Clinical features of post-infectious bronchiolitis obliterans in children undergoing long-term azithromycin treatment

Update in postinfectious bronchiolitis obliterans

Postinfectious bronchiolitis obliterans (PiBO) is a rare and severe form of chronic obstructive lung disease caused by an infectious injury to the lower respiratory tract. The most commonly recognized inciting stimuli leading to PiBO are airway pathogens, such as adenovirus and Mycoplasma. PiBO is characterized by persistent and nonreversible airway obstruction, with functional and radiological evidence of small airway involvement. The literature has limited information on the aetiology, clinical profile, treatment, and outcome of PiBO.

Correlation of DNA load, genotyping, and clinical phenotype of Mycoplasma pneumoniae infection in children

Introduction

This study aimed to investigate the correlation between Mycoplasma pneumoniae (MP)-DNA load in the bronchoalveolar lavage fluid (BALF) of children with MP pneumonia (MPP) and its subtypes, relevant laboratory data, imaging, extrapulmonary complications in infected children, and its clinical significance in evaluating the disease.

Methods

Children hospitalized with MPP at Tianjin Children's Hospital between December 2017 and December 2020 were selected for the study, excluding those with mixed viral, bacterial, and fungal infections. Children were divided into low- and high-load groups according to the MP DNA load in BALF using real-time quantitative fluorescence polymerase chain reaction (PCR). After a successful MP culture, positive specimens were subjected to PCR-Restriction fragment length polymorphism and Multiple-locus variable number tandem repeat analysis typing. Basic data, clinical information, laboratory data, and radiological results were collected from all children included in the study.

Results

The PI-I type dominated the different load groups. Children in the low-load group had more wheezing and shortness of breath; however, children in the high-load group had a higher length of hospitalization, maximum fever temperature, higher chills/chilliness, incidence of abdominal pain, and higher C-reactive protein (CRP), procalcitonin (PCT) and aspartate aminotransferase (AST) levels. Children in the high-load group were more likely to have imaging changes such as pleural effusion, and the incidence of respiratory infections and extrapulmonary complications was higher than that of those in the low-load group. We applied Spearman's correlation analysis to clarify the relationship between MP DNA load and the clinical severity of MPP. We found that MP DNA load was positively correlated with length of hospitalization, maximum fever temperature, CRP, PCT, Interleukin-6 (IL-6), and AST levels, and negatively correlated with fever and cough durations, white blood cell count (WBC), and proportion of monocytes (MONO). The degree of correlation was as follows: length of hospitalization > IL-6 > cough duration > AST > fever duration > PCT > WBC > proportion of MONO > maximum fever temperature > CRP levels.

Conclusions

MP DNA load was not correlated with MP typing but was significantly correlated with the children's clinical phenotype. Therefore, the MP DNA load helps in the early diagnosis of infection and can better predict disease regression.

Artificial Intelligence Algorithm-Based High-Resolution Computed Tomography Image in the Treatment of Children with Bronchiolitis Obliterans by Traditional Chinese Medicine Method of Resolving Phlegm and Removing Blood Stasis

This research was aimed to explore the application of high-resolution computed tomography (HRCT) based on intelligent iterative reconstruction technique in the early diagnosis and treatment of bronchiolitis obliterans (BO) in children and to explore the efficacy of traditional Chinese medicine (TCM) in resolving phlegm and removing blood stasis. Sixty pediatric patients with BO were selected as the study subjects and diagnosed by HRCT scanning, and the scanned images were processed by iterative reconstruction technique. The patients were treated with TCM therapy of resolving phlegm and removing blood stasis alone (group A), HRCT-guided TCM therapy of resolving phlegm and removing blood stasis (group B), and iterative reconstruction HRCT-guided TCM therapy of resolving phlegm and removing blood stasis (group C). The results showed that the lung HRCT image after iterative reconstruction was closer to the original image than that after filtered back projection reconstruction, and the edge of the image after filtered back projection reconstruction was more blurred and the noise was higher. The image obtained by iterative reconstruction technique was smoother and clearer, and the image stability after iterative reconstruction was higher. The treatment results showed that the proportion of moderate and severe obstruction in group C was 5.18%, which was significantly lower than that in group A (18.75%) and group B (11.29%), and group B was significantly lower than that in group A (18.75%) (P < 0.05). The proportion of clinical effect in group C after treatment was 70.18%, significantly higher than that in group A (55.5%) and group B (63.34%), and that in group B was significantly higher than that in group A (55.5%) (P < 0.05). In summary, the lung HRCT after iterative reconstruction can more clearly and intuitively show the lesion site, which has a key role in guiding the early diagnosis and treatment planning of BO; the HRCT image based on iterative reconstruction technique combined with TCM treatment of removing blood stasis and resolving phlegm has a better therapeutic effect on children, with a high application value.

