Efficacy of prednisolone in children hospitalized for recurrent wheezing

Clinical characteristics and differential cytokine expression in hospitalized Taiwanese children with respiratory syncytial virus and rhinovirus bronchiolitis

BACKGROUND

Viral bronchiolitis presents a heterogeneous spectrum. In this study, we investigated the clinical characteristics and the cytokines/chemokines profiles among respiratory syncytial virus (RSV), rhinovirus (RV), and their dual infection in Taiwanese children with viral bronchiolitis.

METHOD

This study was conducted between October 2014 and June 2017. Viral etiology was identified using a Luminex respiratory virus panel and blood cytokines were evaluated using a MILLIPLEX MAP Human Cytokine/Chemokine Panel. Cytokine/Chemokine expressions were compared by clinical severity, steroid treatment, and viral entities.

RESULTS

A total of 184 patients were evaluated; at least one respiratory virus was identified in 163 (88.6%) patients. RSV and RV were the two leading viral etiologies, with 25.5% and 17.3%, respectively. RV bronchiolitis has a comparable severity to RSV but is more common in children of an older age with a history of recurrent wheezing and blood eosinophilia. Decreased tumor necrosis factor-alpha (TNF-α) and interferon gamma (INF-γ) levels were correlated with clinical severity. Patients infected with RV exhibited higher levels of Interleukin (IL)-22, IL-23, IL-25, IL-31, and IL-33 (p < 0.05), whereas those with RSV had higher levels of TNF-α, INF-γ, and IL-10 (p < 0.05). Systemic steroid treatment was associated with higher expressions of IL-4, IL-8, IL-13, and MIP-1α levels (p < 0.05). Cluster analysis revealed a high correlation of IL-33 and IL-31(R² = 0.9731, p < 0.0001).

CONCLUSION

Different viral infections elicited the characteristic clinical presentation and immune profiles in bronchiolitis. Our findings also highlight the role of the IL-33/IL-31 axis in the immunopathogenesis of bronchiolitis.

Safety of corticosteroids in the treatment of acute respiratory disease in children: a systematic review and meta-analysis

BACKGROUND

Oral corticosteroids are often used to treat acute asthma or asthma caused by respiratory tract infection in adult patients, but the effect of oral corticosteroids in young children is still controversial. We conducted a meta-analysis of controlled clinical studies to examine the effect of oral corticosteroids in children with respiratory diseases.

METHODS

Embase, PubMed, Web of Science, Ovid, ClinicalTrials.org from January 2000 to August 2021 were searched for randomized control trials related to the treatment of pediatric respiratory diseases with corticosteroid drugs using the keywords "corticosteroids" and "acute respiratory diseases". After screening the articles, Revman 5.4 software was used for the analysis.

RESULTS

A total of 8 articles (comprising 2,327 patients, 4 kinds of corticosteroids, and 3 types of pediatric respiratory disease) were included in the meta-analysis. The results showed that the length of hospital stay of patients in the experimental group treated with corticosteroids was shorter than that of patients in the control group [mean difference =-2.03, 95% confidence interval (CI): -2.91, -1.14; P<0.00001]. Further, the number and proportion of uncured patients after 3 days of treatment were lower in the experimental group than the control group [odds ratio (OR) =0.55, 95% CI: 0.42, 0.72; P<0.00001]. There were no differences in relation to adverse reactions (OR =0.57, 95% CI: 0.31, 1.07; P=0.08), and the readmission rate between the experimental and control groups (OR =0.94, 95% CI: 0.66, 1.34; P=0.75).

DISCUSSION

Corticosteroid use in the treatment of respiratory diseases in children can significantly shorten hospitalization time and increase the cure rate without increasing adverse reactions.

Big Data, Data Science, and Causal Inference: A Primer for Clinicians

Clinicians handle a growing amount of clinical, biometric, and biomarker data. In this “big data” era, there is an emerging faith that the answer to all clinical and scientific questions reside in “big data” and that data will transform medicine into precision medicine. However, data by themselves are useless. It is the algorithms encoding causal reasoning and domain (e.g., clinical and biological) knowledge that prove transformative. The recent introduction of (health) data science presents an opportunity to re-think this data-centric view. For example, while precision medicine seeks to provide the right prevention and treatment strategy to the right patients at the right time, its realization cannot be achieved by algorithms that operate exclusively in data-driven prediction modes, as do most machine learning algorithms. Better understanding of data science and its tasks is vital to interpret findings and translate new discoveries into clinical practice. In this review, we first discuss the principles and major tasks of data science by organizing it into three defining tasks: (1) association and prediction, (2) intervention, and (3) counterfactual causal inference. Second, we review commonly-used data science tools with examples in the medical literature. Lastly, we outline current challenges and future directions in the fields of medicine, elaborating on how data science can enhance clinical effectiveness and inform medical practice. As machine learning algorithms become ubiquitous tools to handle quantitatively “big data,” their integration with causal reasoning and domain knowledge is instrumental to qualitatively transform medicine, which will, in turn, improve health outcomes of patients.

