Explore the vast range of titles available.

This review on bronchiolitis in young children considers the viruses involved, the current understanding of pathogenesis, host genetic factors and the environment, and the role of season, race, and sex on attack rates and subsequent episodes of wheezing. Few diseases have a greater effect on the health of young children than viral lower respiratory tract illness. Approximately 800,000 children in the United States, or approximately 20% of the annual birth cohort, require outpatient medical attention during the first year of life because of illness caused by respiratory syncytial virus (RSV). 1 Between 2% and 3% of all children younger than 12 months of age are hospitalized with a diagnosis of bronchiolitis, which accounts for between 57,000 and 172,000 hospitalizations annually. 1 – 4 Estimated nationwide hospital charges for care related to bronchiolitis in children younger than 2 years of age exceeded . . .

Viral bronchiolitis is a common clinical syndrome affecting infants and young children. Concern about its associated morbidity and cost has led to a large body of research that has been summarised in systematic reviews and integrated into clinical practice guidelines in several countries. The evidence and guideline recommendations consistently support a clinical diagnosis with the limited role for diagnostic testing for children presenting with the typical clinical syndrome of viral upper respiratory infection progressing to the lower respiratory tract. Management is largely supportive, focusing on maintaining oxygenation and hydration of the patient. Evidence suggests no benefit from bronchodilator or corticosteroid use in infants with a first episode of bronchiolitis. Evidence for other treatments such as hypertonic saline is evolving but not clearly defined yet. For infants with severe disease, the insufficient available data suggest a role for high-flow nasal cannula and continuous positive airway pressure use in a monitored setting to prevent respiratory failure.

Respiratory syncytial virus is a leading cause of bronchiolitis. In a prospective, multicenter, matched case–control study involving infants in France, nirsevimab decreased RSV-associated hospitalization by 83%.

Although electronic cigarettes (e-cigarettes) were initially marketed as a potential smoking-cessation aid and a safer alternative to smoking, the long-term health effect of e-cigarette use (“vaping”) is unknown. Vaping e-liquids expose the user to several potentially harmful chemicals, including diacetyl, a flavouring compound known to cause bronchiolitis obliterans with inhalational exposure (“popcorn worker’s lung”). We report the case of a 17-year-old male who presented with intractable cough, progressive dyspnea and malaise after vaping flavoured e-liquids and tetrahydrocannabinol intensively. Initial physical examination showed fever, tachycardia, hypoxemia, and bibasilar inspiratory crackles on lung auscultation. Computed tomography of the chest showed diffuse centrilobular “tree-inbud” nodularity, consistent with acute bronchiolitis. Multiple cultures, including from 2 bronchoalveolar lavage samples, and biopsy stains, were negative for infection. He required intubation, invasive mechanical ventilation and venovenous extracorporeal membrane oxygenation (ECMO) for refractory hypercapnia. The patient’s condition improved with high-dose corticosteroids. He was weaned off ECMO and mechanical ventilation, and discharged home after 47 days in hospital. Several months after hospital discharge, his exercise tolerance remained limited and pulmonary function tests showed persistent, fixed airflow obstruction with gas trapping. The patient’s clinical picture was suggestive of possible bronchiolitis obliterans, thought to be secondary to inhalation of flavouring agents in the e-liquids, although the exact mechanism of injury and causative agent are unknown. This case of severe acute bronchiolitis, causing near-fatal hypercapnic respiratory failure and chronic airflow obstruction in a previously healthy Canadian youth, may represent vaping-associated bronchiolitis obliterans. This novel pattern of pulmonary disease associated with vaping appears distinct from the type of alveolar injury predominantly reported in the recent outbreak of cases of vaping-associated pulmonary illness in the United States, underscoring the need for further research into all potentially toxic components of e-liquids and tighter regulation of e-cigarettes.