Difference in clinical features and prognosis of severe adenoviral pneumonia in children with different ages

OBJECTIVE

This study aims to analyze the difference in clinical features and prognosis of severe adenovirus pneumonia (SAP) in children of different ages, and analyze the risk factors for poor prognosis in children with SAP.

METHODS

A retrospective observational study was performed to describe the clinical features and analyze the risk factors for death and post-infectious bronchiolitis obliterans (PIBO) in 303 children hospitalized with SAP from January 2015 through to January 2020. The participants were divided into 4 age groups: < 6 months (n = 25, 8.3%); 6-12 months (n = 98, 32.3%); 12-36 months (n = 118, 38.9%); and > 36 months (n = 62, 20.5%).

RESULTS

Fever rate, peak, and duration were the lowest in the < 6 months group, while no significant difference was found among other age groups. Serum levels of lactate dehydrogenase (LDH) and the load of adenovirus were the lowest in the < 6 months group, and the highest in the 6-12 months and 12-36 months groups, respectively. A total of 80.9% of patients recovered, 3.3% of patients died, and 15.8% of patients were diagnosed PIBO. The mortality rate showed no significance between age groups. The > 36 months group had the highest recovery rate and the lowest incidence of PIBO, while the 6-12 months group had the lowest recovery rate and the highest incidence of PIBO. Independent risk factors for PIBO among all participants from the 4 groups were invasive mechanical ventilation, administration of intravenous steroids, duration of fever, and male gender. Independent risk factors for death among all participants from the 4 groups were hypercapnia, low albumin levels, and invasive mechanical ventilation. Risk factor analysis of different ages was not possible due to the limited sample size.

CONCLUSIONS

The morbidity, clinical features, and prognosis of SAP are affected by children's ages. Pediatric patients with a longer duration of fever, hypercapnia, low serum albumin levels, invasive mechanical ventilation, and intravenous steroids use are more likely to develop a poor prognosis in SAP, especially if the patient is male. This article is protected by copyright. All rights reserved.

Risk Factors for Post-infectious Bronchiolitis Obliterans in Children: A Systematic Review and Meta-Analysis

BACKGROUND

Post-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.

METHODS

We 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.

RESULTS

A 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).

CONCLUSION

In 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.

Effects of Inhaled Corticosteroids on Lung Function in Children With Post-infectious Bronchiolitis Obliterans in Remission

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 (FEV₁) 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, FEV₁, 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 FEV₁ 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.

Follow-up on the therapeutic effects of a budesonide, azithromycin, montelukast, and acetylcysteine (BAMA) regimen in children with post-infectious bronchiolitis obliterans

Background

Post-infectious bronchiolitis obliterans (PIBO) is a rare, severe chronic lung disease without optimal treatment. Currently, treatment in children mainly relies on systemic corticosteroids, but long-term use of these drugs may lead to adverse reactions. This study aimed to evaluate the short-term efficacy of the budesonide, azithromycin, montelukast, and acetylcysteine (BAMA) regimen in paediatric PIBO patients and whether it can reduce systemic corticosteroid use.