Factors and mechanisms contributing to the development of preschool wheezing disorders

INTRODUCTION

Half of all children will experience an episode of wheezing by their sixth birthday and acute episodes of wheezing in preschool children account for the majority of all childhood hospital admissions for wheeze. Recurrent preschool wheezing associates with early loss of lung function and a life-long impact on lung health.

AREAS COVERED

We reviewed the literature on PubMed from August 2010-2020 focussing on factors associated with wheeze inception and persistence, paying specific attention to mechanistic studies that have investigated the impact of early life exposures in shaping immune responses in children with underlying susceptibility to wheezing. In particular, the role of early allergen sensitization, respiratory infections, and the impact of the environment on shaping the airway microbiome and resulting immune responses are discussed.

EXPERT OPINION

There is an abundance of associative data showing the role of in utero and postnatal factors influencing wheeze onset and persistence. However, mechanistic and stratified, biomarker-based interventional studies that confirm these associations are now needed if we are to impact the significant healthcare burden resulting from preschool wheezing disorders.

Management of Asthma Exacerbations in the Emergency Department

Asthma exacerbations occur across a wide spectrum of chronic severity; they contribute to millions of emergency department (ED) visits in both children and adults every year. Management of asthma exacerbations is an important part of the continuum of asthma care. The best strategy for ED management of an asthma exacerbation is early recognition and intervention, continuous monitoring, appropriate disposition, and, once improved, multifaceted transitional care that optimizes subacute and chronic asthma management after ED discharge. This article concisely reviews ED evaluation, treatment, disposition, and postdischarge care for patients with asthma exacerbations, based on high-quality evidence (eg, systematic reviews from the Cochrane Collaboration) and current international guidelines (eg, the National Asthma Education and Prevention Program Expert Panel Report 3, Global Initiative for Asthma, and Australian guidelines). Special populations (young children, pregnant women, and the elderly) also are addressed. Despite advances in asthma science, there remain many important evidence gaps in managing ED patients with asthma exacerbation. This article summarizes several of these controversial areas and challenges that merit further investigation.

Respiratory pathogens and clinical outcomes in children with an asthma exacerbation: A systematic review

BACKGROUND

In asthmatic children, respiratory pathogens are identified in 60%-80% of asthma exacerbations, contributing to a significant burden of illness. The role of pathogens in the clinical evolution of exacerbations is unknown.

OBJECTIVE

We systematically reviewed the association between the presence of pathogens and clinical outcomes in children with an asthma exacerbation.

METHOD

PubMed, EMBASE, BIOSIS, and the Cochrane Central Register of Controlled Trials were searched up to October 2016 for studies reporting on respiratory pathogen exposure and clinical outcome. The Risk of Bias in Non-Randomized Studies of Interventions tool was used for quality assessment.

RESULTS

Twenty-eight observational studies (N = 4,224 children) reported on 112 different associations between exposure to any pathogen (n = 45), human rhinovirus (HRV; n = 34), atypical bacteria (n = 21), specific virus (n = 11), or bacteria (n = 1) and outcomes of exacerbation severity (n = 26), health care use (n = 38), treatment response (n = 19), and morbidity (n = 29). Restricting the analysis only to comparisons with a low to moderate risk of bias, we observed an association between HRV and higher exacerbation severity on presentation (regression p = .016) and between the presence of any pathogen and emergency department treatment failure (odds ratio [OR] = 1.57; 95% CI 1.04% to 2.37%). High-quality evidence for effect on morbidity or health care use is lacking.

CONCLUSIONS

Further research on the role of pathogen-treatment interaction and outcomes is required to inform the need for point-of-care, real-time testing for pathogens. Studies with a sufficiently large sample size that address selection bias, correctly adjust for confounding, and rigorously report core patient-centred outcomes are necessary to improve knowledge.

Safety of corticosteroids in young children with acute respiratory conditions: a systematic review and meta-analysis

OBJECTIVE

Adverse events (AEs) associated with short-term corticosteroid use for respiratory conditions in young children.

DESIGN

Systematic review of primary studies.

DATA SOURCES

Medline, Cochrane CENTRAL, Embase and regulatory agencies were searched September 2014; search was updated in 2017.

ELIGIBILITY CRITERIA

Children <6 years with acute respiratory condition, given inhaled (high-dose) or systemic corticosteroids up to 14 days.

DATA EXTRACTION AND SYNTHESIS

One reviewer extracted with another reviewer verifying data. Study selection and methodological quality (McHarm scale) involved duplicate independent reviews. We extracted AEs reported by study authors and used a categorisation model by organ systems. Meta-analyses used Peto ORs (pORs) and DerSimonian Laird inverse variance method utilising Mantel-Haenszel Q statistic, with 95% CI. Subgroup analyses were conducted for respiratory condition and dose.

