Procalcitonin in children admitted to hospital with community acquired pneumonia

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.

Plasma exosomes contain protein biomarkers valuable for the diagnosis of lung cancer

Accumulating evidence indicates that exosomal proteins are critical in diagnosing malignant tumors. To identify novel exosomal biomarkers for lung cancer diagnosis, we isolated plasma exosomes from 517 lung cancer patients and 168 healthy controls (NLs)-186 lung adenocarcinoma (LUAD) patients (screening (SN): 20, validation (VD): 166), 159 lung squamous carcinoma (LUSC) patients (SN: 20, VD: 139), 172 benign nodules (LUBN) patients (SN: 20, VD: 152) and 168 NLs (SN: 20, VD: 148)-and randomly assigned them to the SN or VD group. Proteomic analysis by LC-MS/MS and PRM were performed on all groups. The candidate humoral markers were evaluated and screened by a machine learning method. All selected biomarkers were identified in the VD groups. For LUAD, a 7-protein panel had AUCs of 97.9% and 87.6% in the training and test sets, respectively, and 89.5% for early LUAD. For LUSC, an 8-protein panel showed AUCs of 99.1% and 87.0% in the training and test sets and 92.3% for early LUSC. For LUAD + LUSC (LC), an 8-protein panel showed AUCs of 85.9% and 80.3% in the training and test sets and 87.1% for early LC diagnosis. The characteristics of the exosomal proteome make exosomes potential diagnostic tools.

Procalcitonin and Presepsin as Markers of Infectious Respiratory Diseases in Children: A Scoping Review of the Literature

INTRODUCTION

Procalcitonin and presepsin have been suggested to be able to discriminate bacterial and viral infections, also in children. This scoping review aims to better explore the available evidence around the potential role of these biomarkers in the subgroup of children with respiratory infectious diseases.

METHODS

We performed a systematic scoping review of studies published until March 2023 in the following bibliographic databases: PubMed, EMBASE, Cochrane and SCOPUS.

RESULTS

In children with bacterial infection, procalcitonin values ranged from 0.5 ng/mL to 8.31 ng/dL, while in those hospitalized in an intensive care unit ranged from 0.6 ng/dL to 452.8 ng/dL with PCR from 2 ng/dL to 51.7 ng/dL. In children with viral infections, procalcitonin value values ranged from 0.2 ng/dL to 0.84 ng/dL, while in those hospitalized in an intensive care unit ranged from 0.61 ng/dL to 46.6 ng/dL. No studies on presepsin in children with respiratory infections were retrieved.

CONCLUSIONS

Although the available literature is highly heterogeneous, evidence does not suggest a role of procalcitonin in accurately differentiating bacterial and viral infections in children with respiratory infections. In future, new approaches based on multiple markers may better help determine which febrile children require antibiotics.

Quantitative Value of Bacteria Associated with Leukocytes in Differential Diagnosis of Lower Respiratory Tract Infection in Children, in Comparison to Sputum Culture and Procalcitonin

BACKGROUND

The mortality and morbidity rates in children with lower respiratory tract infection (LRTI) remain high.

OBJECTIVE

To describe the number of bacteria that is associated with leukocytes in differential diagnosis of bacterial, mycoplasma, and viral LRTI in children.

METHODS

Sputum smears were Gram stained for counting single-morphology bacteria associated with leukocytes. The differential diagnostic values of bacterial number were assessed in children with LRTI.

RESULTS

The area under the receiver operating characteristic (ROC) curve was 0.95 for bacterial number in the differential diagnosis of bacterial infection from mycoplasma and viral infections. The area under the ROC curve was 0.62 for procalcitonin and 0.94 for bacterial number in the differential diagnosis of bacterial infection from mycoplasma infection.

CONCLUSION

The number of bacteria associated with leukocytes in sputum was valuable and rapid in differential diagnosis of bacterial infection in children with suspected bacterial, mycoplasma, and viral LRTI.

Community-Acquired Pneumonia in Children

ABSTRACT

Community-acquired pneumonia (CAP) is the most common cause of childhood mortality globally. In the United States, CAP is a leading cause of pediatric hospitalization and antibiotic use and is associated with substantial morbidity. There has been a dramatic shift in microbiological etiologies for CAP in children over time as pneumococcal pneumonia has become less common and viral etiologies have become predominant. There is no commonly agreed on approach to the diagnosis of CAP in children. When indicated, antimicrobial treatment should consist of narrow-spectrum antibiotics. In this article, we will describe the current understanding of the microbiological etiologies, clinical presentation, diagnostic approach, risk factors, treatment, and future directions in the diagnosis and management of pediatric CAP.

Platelet Abnormalities in Children with Laboratory-Confirmed Influenza

BACKGROUND

The role of platelets in the immune response against influenza has been raised, and a diagnostic or prognostic value of platelet parameter abnormalities, including platelet count (PLT), or mean platelet volume (MPV), has been suggested. The study aimed to analyze the prognostic value of platelet parameters in children hospitalized due to laboratory-confirmed influenza.

METHODS

We retrospectively verified the platelet parameters (PLT, MPV, MPV/PLT, and PLT/lymphocyte ratio regarding the influenza complications (acute otitis media, pneumonia, and lower respiratory tract infection-LRTI), and the clinical course (antibiotic treatment, tertiary care transfer, and death).

RESULTS

An abnormal PLT was observed in 84 out of 489 laboratory-confirmed cases (17.2%, 44 thrombocytopaenia cases, and 40 thrombocytoses). Patients' age correlated negatively with PLT (rho = -0.46) and positively with MPV/PLT (rho = 0.44), while MPV was not age-dependent. The abnormal PLT correlated with increased odds of complications (OR = 1.67), including LRTI (OR = 1.89). Thrombocytosis was related to increased odds of LRTI (OR = 3.64), and radiologically/ultrasound-confirmed pneumonia (OR = 2.15), mostly in children aged under 1 year (OR = 4.22 and OR = 3.79, respectively). Thrombocytopaenia was related to antibiotic use (OR = 2.41) and longer hospital stays (OR = 3.03). A lowered MPV predicted a tertiary care transfer (AUC = 0.77), while MPV/PLT was the most versatile parameter in predicting LRTI (AUC = 0.7 in <1 yo), pneumonia (AUC = 0.68 in <1 yo), and antibiotic treatment (AUC = 0.66 in 1-2 yo and AUC = 0.6 in 2-5 yo).

