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

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.

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.

Rapid Diagnostic Tests to Guide Case Management of and Improve Antibiotic Stewardship for Pediatric Acute Respiratory Illnesses in Resource-Constrained Settings: a Prospective Cohort Study in Southwestern Uganda

Pediatric acute respiratory illness (ARI) is one of the most common reasons for evaluation at peripheral health centers in sub-Saharan Africa and is frequently managed based on clinical syndrome alone. Although most ARI episodes are likely caused by self-limited viral infections, the majority are treated with antibiotics. This overuse contributes to the development of antimicrobial resistance. To evaluate the preliminary feasibility and potential impact of adding pathogen-specific and clinical biomarker diagnostic testing to existing clinical management algorithms, we conducted a prospective, observational cohort study of 225 children presenting with malaria-negative, febrile ARI to the outpatient department of a semi-urban peripheral health facility in southwestern Uganda from October 2019 to January 2020. In addition to routine clinical evaluation, we performed influenza and Streptococcus pneumoniae antigen testing and measured levels of C-reactive protein, procalcitonin, and lactate in the clinic's laboratory, and conducted a follow-up assessment by phone 7 days later. Almost one-fifth of participants (40/225) tested positive for influenza. Clinical biomarker measurements were low with C-reactive protein of >40 mg/L in only 11% (13/222) of participants and procalcitonin >0.25 ng/mL in only 13% (16/125). All but two children received antibiotic treatment; only 3% (7/225) were admitted. At follow-up, 59% (118/201) of caregivers reported at least one persistent symptom, but fever had resolved for all children. Positive influenza testing was associated with persistent symptoms. In summary, we demonstrate that simple, rapid pathogen-specific testing and biomarker measurement are possible in resource-limited settings and could improve syndromic management and, in turn, antibiotic stewardship. IMPORTANCE Globally, respiratory illness is one of the most common reasons that children seek care. It is often treated inappropriately with antibiotics, which can drive the development of antibiotic resistance. In resource-rich settings, testing for specific pathogens or measurement of clinical biomarkers, such as procalcitonin and C-reactive protein, is often employed to help determine which children should receive antibiotics. However, there are limited data on the use of these tests in resource-constrained, outpatient contexts in sub-Saharan Africa. We enrolled children with respiratory illness presenting to a clinic in southwestern Uganda and performed testing for influenza, Streptococcus pneumoniae, C-reactive protein, and procalcitonin on-site. Almost all children received antibiotics. We demonstrate that employing clinical algorithms that include influenza and clinical biomarker testing could significantly decrease antibiotic prescriptions. Our study therefore provides preliminary data to support the feasibility and potential utility of diagnostics to improve management of respiratory illness in resource-constrained settings.

Impact of bronchiolitis guidelines publication on primary care prescriptions in the Italian pediatric population

In Italy, two clinical practice guidelines for the diagnosis and treatment of bronchiolitis were published in October 2014 and December 2015. We evaluated prescriptions for bronchiolitis in children aged 0–24 months before (December 2012–December 2014), in between (December 2014–December 2015) and after (December 2015–December 2018) the guidelines publications. Data were retrieved from the Pedianet database; the measured outcomes were prescriptions rates of antibiotics, corticosteroids, β2-agonists, and other respiratory drugs. In 1011 out of 1581 episodes, patients received at least one treatment, with a total of 2003 prescriptions. The rate of treated bronchiolitis decreased from 66% to 57% (p < 0.001) after the publication of the second guideline; the highest reduction was in younger patients (from 57% to 44%, p = 0.013). Overall antibiotic prescriptions rate did not change, with 31.6% of the patients still receiving them. Our results confirm unnecessary non-evidence-based treatments in the primary care setting, with few changes after the guidelines publications.

Pneumonia Severity in Children: Utility of Procalcitonin in Risk Stratification

OBJECTIVES

To determine if serum procalcitonin, an indicator of bacterial etiology in pneumonia in all ages and a predictor of severe pneumonia in adults, is associated with disease severity in children with community-acquired pneumonia.

METHODS

We prospectively enrolled children 2 months to <18 years with clinical and radiographic pneumonia at 2 children's hospitals (2014-2019). Procalcitonin samples were obtained at presentation. An ordinal outcome scale of pneumonia severity was defined: very severe (intubation, shock, or death), severe (intensive care admission without very severe features and/or high-flow nasal cannula), moderate (hospitalization without severe or very severe features), and mild (discharge). Hospital length of stay (LOS) was also examined. Ordinal logistic regression was used to model associations between procalcitonin and outcomes. We estimated adjusted odds ratios (aORs) for a variety of cut points of procalcitonin ranging from 0.25 to 3.5 ng/mL.

RESULTS

The study included 488 children with pneumonia; 30 (6%) were classified as very severe, 106 (22%) as severe, 327 (67%) as moderate, and 25 (5%) as mild. Median procalcitonin in the very severe group was 5.06 (interquartile range [IQR] 0.90-16.83), 0.38 (IQR 0.11-2.11) in the severe group, 0.29 (IQR 0.09-1.90) in the moderate group, and 0.21 (IQR 0.12-1.2) in the mild group. Increasing procalcitonin was associated with increasing severity (range of aORs: 1.03-1.25) and increased LOS (range of aORs: 1.04-1.36). All comparisons were statistically significant.

