A double-blind, placebo-controlled, randomized trial of montelukast for acute bronchiolitis

Bronchiolitis: evidence-based management in high-risk infants in the intensive care setting

AIM

Systematically review the management of infants with severe bronchiolitis in a paediatric intensive care unit (PICU) setting with a focus on high-risk infants to identify gaps in evidence-based knowledge.

METHODS

This systematic review utilised Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P) to examine the literature on the PICU management of bronchiolitis in infants <24 months old. Three databases, Embase, PubMed and Medline, were searched and higher levels of evidence I, II and III were included.

RESULTS

There were 455 papers reviewed and 26 met the inclusion criteria. Furthermore, 19 of these studied respiratory interventions such as positive airway pressure and oxygen delivery. The remaining 7 examined: erythropoietin, caffeine, dexamethasone, protein supplementation, ribavirin, respiratory syncytial virus immune globulin, or diuretic therapy. Of the 26 studies, 20 excluded infants with high-risk conditions. Therapies showing favourable outcomes included Heliox, prophylactic dexamethasone pre-extubation, protein supplementation, and diuretic use.

CONCLUSIONS

Clinical trials for bronchiolitis management frequently exclude high-risk children. Innovative study design in the future may improve access to clinical trials for the management of bronchiolitis in high-risk infants in a PICU setting.

IMPACT

Clinical trials for bronchiolitis management frequently exclude high-risk children. We review the evidence base for the management of an under-investigated patient demographic in the setting of acute bronchiolitis. Randomised controlled trials are needed to determine the efficacy of management strategies for bronchiolitis in high-risk infants in a paediatric intensive care setting.

Bronchiolitis therapies and misadventures

Viral bronchiolitis, which is most commonly caused by an infection with the respiratory syncytial virus (RSV), can lead to respiratory difficulties in young children which may require hospitalization. Despite years of research and medical trials, the mainstay of bronchiolitis treatment remains supportive only. This review provides an overview of the history of different treatments for bronchiolitis, including those that failed, as well as new therapies that are under study. Future studies for the treatment of bronchiolitis should consider different age-groups, important subgroups (i.e., those with a prior history of wheezing, those with a family history of asthma and those with non-RSV viral etiologies) whose response to treatment may differ from that of the composite group.

Pranlukast treatment and the use of respiratory support in infants with respiratory syncytial virus infection

Background

In infants, respiratory syncytial virus (RSV) infection occasionally causes severe symptoms requiring respiratory support; however, supportive care is the primary treatment. This study compared the use of respiratory support among infants with RSV infection treated with or without pranlukast.

Methods

This retrospective cohort study included infants aged <10 months with RSV infection who were admitted to three secondary level hospitals in Japan between 2012 and 2019. The infants were divided into two groups depending on whether they were treated with pranlukast. The primary outcome was the receiving respiratory support (high-flow nasal cannula, nasal continuous positive airway pressure, or ventilator). The secondary outcomes were the length of hospital stay, and the Global Respiratory Severity Score (GRSS) on starting respiratory support or at the time of the worst signs during hospitalization. We performed a propensity score-matched analysis.

Results

A total of 492 infants, including 147 propensity score-matched pairs, were included in the analysis. The use of respiratory support was significantly lower in infants treated with pranlukast (3.4% [5/147]) than those treated without pranlukast (11.6% [17/147]; P = 0.01). In the propensity score-matched analysis, pranlukast use was associated with a significantly lower chance of needing respiratory support (odds ratio: 0.27, 95% confidence interval: 0.08–0.79; P = 0.01); however, the length of hospital stay (median: 4 days) and the GRSS (median: 2.804 and 2.869 for infants treated with and without pranlukast, respectively) did not differ significantly between propensity score-matched pairs.

Conclusions

Pranlukast use was associated with a reduced likelihood of requiring respiratory support in infants aged <10 months with RSV infection.

Utility of the Global Respiratory Severity Score for predicting the need for respiratory support in infants with respiratory syncytial virus infection

Background

Respiratory syncytial virus (RSV) is a common cause of acute respiratory infection in children. One of the most important strategies for treatment of an RSV infection is to decide whether the patient needs respiratory support. This study aimed to assess the validity and clinical benefit of the Global Respiratory Severity Score (GRSS) and the Wang bronchiolitis severity score (WBSS) for clinical decision-making regarding providing respiratory support (high-flow nasal cannula, nasal continuous positive airway pressure, or ventilator) in infants with an RSV infection.

Study design and methods

This retrospective cohort study enrolled 250 infants aged under 10 months who were admitted to Atsugi City Hospital with an RSV infection between January 2012 and December 2019. The utility of these scores was evaluated for assessing the need for respiratory support through decision curve analysis by calculating the optimal GRSS and WBSS cut-offs for predicting the need for respiratory support.

Results

Twenty-six infants (10.4%) received respiratory support. The optimal cut-offs for the GRSS and the WBSS were 4.52 and 7, respectively. Decision curve analysis suggested that the GRSS was a better predictive tool than the WBSS if the probability of needing respiratory support was 10–40%.

Conclusions

The GRSS was clinically useful in determining the need for respiratory support in infants aged under 10 months with an RSV infection.

Decision-making in acute viral bronchiolitis: A universal guideline and a publication gap

Background

Acute viral bronchiolitis is very common in infants and children up to 2 years. Some patients develop serious respiratory symptoms and need to be hospitalized. In 2014, the American Academy of Pediatrics (AAP) published a guideline on acute bronchiolitis which has gained global acceptance. We hypothesized that a publication gap, which is increasingly perceived in clinical medicine, might have also affected these universal recommendations.

Methods

We determined the proportion of published and unpublished studies registered at ClinicalTrials.gov that were marked as completed by October 1^st 2018. The major trial and literature databases were used to search for publications. In addition, the study investigators were contacted directly.

Results

Of the 69 registered studies on the treatment of acute viral bronchiolitis, only 50 (72%) have been published by November 2019. Published trials contained data from n = 9403 patients, whereas n = 4687 patients were enrolled in unpublished trials. Median time to publication was 20 months, and only 8 of 50 trials were published within 12 months after completion. Only 40% of the clinical trials that were completed after the release of the AAP guideline were subsequently published as compared to 80% before 2014.

