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Abstract Background Post-infectious bronchiolitis obliterans (PIBO) is the most common sequelae in children with adenovirus pneumonia (ADVP). However, there are few studies on the risk factors for PIBO occurrence. This study aims to investigate the risk factors for PIBO in pediatric patients with severe ADVP, especially after invasive mechanical ventilation (IMV), as well as to build a nomogram prediction model. Methods The clinical data, laboratory and imaging features, and treatment of 863 children with ADVP under 3 years old who were admitted to our hospital from January to December 2019 were retrospectively analyzed. Among them, 66 children with severe ADVP received IMV treatment. The situation and the influencing factors of PIBO in children with severe ADVP were explored, and a nomogram prediction model was constructed. Results Among the 863 cases of ADVP, 46 cases (5.33%) developed PIBO. Duration of fever, IMV, complications, and neutrophil percentage were independent risk factors for PIBO in children with ADVP. Among the 66 patients with ADVP who underwent IMV, 33 patients (50.0%) developed PIBO. Gender, duration of fever, adenovirus (ADV) load, and mixed fungal coinfections were independent risk factors for PIBO. In the nomogram prediction model analysis, the area under the curve (AUC) was 0.857; in addition, Hosmer‒Lemeshow (H–L) detection reflected good alignment (χ2 = 68.75, P

Hao-Qi Zheng,1 Yu-Cong Ma,1 Yu-Quan Chen,2 Yan-Yue Xu,1 Yan-Lin Pang,1 Li Liu1 1Department of Pediatrics, The First Hospital of Jilin University, Changchun, 130021, People’s Republic of China; 2Institute of Medical Information/Library, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100020, People’s Republic of ChinaCorrespondence: Li Liu, Department of Pediatrics, The First Hospital of Jilin University, Changchun, 130021, People’s Republic of China, Email lli01@jlu.edu.cnPurpose: Severe mycoplasma pneumoniae (MP) pneumonia can cause bronchiolitis obliterans (BO). In order to improve the prognosis of BO, it is necessary to grasp the clinical characteristics and risk factors of BO after severe MP pneumonia and intervene as soon as possible.Patients and Methods: This study retrospectively analyzed the clinical data of 110 patients with severe MP pneumonia, and divided them into BO group (22 cases) and non-BO group (88 cases). The clinical characteristics of BO group were analyzed, and the clinical data of two groups were compared to identify the risk factors of BO.Results: At the time of diagnosis, all BO patients had symptoms of cough and wheezing, and 10 (45.45%) had decreased exercise intolerance. Lung function showed moderate to severe obstructive ventilatory dysfunction, high-resolution computed tomography (HRCT) showed mosaic perfusion patterns. Multivariate binomial regression analysis showed that higher levels of serum lactate dehydrogenase (LDH) and hypoxemia were independent risk factors for BO after severe MP pneumonia.Conclusion: Higher levels of serum LDH and hypoxemia were independent risk factors for BO after severe MP pneumonia. For patients with risk factors, clinicians should regular follow-up for early diagnosis and intervention of BO.Keywords: children, bronchiolitis obliterans, mycoplasma pneumoniae pneumonia, post-infectious bronchiolitis obliterans, risk factors

Background: Post-infectious bronchiolitis obliterans (PIBO) is the most common sequelae in children with adenovirus pneumonia (ADVP). However, there are few studies on the risk factors for PIBO occurrence. This study aims to investigate the risk factors for PIBO in pediatric patients with severe ADVP, especially after invasive mechanical ventilation (IMV), as well as to build a nomogram prediction model. Methods: The clinical data, laboratory and imaging features, and treatment of 863 children with ADVP under 3 years old who were admitted to our hospital from January to December 2019 were retrospectively analyzed. Among them, 66 children with severe ADVP received IMV treatment. The situation and the influencing factors of PIBO in children with severe ADVP were explored, and a nomogram prediction model was constructed. Results: Among the 863 cases of ADVP, 46 cases (5.33%) developed PIBO. Duration of fever, IMV, complications, and neutrophil percentage were independent risk factors for PIBO in children with ADVP. Among the 66 patients with ADVP who underwent IMV, 33 patients (50.0%) developed PIBO. Gender, duration of fever, adenovirus (ADV) load, and mixed fungal coinfections were independent risk factors for PIBO. In the nomogram prediction model analysis, the area under the curve (AUC) was 0.857; in addition, Hosmer‒Lemeshow (H–L) detection reflected good alignment (χ2 = 68.75, P < 0.01). Conclusions: A nomogram prediction model, which can be utilized to predict PIBO occurrence in pediatric patients with ADVP after IMV at an early time period, was successfully built. [ABSTRACT FROM AUTHOR]