CONCLUSIONS

Higher procalcitonin was associated with increased severity and LOS. Procalcitonin may be useful in helping clinicians evaluate pneumonia severity.

Diagnostic Accuracy of Routinely Available Biomarkers to Predict Bacteremia in Children With Community-Acquired Pneumonia: A Secondary Analysis of the GPIP/ACTIV Pneumonia Study in France, 2009-2018

Objective(s): Blood cultures (BC), when performed in children seen in the emergency department with community-acquired pneumonia (CAP), are most of the time sterile. We described the diagnostic accuracy of white blood cells (WBC), absolute neutrophils count (ANC), C-reactive protein (CRP), and procalcitonin (PCT) to predict blood culture (BC) result in childhood CAP. Study Design: Secondary analysis of a prospective study carried out in eight pediatric emergency departments (France, 2009-2018), including children (≤15 years) with CAP. Analyses involved univariate comparisons and ROC curves. Results: We included 13,752 children with CAP. BC was positive in 137 (3.6%) of the 3,829 children (mean age 3.7 years) in whom it was performed, mostly with Streptococcus pneumoniae (n = 107). In children with bacteremia, ANC, CRP and PCT levels were higher (median 12,256 vs. 9,251/mm³, 223 vs. 72 mg/L and 8.6 vs. 1.0 ng/mL, respectively; p ≤ 0.002), but WBC levels were not. The area under the ROC curve of PCT (0.73 [95%CI 0.64-0.82]) was significantly higher (p ≤ 0.01) than that of WBC (0.51 [0.43-0.60]) and of ANC (0.55 [0.46-0.64]), but not than that of CRP (0.66 [0.56-0.76]; p = 0.21). CRP and PCT thresholds that provided a sensitivity of at least 90% were 30 mg/L and 0.25 ng/mL, respectively, for a specificity of 25.4 and 23.4%, respectively. CRP and PCT thresholds that provided a specificity of at least 90% were 300 mg/L and 20 ng/mL, respectively, for a sensitivity of 31.3 and 28.9%, respectively. Conclusions: PCT and CRP are the best routinely available predictive biomarkers of bacteremia in childhood CAP.

How does one choose the appropriate pharmacotherapy for children with lower respiratory tract infections?

INTRODUCTION

The definition of acute lower respiratory tract infection (LRTI) includes any infection involving the respiratory tract below the level of the larynx. In children, the most common acute LRTIs, and those with the greatest clinical relevance, are community-acquired pneumonia (CAP), bronchiolitis, bronchitis and tuberculosis (TB). The clinical relevance of LRTIs implies that they must be addressed with the most effective therapy. Antibiotics and antivirals play an essential role in this regard.

AREAS COVERED

In this paper, the most recent advances in the drug treatment of LRTIs in children are discussed.

EXPERT OPINION

Although LRTIs are extremely common and one of the most important causes of hospitalization and death in children, anti-infective therapy for these diseases remains unsatisfactory. For CAP and BR, the most important problem is the overuse and misuse of antibiotics; for BCL, the lack of drugs with demonstrated efficacy, safety and tolerability; for TB, the poor knowledge on the true efficacy and safety of the new drugs specifically planned to overcome the problem of MDR M. tuberculosis strains. There is still a long way to go for the therapy of pediatric LRTIs to be considered satisfactory.

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.

Wheezing independently predicts viral infection in children with community-acquired pneumonia

AIM

To assess whether there was a difference in the frequency of symptoms and signs among children with community-acquired pneumonia (CAP) with viral or bacterial infection.

METHODS

A prospective cross-sectional study was conducted in Salvador, Brazil. Children less than 5-years-old hospitalized with CAP were recruited. Viral or only bacterial infection was diagnosed by an investigation of 11 viruses and 8 bacteria. Bacterial infection was diagnosed by blood culture, detection of pneumococcal DNA in acute buffy coat, and serological tests. Viral infection was diagnosed by detection of respiratory virus in nasopharyngeal aspirate and serological tests. Viral infection comprised only viral or mixed viral-bacterial infection subgroups.

RESULTS

One hundred and eighty-eight patients had a probable etiology established as only viral (51.6%), mixed viral-bacterial (30.9%), and only bacterial infection (17.5%). Asthma was registered for 21.4%. Report of wheezing (47.4% vs 21.2%; P = 0.006), rhonchi (38.0% vs 15.2%; P = 0.01), and wheezing detected on physical examination (51.0% vs 9.1%; P < 0.001) were the differences found. Among children with asthma, detected wheezing was the only different finding when children with viral infection were compared with those with only bacterial infection (75.0% vs 0%; P = 0.008). By multivariable analysis, viral infection (AdjOR [95% CI]: 9.6; 95%CI: 2.7-34.0), asthma (AdjOR [95% CI]: 4.6; 95%CI: 1.9-11.0), and age (AdjOR [95% CI]: 0.95; 95%CI: 0.92-0.97) were independently associated with wheezing on physical examination. The positive predictive value of detected wheezing for viral infection was 96.3% (95% CI: 90.4-99.1%).

CONCLUSION

Wheezing detected on physical examination is an independent predictor of viral infection.