CONCLUSIONS

Platelet parameters, including PLT count abnormalities and MPV/PLT ratio, are related to the increased odds of complications and a more severe disease course, and may add important data in assessing pediatric influenza patients, but should be interpreted cautiously due to age-related specificities.

The Etiology of Community-Acquired Pneumonia Correlates with Serum Inflammatory Markers in Children

Community-acquired pneumonia (CAP) severely affects pediatric hospitalizations. This study assessed the contribution of CAP to hospitalizations, its etiology in relationship with age, and the inflammatory markers. Between 2013 and 2018, 1064 CAP patients were hospitalized and diagnosed with bacterial/possibly bacterial pneumonia (BP), viral/possibly viral pneumonia (VP) and atypical pneumonia (AP). The etiology was confirmed using blood/pleural fluid culture/polymerase chain reaction (PCR), rapid antigen test/PCR in nasopharyngeal swabs, or serological studies. CAP accounted for 9.9% of hospitalizations and 14.8% of patient days. BP was diagnosed in 825 (77.5%), VP in 190 (17.9%), and AP in 49 (4.6%) cases; the confirmed etiology (n = 209; 20%) included mostly influenza (39%; n = 82), respiratory syncytial virus (RSV, 35%; n = 72), and Mycoplasma pneumoniae (19%; n = 39). VP frequency decreased with age (41% in < 3 mo to 9% in ≥ 60 mo), in contrast to AP (13% in ≥ 60 mo). Among the analyzed parameters, the best differentiating potential was shown by: C-reactive protein (CRP, AUCBP-VP = 0.675; 95% CI: 0.634−0.715), procalcitonin (AUCBP-AP = 0.73; 95% CI: 0.67−0.794), and CRP/procalcitonin (AUCAP-VP = 0.752; 95% CI: 0.67−0.83); a good positive predictive value (88.8%, 98.3%, and 91.6%, respectively) but a low negative predictive value (29.5%, 13.1%, and 40.7%, respectively) was observed. CAP influences hospital patient days more than the crude number of patients would suggest. On a clinical basis, BP is mainly recognized, although viral pneumonia is confirmed most often. RSV and influenza are responsible for a huge percentage of hospitalized cases, as well as M. pneumoniae in children aged ≥ 5 years. Serum inflammatory markers may help differentiate etiological factors.

Biomarkers and their Clinical Applications in Pediatrics

Biomarker studies are becoming increasingly interesting for many fields of medicine. The use of biomarkers in medicine is involved in detecting diseases and supporting diagnosis and treatment decisions. New research and new discoveries on the molecular basis of the disease show that there may be a number of promising new biomarkers for use in daily clinical practice. Clinical trials in children lag behind adult research both in quality and quantity. The number of biomarkers validated to optimize pediatric patient management is limited. In the pathogenesis of many diseases, it should not be extrapolated to the pediatric clinical setting, taking into account that biomarkers that are effective in adults are clearly different in children and that ontogeny directly affects disease development and therapeutic response in children. The search for ideal biomarkers or markers that can make an early and definitive diagnosis in neonatal sepsis is still ongoing. The ideal biomarker for pediatric diseases should be costeffective, noninvasive, applicable to pediatric specific diseases, and its results should correspond to age-related physiological changes. Lactate, troponin and B-type natriuretic peptide are valuable biomarkers in the evaluation and management of critically ill children with cardiac disease. Tumor markers in children are biochemical substances used in the clinical treatment of pediatric tumors and to detect the presence of cancer (regression or progression). In this chapter, current and brief information about biomarkers and their clinical applications used in the diagnosis and monitoring of pediatric diseases is presented.;

Procalcitonin is associated with postnatal respiratory condition severity in preterm neonate

INTRODUCTION

Postnatal respiratory failure is common in preterm neonates and is difficult to distinguish from early-onset neonatal bacterial infection by clinical symptoms. Similar to C-reactive protein (CRP), procalcitonin (PCT) is used as a marker of bacterial infection. Recently, it has been reported that the serum PCT levels increase because of respiratory failure immediately after birth. However, there is insufficient information concerning the relationship between biological inflammation markers, such as PCT and CRP, and postnatal respiratory condition severity.

METHODS

Preterm neonates were classified according to the received respiratory management as follows: nonrespiratory support (NRS), respiratory support (RS), surfactant administration therapy (STA), and STA with nitric oxide inhalation therapy (NO). The median serum PCT and CRP levels at 12-36 h postnatally were compared among the four groups. Additionally, the median serum PCT and CRP levels in the STA group were compared by STA timing and STA number.

RESULTS

The PCT levels for the NRS, RS, STA, and NO groups were 1.04, 6.46, 12.93, and 86.79 μg/L, respectively; the CRP levels were 0.40, 0.80, 1.10, and 16.40 mg/L, respectively. The PCT levels were significantly lower among neonates receiving STA in the birth subgroup (4.82 μg/L) than among those receiving STA in the admission subgroup (14.71 μg/L). The PCT levels were significantly higher among the STA multiple-dose subgroup (24.87 μg/L) than among the STA single-dose subgroup (12.47 μg/L). No significant differences in the CRP levels were observed.

CONCLUSION

The serum PCT levels in preterm neonates were associated with postnatal respiratory condition severity.

A Tool to Distinguish Viral From Bacterial Pneumonia

BACKGROUND

Establishing the etiology of community-acquired pneumonia (CAP) in children at admission is challenging. Most of the admitted children with CAP receive antibiotics. We aimed to build and validate a diagnostic tool combining clinical, analytical and radiographic features to differentiate viral from bacterial CAP, and among bacterial CAP, typical from atypical bacteria.

METHODS

Design-observational, multi-center, prospective cohort study was conducted in 2 phases. Settings: 24 secondary and tertiary hospitals in Spain. Patients-A total of 495 consecutive hospitalized children between 1 month and 16 years of age with CAP were enrolled. Interventions-A score with 2 sequential steps was built (training set, 70% patients, and validation set 30%). Step 1 differentiates between viral and bacterial CAP and step 2 between typical and atypical bacterial CAP. Optimal cutoff points were selected to maximize specificity setting a high sensitivity (80%). Weights of each variable were calculated with a multivariable logistic regression. Main outcome measures-Viral or bacterial etiology.