RESULTS

Eighty-five studies (11 505 children) were included; 68 were randomised trials. Methodological quality was poor overall due to lack of assessment and inadequate reporting of AEs. Meta-analysis (six studies; n=1373) found fewer cases of vomiting comparing oral dexamethasone with prednisone (pOR 0.29, 95% CI 0.17 to 0.48; I²=0%). The mean difference in change-from-baseline height after one year between inhaled corticosteroid and placebo was 0.10 cm (two studies, n=268; 95% CI -0.47 to 0.67). Results from five studies with heterogeneous interventions, comparators and measurements were not pooled; one study found a smaller mean change in height z-score with recurrent high-dose inhaled fluticasone over one year. No significant differences were found comparing systemic or inhaled corticosteroid with placebo, or between corticosteroids, for other AEs; CIs around estimates were often wide, due to small samples and few events.

CONCLUSIONS

Evidence suggests that short-term high-dose inhaled or systemic corticosteroids use is not associated with an increase in AEs across organ systems. Uncertainties remain, particularly for recurrent use and growth outcomes, due to low study quality, poor reporting and imprecision.

Respiratory Viruses and Treatment Failure in Children With Asthma Exacerbation

: media-1vid110.1542/5771275574001PEDS-VA_2017-4105Video Abstract OBJECTIVES: Respiratory pathogens commonly trigger pediatric asthma exacerbations, but their impact on severity and treatment response remains unclear.

METHODS

We performed a secondary analysis of the Determinants of Oral Corticosteroid Responsiveness in Wheezing Asthmatic Youth (DOORWAY) study, a prospective cohort study of children (aged 1-17 years) presenting to the emergency department with moderate or severe exacerbations. Nasopharyngeal specimens were analyzed by RT-PCR for 27 respiratory pathogens. We investigated the association between pathogens and both exacerbation severity (assessed with the Pediatric Respiratory Assessment Measure) and treatment failure (hospital admission, emergency department stay >8 hours, or relapse) of a standardized severity-specific treatment. Logistic multivariate regressions were used to estimate average marginal effects (absolute risks and risk differences [RD]).

RESULTS

Of 958 participants, 61.7% were positive for ≥1 pathogen (rhinovirus was the most prevalent [29.4%]) and 16.9% experienced treatment failure. The presence of any pathogen was not associated with higher baseline severity but with a higher risk of treatment failure (20.7% vs 12.5%; RD = 8.2% [95% confidence interval: 3.3% to 13.1%]) compared to the absence of a pathogen. Nonrhinovirus pathogens were associated with an increased absolute risk (RD) of treatment failure by 13.1% (95% confidence interval: 6.4% to 19.8%), specifically, by 8.8% for respiratory syncytial virus, 24.9% for influenza, and 34.1% for parainfluenza.

CONCLUSIONS

Although respiratory pathogens were not associated with higher severity on presentation, they were associated with increased treatment failure risk, particularly in the presence of respiratory syncytial virus, influenza, and parainfluenza. This supports influenza prevention in asthmatic children, consideration of pathogen identification on presentation, and exploration of treatment intensification for infected patients at higher risk of treatment failure.

Efficacy of oral corticosteroids in the treatment of acute wheezing episodes in asthmatic preschoolers: Systematic review with meta-analysis

RATIONALE

Systemic corticosteroids (SCS) are used for treat preschoolers with acute asthma or wheezing exacerbations, with conflicting results.

OBJECTIVE

To evaluate the effectiveness of oral corticosteroids (OCS) compared to placebo in preschoolers presenting with acute asthma/wheezing exacerbations.

METHODS

Five electronic databases were searched for all placebo-controlled, randomized clinical trials of OCS in children <6 years of age presenting with recurrent wheezing/asthma exacerbations of any severity. Primary outcomes were hospitalizations, unscheduled emergency department (ED) visits in following month, need of additional OCS courses, and length of stay (ED or hospital).

RESULTS

Eleven studies met inclusion criteria (n = 1,733); four were conducted on an outpatient basis, five in inpatients, and two in the ED. Significant heterogeneity was found when pooling all studies, and thus analysis was stratified by trial setting. Among the outpatient studies, children who received OCS had a higher hospitalization rate (RR: 2.15 [95%CI = 1.08-4.29], I(2)  = 0%) compared to those to received placebo. Among the ED studies, children who received OCS had a lower risk of hospitalization (RR: 0.58 [0.37-0.92], I(2)  = 0%). Among the inpatient studies, children who received OCS needed fewer additional OCS courses than those on placebo (RR: 0.57 [0.40-0.81], I(2)  = 0%).

CONCLUSIONS

Treatment with OCS in the ED or hospital may be beneficial in toddlers and preschoolers with frequent asthma/wheezing exacerbations. However, more studies are needed before OCS can be broadly recommended for this age group. Future trials should be carefully designed to avoid bias and according to our findings regarding administration setting. Pediatr Pulmonol. 2016;51:868-876. © 2016 Wiley Periodicals, Inc.