Methods

This was a prospective study. From June 2017 to July 2020, patients diagnosed with PIBO at Yuying Children’s Hospital of Wenzhou Medical University were treated with the BAMA regimen for 3 months. Methylprednisolone was added only when the clinical manifestations did not improve or deteriorated. All patients were followed up every 2 to 4 weeks, and changes in clinical symptoms were recorded. Pulmonary function tests and high-resolution computed tomography (HRCT) were performed, and systemic corticosteroid use was recorded after the 3-month follow-up.

Results

A total of 75 patients with PIBO were included; overall, 54 patients completed the course of treatment. After treatment, the respiratory manifestations were improved in 37 patients (68.5%), but 4 patients (7.4%) showed decreased exercise tolerance, and 2 patients (3.7%) were readmitted to the hospital. Additionally, 17 (56.7%) of the 30 patients whose pulmonary function was re-examined showed improvement, and 28 (77.8%) of the 36 patients who underwent HRCT showed marked improvement. Importantly, 20 patients (54.1%) received systemic corticosteroids for 2 weeks or less, while 31.5% of patients used no corticosteroids.

Conclusions

The BAMA regimen effectively relieved clinical symptoms and signs of PIBO in children, improved pulmonary function and HRCT manifestations, and reduced the use of systemic corticosteroids.

Post-infectious bronchiolitis obliterans in children: Clinical and radiological evaluation and long-term results

BACKGROUND AND OBJECTIVE

This study aims to evaluate clinical and radiological findings and treatment outcomes of the patients with PIBO.

METHODS

One hundred fourteen children were enrolled. Initial demographic and clinical findings were evaluated. Pre- and post-treatment clinical and radiological findings were compared.

RESULTS

The median age of the patients at initial pulmonary injury was 7,2 months, the median age at diagnosis was 17.5 months. Persistent wheezing was the most common complaint. Thirty-five patients had mechanical ventilation history. 82,5% of patients had clinical improvement. Bronchiectasis, atelectasis, hyperinflation and air trapping in HRCT improved significantly with treatment. Post-treatment Bhalla scores decreased from 8.3 to 6.5 (p= 0,001). Improvement was observed in radiological and clinical findings after treatment.

CONCLUSIONS

This study is one of the largest studies in the literature and one of the few studies that evaluate clinical and radiological outcomes of patients with PIBO.

Effects of long-term azithromycin therapy on auditory functions in children with chronic respiratory diseases

BACKGROUND AND OBJECTIVES

In recent years, long-term azithromycin (AZT) use has been increased in pediatric patients with chronic respiratory tract problems. In this study, we aimed to assess auditory functions in children on long-term AZT therapy.

METHOD

The study included 43 patients who received long-term AZT treatment and 27 age-matched, healthy controls. In the study and control groups, ear-nose-throat examination, pure tone audiometry, speech recognition threshold (SRT), speech discrimination score (SDS), uncomfortable loudness level (UCL), acoustic reflex tests, and otoacoustic emission tests were performed. The test results were statistically compared between groups.

RESULTS

Mean age was 11.3 ± 0.56 years in the study group and 9.3 ± 3.07 years in the control group. The medain hearing examination was 8 months after end of AZT treatment (Ranged: 1-12 months). No significant difference was found in normal- and high-frequency audiogram tests at any frequency between study and control groups. Also, no significant difference was found in distortion product otoacoustic emissions (DPOAE) and transient evoked otoacoustic emissions (TEOAE) tests between groups. Also, there was no significant difference in acoustic reflex, SRT, SDS, and UCL test results between study and control groups.

CONCLUSION

This is the first study assessing auditory functions comprehensively in pediatric patients who received long-term AZT therapy. In this study, it was shown that long-term AZT use had no deleterious effect on auditory function tests.

Therapeutic effect of budesonide, montelukast and azithromycin on post-infectious bronchiolitis obliterans in children

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.

Postinfectious bronchiolitis obliterans masked by misdiagnosis as asthma

OBJECTIVES

Asthma and postinfectious bronchiolitis obliterans (PIBO) have similar clinical findings, and PIBO may be misdiagnosed with asthma. This study aimed to determine the clinical features of PIBO in children and the causes of delay in its diagnosis.