RESULTS

In total, 262 (53%) children (median age: 2 years, 52.3% male) had an etiologic diagnosis. In step 1, bacterial CAPs were classified with a sensitivity = 97%, a specificity = 48%, and a ROC's area under the curve = 0.81. If a patient with CAP was classified as bacterial, he/she was assessed with step 2. Typical bacteria were classified with a sensitivity = 100%, a specificity = 64% and area under the curve = 0.90. We implemented the score into a mobile app named Pneumonia Etiology Predictor, freely available at usual app stores, that provides the probability of each etiology.

CONCLUSIONS

This 2-steps tool can facilitate the physician's decision to prescribe antibiotics without compromising patient safety.

CON: Procalcitonin does not have clinical utility in children with community-acquired pneumonia

Most clinical studies supporting procalcitonin (PCT)-guided management of lower respiratory tract infections have been performed in adults. There is a paucity of studies evaluating the clinical impact of PCT use in children and limited data informing age-appropriate PCT cut-offs; diagnostic accuracy in immunocompromised children; patient subgroups most likely to benefit from PCT testing; whether PCT adds value beyond available rapid molecular viral diagnostics; and optimal implementation strategies for PCT-guided treatment. At the present time there is little evidence to support routine use of PCT to aid management of paediatric pneumonia.

PRO: Procalcitonin has clinical utility in children with community-acquired pneumonia

Procalcitonin (PCT) is a useful, albeit imperfect, diagnostic aid that can help clinicians make more informed decisions around antibiotic use in children with lower respiratory tract infections (LRTI), including community-acquired pneumonia (CAP). Recent data suggest that a very low PCT concentration has a high negative predictive value to identify a population of children at low risk of typical bacterial infections. Although the preponderance of data on the clinical utility of PCT in LRTI come from adult studies, the potential for benefit is likely greatest in paediatric CAP and other LRTIs where viral aetiologies predominate, yet antibiotics are frequently prescribed.

Point of care diaphragm ultrasound: An objective tool to predict the severity of pneumonia and outcomes in children

BACKGROUND

Pneumonia is one of the most common serious infections in children. Scoring systems have been adopted to quantify the severity of the disease, but they were based on clinical findings that can vary according to the subjective assessment of the clinician. We hypothesized that diaphragm ultrasound (DUS) parameters may be a new useful tool to objectively score the severity of the disease and predict outcomes in children with pneumonia.

METHODS

Children diagnosed with pneumonia, aged between 1 month and 18 years, were prospectively evaluated in the pediatric emergency department. The Pediatric Respiratory Severity Score was used to indicate the severity of the disease and DUS was performed. Diaphragm thickness at the end of inspiration and expiration, thickening fraction (TF), diaphragm excursion, inspiratory slope (IS), expiratory slope (ES), and total duration time of the respiratory cycle were calculated.

RESULTS

There were 96 patients enrolled in the study. Inspiratory slope and ES measurements had positive correlations with respiratory rate and length of stay in the hospital and negative correlations with oxygen saturation levels. Furthermore, TF values were negatively correlated with respiratory rate and length of stay in the emergency department. Patients with higher clinical scores had increased IS and ES and decreased TF values.

CONCLUSION

DUS can be a promising and useful tool to assess diaphragmatic dysfunction in patients diagnosed with pneumonia. Diaphragm parameters, especially TF, IS, and ES, may provide objective and reliable information to predict the severity of the illness, the need for respiratory support, and outcomes.

Improved Diagnostics Help to Identify Clinical Features and Biomarkers That Predict Mycoplasma pneumoniae Community-acquired Pneumonia in Children

BACKGROUND

There are no reliable signs or symptoms that differentiate Mycoplasma pneumoniae (Mp) infection in community-acquired pneumonia (CAP) from other etiologies. Additionally, current diagnostic tests do not reliably distinguish between Mp infection and carriage. We previously determined that the measurement of Mp-specific immunoglobulin M antibody-secreting cells (ASCs) by enzyme-linked immunospot assay allowed for differentiation between infection and carriage. Using this new diagnostic test, we aimed to identify clinical and laboratory features associated with Mp infection.

METHODS

This is a prospective cohort study of children, 3-18 years of age, with CAP from 2016 to 2017. Clinical features and biomarkers were compared between Mp-positive and -negative groups by Mann-Whitney U test or Fisher exact test, as appropriate. Area under the receiver operating characteristic curve (AUC) differences and optimal thresholds were determined by using the DeLong test and Youden J statistic, respectively.

RESULTS

Of 63 CAP patients, 29 were Mp-positive (46%). Mp positivity was statistically associated with older age (median, 8.6 vs 4.7 years), no underlying disease, family with respiratory symptoms, prior antibiotic treatment, prolonged prodromal respiratory symptoms and fever, and extrapulmonary (skin) manifestations. Lower levels of C-reactive protein, white blood cell count, absolute neutrophil count, and procalcitonin (PCT), specifically PCT <0.25 μg/L, were statistically associated with Mp infection. A combination of age >5 years (AUC = 0.77), prodromal fever and respiratory symptoms >6 days (AUC = 0.79), and PCT <0.25 μg/L (AUC = 0.81) improved diagnostic performance (AUC = 0.90) (P = .05).

CONCLUSIONS

A combination of clinical features and biomarkers may aid physicians in identifying patients at high risk for Mp CAP.

Predicting Bacterial Versus Viral Infection, or None of the Above: Current and Future Prospects of Biomarkers

Sepsis and pneumonia cause significant morbidity and mortality worldwide. Despite improvements in diagnostic methodologies for organism identification, the early recognition and further risk stratification of these infections can be challenging. Although traditional clinical scoring systems are beneficial for the management of sepsis and pneumonia, biomarkers supporting the diagnosis and management of these infectious diseases are needed. Many biomarkers have been identified and there is no lack of studies and meta-analyses assessing the utility of biomarkers. Focusing primarily on sepsis and pneumonia, this article discusses the most commonly used biomarkers for which clinical laboratory testing methods are available.

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.