An update on the efficacy of oral corticosteroids in the treatment of wheezing episodes in preschool children

Traditionally, oral corticosteroids (OCSs) have been the mainstay of treatment for acute wheezing episodes among preschool children with a history of recurrent wheezing. Although there is substantial evidence for the efficacy of OCSs as a treatment for asthma exacerbations in school-aged children and adolescents, recent clinical studies questioned the benefits of OCSs as a treatment for acute wheezing in preschool children. This review summarizes the current evidence on the efficacy of OCSs as a treatment for acute wheezing episodes among preschool age children with episodic wheezing, focusing on studies performed in three different settings: OCS treatment initiated by parents in the outpatient setting, OCS treatment initiated in the emergency department (ED), and OCS treatment among hospitalized preschool children. The results of most studies reviewed in this paper do not support the efficacy of OCS treatment among preschool children with recurrent wheezing. The heterogeneity of early childhood wheezing and asthma might be part of the explanation for lack of efficacy of this intervention noted in multiple studies.

Rhinovirus and the developing lung

Human rhinovirus (HRV) infections are now widely accepted as the commonest cause of acute respiratory illnesses (ARIs) in children. Advanced PCR techniques have enabled HRV infections to be identified as causative agents in most common ARIs in childhood including bronchiolitis, acute asthma, pneumonia and croup. However, the long-term implications of rhinovirus infections are less clear. The aim of this review is to examine the relationship between rhinovirus infections and disorders of the lower airways in childhood.

Determinants Of Oral corticosteroid Responsiveness in Wheezing Asthmatic Youth (DOORWAY): protocol for a prospective multicentre cohort study of children with acute moderate-to-severe asthma exacerbations

INTRODUCTION

Oral corticosteroids are the cornerstone of acute asthma management in the emergency department. Recent evidence has raised doubts about the efficacy of this treatment in preschool-aged children with viral-induced wheezing and in smoking adults. The aims of the study were to: (1) document the magnitude of response to oral corticosteroids in children presenting to the emergency department with moderate or severe asthma; (2) quantify potential determinants of response to corticosteroids and (3) explore the role of gene polymorphisms associated with the responsiveness to corticosteroids.

METHODS AND ANALYSIS

The design is a prospective cohort study of 1008 children aged 1-17 years meeting a strict definition of asthma and presenting with a clinical score of ≥4 on the validated Pediatric Respiratory Assessment Measure. All children will receive standardised severity-specific treatment with prednisone/prednisolone and cointerventions (salbutamol with/without ipratropium bromide). Determinants, namely viral aetiology, environmental tobacco smoke and single nucleotide polymorphism, will be objectively documented. The primary efficacy endpoint is the failure of emergency department (ED) management within 72 h of the ED visit. Secondary endpoints include other measures of asthma severity and time to recovery within 7 days of the index visit. The study has 80% power for detecting a risk difference of 7.5% associated with each determinant from a baseline risk of 21%, at an α of 0.05.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from all participating institutions. An impaired response to systemic steroids in certain subgroups will challenge the current standard of practice and call for the immediate search for better approaches. A potential host-environment interaction will broaden our understanding of corticosteroid responsiveness in children. Documentation of similar effectiveness of corticosteroids across determinants will provide the needed reassurance regarding current treatment recommendations.

RESULTS

Results will be disseminated at international conferences and manuscripts targeted at emergency physicians, paediatricians, geneticists and respirologists.

TRIAL REGISTRATION NUMBER

This study is registered at Clinicaltrials.gov (NCT02013076).

Infectious pathogens and bronchiolitis outcomes

Bronchiolitis is a common early childhood illness and an important cause of morbidity, it is the number one cause of hospitalization among US infants. Bronchiolitis is also an active area of research, and recent studies have advanced our understanding of this illness. Although it has long been the conventional wisdom that the infectious etiology of bronchiolitis does not affect outcomes, a growing number of studies have linked specific pathogens of bronchiolitis (e.g., rhinovirus) to short- and long-term outcomes, such as future risk of developing asthma. The authors review the advent of molecular diagnostic techniques that have demonstrated diverse pathogens in bronchiolitis, and they review recent studies on the complex link between infectious pathogens of bronchiolitis and the development of childhood asthma.

Pharmacological approach to wheezing in preschool children

INTRODUCTION

Wheezing disorders are very common during childhood (particularly among preschool children), and represent a significant burden for patients, their families, the healthcare system, and society as a whole. Identifying wheezing phenotypes, and recognizing the risk factors associated with each, may help to predict long-term outcomes, distinguish high-risk children who may benefit from secondary prevention measures, and ensure that the most effective therapy is prescribed for each case.

AREAS COVERED

The main aim of this review is to analyze the characteristics of the drugs currently used to treat wheezing in preschool children, and discuss the results obtained in children with different wheezing phenotypes.

EXPERT OPINION

The continuous or intermittent administration of various oral or inhaled drugs could theoretically be effective in preventing or controlling wheezing in preschool children. However, the optimal management of acute preschool wheezing episodes has not yet been determined mainly because of their phenotypical heterogeneity.

Bronchial hyperresponsiveness in an adult population in Helsinki: decreased FEV1 , the main determinant

Introduction

Bronchial hyperresponsiveness (BHR) elevates the risk for development of respiratory symptoms and accelerates the decline in forced expiratory volume in the first second (FEV₁). We thus aimed to assess the prevalence, determinants and quantity of BHR in Helsinki.