Conclusion

There is a significant publication gap regarding therapy of acute viral bronchiolitis that may have influenced certain recommendations of the AAP guideline. In turn, recommendations of the guideline might have discouraged investigators to publish their results after its release.

Immune biomarkers predicting bronchiolitis disease severity: A systematic review

Bronchiolitis is one of the leading causes of hospitalisation in infancy, with highly variable clinical presentations ranging from mild disease safely managed at home to severe disease requiring invasive respiratory support. Identifying immune biomarkers that can predict and stratify this variable disease severity has important implications for clinical prognostication/disposition. A systematic literature search of the databases Embase, PubMed, ScienceDirect, Web of Science, and Wiley Online Library was performed. English language studies that assessed the association between an immune biomarker and bronchiolitis disease severity among children aged less than 24 months were included. 252 distinct biomarkers were identified across 90 studies. A substantial degree of heterogeneity was observed in the bronchiolitis definitions, measures of disease severity, and study designs. 99 biomarkers showed some significant association with disease severity, but only 18 were significant in multiple studies. However, all of these candidate biomarkers had comparable studies that reported conflicting results. Conclusion: The heterogeneity among included studies and the lack of a consistently significant biomarker highlight the need for consensus on bronchiolitis definitions and severity measures, as well as further studies assessing their clinical utility both in isolation and in combination.

Bronchiolitis in children: The Saudi initiative of bronchiolitis diagnosis, management, and prevention (SIBRO)

Bronchiolitis is the leading cause of admissions in children less than two years of age. It has been recognized as highly debated for many decades. Despite the abundance of literature and the well-recognized importance of palivizumab in the high risk groups, and despite the existence of numerous, high-quality, recent guidelines on bronchiolitis, the number of admissions continues to increase. Only supportive therapy and few therapeutic interventions are evidence based and proved to be effective. Since Respiratory Syncytial Virus (RSV) is the major cause of bronchiolitis, we will focus on this virus mostly in high risk groups like the premature babies and children with chronic lung disease and cardiac abnormalities. Further, the prevention of RSV with palivizumab in the high risk groups is effective and well known since 1998; we will discuss the updated criteria for allocating infants to this treatment, as this medication is expensive and should be utilized in the best condition. Usually, diagnosis of bronchiolitis is not challenging, however there has been historically no universally accepted and validated scoring system to assess the severity of the condition. Severe RSV, especially in high risk children, is unique because it can cause serious respiratory sequelae. Currently there is no effective curative treatment for bronchiolitis. The utility of different therapeutic interventions is worth a discussion.

Viral Lower Respiratory Tract Infections

Lower respiratory tract infections in children are often viral in origin. Unfortunately in this time of significant antimicrobial resistance of infectious organisms, especially bacteria, there is still a tendency for clinicians to manage a child who coughs with antibiotics. In addition, the World Health Organization (WHO) has defined “pneumonia” as a condition that only occurs in children who have “fast breathing or chest wall indrawing”. That would delineate upper respiratory tract infections from those in the lower airway. However, in addition to pneumonia another important entity exists in the lower respiratory tract that is almost always viral in origin. This condition is acute viral bronchiolitis. The concept of “acute lower respiratory tract infection” (ALRTI) has emerged and it is becoming increasing evident from a number of studies that the infectious base of both acute pneumonia (AP) and acute bronchiolitis in children has a mixed etiology of microorganisms. Therefore, whilst certain clinical phenotypes do not require antibiotics the actual microbial etiology is much less distinct.

Montelukast, current indications and prospective future applications

INTRODUCTION

Montelukast is recommended for the treatment of asthma, exercise -induced bronchospasm and allergic rhinitis. Several trials demonstrated potential therapeutic effects in other respiratory conditions, and different animal-model-based studies explored potential pharmacological actions in non-respiratory conditions.

AREAS COVERED

Clinical investigations on the pharmacotherapeutic effects of montelukast, in addition to in-vivo studies on animal models of non-respiratory diseases. The data discussed in this review were mainly obtained from clinical randomized trials, real-life studies, and studies based on animal models as approve of concept. As a condition, all of the discussed articles were published in journals cited by Pubmed. Expert commentary: The current clinical data are in favor of montelukast use in the management of chronic asthma as an add-on or alternative therapy to the inhaled corticosteroids. Further clinical trials are required to confirm the effectiveness and feasibility of montelukast for the treatment of conditions other than the current clinical indications.

[Seasonality in asthma: Impact and treatments]

The role of seasons should be taken into account in the management of asthma. The environment varies between seasons and it is well documented that asthma is modulated by environment. Viruses cause asthma exacerbations peak, in winter, in adults while the peak is present in September in children. Allergens are probably a less powerful source of asthma exacerbation than viruses but pollen involvement in spring and summer and dust mites in autumn are indisputable. Air pollutants, present in summer during the hottest periods, are also highly involved in asthma exacerbations. Indoor air pollution, in winter, is also implicated in asthma disease. All these environmental factors are synergistic and increase the risk of asthma exacerbation. Therapies should be adapted to each season depending on environmental factors potentially involved in the asthma disease.