Procalcitonin Identifies Bacterial Coinfections in Vietnamese Children with Severe Respiratory Syncytial Virus Pneumonia

This study assessed the diagnostic value of interleukin- (IL-) 6, high-sensitivity C-reactive protein (hs-CRP), and procalcitonin (PCT) in differentiating severe pneumonia caused by respiratory syncytial virus (RSV) alone and RSV with bacterial coinfections among Vietnamese children under 5 years old. A cross-sectional study on 70 children with severe RSV pneumonia was conducted. IL-6, hs-CRP, and PCT tests were performed. Receiver operating characteristic (ROC) analysis was employed to measure the diagnostic values of PCT, IL-6, and hs-CRP. Of 70 children, 11 children were confirmed to have bacterial coinfections. The most common bacterial coinfection was Haemophilus influenzae. This study underlined that inflammatory biomarkers such as PCT had a moderate-to-high capability of disseminating severe pneumonia children with RSV alone or RSV and bacterial coinfections. This may support clinicians in administrating appropriate antibiotics to children suffering from severe RSV pneumonia.

Serum Procalcitonin Levels in Children with Clinical Syndromes for Targeting Antibiotic Use at an Emergency Department of a Kenyan Hospital

Serum procalcitonin (PCT) was measured in 228 children aged 1 month to 15 years at an emergency department of a hospital located in an area without local malaria transmission in children with suspected infections; 21% (49) children had a clinical syndrome for suspected bacterial infections (Syndrome+ve). In children with Syndrome+ve criteria, 27/49 (55.1%) had PCT ≥0.5 µg/l but only 59/179 (32.9%) of those Syndrome-ve had abnormal PCT, χ2 = 8.0, p = 0.005; positive likelihood ratio = 2.0 [95% confidence interval (CI) 1.2-3.3]; negative likelihood ratio = 0.8 (95% CI 0.7-1.0). In patients with pneumonia, 9/15 (60%) with severe pneumonia had PCT ≥0.5 µg/l compared to 11/21 (52.4%) with non-severe pneumonia, χ2 = 0.2, p = 0.65. Children with clinical signs of pneumonia or clinical signs suggestive of bacterial infections fulfilling clinical syndromic definitions for suspected bacterial infections commonly have elevated PCT level. PCT levels are associated with disease severity and antibiotic trials guided by PCT levels may be needed where cultures are not available.

Host Inflammatory Biomarkers of Disease Severity in Pediatric Community-Acquired Pneumonia: A Systematic Review and Meta-analysis

Background

Community-acquired pneumonia (CAP) is the leading cause of death in children. Identification of reliable biomarkers offers the potential to develop a severity quantitative score to assist in clinical decision-making and improve outcomes.

Methods

A systematic review and meta-analysis was performed in PubMed and EMBASE on November 13, 2018, to examine the association between host inflammatory biomarkers and CAP severity in children. The inclusion criteria were case–control, cross-sectional, and cohort studies that examined candidate serum biomarkers. We extracted outcomes of interest, means, and standardized mean differences (SMDs) of plasma and serum levels of biomarkers together with information on disease severity. Meta-analysis was performed. This review was registered in the PROSPERO international registry (CRD42019123351).

Results

Two hundred seventy-two abstracts were identified, and 17 studies were included. Among the biomarkers evaluated, levels of C-reactive protein (CRP; SMD, 0.63; 95% confidence interval [CI], 0.35 to 0.91), interleukin (IL)-6 (SMD, 0.46; 95% CI, 0.25 to 0.66), IL-8 (SMD, 0.72; 95% CI, 0.15 to 1.29), neutrophil count (SMD, 0.27; 95% CI, 0.07 to 0.47), and procalcitonin (SMD, 0.68; 95% CI, 0.20 to 1.15) were substantially increased in severe CAP. In contrast, IL-2 concentrations (SMD, –0.24; 95% CI, –0.45 to –0.03) were higher in nonsevere CAP. Study heterogeneity was reported to be high (I² > 75%), except for IL-2, IL-5, IL-6, and IL-12p70, which were classified as moderate (I² = 50%–74%). Only neutrophil and white blood cell counts were described by studies exhibiting a low level of heterogeneity.

Conclusions

Our results suggest that host biomarkers, and especially CRP, IL-6, IL-8, and procalcitonin levels, have the potential to predict severe CAP in pediatric populations.

Challenges in the diagnosis of paediatric pneumonia in intervention field trials: recommendations from a pneumonia field trial working group

Pneumonia is a leading killer of children younger than 5 years despite high vaccination coverage, improved nutrition, and widespread implementation of the Integrated Management of Childhood Illnesses algorithm. Assessing the effect of interventions on childhood pneumonia is challenging because the choice of case definition and surveillance approach can affect the identification of pneumonia substantially. In anticipation of an intervention trial aimed to reduce childhood pneumonia by lowering household air pollution, we created a working group to provide recommendations regarding study design and implementation. We suggest to, first, select a standard case definition that combines acute (≤14 days) respiratory symptoms and signs and general danger signs with ancillary tests (such as chest imaging and pulse oximetry) to improve pneumonia identification; second, to prioritise active hospital-based pneumonia surveillance over passive case finding or home-based surveillance to reduce the risk of non-differential misclassification of pneumonia and, as a result, a reduced effect size in a randomised trial; and, lastly, to consider longitudinal follow-up of children younger than 1 year, as this age group has the highest incidence of severe pneumonia.

Procalcitonin Levels in Critically Ill Children With Status Asthmaticus

BACKGROUND

Children with status asthmaticus (SA) often present with fever and are evaluated with chest radiographs (CXRs). In the absence of a confirmatory test for bacterial infection, antibiotics are started whenever there are radiological infiltrates or if there is a suspicion of pneumonia. We undertook this study to determine if serum procalcitonin (PCT) levels at admission are altered in critically ill children with SA. We also sought to determine if serum PCT levels are elevated in children with radiological infiltrates or in children who were treated with antibiotics.

METHODS

This is a prospective single-center observational study evaluating serum PCT levels in critically ill children with SA. Study subjects included children 1 to 21 years old, admitted to a pediatric intensive care unit (PICU) with SA between March 2012 and April 2013. For the purposes of this study, patients whose CXRs were read by the radiologist as probable bacterial pneumonia was defined as having "radiological bacterial pneumonia," whereas patients who received antibiotics by the treating physician were defined as having "clinician-diagnosed pneumonia."

