM antibody against mycoplasma and/or polymerase chain reaction. We evaluated the relationships between C-reactive protein (CRP), PCT, and lactate dehydrogenase (LDH) levels and white blood cell (WBC) counts, and clinical severity of the disease. We used multivariate logistic regression analysis to estimate the odds ratio for prolonged fever (>3 days after admission) and hospital stay (> 6 days), comparing quintiles 2-5 of the PCT levels with the lowest quintile.

RESULTS

The serum PCT and CRP levels were higher in children with fever and hospital stay than in those with fever lasting ≤ 3 days after admission and hospital stay ≤ 6 days. CRP level was higher in segmental/lobar pneumonia than in bronchopneumonia. The LDH level and WBC counts were higher in children with fever lasting for >3 days before compared to those with fever lasting for ≤ 3 days. The highest quintile of PCT levels was associated with a significantly higher risk of prolonged fever and/or hospital stay than the lowest quintile.

CONCLUSION

Serum PCT and CRP levels on admission day were associated with persistent fever and longer hospitalization in children with MPP.

Viral pneumonia: etiologies and treatment

Viral pathogens are increasingly recognized as a cause of pneumonia, in immunocompetent patients and more commonly among immunocompromised. Viral pneumonia in adults could present as community-acquired pneumonia (CAP), ranging from mild disease to severe disease requiring hospital admission and mechanical ventilation. Moreover, the role of viruses in hospital-acquired pneumonia and ventilator-associated pneumonia as causative agents or as co-pathogens and the effect of virus detection on clinical outcome are being investigated.More than 20 viruses have been linked to CAP. Clinical presentation, laboratory findings, biomarkers, and radiographic patterns are not characteristic to specific viral etiology. Currently, laboratory confirmation is most commonly done by detection of viral nucleic acid by reverse transcription-PCR of respiratory secretions.Apart from the US Food and Drug Administration-approved medications for treatment of influenza pneumonia, the treatment of non-influenza respiratory viruses is limited. Moreover, the evidence supporting the use of available antivirals to treat immunocompromised patients is modest at best. With the widespread use of molecular diagnostics, an aging population, and advancement in cancer therapy, physicians will face a bigger challenge in managing viral respiratory tract infections. Emphasis on infection control measures to prevent the spread of respiratory viruses especially in healthcare settings is extremely important.

Cytokine kinetic profiles in children with acute lower respiratory tract infection: a post hoc descriptive analysis from a randomized control trial

OBJECTIVES

Standard inflammatory markers and chest radiography lack the ability to discriminate bacterial from non-bacterial lower respiratory tract infection (LRTI). Cytokine profiles may serve as biomarkers for LRTI, but their applicability to identify aetiology, severity of disease and need for antibiotic prescription in children remains poorly defined. Objectives were to determine the cytokine kinetic profiles over 5 days in paediatric patients with LRTI, to investigate the relationship between cytokine patterns, and clinical and laboratory variables.

METHODS

We included patients aged 1 month to 18 years, with febrile LRTI and three consecutive cytokines measurements on days 1, 3 and 5 of a randomized controlled trial (ProPAED study). We evaluated differences in cytokine concentrations between days and associations with clinical and laboratory variables.

RESULTS

A total of 181 patients (median age 4.1 years) were included; 72/181 (40%) received antibiotics. Serum concentrations of interferon (IFN)-γ, interleukin (IL)-1ra, IL-6, IL-10, IFN-γ-inducible protein (IP)-10 and tumor necrosis factor-α were elevated on day 1 and decreased subsequently, with the greatest decline between day 1 and 3 (by -8 to >-94%). Procalcitonin (PCT) and C-reactive protein (CRP) values showed a protracted decrease with the most prominent reduction in concentrations between days 3 and 5. Significantly elevated IL-6 concentrations were associated with hospital admission, antibiotic treatment, and prolonged antibiotic treatment. Bacteraemic LRTI patients had higher concentrations of IL-1ra (p <0.0055) and IL-6 (p <0.0055) on day 1.