Novel montelukast sodium-loaded stable oral suspension bioequivalent to the commercial granules in rats

To develop a montelukast sodium-loaded stable oral suspension bioequivalent to the commercial granules in rats, several montelukast sodium-loaded suspensions were prepared with a suspending agent, stabilizers and anti-aggregation agents, and their stabilities were investigated by visually observing the sedimentation phenomenon and determining the concentration of the degradation product. Moreover, dissolution and pharmacokinetic studies of the optimized formulation were examined in rats compared to commercial montelukast sodium-loaded granules. Avicel RC-591 (Avicel), a suspending agent, prevented the sedimentation of these suspensions at >2.496 (w/v) per cent composition. Amongst the stabilizers tested, fumaric acid provided the lowest concentration of montelukast sulphoxide (a degradation product) in these suspensions at 40 °C, demonstrating its excellent stabilizing activity. Furthermore, as an anti-aggregation agent, glycerin gave lower amounts of degradation product than those with poloxamer 407 and Tween 80. In particular, montelukast-loaded oral suspension, an aqueous suspension containing montelukast sodium/Avicel/fumaric acid/glycerin at a concentration of 312/2496/15.6/62.4 (mg/100 ml), and the commercial granules exhibited similar dissolution profiles in 0.5% (w/v) aqueous solution of sodium lauryl sulphate. Moreover, the pharmacokinetics in rats provided by this suspension was comparable to that of the commercial granules, suggesting that they were bioequivalent. In addition, it was physically and chemically stable at 40 °C for at least 6 months. Thus, this montelukast sodium-loaded oral suspension, with bioequivalence to the commercial granules and excellent stability, could be a prospective dosage form for the treatment of asthma.

Latest options for treatment of bronchiolitis in infants

Bronchiolitis is the most frequent pathology associated with lower respiratory tract infection in newborns and young infants. The treatment of bronchiolitis is essentially supportive therapy for respiratory distress, hypoxia and dehydration. To date, no specific antiviral drug is used on a routine basis for the treatment of RSV infections. Currently, the only antiviral drug approved for the infection is ribavirin; however, its use is limited due to adverse side effects and the risks it poses to healthcare providers. Moreover, several drugs have been routinely administered for years in infants with acute RSV bronchiolitis, even if their efficacy is often not confirmed by clinical evidence, and studies on emerging antiviral drugs are still ongoing. In the present paper we review the recent literature about the drugs used during acute bronchiolitis and we summarize the main recommendations of national and international guidelines and the latest options for the treatment of bronchiolitis.

Characteristics of respiratory syncytial virus-induced bronchiolitis co-infection with Mycoplasma pneumoniae and add-on therapy with montelukast

BACKGROUND

The influence of Mycoplasma pneumoniae (MP) infection on bronchiolitis remains unclear. Additionally, reports on the efficacies of leukotriene receptor antagonists in the treatment of bronchiolitis have been inconclusive.

METHODS

Children with respiratory syncytial virus (RSV)-induced bronchiolitis were divided into two groups: RSV+MP group and RSV group. Each group was randomly divided into two subgroups: one received routine and placebo treatment, while the other received routine and montelukast treatment for 9 months. The cumulative numbers of wheezing episodes and recurrent respiratory tract infections were recorded. Blood parameters were determined.

RESULTS

Patients in the RSV+MP group exhibited an older average age, fever, more frequent flaky and patchy shadows in chest X-rays, more frequent extrapulmonary manifestations, and longer hospital stays compared with patients in the RSV group. Additionally, higher baseline blood eosinophil counts, eosinophil cationic protein (ECP), total immunoglobulin E (IgE), interleukin (IL)-4, IL-5, IL-4/interferon-γ ratios, leukotriene (LT) B4, and LTC4, and lower baseline lipoxin A4 (LXA4)/LTB4 ratios were observed in the RSV+MP group compared with the RSV group. Montelukast treatment decreased the cumulative numbers of recurrent wheezing episodes and recurrent respiratory tract infections at 9 and 12 months. This efficacy may be related to the montelukast-induced reductions in peripheral eosinophil counts, ECP and total IgE, as well as the montelukast-dependent recovery in T helper (Th) 1/Th2 balance and LXA4/LTB4 ratios in children with bronchiolitis.

CONCLUSIONS

RSV bronchiolitis with MP infection was associated with clinical and laboratory features that differed from those of RSV bronchiolitis without MP infection. Add-on therapy with montelukast for 9 months was beneficial for children with bronchiolitis at 9 and 12 months after the initiation of treatment.

Effect of montelukast on clinical score and cytokine levels of infants for clinically diagnosed acute bronchiolitis

BACKGROUND

Acute bronchiolitis comprises a major cause for morbidity in infants with viral infection which induces an immune inflammatory response that may produce long lasting harmful effects. Currently, there is no effective therapy for bronchiolitis.

OBJECTIVE

Our aim was to investigate the efficacy of five-day montelukast therapy in acute bronchiolitis management.

METHODS

The study included 50 infants with acute bronchiolitis. The infants with first episode of acute bronchiolitis were randomly assigned to receive daily montelukast dose of 4mg over five days after admission or no treatment. Plasma eotaxin, IL-4, IL-8 and IFN-gamma levels were evaluated before and after treatment by ELISA method. In the present study, the primary outcome measure was change in clinical severity score, whilst secondary outcome measures were changes in plasma eotaxin, IL-4, IL-8, IFN-gamma levels.

RESULTS

No significant differences was found in clinical severity score with five-day montelukast treatment (p>0.05, Mann-Whitney U test). There were no significant differences in plasma eotaxin, IL-4, IL-8, IFN-gamma levels between the groups (p>0.05 Mann-Whitney U test). There was significant decrease in plasma IFN-gamma levels following five-day montelukast treatment (p=0.027, Wilcoxon). There were no significant differences in plasma IL-4, IL-8, IFN-gamma levels between the groups after five-day montelukast treatment (p>0.05, Wilcoxon). There was significant increase in eotaxin levels after five-day montelukast treatment (p=0.009, Wilcoxon).

CONCLUSION

Our study showed that montelukast affected plasma IFN-gamma and eotaxin levels after five days of treatment. Further studies are needed to demonstrate effects of montelukast on chemokine levels in bronchiolitis.

Leukotriene inhibitors for bronchiolitis in infants and young children

BACKGROUND

Bronchiolitis is an acute inflammatory illness of the bronchioles common among infants and young children. It is often caused by the respiratory syncytial virus (RSV). Management of bronchiolitis varies between clinicians, reflecting the lack of evidence for a specific treatment approach. The leukotriene pathway has been reported to be involved in the pathogenesis of bronchiolitis. Leukotriene inhibitors such as montelukast have been used in infants and young children with bronchiolitis. However, the results from limited randomised controlled trials (RCTs) are controversial and necessitate a thorough evaluation of their efficacy for bronchiolitis in infants and young children.