Owing to the rarity of post-infectious bronchiolitis obliterans (PIBO), pulmonary function in children with PIBO has been mainly investigated in small-sample sized studies. This systematic review and meta-analysis investigated pulmonary function in children with PIBO, regardless of age at respiratory insult and PIBO diagnosis. A systematic literature search revealed 16 studies reporting pulmonary function data in 480 children with PIBO. Levels of key pulmonary function parameters were summarized by pooled mean difference (MD) only in children with PIBO, and a random effect model was used. Pooled MDs (95% confidence interval [CI]) for FEV1, FVC, and FEF25–75% were 51.4, (44.2 to 58.5), 68.4 (64.4 to 72.3), and 26.5 (19.3 to 33.6) % predicted, respectively, with FEV1/FVC of 68.8% (62.2 to 75.4). Pooled MDs (95% CI) of the z-scores for FEV1, FVC, and FEF25–75% were −2.6 (−4.2 to −0.9), −1.9 (−3.2 to −0.5), and −2.0 (−3.6 to −0.4). Pooled MD (95% CI) for the diffusion capacity of the lungs for carbon monoxide from two studies was 64.9 (45.6 to 84.3) % predicted. The post-bronchodilator use change in the FEV1 in three studies was 6.1 (4.9 to 7.2). There was considerable heterogeneity across the studies. PIBO is associated with moderately impaired pulmonary function, and this review facilitates an understanding of PIBO pathophysiology in children. [ABSTRACT FROM AUTHOR]

Post-infectious bronchiolitis obliterans (PIBO), one of the major complications of respiratory tract infection, is commonly underdiagnosed. To identify the risk groups that may develop PIBO and avoid misdiagnoses, we investigated the risk factors associated with the development of PIBO. We searched PubMed, Embase, and MEDLINE databases for studies that included risk factors for the development of PIBO published from inception to 13 June 2022. We limited our search to studies that reported the estimates of odds ratio (OR), hazard ratio (HR), or relative risks for developing PIBO. A fixed-effect and a random-effect model were used. We included seven studies reporting data on the risk factors for PIBO in 344 children with PIBO and 1310 control children. Twenty-two variables, including sex, age, respiratory pathogens, symptoms, laboratory and radiologic findings, and mechanical ventilation, were mentioned in at least one study. The significant risk factors mentioned in two or more studies included elevated lactate dehydrogenase levels, pleural effusion, hypoxemia, sex, and mechanical ventilation. The significance of the duration of hospitalization and fever as risk factors for PIBO differed when the studies were classified according to the statistical method. In addition, the risk factors differed according to respiratory infection pathogens. This meta-analysis identified potential risk factors associated with the development of PIBO. The results of this study highlight the importance of avoiding misdiagnosis and help establish management strategies for patients at a high risk of developing PIBO. [ABSTRACT FROM AUTHOR]