METHODS

We retrospectively evaluated all patients diagnosed with PIBO in four pediatric pulmonology centers between 2007 and 2018. In total, 64 PIBO patients were retrospectively reviewed. We compared the clinical and laboratory differences between PIBO patients who had initially been misdiagnosed with asthma and correctly diagnosed with PIBO.

RESULTS

Of the 64 patients, 22 (34.4%) had initially been misdiagnosed with asthma. Adenovirus was the most common infectious agent in children. The age upon diagnosis was older, and the symptom duration was significantly longer in patients misdiagnosed with asthma (P < .05). There were no statistical differences in terms of sex, history of prematurity, duration of hospitalization, treatment, history of oxygen or mechanical ventilation support, pulmonary function test (PFT) results and asthma-predisposing findings between the two groups (P > .05).

CONCLUSIONS

Patients with PIBO who had initially been misdiagnosed with asthma were correctly diagnosed at older ages and had longer symptom duration. Asthma may mask PIBO diagnosis by the similarity of symptoms and the clinical response to inhaled β2-agonist or steroid treatment. PFTs may not help clinicians because of the age of children. The delay in the diagnosis of PIBO is probably attributable to the fact that some clinicians fail to include PIBO in the differential diagnosis when there is no clinical response to asthma medication.

Postinfectious Bronchiolitis Obliterans in Children: Diagnostic Workup and Therapeutic Options: A Workshop Report

Bronchiolitis obliterans (BO) is a rare, chronic form of obstructive lung disease, often initiated with injury of the bronchiolar epithelium followed by an inflammatory response and progressive fibrosis of small airways resulting in nonuniform luminal obliteration or narrowing. The term BO comprises a group of diseases with different underlying etiologies, courses, and characteristics. Among the better recognized inciting stimuli leading to BO are airway pathogens such as adenovirus and mycoplasma, which, in a small percentage of infected children, will result in progressive fixed airflow obstruction, an entity referred to as postinfectious bronchiolitis obliterans (PIBO). The present knowledge on BO in general is reasonably well developed, in part because of the relatively high incidence in patients who have undergone lung transplantation or bone marrow transplant recipients who have had graft-versus-host disease in the posttransplant period. The cellular and molecular pathways involved in PIBO, while assumed to be similar, have not been adequately elucidated. Since 2016, an international consortium of experts with an interest in PIBO assembles on a regular basis in Geisenheim, Germany, to discuss key areas in PIBO which include diagnostic workup, treatment strategies, and research fields.

Presumptive Development of Fibrotic Lung Disease From Bordetella bronchiseptica and Post-infectious Bronchiolitis Obliterans in a Dog

A 7-month-old Miniature Poodle acquired from a pet store developed cough and subsequently respiratory distress compatible with Bordetella bronchiseptica infection. Partial but incomplete resolution of clinical signs and thoracic radiographic/computed tomographic imaging lesions were noted with use of susceptibility-guided antimicrobials. Additionally, a concern for an infectious nidus led to left cranial lung lobectomy at 9 months of age. Histopathology predominantly revealed polypoid and constrictive bronchiolitis obliterans (i.e., small airway disease). Intermittent antimicrobial administration over the next 5 years failed to blunt progressive clinical signs. At 8 years, necropsy confirmed severe airway-centered interstitial fibrosis. This pattern of fibrosis was strongly suggestive of underlying small airway disease as the trigger. In retrospect, post-infectious bronchiolitis obliterans (PIBO), a syndrome in young children caused by pulmonary infections but not yet recognized in pet dogs, likely initiated a pathway of fibrosis in this dog. In dogs with risk factors for community-acquired pathogens such as Bordetella bronchiseptica, PIBO is a differential diagnosis with development of severe, persistent respiratory signs incompletely responsive to appropriate antimicrobials. Untreated PIBO may lead to airway-centered interstitial fibrosis. Future study is required to determine if targeted therapy of PIBO could alter the course of end-stage pulmonary fibrosis.