OBJECTIVES

To assess the efficacy and safety of leukotriene inhibitors for bronchiolitis in infants and young children.

SEARCH METHODS

We searched CENTRAL (2014, Issue 5), MEDLINE (1946 to April week 4, 2014), EMBASE (1974 to May 2014), CINAHL (1981 to May 2014), LILACS (1982 to May 2014), Web of Science (1985 to May 2014), WHO ICTRP and ClinicalTrials.gov (6 May 2014).

SELECTION CRITERIA

RCTs comparing leukotriene inhibitors versus placebo or another intervention in infants and young children under two years of age diagnosed with bronchiolitis. Our primary outcomes were length of hospital stay and all-cause mortality. Secondary outcomes included clinical severity score, percentage of symptom-free days, percentage of children requiring ventilation, oxygen saturation, recurrent wheezing, respiratory rate and clinical adverse effects.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane Collaboration methodological practices. Two authors independently assessed trial eligibility and extracted data, such as general information, participant characteristics, interventions and outcomes. We assessed risk of bias and graded the quality of the evidence. We used Review Manager software to pool results and chose random-effects models for meta-analysis.

MAIN RESULTS

We included five studies with a total of 1296 participants under two years of age hospitalised with bronchiolitis. Two studies with low risk of bias compared 4 mg montelukast (a leukotriene inhibitor) daily use from admission until discharge with a matching placebo. Both selected length of hospital stay as a primary outcome and clinical severity score as a secondary outcome. However, the effects of leukotriene inhibitors on length of hospital stay and clinical severity score were uncertain due to considerable heterogeneity between the study results and wide confidence intervals around the estimated effects (hospital stay: mean difference (MD) -0.95 days, 95% confidence interval (CI) -3.08 to 1.19, P value = 0.38, low quality evidence; clinical severity score on day two: MD -0.57, 95% CI -2.37 to 1.23, P value = 0.53, low quality evidence; clinical severity score on day three: MD 0.17, 95% CI -1.93 to 2.28, P value = 0.87, low quality evidence). The other three studies compared montelukast for several weeks for preventing post-bronchiolitis symptoms with placebo. We assessed one study as low risk of bias, whereas we assessed the other two studies as having a high risk of attrition bias. Due to the significant clinical heterogeneity in severity of disease, duration of treatment, outcome measurements and timing of assessment, we did not pool the results. Individual analyses of these studies did not show significant differences between the leukotriene inhibitors group and the control group in symptom-free days and incidence of recurrent wheezing. One study of 952 children reported two deaths in the leukotriene inhibitors group: neither was determined to be drug-related. No data were available on the percentage of children requiring ventilation, oxygen saturation and respiratory rate. Finally, three studies reported adverse events including diarrhoea, wheezing shortly after administration and rash. No differences were reported between the study groups.

AUTHORS' CONCLUSIONS

The current evidence does not allow definitive conclusions to be made about the effects of leukotriene inhibitors on length of hospital stay and clinical severity score in infants and young children with bronchiolitis. The quality of the evidence was low due to inconsistency (unexplained high levels of statistical heterogeneity) and imprecision arising from small sample sizes and wide confidence intervals, which did not rule out a null effect or harm. Data on symptom-free days and incidence of recurrent wheezing were from single studies only. Further large studies are required. We identified one registered ongoing study, which may make a contribution in the updates of this review.

Inter-society consensus document on treatment and prevention of bronchiolitis in newborns and infants

Acute bronchiolitis is the leading cause of lower respiratory tract infection and hospitalization in children less than 1 year of age worldwide. It is usually a mild disease, but some children may develop severe symptoms, requiring hospital admission and ventilatory support in the ICU. Infants with pre-existing risk factors (prematurity, bronchopulmonary dysplasia, congenital heart diseases and immunodeficiency) may be predisposed to a severe form of the disease. Clinical diagnosis of bronchiolitis is manly based on medical history and physical examination (rhinorrhea, cough, crackles, wheezing and signs of respiratory distress). Etiological diagnosis, with antigen or genome detection to identify viruses involved, may have a role in reducing hospital transmission of the infection. Criteria for hospitalization include low oxygen saturation (<90-92%), moderate-to-severe respiratory distress, dehydration and presence of apnea. Children with pre-existing risk factors should be carefully assessed.To date, there is no specific treatment for viral bronchiolitis, and the mainstay of therapy is supportive care. This consists of nasal suctioning and nebulized 3% hypertonic saline, assisted feeding and hydration, humidified O2 delivery. The possible role of any pharmacological approach is still debated, and till now there is no evidence to support the use of bronchodilators, corticosteroids, chest physiotherapy, antibiotics or antivirals. Nebulized adrenaline may be sometimes useful in the emergency room. Nebulized adrenaline can be useful in the hospital setting for treatment as needed. Lacking a specific etiological treatment, prophylaxis and prevention, especially in children at high risk of severe infection, have a fundamental role. Environmental preventive measures minimize viral transmission in hospital, in the outpatient setting and at home. Pharmacological prophylaxis with palivizumab for RSV bronchiolitis is indicated in specific categories of children at risk during the epidemic period. Viral bronchiolitis, especially in the case of severe form, may correlate with an increased incidence of recurrent wheezing in pre-schooled children and with asthma at school age.The aim of this document is to provide a multidisciplinary update on the current recommendations for the management and prevention of bronchiolitis, in order to share useful indications, identify gaps in knowledge and drive future research.

Recent advances in management of bronchiolitis

Background

Bronchiolitis is one of the major causes for hospital admissions in infants. Managing bronchiolitis, both in the outpatient and inpatient setting remains a challenge to the treating pediatrician. The effectiveness of various interventions used for infants with bronchiolitis remains unclear.

Need and purpose

To evaluate the evidence supporting the use of currently available treatment and preventive strategies for infants with bronchiolitis and to provide practical guidelines to the practitioners managing children with bronchiolitis.