BackgroundPost-infectious bronchiolitis obliterans (PIBO) is a long-term sequela after an initial insult to the lower respiratory tract. A comprehensive understanding of the factors that contribute to a high risk of developing PIBO is important to help define therapeutic strategies and improve prognosis.MethodsWe performed a systematic review of published literature available in the online databases including PubMed, Embase, Web of Science, CNKI, Wan Fang, and VIP, with the last search updated on 27 January 2022. Observational studies and case-control studies that provide sufficient data to examine associations between potential risk factors and PIBO were included. Pooled odds ratio (OR) or mean difference (MD) with 95% confidence interval (CI) and heterogeneity were calculated.ResultsA total of 14 risk factors were selected from 9 studies included in the analysis. The strongest risk factors were hypoxemia, mechanical ventilation, tachypnea, and wheezing. Hypoxemia conferred the greatest risk with pooled OR of 21.54 (95% CI: 10–46.36, p < 0.001). Mechanical ventilation ranked second (pooled OR 14.61, 95% CI: 7.53–28.35, p < 0.001). Use of γ-globulin, use of glucocorticoids, co-infection of bacteria, a history of wheezing, and being male were other prominent risk factors. The effects of premature birth, allergic rhinitis, and imaging finding (pulmonary consolidation, atelectasis, pleural effusion) are less clear and require further confirmation. Cases that developing PIBO had a lower age compared with controls (MD, −8.76 months, 95% CI: −16.50 to −1.02, p = 0.03). No significant differences were observed in the duration of fever (MD, 1.74 days, 95% CI: −0.07 to 3.54, p = 0.06). Children diagnosed with PIBO had higher LDH levels (MD, 264.69 U/L, 95% CI: 67.43 to 461.74, p = 0.008) and duration of hospitalization (MD, 4.50 days, 95% CI: 2.63 to 6.37, p < 0.001).ConclusionIn this study, we found that the strongest risk factors for PIBO were hypoxemia, mechanical ventilation, tachypnea, and wheezing. Use of glucocorticoids, γ-globulin, co-infection of bacteria, a history of wheezing, and being male may also play a role. The factors discussed above can inform the generation of a clinical prediction model for the developing PIBO in children.

BackgroundPost-infectious bronchiolitis obliterans (PIBO) is a rare and irreversible chronic obstructive pulmonary disease with no specific treatment, especially for patients with PIBO in remission. In this study, we evaluated the effects of continuous inhaled corticosteroids (ICSs) and intermittent ICSs on lung function in the remission of PIBO.MethodsThis was a retrospective study, and all the subjects we included were divided into continuous ICS group and intermittent ICS group according to treatment regimens. Patients in continuous ICS group received continuous ICSs (2 times a day), and patients in intermittent ICS group received intermittent ICSs (inhaled corticosteroids after acute respiratory tract infection or wheezing). Different lung function tests were performed at different ages. Tidal breathing lung function tests were performed in patients with PIBO aged ≤ 5 years, and the lung ventilation function test and the bronchial dilation test were performed in patients with PIBO aged more than 5 years. Lung function was assessed at the beginning of follow-up and at the end of follow-up (1 year of ICSs).ResultsAfter 1 year of ICSs, patients aged more than 5 years, forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV1) were significantly higher than at the beginning of follow-up. After 1 year of ICSs, the difference in VT/Kg, TPTEF/TE, and VPEF/VE between the end and the beginning of follow-up in continuous ICS group shows an upward trend. But those showed a downward trend in intermittent ICS group. FVC, FEV1, and maximal mid-expiratory flow velocity 25–75% (MMEF25–75%) of continuous ICS group were significantly higher than at the beginning of follow-up. The difference in FEV1 and MMEF25–75% between the end of follow-up and the beginning of follow-up in continuous ICS group was significantly higher than that in intermittent ICS group. A total of 52.94% of patients with PIBO aged more than 5 years were positive for bronchial dilation tests.ConclusionInhaled corticosteroids can effectively improve lung function and relieve airway obstruction in patients aged more than 5 years in PIBO remission, especially continuous ICSs. Patients with PIBO may have reversible airflow limitations.