RESULTS

Sixty-one patients with a median age of 7.3 years (interquartile range, 4-10 years) were included in the study. Fifty-one percent were male. Average Pediatric Risk of Mortality III score was 2.7 (SD, 2.9). Three patients (5%) were determined to have radiological bacterial pneumonia, whereas 52 (85%) did not. Six patients (10%) were indeterminate. The mean PCT level for all patients was 0.65 (SD, 1.54) ng/mL, whereas the median PCT level was 0.3 ng/mL. There was no significant difference in the mean PCT levels between the patients with and without clinician-diagnosed pneumonia (0.33 [SD, 0.36] vs 0.69 [SD, 1.67], P = 0.44). Using a PCT cutoff level of 0.5 ng/mL, a significant association was found with the presence of fever (P = 0.004), but no significant association was found with the presence of CXR infiltrates, radiological bacterial pneumonia, hospital length of stay, PICU length of stay, Pediatric Risk of Mortality III scores, or receipt of antibiotics.

CONCLUSIONS

Serum PCT level was not elevated to greater than 0.5 ng/mL in 75% of this cohort of critically ill children with SA admitted to PICU. Presence of CXR infiltrates was not associated with higher PCT levels. Large clinical trials are needed to study the diagnostic and predictive role of PCT in this patient population.

CYFRA21-1 tests in the diagnosis of non-small cell lung cancer: A meta-analysis

OBJECTIVE

The aim of the study was to evaluate the diagnostic value of soluble fragment of cytokeratin 19 (CYFRA21-1) tests in detecting non-small cell lung cancer (NSCLC), including squamous cell carcinoma, lung adenocarcinoma, and large cell carcinoma.

METHODS

The relevant studies were identified from PubMed, Embase and the Cochrane Library before November 2018. Summary estimates for sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of CYFRA21-1 tests for the diagnosis of NSCLC were calculated using the random effects model. A summary receiver operating characteristic (SROC) curve was used to assess the overall effectiveness of the test. Meta-DiSc 1.4 and Stata11.0 were applied to the statistical analysis. Publication bias was detected using Egger's test.

RESULTS

A total of 22 studies consisting of 7910 NSCLC patients (squamous cell carcinoma/lung adenocarcinoma/large cell carcinoma) and 2630 benign lesions patients that met the inclusion criteria were included. The meta-analysis showed that CYFRA21-1 tests had a relatively high accuracy for squamous cell carcinoma detection and a lower accuracy for lung adenocarcinoma detection. The overall sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of CYFRA21-1 tests for squamous cell carcinoma detection were 0.72 (95% confidence interval (CI) 0.70, 0.74), 0.94 (95% CI 0.92, 0.95), 9.73 (95% CI 7.06, 13.40), 0.37 (95% CI 0.29, 0.47), and 27.30 (95% CI 17.68, 42.16), respectively. The area under the SROC curve was 0.9171 (Q* = 0.8500). No publication bias was tested in the squamous cell carcinoma (P = 0.567) and lung adenocarcinoma (P = 0.378) groups.

CONCLUSIONS

CYFRA21-1 tests might be appropriate for detecting squamous cell carcinoma.

The Use of Procalcitonin for Prediction of Pulmonary Bacterial Coinfection in Children With Respiratory Failure Associated With Viral Bronchiolitis

Objectives. Viral bronchiolitis is a frequent cause of pediatric hospitalization and respiratory failure. Procalcitonin (PCT) is a biomarker used to identify serious bacterial infection and can distinguish bacterial and viral infections. Concomitant bacterial pneumonia is not rare in viral bronchiolitis and can lead to a worse clinical course. This study examined the use of PCT in pediatric patients with respiratory failure attributed to viral bronchiolitis to predict concomitant bacterial pneumonia. Methods. This prospective descriptive study evaluated children less than 4 years of age who underwent endotracheal intubation for respiratory failure due to viral bronchiolitis. PCT levels and endotracheal aspirate cultures were obtained at admission. Bacterial pneumonia was defined as at least moderate growth of a single pathogenic organism from endotracheal culture. PCT levels were evaluated in groups with and without concomitant bacterial pneumonia. Results. Thirty-five patients were enrolled between February 2013 and May 2015. All subjects tested positive for at least 1 viral pathogen by nasal wash polymerase chain reaction or enzyme immunoassay. The top viruses obtained were respiratory syncytial virus (n = 15, 42.8%) and rhinovirus (n = 8, 22.9%). The incidence of bacterial pneumonia was 60% (21/35). The PCT median was 0.93 ng/mL (interquartile range = 0.25-6.64) in the bacterial pneumonia group and 1.85 ng/mL (interquartile range = 0.28-7.94) in the nonbacterial pneumonia group. No correlation was found between PCT and bronchiolitis with bacterial coinfection (P = .74). Conclusion. Incidence of bacterial coinfection in patients with respiratory failure and viral bronchiolitis was high. PCT did not predict concomitant bacterial pneumonia in children with viral bronchiolitis.

Approach to Neonates and Young Infants with Fever without a Source Who Are at Risk for Severe Bacterial Infection

INTRODUCTION

Among neonates and infants <3 months of age with fever without a source (FWS), 5% to 15% of cases are patients with fever caused by a serious bacterial infection (SBI). To favour the differentiation between low- and high-risk infants, several algorithms based on analytical and clinical parameters have been developed. The aim of this review is to describe the management of young infants with FWS and to discuss the impact of recent knowledge regarding FWS management on clinical practice.

MATERIALS AND METHODS

PubMed was used to search for all of the studies published over the last 35 years using the keywords: "fever without source" or "fever of unknown origin" or "meningitis" or "sepsis" or "urinary tract infection" and "neonate" or "newborn" or "infant <90 days of life" or "infant <3 months".

RESULTS AND DISCUSSION

The selection of neonates and young infants who are <3 months old with FWS who are at risk for SBI remains a problem without a definitive solution. The old Rochester criteria remain effective for identifying young infants between 29 and 60 days old who do not have severe bacterial infections (SBIs). However, the addition of laboratory tests such as C-reactive protein (CRP) and procalcitonin (PCT) can significantly improve the identification of children with SBI. The approach in evaluating neonates is significantly more complicated, as their risk of SBIs, including bacteremia and meningitis, remains relevant and none of the suggested approaches can reduce the risk of dramatic mistakes. In both groups, the best antibiotic must be carefully selected considering the clinical findings, the laboratory data, the changing epidemiology, and increasing antibiotic resistance of the most common infectious bacteria.

Molecular Distance to Health Transcriptional Score and Disease Severity in Children Hospitalized With Community-Acquired Pneumonia

Background: Community-acquired pneumonia (CAP) is a leading cause of hospitalization and mortality in children. Diagnosis remains challenging and there are no reliable tools to objectively risk stratify patients or predict clinical outcomes. Molecular distance to health (MDTH) is a genomic score that measures the global perturbation of the transcriptional profile and may help classify patients by disease severity. We evaluated the value of MDTH to assess disease severity in children hospitalized with CAP.