Objectives

This study involved 292 randomly selected subjects age 26–66 years, women comprising 58%.

Methods

Following a structured interview, a spirometry, a bronchodilation test, and a skin-prick test, we assessed a bronchial challenge test with inhaled histamine using a dosimetric tidal breathing method. Results included the provocative dose inducing a decrease in FEV₁ by 15% (PD₁₅FEV₁) and the dose-response slope. For statistical risk factor-analyses, the severity of BHR was considered; PD₁₅ values ≤1.6 mg (BHR) and ≤0.4 mg [moderate or severe BHR (BHR_ms)] served as cut-off levels.

Results

BHR presented in 21.2% and BHR_ms in 6.2% of the subjects. FEV₁ < 80% of predicted [odds ratio (OR) 4.09], airway obstruction (FEV₁/forced vital capacity < 88% of predicted) (OR 4.33) and history of respiratory infection at age <5 (OR 2.65) yielded an increased risk for BHR as ORs in multivariate analysis. For BHR_ms, the determinants were decreased FEV₁ below 80% of predicted (OR 27.18) and airway obstruction (OR 6.16). Respiratory symptoms and asthma medication showed a significant association with BHR.

Conclusions

Of the adult population of Helsinki, 21% showed BHR to inhaled histamine. The main determinants were decreased FEV₁ and airway obstruction. Quantitative assessment of BHR by different cut-off levels provides a tool for characterization of phenotypes of airway disorders in epidemiologic and clinical studies.

Please cite this paper as: Juusela M, Pallasaho P, Sarna S, Piirilä P, Lundbäck B and Sovijärvi A. Bronchial hyperresponsiveness in an adult population in Helsinki: decreased FEV₁, the main determinant. Clin Respir J 2013; 7: 34–44.

New molecular virus detection methods and their clinical value in lower respiratory tract infections in children

During the past decade, several new respiratory viruses and their subgroups have been discovered. All these new viruses, as well as previously known respiratory viruses, can be detected by sensitive PCR methods, which have become popular in the diagnostic workup of respiratory viral infections. Currently, respiratory viruses can be detected in up to 95% of children with lower respiratory tract illness. On the other hand, virus detection rates in asymptomatic children are also high (up to 68%), as are coinfection rates in symptomatic children (up to 43%) and justified concerns of causality have been raised. Imposing progress has been made in developing multiplex quantitative PCR assays; here, several primer sets are run within a single PCR mixture. These PCR assays give a better understanding of the dominant viral infection, of viral infections that may be incipient and of any waning infections than does a single-target PCR. Multiplex PCR assays are also gaining popularity due to their cost-effectiveness and short throughput time compared to multiple single-target PCRs. Our understanding of the indications of virus PCRs and our ability to interpret the results from a clinical point of view have improved. This paper reviews the progress in PCR assays and discusses their role in the diagnosis of lower respiratory tract infections in children.

Inhaled corticosteroids for subacute cough in children

BACKGROUND

Cough is the most common symptom presenting to primary healthcare services. Cough in children is associated with significant morbidity for both children and their parents. While inhaled corticosteroids (ICS) can potentially reduce cough associated with airway inflammation and airway hyper-reactivity, use of ICS in children is not without potential adverse effects. Therefore, it would be beneficial to clinical practice to evaluate the evidence for the efficacy of ICS in reducing the severity of cough in children with subacute cough (defined as cough duration of two to four weeks) systematically.

OBJECTIVES

To evaluate the efficacy of ICS in reducing the severity of cough in children with subacute cough.

SEARCH METHODS

The Cochrane Register of Controlled Trials (CENTRAL), the Cochrane Airways Group Specialised Register, MEDLINE, EMBASE, review articles and reference lists of relevant articles were searched. The latest searches were performed in November 2011.

SELECTION CRITERIA

All randomised controlled trials (RCTs) comparing ICS with a control group in children with subacute cough were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Search results were reviewed against pre-determined criteria for inclusion. Two sets of review authors independently selected, extracted and assessed the data for inclusion. Study authors were contacted for further information where required. Data were analysed as 'intention to treat'.

MAIN RESULTS

The search identified 1178 potentially relevant titles; however, there were no published studies that were specifically designed to answer this question. Two studies met criteria for inclusion in the review and 98 children were included in the meta-analysis. There was no significant difference between groups in the proportion of children 'not cured' at follow-up (primary outcome measure), with a pooled odds ratio (OR) of 0.61 (95% confidence interval (CI) 0.24 to 1.55). However, the included studies were limited in their ability to answer the review question by the fact that all participants were infants, post acute bronchiolitis illness, and cough duration at the start of study medication was ill-defined.

AUTHORS' CONCLUSIONS

There is currently no evidence to support the use of ICS for treatment of subacute cough in children. However, this systematic review is limited by the small number of studies available for analysis and the size, quality and design of these studies. Further well-designed RCTs are required to support or refute the efficacy of treatment with ICS in children with subacute cough.