Objectives: Post‐infectious bronchiolitis obliterans (PiBO) is a rare, chronic disease initiated by severe infection and followed by perpetuating inflammation and obliteration of the small airways. MicroRNAs (miRNAs) have been proposed to play a central role as epigenetic regulators, which control resolution and prevent the uncontrolled progress of inflammation. The aim of this study was to define biomarkers on the level of post‐transcriptional gene regulation in order to characterise PiBO. Methods: A total of 39 patients with well‐defined PiBO and 31 controls from two centres, Barcelona, Spain, and Frankfurt, Germany, were analysed by next‐generation sequencing (NGS). The evaluation of the biological targets of the miRNAs was performed by pathway enrichment analysis and protein–protein interaction network analysis respectively. Results: Patients with PiBO had significantly lower lung function values and increased airway inflammation in induced sputum as indicated by total cell counts, neutrophils, IL‐1β, IL‐6, IL‐8 and TGF‐β compared to controls. Next‐generation sequencing analysis revealed a total of 22 dysregulated miRNAs, which passed significance threshold for Padj ≤ 0.001 with 17 being upregulated and 5 being downregulated. Of these dysregulated miRNAs, miR‐335‐5p, miR‐186‐5p, miR‐30b‐5p and miR‐30c‐5p were further validated using qRT‐PCR. Interestingly, these miRNAs are functionally implicated in cytokine–cytokine receptor interaction, TGF‐β signalling and FoxO signalling pathway and significantly correlated with lung function values (FEV1). Conclusion: Our results demonstrate an aberrant miRNA expression profile in PiBO, which impacts pathways responsible for the regulation of inflammation and fibrosis. The defined miRNAs are useful biomarkers and should be assessed as potential target in the field of miRNA therapeutics. [ABSTRACT FROM AUTHOR]

Abstract Objectives Post‐infectious bronchiolitis obliterans (PiBO) is a rare, chronic disease initiated by severe infection and followed by perpetuating inflammation and obliteration of the small airways. MicroRNAs (miRNAs) have been proposed to play a central role as epigenetic regulators, which control resolution and prevent the uncontrolled progress of inflammation. The aim of this study was to define biomarkers on the level of post‐transcriptional gene regulation in order to characterise PiBO. Methods A total of 39 patients with well‐defined PiBO and 31 controls from two centres, Barcelona, Spain, and Frankfurt, Germany, were analysed by next‐generation sequencing (NGS). The evaluation of the biological targets of the miRNAs was performed by pathway enrichment analysis and protein–protein interaction network analysis respectively. Results Patients with PiBO had significantly lower lung function values and increased airway inflammation in induced sputum as indicated by total cell counts, neutrophils, IL‐1β, IL‐6, IL‐8 and TGF‐β compared to controls. Next‐generation sequencing analysis revealed a total of 22 dysregulated miRNAs, which passed significance threshold for Padj ≤ 0.001 with 17 being upregulated and 5 being downregulated. Of these dysregulated miRNAs, miR‐335‐5p, miR‐186‐5p, miR‐30b‐5p and miR‐30c‐5p were further validated using qRT‐PCR. Interestingly, these miRNAs are functionally implicated in cytokine–cytokine receptor interaction, TGF‐β signalling and FoxO signalling pathway and significantly correlated with lung function values (FEV1). Conclusion Our results demonstrate an aberrant miRNA expression profile in PiBO, which impacts pathways responsible for the regulation of inflammation and fibrosis. The defined miRNAs are useful biomarkers and should be assessed as potential target in the field of miRNA therapeutics.

Owing to the rarity of post-infectious bronchiolitis obliterans (PIBO), pulmonary function in children with PIBO has been mainly investigated in small-sample sized studies. This systematic review and meta-analysis investigated pulmonary function in children with PIBO, regardless of age at respiratory insult and PIBO diagnosis. A systematic literature search revealed 16 studies reporting pulmonary function data in 480 children with PIBO. Levels of key pulmonary function parameters were summarized by pooled mean difference (MD) only in children with PIBO, and a random effect model was used. Pooled MDs (95% confidence interval [CI]) for FEV1, FVC, and FEF25–75% were 51.4, (44.2 to 58.5), 68.4 (64.4 to 72.3), and 26.5 (19.3 to 33.6) % predicted, respectively, with FEV1/FVC of 68.8% (62.2 to 75.4). Pooled MDs (95% CI) of the z-scores for FEV1, FVC, and FEF25–75% were −2.6 (−4.2 to −0.9), −1.9 (−3.2 to −0.5), and −2.0 (−3.6 to −0.4). Pooled MD (95% CI) for the diffusion capacity of the lungs for carbon monoxide from two studies was 64.9 (45.6 to 84.3) % predicted. The post-bronchodilator use change in the FEV1 in three studies was 6.1 (4.9 to 7.2). There was considerable heterogeneity across the studies. PIBO is associated with moderately impaired pulmonary function, and this review facilitates an understanding of PIBO pathophysiology in children.