In September 2023, France was one of the first countries that started a national immunisation campaign with nirsevimab, a new monoclonal antibody against respiratory syncytial virus (RSV). Using data from a network of paediatric intensive care units (PICUs), we aimed to estimate nirsevimab effectiveness against severe cases of RSV bronchiolitis in France. We conducted a case–control study based on the test‐negative design and included 288 infants reported by 20 PICUs. We estimated nirsevimab effectiveness at 75.9% (48.5–88.7) in the main analysis and 80.6% (61.6–90.3) and 80.4% (61.7–89.9) in two sensitivity analyses. These real‐world estimates confirmed the efficacy observed in clinical studies.

Respiratory syncytial virus (RSV) causes most of the cases of bronchiolitis and thousands of deaths annually, particularly in infants less than 6 months old. In Catalonia (Spain), infants born between April 2023 and March 2024 aged 0–6 months during their first RSV season have been candidates to receive nirsevimab, the novel monoclonal antibody against RSV, since October 2023. We aimed to analyse the dynamics of all-causes bronchiolitis diagnoses and RSV community infections in the current season and compare them to pre-nirsevimab epidemics. We collected epidemiological data from the Information System for Surveillance of Infections in Catalonia (SIVIC) on daily all-causes bronchiolitis clinical diagnoses and RSV-confirmed cases provided by rapid antigen tests in primary care practices. We calculated the rate ratio (RR) for the incidence of all-causes bronchiolitis for children aged 0-11 m-old with respect to 12-35 m-old between September 2014 and January 2024. We analysed the RR of the incidence of RSV-confirmed infection for 0-11 m-old and 12-35 m-old with respect to the > 35 m-old, from January 2021 to January 2024. We then computed the relative difference of the RR, designated as percentage of reduction of risk, between season 2023/2024 and former epidemics. With a global coverage recorded rate for nirsevimab of 82.2% in January 2024, the age-specific 0-11 m-old RR (95% CI) of RSV infection incidence for > 35 m-old was 1.7 (1.5–2.0) in season 2023/2024. The RR (95% CI) had been 7.4 (5.6–9.9), 8.8 (6.9–11.3), and 7.1 (5.7–8.9) in 2020/2021, 2021/2022, and 2022/2023, respectively. Regarding the incidence of all-causes bronchiolitis for the 0-11 m-old group compared to the 12-35 m-old, the pre-pandemic (2014/2015–2019/2020) and 2022/2023 RR (95% CI) were 9.4 (9.2–9.6) and 6.0 (5.7–6.2), respectively, significantly higher than the RR of 3.6 (3.4–3.8) for the most recent season, 2023/2024. Conclusion : Concurring with the introduction of nirsevimab, the risk of RSV infection for infants aged 0-11 m-old compared to > 35 m-old has been reduced by 75.6% (73.4–77.5) in last season, and the risk for all-causes bronchiolitis for 12-35 m-old by 61.9% (60.9–62.9) from the pre-pandemic period and by 39.8% (39.3–40.2) from the 2022/2023 epidemic, despite high RSV community transmission, especially in older infants What is Known: • RSV is responsible for approximately 70% of bronchiolitis cases and causes severe disease, particularly in infants < 6 months of age. • Nirsevimab effectiveness against RSV-associated disease, particularly hospitalisations, was expected to be around 80%; other Spanish regions, such as Galicia and Valencia, and European countries including Luxembourg and Germany, have already reported good results in implementing nirsevimab to prevent RSV-associated hospitalisations and PICU stays. What is New: • We provide insight into the community incidence of RSV and all-causes bronchiolitis for season 2023/2024, when nirsevimab has been introduced to the Catalan population, using.   primary healthcare data, which enabled us to assess the burden of RSV infections and bronchiolitis in the commonly seasonally saturated primary healthcare practices. • Our study reveals that the risk of all-causes bronchiolitis for infants aged 0-11 m-old compared to older infants was reduced by 40% compared to the previous season and 62% compared to pre-pandemic standards, and for RSV infection it was reduced by 76%.