Phenotype-directed treatment of pre-school-aged children with recurrent wheeze

Wheeze in childhood may comprise different underlying diseases. Disease-specific treatment could potentially improve treatment efficacy. Various attempts have been made to differentiate between pre-school wheeze phenotypes. In this review, the results of clinical trials evaluating treatment of pre-school wheeze are discussed, with specific emphasis on the characteristics and phenotype of the study populations. Evidence suggests that systemic corticosteroids are not beneficial for the treatment of mild-to-moderate exacerbations of pre-school wheeze, irrespective of phenotype. The use of high-dose intermittent inhaled corticosteroid treatment cannot be recommended because of unacceptable side effects. Treatment with regular inhaled corticosteroids and leukotriene antagonists offer modest benefit, but neither treatment reduces hospitalisation rates. There is currently some evidence for a phenotype-specific effect of treatment. Phenotype-directed treatment of pre-school wheeze is currently limited by our ability to accurately differentiate between clinically useful phenotypes.

Steroid responsiveness and wheezing phenotypes

Oral corticosteroids are the cornerstone of management of acute moderate or severe asthma whilst preventive inhaled corticosteroids are the mainstay of the preventive management of children with asthma. Yet, variation in the magnitude of response to corticosteroids has been observed. There is increasing evidence that preschool-aged children with viral-induced asthma may display a certain degree of corticosteroid resistance, requiring higher doses of corticosteroids to overcome it. The identification of determinants of responsiveness is complicated by design issues, including heterogeneous populations of children with asthma and bronchiolitis or of children with viral-induced and multi-trigger asthma phenotypes in published trials. Potential key determinants of responsiveness may include age, trigger, phenotype, tobacco smoke exposure and genotype. The mechanistic pathway for corticoresistance may originate from a gene-environment interaction, leading to non-eosinophilic airway inflammation. The clinician should carefully confirm the diagnosis of asthma and ascertain the phenotype to select appropriate phenotype-specific therapy.

No efficacy of prednisolone in acute wheezing associated with human bocavirus infection

The efficacy of prednisolone in acute wheezing associated with human bocavirus infection was investigated in 232 hospitalized children (median age, 1.6 years). Clinical history, atopy status, and viral etiology were carefully studied. Outcomes included hospitalization time, duration of symptoms, and occurrence of relapses. No efficacy of prednisolone was found in children with serologically confirmed acute human bocavirus infection.

Impulse oscillometry in the evaluation of diseases of the airways in children

OBJECTIVE

To provide an overview of impulse oscillometry and its application to the evaluation of children with diseases of the airways.

DATA SOURCES

Medline and PubMed search, limited to English language and human disease, with keywords forced oscillation, impulse oscillometry, and asthma.

STUDY SELECTIONS

The opinions of the authors were used to select studies for inclusion in this review.

RESULTS

Impulse oscillometry is a noninvasive and rapid technique requiring only passive cooperation by the patient. Pressure oscillations are applied at the mouth to measure pulmonary resistance and reactance. It is employed by health care professionals to help diagnose pediatric pulmonary diseases such asthma and cystic fibrosis; assess therapeutic responses; and measure airway resistance during provocation testing.

CONCLUSIONS

Impulse oscillometry provides a rapid, noninvasive measure of airway impedance. It may be easily employed in the diagnosis and management of diseases of the airways in children.

Allergic sensitization is associated with rhinovirus-, but not other virus-, induced wheezing in children

BACKGROUND

Data on the link between atopy and viral wheeze are limited.

AIM

To evaluate the association between IgE sensitization and viral infection in wheezing children.

METHODS

This is an observational study in hospitalized wheezing children (n = 247; median age 1.6 ; interquartile range 1.1, 2.9). Eighteen respiratory viral infections were studied using all available methods. A specific immunoglobulin E (IgE) sensitization for common food and aeroallergens and other atopy-related variables including total IgE, blood and nasal eosinophils, exhaled nitric oxide, eczema and atopic eczema, parental allergy and asthma, number of wheezing episodes, positive asthma predictive index or asthma and use of inhaled corticosteroid were correlated with specific viral etiology.

RESULTS

Atopy was closely associated with sole rhinovirus etiology (n = 58) but not with sole respiratory syncytial virus, sole enterovirus, sole human bocavirus, sole other virus, mixed viral, or virus negative etiology. The number of sensitizations was particularly associated with sole rhinovirus etiology (odds ratio 4.59; 95% confidence interval 1.78, 11.8; adjusted to age and sex), followed by aeroallergen sensitization (respectively; 4.18; 2.00, 8.72), total IgE level (2.06; 1.32, 3.21), food allergen sensitization (2.02; 1.08, 3.78), and nasal eosinophil count (1.52; 1.08, 2.13).

CONCLUSIONS

According to our data, allergic sensitization is positively linked to rhinovirus-, but not other virus-, associated wheezing and calls attention for studies to test rhinovirus-associated wheezing as a part of asthma risk indices.

Correlation of viral load of respiratory pathogens and co-infections with disease severity in children hospitalized for lower respiratory tract infection

Background

The clinical significance of viral load and co-infections in children with respiratory infections is not clear.