Background: Jilin Province, located in northeastern China, recently experienced a human adenovirus (HAdV) epidemic. Few studies involving hospitalized pediatric patients with pneumonia caused by HAdV in our region exist. HAdV pneumonia can lead to severe long-term respiratory sequelae, such as post-infectious bronchiolitis obliterans (PIBO), which has a poor prognosis and greatly influences the quality of life of pediatric patients. However, studies on the risk factors for PIBO are limited.Objective: To describe the HAdV pneumonia prevalence and determine potential risk factors for PIBO development among hospitalized children in Jilin Province, China.Methods: The data of 187 children with HAdV pneumonia (10 months−12 years old) admitted to the First Hospital of Jilin University during an outbreak between October 2018 and January 2020 were retrospectively studied. We analyzed the epidemiological characteristics of HAdV pneumonia, focusing on severe HAdV pneumonia (66 cases). The risk factors for BO development were determined by comparing the demographic and clinical data of the BO and non-BO groups.Results: The largest number of HAdV pneumonia cases occurred in January 2019 (severe n = 18, general n = 21), followed by December 2018 (severe n = 14, general n = 11), June 2019 (general n = 17), July 2019 (general, n = 14), and May 2019 (general, n = 13). In total, 91.98% of the children with HAdV pneumonia were

Post-infectious bronchiolitis obliterans (PIBO), one of the major complications of respiratory tract infection, is commonly underdiagnosed. To identify the risk groups that may develop PIBO and avoid misdiagnoses, we investigated the risk factors associated with the development of PIBO. We searched PubMed, Embase, and MEDLINE databases for studies that included risk factors for the development of PIBO published from inception to 13 June 2022. We limited our search to studies that reported the estimates of odds ratio (OR), hazard ratio (HR), or relative risks for developing PIBO. A fixed-effect and a random-effect model were used. We included seven studies reporting data on the risk factors for PIBO in 344 children with PIBO and 1310 control children. Twenty-two variables, including sex, age, respiratory pathogens, symptoms, laboratory and radiologic findings, and mechanical ventilation, were mentioned in at least one study. The significant risk factors mentioned in two or more studies included elevated lactate dehydrogenase levels, pleural effusion, hypoxemia, sex, and mechanical ventilation. The significance of the duration of hospitalization and fever as risk factors for PIBO differed when the studies were classified according to the statistical method. In addition, the risk factors differed according to respiratory infection pathogens. This meta-analysis identified potential risk factors associated with the development of PIBO. The results of this study highlight the importance of avoiding misdiagnosis and help establish management strategies for patients at a high risk of developing PIBO.

Background: Pulmonary neutrophils may play a crucial role in the development of bronchiolitis obliterans (BO) following measles virus infection. IL-27 could potentially have a negative regulatory effect on the release of reactive oxygen species and cytotoxic granules in neutrophils., Objective: To investigate the levels of IL-27 in the bronchoalveolar lavage fluid (BALF) of children with post-infectious bronchiolitis obliterans (PIBO) and analyze the relationship between IL-27 levels and neutrophil proportions., Methods: A total of 24 children with PIBO were recruited for the experimental group, while 23 children with bronchial foreign bodies were included in the control group. Bronchoscopic alveolar lavage was performed in both groups. The levels of IL-27 in BALF were measured using enzyme-linked immunosorbent assay (ELISA). The proportions of neutrophils in BALF were determined by smear staining. The relationship between the levels of IL-27 in BALF and the neutrophil proportions was analyzed by the Pearson test., Results: The levels of IL-27 in BALF were significantly lower in children with PIBO compared to children with bronchial foreign bodies (p<0.05). Additionally, the proportions of neutrophils in BALF were significantly higher in children with PIBO compared to children with bronchial foreign bodies (p<0.05). The levels of IL-27 were negatively correlated with the neutrophil proportions in BALF in children with PIBO (p<0.05), but not in children with bronchial foreign bodies (p>0.05)., Conclusion: The present study suggests that a decrease in IL-27 may be associated with an increase in neutrophils in BALF and may contribute to the pathogenesis of PIBO.