Methods: Children hospitalized with CAP and matched healthy controls were enrolled in a prospective observational study. Blood samples were obtained for transcriptome analyses within 24 h of hospitalization. MDTH scores were calculated to assess disease severity and correlated with laboratory markers, such as white blood cell count, c-reactive protein (CRP), and procalcitonin (PCT), and clinical outcomes, including duration of fever and duration of hospitalization (LOS). Univariate and multivariable logistic regression were applied to assess factors associated with LOS and duration of fever after hospitalization.

Results: Among children hospitalized with CAP (n = 152), pyogenic bacteria (PB) were detected in 16 (11%), Mycoplasma pneumoniae was detected in 41 (28%), respiratory viruses (RV) alone were detected in 78 (51%), and no pathogen was detected in 17 (11%) children. Statistical group comparisons identified 6,726 genes differentially expressed in patients with CAP vs. healthy controls (n = 39). Children with confirmed PB had higher MDTH scores than those with RV (p < 0.05) or M. pneumoniae (p < 0.01) detected alone. CRP (r = 0.39, p < 0.0001), PCT (r = 0.39, p < 0.0001), and MDTHs (r = 0.24, p < 0.01) correlated with duration of fever, while only MDTHs correlated with LOS (r = 0.33, p < 0.0001). Unadjusted analyses showed that both higher CRP and MDTHs were associated with longer LOS (OR 1.04 [1–1.07] and 1.12 [1.04–1.20], respectively), however, only MDTH remained significant when adjusting for other covariates (aOR 1.11 [1.01–1.22]).

Conclusions: In children hospitalized with CAP MDTH score measured within 24 h of admission was independently associated with longer duration of hospitalization, regardless of the pathogen detected. This suggests that transcriptional biomarkers may represent a promising approach to assess disease severity in children with CAP.

The usefulness of serum procalcitonin, C-reactive protein, soluble triggering receptor expressed on myeloid cells 1 and Clinical Pulmonary Infection Score for evaluation of severity and prognosis of community-acquired pneumonia in elderly patients

AIMS

To comparatively analyze the usefulness of serum procalcitonin (PCT), C-reactive protein (CRP), soluble triggering receptor expressed on myeloid cells 1 (sTREM-1) and Clinical Pulmonary Infection Score (CPIS) for assessing the severity and prognosis of community-acquired pneumonia (CAP) in the elderly.

METHODS

A total of 214 elderly patients with CAP and 106 healthy persons were enrolled in this prospective study. On the admission day, serum inflammatory markers, including CRP, PCT, sTREM-1, and CPIS were analyzed. By severity, the CAP patients were subdivided into non-severe CAP group and severe CAP group. By outcome, the patients were classified into survival group and death group. The efficiency of three inflammatory markers and CPIS on predicting prognosis of pneumonia patients was then analyzed.

RESULTS

The serum inflammatory markers and CPIS were significantly higher in CAP patients than in healthy controls. These biomarkers and CPIS were significantly higher in patients with severe CAP than in patients with non-severe CAP. Compared with patients who would survive, these markers and CPIS were significantly higher in patients who would die. Receiver operating characteristic curve analysis showed that the area under the curve and sensitivity were higher for serum sTREM-1 than for other indicators, while the specificity of serum PCT was the highest.

CONCLUSIONS

Serum CRP, PCT, and sTREM-1 and CPIS determined on the admission day are effective indicators to evaluate the severity and prognosis of CAP in the elderly. The prognostic value of PCT and sTREM-1 is better than that of CRP and CPIS.

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.

Is Procalcitonin Useful in Pediatric Critical Care Patients?

This review examines the use of procalcitonin in different clinical situations in the pediatric patient, with special emphasis on those requiring intensive care. We review the latest articles on its potency as a biomarker in both infectious processes at diagnosis and on the response to treatment.

Procalcitonin Accurately Identifies Hospitalized Children With Low Risk of Bacterial Community-Acquired Pneumonia

BACKGROUND

Lower procalcitonin (PCT) concentrations are associated with reduced risk of bacterial community-acquired pneumonia (CAP) in adults, but data in children are limited.

METHODS

We analyzed serum PCT concentrations from children hospitalized with radiographically confirmed CAP enrolled in the Centers for Disease Control and Prevention's Etiology of Pneumonia in the Community (EPIC) Study. Blood and respiratory specimens were tested using multiple pathogen detection methods for typical bacteria (eg, Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus), atypical bacteria (Mycoplasma pneumoniae and Chlamydophila pneumoniae), and respiratory viruses. Multivariable regression was used to assess associations between PCT concentrations and etiology and severity.

RESULTS

Among 532 children (median age, 2.4 years; interquartile range [IQR], 1.0-6.3), patients with typical bacteria had higher PCT concentrations (±viruses; n = 54; median, 6.10; IQR, 0.84-22.79 ng/mL) than those with atypical bacteria (±viruses; n = 82; median, 0.10; IQR, 0.06-0.39 ng/mL), viral pathogens only (n = 349; median, 0.33; IQR, 0.12-1.35 ng/mL), or no pathogen detected (n = 47; median, 0.44; IQR, 0.10-1.83 ng/mL) (P < .001 for all). No child with PCT <0.1 ng/mL had typical bacteria detected. Procalcitonin <0.25 ng/mL featured a 96% negative predictive value (95% confidence interval [CI], 93-99), 85% sensitivity (95% CI, 76-95), and 45% specificity (95% CI, 40-50) in identifying children without typical bacterial CAP.

CONCLUSIONS

Lower PCT concentrations in children hospitalized with CAP were associated with a reduced risk of typical bacterial detection and may help identify children who would not benefit from antibiotic treatment.