Objective

To evaluate the correlation of viral load as well as viral and bacterial co-infections with disease severity in hospitalized children with lower respiratory tract infections (LRTIs).

Study design

This is a prospective study conducted in children admitted for LRTIs for two seasons. To determine viral and bacterial load of respiratory pathogens we performed multiplex real-time polymerase chain reaction and semiquantitative bacterial cultures on nasopharyngeal aspirates (NPA).

Results

During the study period 244 (60%) children were hospitalized for LRTI with acute virus-induced wheezing and 160 (40%) for radiologic confirmed pneumonia. In the first NPA, viruses were identified in 315 (78%) of the 404 samples and bacteria in 198 (63.3%) of 311 samples. The viral load significantly decreased between the first and second NPA sample in most single and viral co-infections, except rhinovirus and human bocavirus infections. Viral load was inversely related to CRP in RSV infections, whereas a positive correlation was observed in adenovirus infections. Duration of hospitalization was significantly longer in RSV single infections compared to rhinovirus single infections whereas in the latter, leucocytosis and use of systemic steroids was more common. In RSV viral co-infections the presence of fever, leucocytosis, and the use of antibiotics was significantly more frequent. Positive cultures of Haemophilus influenzae dominated in RSV and rhinovirus single infections and Moraxella catarrhalis in RSV viral co-infections.

Conclusions

Specific viral single and co-infections as well as viral load contribute to disease severity in children with LRTIs.

Nasopharyngeal bacterial colonization during the first wheezing episode is associated with longer duration of hospitalization and higher risk of relapse in young children

The purpose of this study was to examine the association between bacterial colonization/infection and respiratory outcomes in children younger than 3 years old who were hospitalized for their first wheezing episode. This was an observational study. The primary outcome was hospitalization time and the secondary outcomes included relapses within 2 months and time to recurrent wheezing (i.e. three physician confirmed wheezing episodes) within 12 months. Bacterial antibody assays for Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Mycoplasma pneumoniae and Chlamydia pneumoniae were studied as well as nasopharyngeal bacterial culture for the three former and urine pneumococcal antigen. Nasopharyngeal bacterial culture was positive in 31/52 (60%) children, serologic evidence of bacterial infection was found in 17/96 (18%) children, urine pneumococcal antigen was positive in 24/101 (24%), and any bacterial detection method was positive in 53/106 (50%) children. The children with positive nasopharyngeal bacterial culture had longer duration of hospitalization (hazard ratio 2.4) and more often relapsed within two months than those with negative culture (odds ratio 7.3). In this study, half of the first time wheezing children had bacterial colonization or symptomatic or asymptomatic bacterial infection. The bacterial colonization (i.e. positive nasopharyngeal bacterial culture) was associated with longer duration of hospitalization and higher risk of recurrent wheezing.

Paediatric asthma: everything that seemed to be certain no longer is

'Paediatric asthma: everything that seemed to be certain no longer is', holds the promise of leaving you with more questions than answers at the end of this review of paediatric asthma 2008-2009. This has often been true for asthma research, in particular over the past few years. Research with direct consequences for a clinician managing children with wheezing or asthma is discussed such as limitations in the characterisation of asthma phenotypes and the influence of early viral infections on asthma and the development of atopic sensitisation. It appears that wheezing in preschool children with specific viral pathogens confers differential rates of asthma risk. Viruses and day-care shift respiratory morbidity to an early age when it is more troublesome than at a later age but are not protective for sensitisation or asthma. What needs to be further explored is the relationship between viruses and recurrent wheeze or asthma in studies with stringently defined phenotypes including personal atopic status, timing of infection, and severity of infection. A modification of preschool wheeze phenotypes or replacement by other phenotypes that have been defined with the application of different methods is needed. Oral corticosteroids should not be prescribed in preschool children with acute mild to moderate viral wheeze, unless a severe outcome is anticipated or if the child has a classic atopic phenotype. Despite initial high expectations, FeNO was proven not to be beneficial for routine monitoring of asthma treatment.

Respiratory viral infections in infants: causes, clinical symptoms, virology, and immunology

In global terms, respiratory viral infection is a major cause of morbidity and mortality. Infancy, in particular, is a time of increased disease susceptibility and severity. Early-life viral infection causes acute illness and can be associated with the development of wheezing and asthma in later life. The most commonly detected viruses are respiratory syncytial virus (RSV), rhinovirus (RV), and influenza virus. In this review we explore the complete picture from epidemiology and virology to clinical impact and immunology. Three striking aspects emerge. The first is the degree of similarity: although the infecting viruses are all different, the clinical outcome, viral evasion strategies, immune response, and long-term sequelae share many common features. The second is the interplay between the infant immune system and viral infection: the immaturity of the infant immune system alters the outcome of viral infection, but at the same time, viral infection shapes the development of the infant immune system and its future responses. Finally, both the virus and the immune response contribute to damage to the lungs and subsequent disease, and therefore, any prevention or treatment needs to address both of these factors.