Methods

A search of articles published on bronchiolitis was performed using PubMed. The areas of focus were diagnosis, treatment and prevention of bronchiolitis in children. Relevant information was extracted from English language studies published over the last 20 years. In addition, the Cochrane Database of Systematic Reviews was searched.

Results and Conclusions

Supportive care, comprising of taking care of oxygenation and hydration, remains the corner-stone of therapy in bronchiolitis. Pulse oximetry helps in guiding the need for oxygen administration. Several recent evidence-based reviews have suggested that bronchodilators or corticosteroids lack efficacy in bronchiolitis and should not be routinely used. A number of other novel therapies (such as nebulized hypertonic saline, heliox, CPAP, montelukast, surfactant, and inhaled furosemide) have been evaluated in clinical trials, and although most of them did not show any beneficial results, some like hypertonic saline, surfactant, CPAP have shown promising results.

Respiratory syncytial virus bronchiolitis in children

Respiratory syncytial virus is a highly infectious virus that commonly causes bronchiolitis and leads to high morbidity and a low, but important, incidence of mortality. Supportive therapy is the foundation of management. Hydration/nutrition and respiratory support are important evidence-based interventions. For children with severe disease, continuous positive airway pressure or mechanical ventilation may be necessary. Ribavirin may be used for treatment of patients with severe disease. Palivizumab provides important ongoing immunoprophylaxis during epidemic months for high-risk infants. Caregiver education and incorporating an explanation of all therapies and anticipatory guidance, including strategies for reducing the risk of infection, are vital.

Antileukotriene agents for the treatment of lung disease

Leukotrienes (LTs) C4, D4, and E4, collectively termed cysteinyl LTs (cysLTs), are lipid mediators formed by the 5-lipoxygenase (5-LO) pathway of arachidonic acid metabolism. Originally recognized for their potent bronchoconstrictor actions, they were subsequently determined also to promote inflammation, microvascular permeability, and mucus secretion. These actions that are so central to asthma pathophysiology are mediated to a significant extent by ligation of the cysLT receptor 1 (CysLT1). Antagonism of CysLT1 and inhibition of 5-LO have both been shown to have clinical use in the management of asthma, but substantial interindividual heterogeneity is observed in the response to these agents. In this article, we review the biologic actions of LTs, their biosynthetic pathways and cognate receptors, the pharmacology of available anti-LT agents, and the clinical evidence for the use of anti-LT agents as monotherapy and combination therapy in asthma. We also consider heterogeneity of response, the possible roles of cysLT receptors other than CysLT1, the role of another class of LT, LTB4, and the potential role of LTs in lung diseases other than asthma.

Treatment of bronchiolitis: state of the art

Bronchiolitis is a leading cause of acute illness and hospitalization for infants and young children worldwide. It is usually a mild disease, but the few children developing severe symptoms need to be hospitalized and some will need ventilatory support. To date, the mainstay of therapy has been supportive care, i.e. assisted feeding and hydration, minimal handling, nasal suctioning and oxygen therapy. In recent years the delivery of oxygen has been improved by using a high-flow nasal cannula. At the same time, the discovery of nebulized hypertonic saline enables better airway cleaning with a benefit for respiratory function. The possible role of any pharmacological approach is still debated: many pharmacological therapies tried in the past, ranging from bronchodilators to corticosteroids, were found to offer no benefit in this disease. More recently, nebulized adrenaline demonstrated a short-term benefit. Prophylaxis and prevention, especially in children at high risk of severe infection, such as prematurely born infants and children with bronchopulmonary dysplasia, have a fundamental role in dealing with this disease. In this review, we focus on current recommendations for the management and prevention of bronchiolitis, paying particular attention to the latest literature in search of answers to the questions that remain open.

[Inhalation therapy: provocation tests, infectious risks, acute bronchiolitis and ENT diseases. GAT aerosolstorming, Paris 2011]

Communications from the 2011 meeting of the GAT are reported in this second article on the practical management of bronchial provocation tests and infectious risks associated with the use of nebulization. Recent advances on the role of nebulized hypertonic saline in the treatment of acute bronchiolitis in infants and of the nebulization in sinusal diseases are also reported.

Environmental factors association between asthma and acute bronchiolitis in young children--a perspective cohort study

Acute bronchiolitis and asthma are respiratory tract diseases of childhood that are characterized by wheezing. However, the diagnosis of asthma is difficult in patients younger than 2 years. We evaluated the association between asthma or acute bronchiolitis and various risk factors in young children. This perspective cohort study included a study group of children younger than 2 years with a recorded diagnosis of acute bronchiolitis (N = 4,586) as well as a control group (N = 4,263). Children in both groups were registered between January 1, 2004 and December 31, 2004, on the Taiwan Longitudinal Health Insurance Database (2005), and each child was followed in our study until December 31, 2006, using data from the same source. Of the 8,849 children in our study, 355 experienced asthma during the 3-year follow-up period. Among these 355 asthma patients, 332 children (29.1 per 1,000 person-years, 95% CI 26.2-36.4) belonged to the acute bronchiolitis cohort and 23 children (2.0 per 1,000 person-years, 95% CI 13.3-29.9) belonged to the comparison cohort. Cox proportional hazard regression analysis showed that children with acute bronchiolitis were more likely to have asthma than the control population, after adjustment for potential confounders (adjusted hazard ratio [HR] 13.55, 95% CI 8.87-20.71). Boys with acute bronchiolitis had a higher HR for asthma than girls during the 3-year follow-up. Children with acute bronchiolitis who lived in rural areas had a 1.49 HR for asthma compared with their urban counterparts. Children living in the northern region of Taiwan had a higher HR ratio than those in other regions. Sex, urbanization, and geographic region all showed significant associations with acute bronchiolitis and asthma. Based on the asthma-free survival curves of Kaplan-Meier analysis in our study, young children with acute bronchiolitis should be monitored for 2 years to prevent them from developing asthma. This was the first study to evaluate the length of time for which acute bronchiolitis poses a risk for the development of asthma in young children.