Post-infectious bronchiolitis obliterans

Bronchiolitis obliterans is a rare and severe chronic lung disease resulting from a lower respiratory tract lesion. It may occur after a bone marrow or lung transplantation, infectious diseases, or less frequently after inhaling toxic substances or after connective tissue diseases. Pathology, pathogenesis, and molecular biology, as well as the best treatment of bronchiolitis obliterans, remain the subject of ongoing research. This review discusses our current knowledge of different areas of bronchiolitis obliterans associated with infectious lesions.

Clinical features of postinfectious bronchiolitis obliterans in children undergoing long-term nebulization treatment

BACKGROUND

Limited data are available in relation to the clinical features of PIBO undergoing prolonged nebulization treatment with budesonide, terbutaline and ipratropium bromide. This retrospective study aimed to outline the features of clinical, high-resolution computed tomography (HRCT) and pulmonary function test (PFT) of PIBO, undergoing maintenance therapy utilizing a triple nebulization treatment and to determine the factors associated with prognosis.

METHODS

Children diagnosed with PIBO were followed up between April 2014 and March 2017. The clinical features after maintenance nebulization treatment for 12 months were thereafter summarized.

RESULTS

Thirty patients, 21 boys and 9 girls, were enrolled in the study. The median age of patients was 17.4 months, with a range between 3.0 and 33 months. Persistent coughing and wheezing were detected whilst wheezing and crackles were the common manifestations presented. HRCT scans revealed patchy ground and glass opacity, while PFT showed fixed airway obstruction in all patients. Four patients were lost during follow-up. After treatment, the clinical symptoms were improved greatly in all patients (P < 0.01). The mean increase in the percentage of TPEF%TE and VPEF%VE were improved greatly (P < 0.01). Images of the HRCT scan indicated marked improvements in 18 patients (81.8%) in comparison with scans obtained pre-treatment.

CONCLUSIONS

Our data suggest a potential role of long-term nebulization treatment of budesonide, terbutaline, ipratropium bromide on PIBO, due to its efficacy as indicated in the improved clinical symptoms, pulmonary functions and CT manifestations identified in the children. New prospective and controlled studies are required to confirm this proposition.

Combined pirfenidone, azithromycin and prednisolone in post-H1N1 ARDS pulmonary fibrosis

There are no specific data on the management of pulmonary fibrosis post-H1N1 ARDS. We present the cases of three patients who responded positively to treatment with pirfenidone, azithromycin and prednisolone. Three males, aged 40, 45 and 59 years, had H1N1 ARDS requiring mechanical ventilation for two weeks or longer. After weaning off ventilation, they had persistent symptoms and hypoxemia at rest despite receiving prednisolone and home oxygen for at least three weeks following discharge. Computed tomography (CT) of the chest showed fibrosis and traction bronchiectasis. At presentation, they could not perform spirometry. Investigations ruled out infection. Pirfenidone (600 mg daily escalated to maximum tolerable dose of 2.4 gm daily) and azithromycin (500 mg thrice weekly) were added off-label to prednisolone. In one patient pirfenidone was discontinued after three months due to an adverse reaction and azithromycin was continued for nine months. At one year follow-up, all patients had symptomatic improvement, better effort tolerance, regression of opacities and no progression of fibrosis on CT, and improvement in spirometry and six minute walk tests. Pirfenidone and azithromycin added to prednisolone may have led to clinical and radiological improvement. The current experience suggests that this treatment approach to pulmonary fibrosis post-H1N1 ARDS be studied further. (Sarcoidosis Vasc Diffuse Lung Dis 2018; 35: 85-90).

Lung Clearance Index and Quantitative Computed Tomography of Post-Infectious Bronchiolitis Obliterans in Infants