Procalcitonin: The marker of pediatric bacterial infection

Timely recognition of systemic bacterial infections in pediatric care setting is the basis for effective treatment and control. This review provides an overview of procalcitonin (PCT) as an early marker for the detection of severe, invasive bacterial infection in children. Almost all articles on biochemical property and clinical studies in PubMed and Scopus databases regarding their use in pediatric infections and the use of PCT as a marker of bacterial infections were examined. Various methods and analyzers are currently available for the evaluation of PCT. Employment of PCT in the identification of neonatal bacterial infection is a complex process in some conditions. Age specific cut-off, underlying syndrome, and maternal antibiotics usage should be considered when PCT is to be applied in neonates. PCT might be false-negative in these conditions. However, if used appropriately, it can lead to a higher specificity than other immunologic markers. Due to its correlation with the severity of infection, PCT can consequently be used as a prognostic indicator especially for sepsis and urinary tract infection. It is, therefore, a practical supplementary means for the identification of bacterial infections in pediatric health settings.

Cerebrospinal fluid procalcitonin as a biomarker of bacterial meningitis in neonates

OBJECTIVE

The objective of the study was to study the performance of cerebrospinal fluid (CSF) procalcitonin as a marker for bacterial meningitis in neonates, and to determine its optimal 'cutoff' in CSF that can be called significant for the diagnosis.

STUDY DESIGN

Neonates qualifying for lumbar puncture were prospectively studied. Procalcitonin and established CSF parameters were recorded.

RESULTS

At a cut-off value of 0.33 ng ml^-1, CSF procalcitonin had a sensitivity of 0.92, specificity of 0.87, with positive and negative likelihood ratios of 7.13 and 0.092, respectively. The area under the curve for different CSF parameters was: 0.926 (0.887 to 0.964) (P<0.001) for procalcitonin, 0.965 (0.956 to 0.974) for total leukocyte count, 0.961 (0.94 to 0.983) for neutrophil count, 0.874 (0.825 to 0.923) for protein, 0.946 (0.914 to 0.978) for sugar and 0.92 (0.955 to 0.992) for CSF:serum sugar ratio. The lumbar puncture was traumatic in 36 (21.4%) patients; out of these 15 (41.7%) had bacterial meningitis and 21 (58.3%) had no meningitis. In traumatic lumbar tap group, the median (IQR) CSF procalcitonin in patients with and without meningitis was 1.41 (0.32-3.42) ng/ml and 0.21(0.20-0.31) ng/ml respectively (p<0.05).

CONCLUSIONS

Procalcitonin measurement has diagnostic efficiency similar to the established CSF markers. Routine assessment of procalcitonin in clean non-contaminated CSF may not yield additional information, but it may have clinical utility in situations where diagnosis of meningitis is in dilemma, as in the case of blood contamination of CSF in traumatic lumbar punctures.

Severity of Pneumonia in Under 5-Year-Old Children from Developing Countries: A Multicenter, Prospective, Observational Study

Pneumonia is the leading cause of death in children. The objectives were to evaluate the microbiological agents linked with hypoxemia in hospitalized children with pneumonia from developing countries, to identify predictors of hypoxemia, and to characterize factors associated with in-hospital mortality. A multicenter, observational study was conducted in five hospitals, from India (Lucknow, Vadu), Madagascar (Antananarivo), Mali (Bamako), and Paraguay (San Lorenzo). Children aged 2-60 months with radiologically confirmed pneumonia were enrolled prospectively. Respiratory and whole blood specimens were collected, identifying viruses and bacteria by real-time multiplex polymerase chain reaction (PCR). Microbiological agents linked with hypoxemia at admission (oxygen saturation < 90%) were analyzed by multivariate logistic regression, and factors associated with 14-day in-hospital mortality were assessed by bivariate Cox regression. Overall, 405 pneumonia cases (3,338 hospitalization days) were analyzed; 13 patients died within 14 days of hospitalization. Hypoxemia prevalence was 17.3%. Detection of human metapneumovirus (hMPV) and respiratory syncytial virus (RSV) in respiratory samples was independently associated with increased risk of hypoxemia (adjusted odds ratio [aOR] = 2.4, 95% confidence interval [95% CI] = 1.0-5.8 and aOR = 2.5, 95% CI = 1.1-5.3, respectively). Lower chest indrawing and cyanosis were predictive of hypoxemia (positive likelihood ratios = 2.3 and 2.4, respectively). Predictors of death were Streptococcus pneumoniae detection by blood PCR (crude hazard ratio [cHR] = 4.6, 95% CI = 1.5-14.0), procalcitonin ≥ 50 ng/mL (cHR = 22.4, 95% CI = 7.3-68.5) and hypoxemia (cHR = 4.8, 95% CI = 1.6-14.4). These findings were consistent on bivariate analysis. hMPV and RSV in respiratory samples were linked with hypoxemia, and S. pneumoniae in blood was associated with increased risk of death among hospitalized children with pneumonia in developing countries.

The utility of procalcitonin in the prediction of serious bacterial infection in a tertiary paediatric intensive care unit

To determine utility of procalcitonin (PCT) for the prediction of bacterial infection in critically ill children, we analysed the relationship between serum PCT, cultures and other laboratory markers of bacterial sepsis or viral infection in a tertiary paediatric intensive care unit (PICU). The outcome measures were levels of PCT in proven bacteraemia, pneumonia and viral respiratory infection; and comparison of PCT to immature to total neutrophil ratio (ITR) in prediction of bacteraemia. In 420 children with suspected sepsis, 1,226 serum PCT levels were analysed. Children with bacteraemia had a higher median PCT (2.03 ng/ml, interquartile range [IQR] 0.67-42.4) than those who did not have bacteraemia (0.82 ng/ml, IQR 0.295-2.87) (P=0.033). PCT was a significant but only moderate predictor of bacteraemia (AUC 0.65). In 866 episodes of suspected sepsis where paired PCT and ITR were performed, the median ITR in children with bacteraemia was 0.19 ng/ml (IQR 0.04-0.35), and the median PCT was 6.5 ng/ml (IQR 0.71-61.8). PCT was a marginally better predictor of bacteraemia (AUC 0.69) than the ITR (AUC 0.66). In children with viral respiratory tract infection only, the median PCT was 1.26 ng/ml (0.35-5.5), and in those with likely bacterial pneumonia the median PCT was 0.80 ng/ml (IQR 0.28-1.70). In a heterogeneous population of children in a tertiary PICU, PCT measured at a single timepoint was a moderate predictor of proven bacteraemia. In our population PCT did not reliably identify localised bacterial infection or distinguish bacterial from viral respiratory infection.

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.