CONCLUSIONS

We observed an earlier decrease of elevated cytokines compared to PCT or CRP. Both pro- and anti-inflammatory cytokines may serve as markers for severity of LRTI.

Pediatric Community-Acquired Pneumonia in the United States: Changing Epidemiology, Diagnostic and Therapeutic Challenges, and Areas for Future Research

Community-acquired pneumonia (CAP) is one of the most common serious infections in childhood. This review focuses on pediatric CAP in the United States and other industrialized nations, specifically highlighting the changing epidemiology of CAP, diagnostic and therapeutic challenges, and areas for further research.

Prognostic scores and biomarkers for pediatric community-acquired pneumonia: how far have we come?

This article aimed to review the current prognostic and diagnostic tools used for community-acquired pneumonia (CAP) and highlight those potentially applicable in children with CAP. Several scoring systems have been developed to predict CAP mortality risk and serve as guides for admission into the intensive care unit. Over the years, clinicians have adopted these tools for improving site-of-care decisions because of high mortality rates in the extremes of age. The major scoring systems designed for geriatric patients include the Pneumonia Severity Index and the confusion, uremia, respiratory rate, blood pressure, age >65 years (CURB-65) rule, as well as better predictors of intensive care unit admission, such as the systolic blood pressure, multilobar chest radiography involvement, albumin level, respiratory rate, tachycardia, confusion, oxygenation and arterial pH (SMART-COP) score, the Infectious Diseases Society of America/American Thoracic Society guidelines, the criteria developed by España et al as well as the systolic blood pressure, oxygenation, age and respiratory rate (SOAR) criteria. Only the modified predisposition, insult, response and organ dysfunction (PIRO) score has so far been applied to children with CAP. Because none of the tools is without its limitations, there has been a paradigm shift to incorporate biomarkers because they are reliable diagnostic tools and good predictors of disease severity and outcome, irrespective of age group. Despite the initial preponderance of reports on their utility in geriatric CAP, much progress has now been made in demonstrating their usefulness in pediatric CAP.

Profile of C-reactive protein, white cells and neutrophil populations in febrile children from rural north-eastern Tanzania

Introduction

C-reactive protein (CRP), white blood cell (WBC) and absolute neutrophil counts (ANC) are important inflammatory biomarkers in the early diagnosis of infections. However, little is known on their profile and usefulness in fever case management in children attending outpatient clinic in rural north-eastern Tanzania.

Methods

Patients aged between 2 and 59 months presenting with fever at Korogwe District Hospital were enrolled. Venous blood was collected for evaluation of serum CRP, WBC and ANC. Individual patient diagnosis was based on integrated management of childhood illness (IMCI) guidelines and laboratory investigations (blood and urine cultures).

Results

A total of 867 patients were enrolled, out of which 691 (79.7%) had complete clinical and laboratory data available for analysis. Acute upper respiratory tract infection 284 (41.1%), acute gastroenteritis 127 (18.4%) and pneumonia 100 (14.5%) were the most frequent diagnoses. The geometric mean levels of serum CRP, WBC and ANC were 10.4 (95% CI: 9.2 - 11.8), 11.5 (95% CI: 11.1 - 11.9) and 5.5 (95% CI: 5.2 - 5.8), respectively. CRP≤20, WBC≤15 (10³cells/µL) and ANC≤10 10³cells/µL) were observed in the majority of the patients with upper respiratory tract infection, pneumonia, acute gastroenteritis and non-specific febrile illness. Only serum CRP levels were positively correlated with positive blood cultures at a calculated cut-off value of 37.3 mg/L, giving a specificity of 77.8% and sensitivity of 74.2%.

Conclusion

CRP assessment together with IMCI guidelines may be useful in assisting the diagnosis and management of paediatric febrile infections in Tanzania.