Update on leukotriene receptor antagonists in preschool children wheezing disorders

Asthma is the most common chronic disease in young children. About 40% of all preschool children regularly wheeze during common cold infections. The heterogeneity of wheezing phenotypes early in life and various anatomical and emotional factors unique to young children present significant challenges in the clinical management of this problem. Anti-inflammatory therapy, mainly consisting of inhaled corticosteroids (ICS), is the cornerstone of asthma management. Since Leukotrienes (LTs) are chemical mediators of airway inflammation in asthma, the leukotriene receptor antagonists (LTRAs) are traditionally used as potent anti-inflammatory drugs in the long-term treatment of asthma in adults, adolescents, and school-age children. In particular, montelukast decreases airway inflammation, and has also a bronchoprotective effect. The main guidelines on asthma management have confirmed the clinical utility of LTRAs in children older than five years. In the present review we describe the most recent advances on the use of LTRAs in the treatment of preschool wheezing disorders. LTRAs are effective in young children with virus-induced wheeze and with multiple-trigger disease. Conflicting data do not allow to reach definitive conclusions on LTRAs efficacy in bronchiolitis or post-bronchiolitis wheeze, and in acute asthma. The excellent safety profile of montelukast and the possibility of oral administration, that entails better compliance from young children, represent the main strengths of its use in preschool children. Montelukast is a valid alternative to ICS especially in poorly compliant preschool children, or in subjects who show adverse effects related to long-term steroid therapy.

Treatment of acute viral bronchiolitis

Acute viral bronchiolitis represents the most common lower respiratory tract infection in infants and young children and is associated with substantial morbidity and mortality. Respiratory syncytial virus is the most frequently identified virus, but many other viruses may also cause acute bronchiolitis. There is no common definition of acute viral bronchiolitis used internationally, and this may explain part of the confusion in the literature. Most children with bronchiolitis have a self limiting mild disease and can be safely managed at home with careful attention to feeding and respiratory status. Criteria for referral and admission vary between hospitals as do clinical practice in the management of acute viral bronchiolitis, and there is confusion and lack of evidence over the best treatment for this condition. Supportive care, including administration of oxygen and fluids, is the cornerstone of current treatment. The majority of infants and children with bronchiolitis do not require specific measures. Bronchodilators should not be routinely used in the management of acute viral bronchiolitis, but may be effective in some patients. Most of the commonly used management modalities have not been shown to have a clear beneficial effect on the course of the disease. For example, inhaled and systemic corticosteroids, leukotriene receptor antagonists, immunoglobulins and monoclonal antibodies, antibiotics, antiviral therapy, and chest physiotherapy should not be used routinely in the management of bronchiolitis. The potential effect of hypertonic saline on the course of the acute disease is promising, but further studies are required. In critically ill children with bronchiolitis, today there is little justification for the use of surfactant and heliox. Nasal continuous positive airway pressure may be beneficial in children with severe bronchiolitis but a large trial is needed to determine its value. Finally, very little is known on the effect of the various interventions on the development of post-bronchiolitic wheeze.

Care of infants and children with bronchiolitis: a systematic review

Bronchiolitis is the most frequent cause of hospitalization in the infant population. Management varies widely, and the efficacy of many routinely implemented therapies is not supported by evidence. The purpose of the systematic review was to identify the best evidence available regarding the care of infants and children with bronchiolitis. A two-phase literature search was performed, and 20 publications were appraised. An abundance of evidence regarding management of bronchiolitis was revealed resulting in numerous recommendations. Use of a clinical pathway is proposed as a possible solution for moving this evidence into practice.

Progress in understanding and controlling respiratory syncytial virus: still crazy after all these years

Human respiratory syncytial virus (RSV) is a ubiquitous pathogen that infects everyone worldwide early in life and is a leading cause of severe lower respiratory tract disease in the pediatric population as well as in the elderly and in profoundly immunosuppressed individuals. RSV is an enveloped, nonsegmented negative-sense RNA virus that is classified in Family Paramyxoviridae and is one of its more complex members. Although the replicative cycle of RSV follows the general pattern of the Paramyxoviridae, it encodes additional proteins. Two of these (NS1 and NS2) inhibit the host type I and type III interferon (IFN) responses, among other functions, and another gene encodes two novel RNA synthesis factors (M2-1 and M2-2). The attachment (G) glycoprotein also exhibits unusual features, such as high sequence variability, extensive glycosylation, cytokine mimicry, and a shed form that helps the virus evade neutralizing antibodies. RSV is notable for being able to efficiently infect early in life, with the peak of hospitalization at 2-3 months of age. It also is notable for the ability to reinfect symptomatically throughout life without need for significant antigenic change, although immunity from prior infection reduces disease. It is widely thought that re-infection is due to an ability of RSV to inhibit or subvert the host immune response. Mechanisms of viral pathogenesis remain controversial. RSV is notable for a historic, tragic pediatric vaccine failure involving a formalin-inactivated virus preparation that was evaluated in the 1960s and that was poorly protective and paradoxically primed for enhanced RSV disease. RSV also is notable for the development of a successful strategy for passive immunoprophylaxis of high-risk infants using RSV-neutralizing antibodies. Vaccines and new antiviral drugs are in pre-clinical and clinical development, but controlling RSV remains a formidable challenge.

Viral bronchiolitis for the clinician

Viral bronchiolitis is common, and about 98-99% of infants are managed in the home. Because about 95% of infants < 2 years old are infected with respiratory syncytial virus, however, bronchiolitis is the commonest reason for admission to hospital in the first 6 months of life. It is usually a self-limiting condition lasting around a week in previously well children. About 1% of infants are admitted to hospital, and about 10% of hospitalised infants will require admission to the intensive care unit. Respiratory syncytial virus is isolated from about 70% of infants hospitalised with bronchiolitis. The emphasis of hospital treatment is to ensure adequate hydration and oxygenation. Other than supplemental oxygen, little in the way of pharmacological treatment has been demonstrated to alter the course of the illness or the risk of wheezing in the months following bronchiolitis.