Biomarkers in Pediatric Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) is an infectious disease caused by bacteria, viruses, or a combination of these infectious agents. The severity of the clinical manifestations of CAP varies significantly. Consequently, both the differentiation of viral from bacterial CAP cases and the accurate assessment and prediction of disease severity are critical for effectively managing individuals with CAP. To solve questionable cases, several biomarkers indicating the etiology and severity of CAP have been studied. Unfortunately, only a few studies have examined the roles of these biomarkers in pediatric practice. The main aim of this paper is to detail current knowledge regarding the use of biomarkers to diagnose and treat CAP in children, analyzing the most recently published relevant studies. Despite several attempts, the etiologic diagnosis of pediatric CAP and the estimation of the potential outcome remain unsolved problems in most cases. Among traditional biomarkers, procalcitonin (PCT) appears to be the most effective for both selecting bacterial cases and evaluating the severity. However, a precise cut-off separating bacterial from viral and mild from severe cases has not been defined. The three-host protein assay based on C-reactive protein (CRP), tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), plasma interferon-γ protein-10 (IP-10), and micro-array-based whole genome expression arrays might offer more advantages in comparison with former biomarkers. However, further studies are needed before the routine use of those presently in development can be recommended.

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.

Procalcitonin (PCT) and Kawasaki Disease: Does PCT Correlate With IVIG-Resistant Disease, Admission to the Intensive Care Unit, or Development of Coronary Artery Lesions?

BACKGROUND

Kawasaki disease (KD) remains a clinical diagnosis due to the absence of a sensitive and specific diagnostic test. There are limited published data on the usefulness of procalcitonin (PCT) as a biomarker for the diagnosis or prognosis of children with KD. We hypothesized that PCT might be useful in predicting coronary artery lesions (CALs) and intravenous immunoglobulin (IVIG) resistance.

METHODS

Eighty-five children with KD who were hospitalized within the first 10 days of illness were retrospectively reviewed. PCT was measured on stored serum or plasma samples obtained at the time of admission (pre-IVIG). Data were analyzed to determine whether there were statistically significant associations with PCT, erythrocyte sedimentation rate, and C-reactive protein levels and the incidence of CALs, pediatric intensive care unit admission, or IVIG-resistant disease in KD patients.

RESULTS

PCT values in children hospitalized with acute KD ranged from 0.1 ng/mL to 143.9 ng/mL, with a median of 0.49 ng/mL (IQR 0.23-1.29 ng/mL). There was no correlation of PCT with patient age, race, or sex, but it was correlated with day of illness. KD patients with a PCT ≥ 0.5 ng/mL had a significantly higher incidence of IVIG-resistant disease (29% versus 7%, P = .02). There was no association between PCT and development of CALs in our sample.

CONCLUSIONS

Additional research is needed to establish the sensitivity and specificity of PCT for the diagnosis of KD. PCT may be of value in predicting which children are at increased risk for IVIG-resistant disease.

Age-specific percentile-based reference curve of serum procalcitonin concentrations in Japanese preterm infants

Procalcitonin (PCT) levels are elevated early after birth in newborn infants; however, the physiological features and reference of serum PCT concentrations have not been fully studied in preterm infants. The aims of the current study were to establish an age-specific percentile-based reference curve of serum PCT concentrations in preterm infants and determine the features. The PCT concentration peaked in infants at 1 day old and decreased thereafter. At 1 day old, serum PCT concentrations in preterm infants <34 weeks’ gestational age were higher than those in late preterm infants between 34 and 36 weeks’ gestational age or term infants ≥37 weeks’ gestational age. Although the 50-percentile value in late preterm and term infants reached the adult normal level (0.1 ng/mL) at 5 days old, it did not in preterm infants. It took 9 weeks for preterm infants to reach it. Serum PCT concentrations at onset in late-onset infected preterm infants were over the 95-percentile value. We showed that the physiological feature in preterm infants was significantly different from that in late preterm infants, even in those <37 weeks’ gestational age. To detect late-onset bacterial infection and sepsis, an age-specific percentile-based reference curve may be useful in preterm infants.

Procalcitonin and community-acquired pneumonia (CAP) in children

The role of procalcitonin (PCT) as a biomarker for sepsis in adults is well documented, while its role in infections affecting neonatal children remains controversial. Among these infections, Community-Acquired pneumonia (CAP) has been studied extensively, because it's the second cause of death in children in developing countries, and one of the most frequent causes of hospitalization in industrialized countries. The PubMed database and the Cochrane Library were used to search for the following keywords: CAP, procalcitonin, and children. Thirteen articles were studied to determine the role of PCT in CAP management, specifically its usefulness for distinguishing pneumococcal infections from viral and unknown infections, for predicting severity and the correct antibiotic treatment. This paper focuses on the studies performed to identify the best inflammatory biomarker for CAP management. Although there is an increase in studies confirming the usefulness of PCT in CAP management in children, further studies are needed to have better understanding of its role for pediatric CAP management.

Blood Culture in Evaluation of Pediatric Community-Acquired Pneumonia: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

Current guidelines strongly recommend collection of blood cultures (BCs) in children requiring hospitalization for presumed moderate to severe bacterial community-acquired pneumonia (CAP). Our objective was to systematically review the international pediatric literature to evaluate how often BCs are positive in hospitalized children with CAP, identify the most commonly isolated pathogens, and determine the impact of positive BCs on clinical management.

METHODS

We identified articles in PubMed and Scopus published from January 1970 through December 2013 that addressed BCs in children with CAP. We extracted total number of BCs collected and prevalence of positive BCs and used meta-regression to evaluate whether subgroups had any impact on prevalence.

RESULTS

Meta-analysis showed that the overall prevalence of positive BCs was 5.14% (95% confidence interval 3.61-7.28). Studies focusing on severe CAP had a significant effect on prevalence (P=.008), at 9.89% (95% CI 6.79-14.19) compared with 4.17% (95% confidence interval 2.79-6.18) for studies not focusing on severe CAP. The most commonly isolated organisms were Streptococcus pneumoniae (76.7%) followed by Haemophilus influenzae (3.1%) and Staphylococcus aureus (2.1%). Contaminants accounted for 14.7%. Only 3 studies reported on BC-driven change in management, with contrasting findings.

CONCLUSIONS

BCs in pediatric CAP identified organisms in only a small percentage of patients, predominantly S. pneumoniae. False-positive BC rates can be substantial. The 3 studies that examined BC-driven changes in management had conflicting results. This systematic review was limited by heterogeneous case definitions, which may overestimate the true prevalence of positive BCs in hospitalized children.