Optimal treatment options for post-infectious bronchiolitis obliterans (PIBO) have not yet been established. The present study retrospectively analyzed the effect of budesonide, montelukast and azithromycin on treating PIBO in children <5 years old.. Based on treatment regimen, the cohort was divided into group A and group B. Group A received a combination of budesonide, montelukast and azithromycin for at least 3 months and group B received unconventional treatment (budesonide for nebulization intermittently, prednisone, montelukast and antibiotics if necessary) compared with standard treatment. Tidal pulmonary function and symptoms assessment were performed at diagnosis and after 3 months of therapy. There were no significant differences in the sex, age, pulmonary function and symptoms assessment between groups A and B at diagnosis. However, following 3 months of treatment, the time to peak tidal expiratory flow as a proportion of expiratory time, and volume to peak expiratory flow as a proportion of exhaled volume in group A were significantly higher compared with those in group B. The respiratory rate in group A was significantly lower compared with group B. The symptoms assessment score in group A was significantly higher compared with that of group B. In conclusion, the present study demonstrates that combination therapy with budesonide, montelukast and azithromycin improves pulmonary function and respiratory symptoms in PIBO children <5 years old. The present study was retrospectively registered on March 22, 2020 with register no. YY202003-008-HB03. [ABSTRACT FROM AUTHOR]

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The aim of the present study was to outline any predisposing factors and clinical and radiological features of post-infectious bronchiolitis obliterans (PIBO) in pediatric patients, and to determine the effect of long-term azithromycin treatment on these factors. In total, 16 cases of children with PIBO were retrospectively reviewed. Adenovirus and Mycoplasma pneumoniae were the most common etiological agents (12/16) in the children with PIBO. The patients presented with persistent dyspnea, a chronic cough, sputum production and wheezing following the initial lung infection. Chest X-rays indicated pulmonary overinflation and patchy ground-glass opacity. In addition, high-resolution computed tomography (HRCT) scans revealed patchy ground-glass opacity, bronchiectasis, bronchial wall thickening and mosaic perfusion in all 16 cases. A unilateral hyperlucent lung was observed in two cases. All the patients underwent treatment with low-dose azithromycin and prednisone. Follow-up examinations of the 16 cases, varying in duration between 7 and 31 months, showed that the disease condition had improved in 10 cases. However, no significant improvements were identified from the HRCT scans or were observed in the patient condition in the additional six cases. The diagnosis of BO is primarily based on a typical clinical presentation and HRCT observations. Therefore, a typical clinical history and patchy ground-glass opacity features on HRCT scans are screening indices that predict BO development. Steroids are the cornerstone of BO treatment; however, long-term azithromycin treatment can improve the condition of the patients. In summary, PIBO is a disease with a high morbidity rate and should be treated by a multidisciplinary team. Patients should receive follow-up examination for an extended period. Patchy ground-glass opacity features on HRCT scans indicate that clinical suspicion of BO is necessary in children with persistent and severe wheezing. [ABSTRACT FROM AUTHOR]