A three-step diagnosis of pediatric pneumonia at the emergency department using clinical predictors, C-reactive protein, and pneumococcal PCR

Recommendations for the management of community-acquired pneumonia (CAP) advocate that, in the absence of the clinical and laboratory findings typical of bacterial CAP, antibiotics are not required. However, the true value of the clinical and laboratory predictors of pediatric CAP still needs to be assessed. This prospective cohort study in three emergency departments enrolled 142 children with radiological pneumonia. Pneumonia with lung consolidation was the primary endpoint; complicated pneumonia (bacteremia, empyema, or pleural effusion) was the secondary endpoint. We showed that three clinical signs (unilateral hypoventilation, grunting, and absence of wheezing), elevated procalcitonin (PCT), C-reactive protein (CRP), negative nasopharyngeal viral PCR, or positive blood pneumococcal PCR (P-PCR) were significantly associated with both pneumonia with consolidation and complicated pneumonia. Children with negative clinical signs and low CRP values had a low probability of having pneumonia with consolidation (13%) or complicated pneumonia (6%). Associating the three clinical signs, CRP >80 mg/L and a positive P-PCR ruled in the diagnosis of complicated pneumonia with a positive predictive value of 75%.

CONCLUSION

A model incorporating clinical signs and laboratory markers can effectively assess the risk of having pneumonia. Children with negative clinical signs and low CRP are at a low risk of having pneumonia. For children with positive clinical signs and high CRP, a positive blood pneumococcal PCR can more accurately confirm the diagnosis of pneumonia. What is Known: • Distinguishing between bacterial and viral pneumonia in children is challenging. • Reducing the inappropriate use of antibiotics is a priority. What is New: • Children with negative clinical signs and low C-reactive protein (CRP) values have a low probability of having pneumonia. • Children with high CRP values can be tested using a pneumococcal PCR to rule in the diagnosis of pneumonia with a high positive predictive value.

Procalcitonin for Diagnostics and Treatment Decisions in Pediatric Lower Respiratory Tract Infections

Mortality and morbidity remain high in pediatric lower respiratory tract infections (LRTIs) despite progress in research and implementation of global diagnostic and treatment strategies in the last decade. Still, 120 million annual episodes of pneumonia affect children younger than 5 years each year leading to 1.3 million fatalities with the major burden of disease carried by low- and middle-income countries (95%). The definition of pneumonia is still challenging. Traditional diagnostic measures (i.e., chest radiographs, C-reactive protein) are unable to distinguish viral and from bacterial etiology. As a result, common antibiotic overuse contributes to growing antibiotic resistance. We present an overview of current evidence from observational and randomized controlled trials on a procalcitonin (PCT)-based diagnosis of pediatric LRTIs and discuss the need for an adequate PCT threshold for antibiotic treatment decision-making.

Predictors of Airspace Disease on Chest X-ray in Emergency Department Patients With Clinical Bronchiolitis: A Systematic Review and Meta-analysis

BACKGROUND

An abnormal chest X-ray (CXR) inconsistent with simple bronchiolitis is found in 7%-23% of cases. Despite national guidelines stating "current evidence does not support routine radiography in children with bronchiolitis"; the use of CXR in these patients remains high. Inappropriate use of CXR not only exposes children to excess radiation, but also increases medical costs. The majority of the time, CXRs are obtained to diagnose or rule out pneumonia. We aim to provide an evidence-based approach defining the utility of CXR in bronchiolitis for the diagnosis and treatment of bacterial pneumonia.

OBJECTIVES

We performed a systematic review and meta-analysis to describe potential predictors of a CXR with airspace disease in patients with bronchiolitis.

METHODS

We searched the medical literature from 1965 to June 2015 in PubMed/EMBASE using the following PICO formulation of our clinical question, "What characteristic(s) of history/physical examination (H&P) and vital signs (VS) in a child with bronchiolitis should prompt the physician to order a CXR?": Patients-pediatric emergency department (ED) patients (<2 years) with clinical bronchiolitis; Intervention-H&P and VS; Comparator-a CXR positive for airspace disease (+CXR), defined as atelectasis versus infiltrate or infiltrate/consolidation; and Outcome-operating characteristics of H&P and VS predicting an +CXR were calculated: sensitivity, specificity, and likelihood ratios (LR+ or LR-). The methodologic quality of the studies was assessed using the quality assessment of studies of diagnostic accuracy tool (QUADAS-2). We created a test-treatment threshold model based on the operating characteristics of the CXR to accurately identify a child with bronchiolitis and a superimposed bacterial pneumonia while accounting for the risks of a CXR and risks of treating patients with and without a bacterial infection.