Post-infectious bronchiolitis obliterans (BO) could be diagnosed via spirometry and chest computed tomography (CT); however, these tests are limited in infants. We aimed to evaluate the utility of lung clearance index (LCI) and air-trapping lung volume from chest CT in infants. This prospective study included 20 infants (mean age, 10.9 ± 6.3 months) diagnosed with post-infectious BO between 2009 and 2016. All subjects underwent multiple breath washout tests. For quantitative analysis of chest CT, the mean lung area attenuation value was used as an individual cutoff to determine the air-trapping lung volume. The mean cutoff lung attenuation value was −659 Hounsfield units, the mean total lung volume was 265 ml, and the mean air-trapping lung volume percentage was 22.9%. Functional residual capacity correlated with total lung volume and normal attenuation lung volume (p < 0.02). LCI (p < 0.02) and moment ratio (MR) 1 (p < 0.05) correlated with the air-trapping lung volume percentage. The concordance indices of LCI (0.659, p = 0.025) and MR1 (0.642, p = 0.046) were significantly correlated with the air-trapping lung volume percentage from CT. LCI and quantitative air-trapping lung volume from chest CT are feasible, complimentary tools for assessing infants with post-infectious BO.

Clinical and follow-up study of bronchiolitis obliterans in pediatric patients in China

Bronchiolitis obliterans (BO) is in general a rare and life-threatening form of non-reversible obstructive lung disease in which the bronchioles are compressed and narrowed by fibrosis and/or inflammation. The purpose of this study was to evaluate the clinical features of BO in pediatric patients and explore its risk factors. The medical records of 35 pediatric patients with BO at Guangzhou Women and Children’s Medical Center were evaluated. The age at onset of symptoms was 2–42 months (mean 13.3 ± 8.9 months), with age at diagnosis of 5 months–4 years (mean 17.8 ± 9.0 months). High-resolution computed tomography findings included mosaic pattern (100%), atelectasis (37.1%), air trapping (31.4%), and bronchiectasis (20.0%). Three patients received lung biopsies and mainly exhibited an inflammatory process surrounding the lumen of bronchioles. BO predominantly resulted from post-infectious causes (91.4%) which were primarily caused by adenovirus (50%), followed by Mycoplasma pneumoniae (46.7%) and influenza (20%). Pulmonary function tests (PFTs) showed severe and fixed airflow obstruction, decreased compliance, and increased resistance. No significant difference was found between before and after steroid treatment ( P > 0.05). Two patients died owing to severe pulmonary complications, one of whom had inherent immunodeficiency. Our study suggests that the occurrence of BO, especially post-infectious BO, in China is relatively high and might result from primary immunodeficiency diseases in severe cases. Recurrent aspiration pneumonia caused by congenital dysplasia of the larynx and vaccination not on schedule might be potential risk factors for persistent and recurrent BO.

Serum YKL-40 levels may help distinguish exacerbation of post-infectious bronchiolitis obliterans from acute bronchiolitis in young children

Children with post-infectious bronchiolitis obliterans (PIBO) are frequently hospitalized with acute exacerbation, but clinical differentiation of PIBO exacerbation from acute bronchiolitis is often challenging, which may result in treatment delay and chronic lung function impairment. We aimed to examine whether serum YKL-40 and growth factors could be markers for PIBO exacerbation. Thirty-seven children admitted with acute exacerbation of PIBO were enrolled and studied retrospectively. Diagnosis of PIBO was based on clinical history of acute respiratory infection followed by persistent airway obstruction and characteristic findings in high-resolution computed tomography. Serum levels of YKL-40, vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β1, and platelet-derived growth factor (PDGF)-BB were measured on admission. The biomarkers were also examined in children admitted with acute bronchiolitis serving as positive controls (N = 30) and in age-matched controls (N = 20). Only YKL-40 levels were found to be significantly higher in PIBO patients with exacerbation compared with that in bronchiolitis patients and showed a positive correlation with the severity of disease before diagnosis of PIBO.

CONCLUSION

Our results suggest that measuring serum YKL-40 levels might help distinguish exacerbation of PIBO from acute bronchiolitis in young children. What is Known: • The children with post-infectious BO (PIBO) usually have recurrent wheezing and need frequent hospitalization due to acute exacerbation during the first disease years. • Clinical differentiation of PIBO exacerbation from acute bronchiolitis in young children is often challenging, which may result in treatment delay and chronic lung function impairment. What is New: • Measuring serum YKL-40 levels might help distinguish exacerbation of PIBO from acute bronchiolitis in young children.