Background: Post-infectious bronchiolitis obliterans (PIBO) is a rare and irreversible chronic obstructive pulmonary disease with no specific treatment, especially for patients with PIBO in remission. In this study, we evaluated the effects of continuous inhaled corticosteroids (ICSs) and intermittent ICSs on lung function in the remission of PIBO., Methods: This was a retrospective study, and all the subjects we included were divided into continuous ICS group and intermittent ICS group according to treatment regimens. Patients in continuous ICS group received continuous ICSs (2 times a day), and patients in intermittent ICS group received intermittent ICSs (inhaled corticosteroids after acute respiratory tract infection or wheezing). Different lung function tests were performed at different ages. Tidal breathing lung function tests were performed in patients with PIBO aged ≤ 5 years, and the lung ventilation function test and the bronchial dilation test were performed in patients with PIBO aged more than 5 years. Lung function was assessed at the beginning of follow-up and at the end of follow-up (1 year of ICSs)., Results: After 1 year of ICSs, patients aged more than 5 years, forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV 1 ) were significantly higher than at the beginning of follow-up. After 1 year of ICSs, the difference in V T /Kg, TPTEF/TE, and VPEF/VE between the end and the beginning of follow-up in continuous ICS group shows an upward trend. But those showed a downward trend in intermittent ICS group. FVC, FEV 1 , and maximal mid-expiratory flow velocity 25-75% (MMEF 25-75% ) of continuous ICS group were significantly higher than at the beginning of follow-up. The difference in FEV 1 and MMEF 25-75% between the end of follow-up and the beginning of follow-up in continuous ICS group was significantly higher than that in intermittent ICS group. A total of 52.94% of patients with PIBO aged more than 5 years were positive for bronchial dilation tests., Conclusion: Inhaled corticosteroids can effectively improve lung function and relieve airway obstruction in patients aged more than 5 years in PIBO remission, especially continuous ICSs. Patients with PIBO may have reversible airflow limitations., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zheng, Yu, Chen, Lin and Liu.)

Background: Jilin Province, located in northeastern China, recently experienced a human adenovirus (HAdV) epidemic. Few studies involving hospitalized pediatric patients with pneumonia caused by HAdV in our region exist. HAdV pneumonia can lead to severe long-term respiratory sequelae, such as post-infectious bronchiolitis obliterans (PIBO), which has a poor prognosis and greatly influences the quality of life of pediatric patients. However, studies on the risk factors for PIBO are limited. Objective: To describe the HAdV pneumonia prevalence and determine potential risk factors for PIBO development among hospitalized children in Jilin Province, China. Methods: The data of 187 children with HAdV pneumonia (10 months-12 years old) admitted to the First Hospital of Jilin University during an outbreak between October 2018 and January 2020 were retrospectively studied. We analyzed the epidemiological characteristics of HAdV pneumonia, focusing on severe HAdV pneumonia (66 cases). The risk factors for BO development were determined by comparing the demographic and clinical data of the BO and non-BO groups. Results: The largest number of HAdV pneumonia cases occurred in January 2019 (severe n = 18, general n = 21), followed by December 2018 (severe n = 14, general n = 11), June 2019 (general n = 17), July 2019 (general, n = 14), and May 2019 (general, n = 13). In total, 91.98% of the children with HAdV pneumonia were <6 years old (172/187), and 50% of the pediatric patients with severe HAdV pneumonia were <2 years old (33/66). We found that 30.3% of the severe cohort developed BO (20/66), and the strongest independent risk factors for PIBO were persistent wheezing (OR 181.776, 95% CI, 3.385-9,761.543) and acute respiratory failure (OR 51.288, 95% CI, 1.858-1,415.441) during a severe pneumonia episode. Conclusions: The largest number of HAdV pneumonia cases, especially severe cases, occurred in winter in Northeast China, followed by summer. The majority of children admitted with HAdV pneumonia were <6 years old, and half of severe HAdV pneumonia patients were <2 years old. Children who had persistent wheezing or acute respiratory failure during the acute phase of severe HAdV pneumonia were prone to the development of BO., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Yu, Ma, Gao and You.)

Background: Bronchiolitis obliterans (BO), first mentioned in 1901, is a severe and rare chronic lung disease in children. BO has various etiologies and the most common in children is post-infectious BO (PIBO). High resolution CT (HRCT) is an often-used image tool for the diagnosis of BO, and pulmonary scintigraphy is an alternative tool that can functionally evaluate BO. Recently, dual-energy computed tomography (DECT) have also been applied to BO for its accuracy and safety. Here we described the characteristics of HRCT, pulmonary scintigraphy, DECT, and the clinical profiles of patients with PIBO. Methods: This is a retrospective and descriptive study. Data were collected from patients diagnosed with PIBO from 2014 to 2019 in the Pediatric Cardiopulmonary Outpatient Clinics of Kaohsiung Medical University Hospital. The diagnosis was based on clinical, chest X-ray, and HRCT findings. Clinical profile, radiological characteristics, and images of pulmonary scintigraphy were documented. Results: Eight children (4 boys and 4 girls) were diagnosed with PIBO at a mean age of 25.8 months (range 15 to 41 months). Two of our patients developed pulmonary hypertension. The most common HRCT finding is mosaic pattern, where match ventilation/perfusion (V/Q) defects is a general feature in pulmonary scintigraphy. DECT pulmonary blood vasculature images revealed various degrees of decreased perfusion and is compatible with the decreased perfusion on pulmonary scintigraphy. Conclusion: The therapeutic strategy of PIBO is still lacking of standardization. HRCT and V/Q scans are important image tools in diagnosis and follow-up of BO. DECT may be used in BO patients as it has no additional radiation exposure and add value on functional information of HRCT., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2020 Chen, Hsu, Chen, Liu, Wu, Hsu, Cheng and Dai.)