Recurrent wheezing after respiratory syncytial virus or non-respiratory syncytial virus bronchiolitis in infancy: a 3-year follow-up

BACKGROUND

Recent studies have suggested that rhinovirus-associated early wheezing is a greater risk factor for development of recurrent wheezing in children than is early wheezing associated with respiratory syncytial virus (RSV). We determined the development of recurrent wheezing in young children within 3 years after hospitalization for RSV or non-RSV bronchiolitis.

METHODS

We identified retrospectively all children <2 years of age who were admitted to Turku University Hospital because of bronchiolitis in the months of August-December during 1988-2001. The primary outcome was recurrent wheezing that required long-term asthma medication. Data on asthma medications of the individual children were derived from the Social Insurance Institution of Finland.

RESULTS

Within the first year after hospitalization, 36 of 217 (16.6%) children with non-RSV bronchiolitis developed recurrent wheezing, compared with five of 199 (2.5%) children with RSV bronchiolitis [relative risk (RR) 6.6; 95% confidence interval (CI) 2.6-16.5]. The rates of recurrent wheezing were significantly increased in the non-RSV group also within 2 years (RR 2.9; 95% CI 1.7-5.1) and 3 years (RR 3.4; 95% CI 2.0-5.7) after hospitalization. The increased risk of recurrent wheezing in children with non-RSV-associated bronchiolitis was observed both in boys and girls at all time points of the 3-year follow-up, and it was not explained by the age difference between the RSV and non-RSV groups or any confounding seasonal factors.

CONCLUSION

Children hospitalized with bronchiolitis caused by other viruses than RSV develop recurrent wheezing at substantially higher rates during a 3-year follow-up period than do children with RSV-induced bronchiolitis.

Variability in the diagnostic labeling of nonbacterial lower respiratory tract infections: a multicenter study of children who presented to the emergency department

OBJECTIVE

The diagnostic labeling of presumed nonbacterial lower respiratory tract infection is unclear. Our objective was to identify patterns of specific diagnoses and treatments that were given to children who presented with lower respiratory tract infection to US academic emergency departments.

METHODS

Data were collected on all children who were aged <2 years and had lower respiratory tract infection symptoms during a similar 2- to 3-week winter period at 4 pairs of emergency departments from the same state or region. The children were identified by using relevant International Classification of Diseases, Ninth Revision, Clinical Modification codes in the primary diagnosis field. Data were collected by using standardized chart review forms for the index emergency department visit and also for 1 month before through 1 year after the index visit.

RESULTS

Among the 928 children who presented with lower respiratory tract infection symptoms, 676 (73%) were younger than 12 months and 624 (67%) had a primary diagnosis of bronchiolitis. When comparing the assigned diagnoses between emergency department pairs, bronchiolitis was the more common diagnosis at certain hospitals, whereas asthma, cough, and wheeze were more frequent at others. Independent predictors of corticosteroid treatment were visiting specific emergency departments, older age, an asthma diagnosis (compared with bronchiolitis), documented history of wheezing, observed wheezing during the index visit, eosinophil values >4%, previous use of corticosteroids, and parental history of asthma.

CONCLUSIONS

For children who are age <2 years and present to an emergency department with lower respiratory tract infection symptoms, there is large variability in the assigned diagnosis. Children who present to emergency departments that more commonly diagnose lower respiratory tract infection as "asthma" are more likely to receive corticosteroids. As clinicians, we need to develop evidence- and outcome-based definitions for lower respiratory tract infections to guide diagnosis and treatment better.

Atopic characteristics of wheezing children and responses to prednisolone

We wanted to test the hypothesis that the efficacy of systemic corticosteroid is associated with atopic characteristics in wheezing children. A randomized controlled trial comparing oral prednisolone (2 mg/kg/day in 3 divided doses for 3 days) with placebo in hospitalized wheezing children (n = 266, median 1.6 years, range 3 months to 15.2 years) was conducted. In this post-hoc analysis, we assessed the link between the efficacy of prednisolone and several atopic characteristics, such as atopy, aeroallergen sensitization, total IgE level, number of sensitizations, eczema, atopic eczema, blood or nasal eosinophils, exhaled nitric oxide, positive modified asthma predictive index/asthma, inhaled corticosteroid medication and parental asthma/allergy. Virology was studied comprehensively. Our primary endpoint was the time until ready for discharge, and the most important secondary endpoint was the occurrence of relapses during the following 2 months. For statistics, we used interaction analyses in uni- and multivariate regression models. Overall, prednisolone did not decrease any of our predefined clinical endpoints. Neither was the efficacy of prednisolone associated with atopy. However, prednisolone significantly decreased the time until ready for discharge in children with positive modified asthma predictive index/asthma, inhaled corticosteroids, or rhinovirus infection and/or in children without azithromycin treatment. Prednisolone significantly decreased relapses in children with eczema, nasal eosinophilia and rhinovirus infection. The multiple clinical, inflammatory and viral markers associating with the efficacy of prednisolone should be confirmed in prospective trials. It is important that corticosteroid intervention trials have strict design for these potentially confounding factors.