Respiratory syncytial virus disease: update on treatment and prevention

Respiratory syncytial virus (RSV) is the leading cause of acute lower respiratory tract infections in infants and young children, accounting for more than 100,000 hospitalizations per year in the USA. The majority of hospitalizations occur in infants less than 1 year of age. Worldwide, RSV is associated with an annual mortality rate of 160,000-600,000 deaths. Premature infants, and infants with congenital heart disease, neuromuscular disease, structural airway abnormalities and immunodeficiencies are at increased risk for severe RSV disease. Despite the magnitude of RSV disease, treatment remains primarily supportive. Trials of bronchodilators, corticosteroids and montelukast have not demonstrated conclusive clinical benefit. The antiviral drug ribavirin has demonstrated only marginal clinical benefit and is not routinely indicated in treatment of RSV disease. Palivizumab is beneficial in prophylaxis for infants at high-risk for severe RSV infection although optimal indications based on cost-effectiveness considerations have not been defined. Future directions in treatment and prevention of RSV infections likely include the second-generation monoclonal antibody motavizumab, more potent antiviral compounds and more unique anti-inflammatory agents. Vaccination against RSV is in development but not eminent.

Arachidonate 5-lipoxygenase establishes adaptive humoral immunity by controlling primary B cells and their cognate T-cell help

In this study, we report the unique role of arachidonate 5-lipoxygenase (Alox5) in the regulation of specific humoral immune responses. We previously reported an L22 monoclonal antibody with which human primary resting B cells in the mantle zones of lymphoid follicles are well-defined. Proteomics analyses enabled identification of an L22 antigen as Alox5, which was highly expressed by naive and memory B cells surrounding germinal centers. Cellular growth of mantle cell lymphoma cells also seemed to depend on Alox5. Alox5(-/-) mice exhibited weak antibody responses specific to foreign antigens at the initial and recall phases. This was probably attributable to the low number of follicular and memory B cells and the functional loss of interleukin-21-mediated responses of follicular B cells. Moreover, Alox5(-/-) mice could not fully foster the development of follicular B helper T (Tfh) cells even after immunization with foreign antigens. Further experiments indicated that Alox5 affected mortality in experimentally induced enterocolitis in germ-prone circumstances, indicating that Alox5 would endow immunologic milieu. Our results illustrate the novel role of Alox5 in adaptive humoral immunity by managing primary B cells and Tfh cells in vivo.

Recent advances in antileukotriene therapy

PURPOSE OF REVIEW

Despite profound effects of leukotrienes in experimental models, clinical responses to antileukotriene drugs are highly heterogeneous. This review discusses recent advances concerning the molecular mechanisms of antileukotrienes as well as their efficacy in various clinical scenarios and patient groups.

RECENT FINDINGS

Appreciation of the role of leukotriene E4 and the existence of its distinct receptors may explain the limited efficacy of current leukotriene receptor antagonists. Pharmacogenetic studies highlight the influence of several leukotriene pathway genes on clinical responsiveness. Benefits of addition of antileukotrienes to inhaled corticosteroids in chronic adult asthmatics have been shown, but their role in acute asthma is unclear. Evidence suggests they are not a first-line treatment for allergic rhinitis or urticaria, but may provide useful additional therapy. In children antileukotrienes provide symptomatic benefit in preschool wheezers, but have no clear role in bronchiolitis or acute asthma. Adherence to montelukast appears superior to inhaled corticosteroids. Use in sleep-disordered breathing and eosinophilic gastroenteropathies warrants further investigation. Despite recent concerns thorough analysis of existing data suggests antileukotrienes are well tolerated drugs. The possible link with Churg-Strauss syndrome requires further investigation.

SUMMARY

The leukotriene pathway remains an attractive target in asthma and allergic disease, particularly in light of renewed appreciation of the role of leukotriene E4. Clarification of the clinical role of antileukotrienes is needed.

Montelukast in the treatment of asthma and beyond

Asthma is a chronic inflammatory disease affecting over 300 million people worldwide. The common association with allergic rhinitis and the presence of proinflammatory cells and mediators in the circulation of patients qualify asthma as a systemic disease. This characteristic and the fact that the gold-standard therapy for persistent asthma, inhaled corticosteroids, cannot suppress all components of airway inflammation and fail to adequately penetrate into the small airways, warrant the quest for effective systemic anti-asthma therapies. This review describes the most important controlled studies of montelukast, a once-daily leukotriene receptor antagonist, in asthma and allergic rhinitis in both adults and children. Montelukast is a systemically active drug with a targeted, dual mechanism of action, acting both as a bronchodilator and anti-inflammatory. In patients of all ages, montelukast has shown a favorable safety profile and was well-tolerated. Both as monotherapy or in combination with inhaled corticosteroids, montelukast produced clinically relevant improvements in asthma-related parameters, including symptoms, lung function parameters, quality of life and the number of asthma exacerbations. Furthermore, bronchoprotective effects have been reported both against specific and nonspecific bronchoactive stimuli. Similarly, in patients with allergic rhinitis, montelukast produced substantial improvements in symptoms and quality of life. Long-term studies aimed to determine its effects on airway remodeling are still lacking.

Pathology of small airways disease

CONTEXT

The term small airways disease encompasses a generally poorly understood group of lung diseases that may arise primarily within the small airways or secondarily from diseases primarily affecting the bronchi or lung parenchyma. Their histology may be confusing; however, because treatments and prognoses vary, correct pathologic diagnosis is important.

OBJECTIVE

To present a nonexhaustive review of the pathology of primary and secondary small airways diseases, including small airways disease related to tobacco; to various other exposures, including mineral dusts; to diseases involving other areas of the lung with secondary bronchiolar involvement; and to recently described bronchiolitic disorders.

DATA SOURCES

Current literature is reviewed.