Background: The prevalence of macrolide-resistant Mycoplasma pneumoniae (MP) pneumonia has been rapidly increased. MP pneumonia is a risk factor for the development of post-infectious bronchiolitis obliterans (PIBO). The aim of the present study was to identify the risk factors for the development of PIBO after MP pneumonia in the era of increasing macrolide resistance of MP., Materials and Methods: This retrospective study enrolled 150 children with a mean age of 6.0 years admitted to the hospital due to MP pneumonia between May 2019 and February 2020 at a tertiary hospital. The clinical, radiologic, and laboratory data were obtained using retrospective chart review., Results: Eighteen children (12%) were diagnosed with PIBO after MP pneumonia. PIBO was diagnosed after a mean duration of 100.0 days (range, 6-268 days) from symptom onset. The respiratory virus co-infection (adjusted odds ratio [aOR], 4.069; 95% confidence interval [95% CI], 1.224-13.523), adenovirus co-infection (aOR, 5.607; 95% CI, 1.801-17.454), longer duration between symptom onset and admission (aOR, 1.150; 95% CI, 1.020-1.298), higher levels of serum lactate dehydrogenase (LDH) at the time of admission (aOR, 1.001; 95% CI, 1.000-1.003), and poor response to stepwise treatment increased the risk for development of PIBO after MP pneumonia. However, macrolide resistance of MP was not associated with development of PIBO after MP pneumonia., Conclusion: The present study suggests that respiratory virus co-infection, including adenovirus, poor response to the treatment of MP pneumonia, and higher levels of serum LDH, but not macrolide resistance of MP, are risk factors of PIBO after MP pneumonia., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The aim of the present study was to outline any predisposing factors and clinical and radiological features of post-infectious bronchiolitis obliterans (PIBO) in pediatric patients, and to determine the effect of long-term azithromycin treatment on these factors. In total, 16 cases of children with PIBO were retrospectively reviewed. Adenovirus and Mycoplasma pneumoniae were the most common etiological agents (12/16) in the children with PIBO. The patients presented with persistent dyspnea, a chronic cough, sputum production and wheezing following the initial lung infection. Chest X-rays indicated pulmonary overinflation and patchy ground-glass opacity. In addition, high-resolution computed tomography (HRCT) scans revealed patchy ground-glass opacity, bronchiectasis, bronchial wall thickening and mosaic perfusion in all 16 cases. A unilateral hyperlucent lung was observed in two cases. All the patients underwent treatment with low-dose azithromycin and prednisone. Follow-up examinations of the 16 cases, varying in duration between 7 and 31 months, showed that the disease condition had improved in 10 cases. However, no significant improvements were identified from the HRCT scans or were observed in the patient condition in the additional six cases. The diagnosis of BO is primarily based on a typical clinical presentation and HRCT observations. Therefore, a typical clinical history and patchy ground-glass opacity features on HRCT scans are screening indices that predict BO development. Steroids are the cornerstone of BO treatment; however, long-term azithromycin treatment can improve the condition of the patients. In summary, PIBO is a disease with a high morbidity rate and should be treated by a multidisciplinary team. Patients should receive follow-up examination for an extended period. Patchy ground-glass opacity features on HRCT scans indicate that clinical suspicion of BO is necessary in children with persistent and severe wheezing.