RESULTS

We found five studies including 1,139 patients meeting our inclusion/exclusion criteria. Prevalence of a +CXR ranged from 7% to 23%. An oxygen saturation < 95% was the predictor with highest LR+ of 2.3 (95% confidence interval = 1.3 to 3.07) to predict a +CXR. None of the H&P and VS variables were found to have sufficiently low LR- to significantly decrease the pretest probability of finding a +CXR. Our test-treatment threshold model showed that hypoxia (O₂ Sat < 95%) alone complicating bronchiolitis did not show a benefit to obtaining a CXR. Our model only suggested that a CXR maybe indicated for a child with hypoxia (O₂ Sat < 95%) and respiratory failure requiring ventilatory support.

CONCLUSION

No single predictor of a +CXR was of sufficient accuracy to either support or refute ordering a CXR in a child with clinical bronchiolitis. We provide a decision threshold model to estimate a test threshold for obtaining a CXR and a treatment threshold for administering antibiotics. Application of this model requires the clinician to approximate the empiric benefit of antibiotics based on the clinical situation, highlighting the importance of clinical assessment.

Recent Developments in Pediatric Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) is the most common acute infectious cause of death in children worldwide. Consequently, research into the epidemiology, diagnosis, treatment, and prevention of pediatric CAP spans the translational research spectrum. Herein, we aim to review the most significant findings reported by investigators focused on pediatric CAP research that has been reported in 2014 and 2015. Our review focuses on several key areas relevant to the clinical management of CAP. First, we will review recent advances in the understanding of CAP epidemiology worldwide, including the role of vaccination in the prevention of pediatric CAP. We also report on the expanding role of existing and emerging diagnostic technologies in CAP classification and management, as well as advances in optimizing antimicrobial use. Finally, we will review CAP management from the policy and future endeavors standpoint, including the influence of clinical practice guidelines on clinician management and patient outcomes, and future potential research directions that are in the early stages of investigation.

Implications of the inflammatory response for the identification of biomarkers of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is characterized by both local and systemic inflammation. Because inflammation plays a critical role in the development, course and severity of COPD, inflammatory markers have the potential to improve the current diagnostic and prognostic approaches. Local inflammation in COPD is characterized by an infiltration of inflammatory cells, with an increased expression of cytokines, chemokines, enzymes, growth factors and adhesion molecules. Systemic low-grade inflammation is another common but nonspecific finding in COPD. Exacerbations of COPD are acute clinical events accompanied by an exaggerated inflammatory response. Future investigations in the field of COPD biomarkers should take into account different study designs and biochemical assays, disease course and duration, variations in symptom severity and timing of measurement.

Biomarkers for community-acquired pneumonia in the emergency department

Community-acquired pneumonia is one of the most common reasons for emergency department (ED) visits in children and adults. Despite its prevalence, there are many challenges to proper diagnosis and management of pneumonia. There is no accurate and timely etiologic gold standard to differentiate bacterial from viral disease, and there are limitations with precise risk stratification of patients to ensure appropriate site-of-care decisions. Clinical factors obtained by history and physical examination have limited the ability to diagnose pneumonia etiology and severity. Biomarkers offer information about the host response to infection and pathogen activity within the host that can serve to augment clinical features in decision-making. As science and technology progress, novel biomarkers offer great potential in aiding critical decisions for patients with pneumonia. This review summarizes existing knowledge about biomarkers of host response and pathogen activity, in addition to briefly reviewing emerging biomarkers using novel technologies.