CONCLUSIONS

Small airways diseases include a wide variety of diseases of which the pathologist must consider. Uncommon conditions such as diffuse idiopathic neuroendocrine cell hyperplasia and diffuse panbronchiolitis may show relatively specific diagnostic features histologically; however, most small airways diseases exhibit nonspecific histologic features. Conditions not considered primary pulmonary diseases, such as collagen vascular diseases, bone marrow transplantation, and inflammatory bowel disease, must also be considered in patients with small airways changes histologically. Clinical and radiologic correlation is important for obtaining the best possible diagnosis.

A randomized intervention of montelukast for post-bronchiolitis: effect on eosinophil degranulation

OBJECTIVE

To investigate the effect of montelukast on eosinophil degranulation and recurrent wheezing episodes in post-respiratory syncytial virus (RSV) bronchiolitis.

STUDY DESIGN

Two hundred infants (age, 6-24 months) who were hospitalized with their first episode of acute RSV bronchiolitis were randomized in a double-blind, placebo-controlled, parallel comparison of 4-mg montelukast granules (RSV-MONT group) or matching placebo (RSV-PLC group) administered for 3 months. Serum eosinophil-derived neurotoxin (EDN) levels were measured (primary outcome), and recurrent wheezing was documented (secondary outcome) for 12 months. Comparisons were made with control subjects (control group, n = 50).

RESULTS

At the end of the 3-month treatment period, the RSV-PLC group (n = 71) exhibited significantly elevated EDN levels (P < .0001), and the RSV-MONT group (n = 79) showed significantly decreased EDN levels (P < .01) when compared with the initial levels. As a result, EDN levels in the 2 RSV groups significantly differed at this point (P < .0001) and remained different for the entire 12-month follow-up period. Cumulative recurrent wheezing episodes at 12 months were significantly lower in the RSV-MONT group (P = .039).

CONCLUSION

Montelukast treatment reduces eosinophil degranulation and is associated with a decrease in recurrent wheezing episodes in post-RSV bronchiolitis.

Acute viral bronchiolitis in children- a very common condition with few therapeutic options

Acute viral bronchiolitis remains a cause of substantial morbidity and health care costs in young infants. It is the most common lower respiratory tract condition and most common reason for admission to hospital in infants. Many respiratory viruses have been associated with acute viral bronchiolitis although respiratory syncytial virus (RSV) remains the most frequently identified virus. Most infants have a mild self limiting illness while others have more severe illness and require hospital admission and some will need ventilatory support. Differences in innate immune function in response to the respiratory viral insult as well as differences in the geometry of the airways may explain some of the variability in clinical pattern. Young age and history of prematurity remain the most important risk factors although male gender, indigenous status, exposure to tobacco smoke, poor socioeconomic factors and associated co-morbidities such as chronic lung disease and congenital heart disease increase the risks of more severe illness. Supportive therapy remains the major treatment option as no specific treatments to date have been shown to provide clinically important benefits except for inhaled hypertonic saline. Prophylaxis of high risk infants with palivizumab should be considered although the cost effectiveness is still unclear. Many questions remain regarding optimal management approaches for infants requiring hospitalisation with bronchiolitis including use of nasogastric feeding, the optimal role of supplemental oxygen, optimal use of hypertonic saline and the role of combinations of therapies, the use of heliox or modern physiotherapy approaches.

Small Airways Disease

Small airways diseases are best defined pathologically as a diverse group of conditions that primarily involve bronchioles and acartilagenous airways 2 mm or less in diameter, which include membranous bronchioles, respiratory bronchioles, and alveolar ducts. Small airways can be involved with disease primarily or secondarily. The concept of small airways disease varies among specialties, with clinicians generally considering them in terms of terminal airway changes causing airflow obstruction, radiologists considering them in the context of direct signs and indirect signs identified on high-resolution computed tomography scans, and pathologists evaluating them based entirely or almost entirely on the histologic changes present in the bronchioles, with or without associated changes involving bronchi and alveoli. The histologic features of small airways diseases may be confusing because they overlap. There may be incomplete assessment of the histologic process with limited biopsy. Other disease processes may occur along with a small airways disease, and may obscure or confound its histologic features. This article focuses on the histologic changes diagnostic of a variety of primary and secondary small airways diseases. Because the histologic features involve bronchioles, gross findings are often minimal and/or nonspecific. The article provides a nonexhaustive examination of conditions and diseases involving the small airways, focusing on the microscopic features, with emphasis on the limitations of histologic diagnosis and differential diagnosis.

Bronchiolitis: recent evidence on diagnosis and management

Viral bronchiolitis is a leading cause of acute illness and hospitalization of young children. Research into the variation in treatment and outcomes for bronchiolitis across different settings has led to evidence-based clinical practice guidelines. Ongoing investigation continues to expand this body of evidence. Authors of recent surveillance studies have defined the presence of coinfections with multiple viruses in some cases of bronchiolitis. Underlying comorbidities and young age remain the most important predictors for severe bronchiolitis. Pulse oximetry plays an important role in driving use of health care resources. Evidence-based reviews have suggested a limited role for diagnostic laboratory or radiographic tests in typical cases of bronchiolitis. Several large, recent trials have revealed a lack of efficacy for routine use of either bronchodilators or corticosteroids for treatment of bronchiolitis. Preliminary evidence suggests a potential future role for a combination of these therapies and other novel treatments such as nebulized hypertonic saline.

Management of bronchiolitis

Bronchiolitis is the commonest cause of hospital admission in infancy. Severity varies from mild and self-limiting through to respiratory failure requiring intensive care and ventilation. Many viruses cause bronchiolitis, the commonest being respiratory syncytial virus (RSV). Supportive care is the mainstay of treatment, with emphasis on fluid replacement and oxygen therapy. Agents with evidence of no benefit in acute bronchiolitis include β₂ agonists, ipratropium, montelukast, corticosteroids, antiviral agents such as ribavirin or RSV immunoglobulin, physiotherapy, nebulized deoxyribonuclease or antibiotics. It is possible that nebulized epinephrine has a small short-term effect, and that nebulized 3% hypertonic saline administered with a bronchodilator may decrease length of stay in hospital. Preventative strategies such as RSV immunoglobulin or the anti-RSV monoclonal antibody palivizumab can decrease disease severity.