Mycoplasma pneumoniae (MP) bronchiolitis can potentially lead to severe respiratory symptoms and long-term complications. This study aimed to determine the risk factors for the development of hypoxemia in MP bronchiolitis and report its prognosis. From January 2017 to December 2024, a total of 178 children with MP bronchiolitis, including 53 cases in the hypoxemia group and 125 cases in the control group, were selected. The clinical data, laboratory indicators, and imaging findings of the two groups were compared. Binary logistic regression analysis was used to identify the risk factors for the development of hypoxemia, and the receiver operating characteristic curve was employed to validate the predictive effect of the risk factors on hypoxemia. The hypoxemia group exhibited a higher incidence of a history of allergic diseases and wheezing sounds, accompanied by substantial elevations in C-reactive protein levels and greater areas of CT involvement (P < 0.05). The presence of a history of allergic diseases, wheezing sounds, and the number of infected lung lobes were independent risk factors for the development of hypoxemia. The group with hypoxemia demonstrated a delayed improvement in symptoms, signs and lung function during follow-up (P < 0.05). Seven cases of bronchiolitis obliterans were diagnosed in the hypoxemia group while none in the control group. MP bronchiolitis patients with a history of allergic diseases, wheezing sounds, and involvement of at least three lung lobes are prone to developing hypoxemia. And those who experience hypoxemia recover more slowly during short-term follow-up and have a higher incidence of bronchiolitis obliterans.

First recognized as an occupational disorder, obliterative bronchiolitis is now the primary noninfectious pulmonary complication of allogeneic hematopoietic stem-cell transplantation and lung transplantation. This review includes an update on recognition, treatment, and prevention. The term “bronchiolitis obliterans” was historically used by pathologists to refer to two distinct patterns of small-airway disease. The first was characterized by intraluminal polyps in the small airways. It was subsequently named bronchiolitis obliterans with organizing pneumonia and, more recently, cryptogenic organizing pneumonia. The second pattern was characterized by subepithelial inflammatory and fibrotic narrowing of the bronchioles, which is now recognized as obliterative bronchiolitis or constrictive bronchiolitis. 1 , 2 To add to the confusion, physicians may use the term “bronchiolitis obliterans syndrome” to denote the occurrence of an obstructive ventilatory defect that occurs after transplantation (Table 1), particularly in patients . . .

Emerging evidence suggests relationships between the nasopharyngeal metabolome and both the microbiota and severity of bronchiolitis. However, the influence of host systemic metabolism on disease pathobiology remains unclear. We aimed to examine metabolome profiles and their association with more-severe disease, defined by use of positive pressure ventilation (PPV), in infants hospitalized for bronchiolitis. In 140 infants with bronchiolitis, metabolomic profiling was performed on serum; samples from 70 were in a training data set, and samples from 70 were in an independent test data set. We also profiled the nasopharyngeal airway microbiota and examined its association with the serum metabolites. Serum metabolome profiles differed by bronchiolitis severity (P < .001). In total, 20 metabolites in the training data set were significantly associated with the risk of PPV, of which 18 remained significant following adjustment for confounders (false-discovery rate [FDR], < 0.10). Phosphatidylcholine metabolites were associated with higher risks of PPV use, while metabolites from the plasmalogen subpathway were associated with lower risks. The test data set validated these findings (FDR < 0.05). Streptococcus abundance was positively associated with metabolites that are associated with higher risks of PPV. Serum metabolomic signatures were associated with both the nasopharyngeal microbiota and the severity of bronchiolitis. Our findings advance research into the complex interrelations between the airway microbiome, host systemic response, and pathobiology of bronchiolitis.

Viral bronchiolitis is the most common cause of admission to hospital for infants in high-income countries. Respiratory syncytial virus accounts for 60–80% of bronchiolitis presentations. Bronchiolitis is diagnosed clinically without the need for viral testing. Management recommendations, based predominantly on high-quality evidence, advise clinicians to support hydration and oxygenation only. Evidence suggests no benefit with use of glucocorticoids or bronchodilators, with further evidence required to support use of hypertonic saline in bronchiolitis. Evidence is scarce in the intensive care unit. Evidence suggests use of high-flow therapy in bronchiolitis is limited to rescue therapy after failure of standard subnasal oxygen only in infants who are hypoxic and does not decrease rates of intensive care unit admission or intubation. Despite systematic reviews and international clinical practice guidelines promoting supportive rather than interventional therapy, universal de-implementation of interventional care in bronchiolitis has not occurred and remains a major challenge.