Diagnosis of Bronchiolitis Obliterans with Computed Tomography in Children

Interstitial lung diseases in inborn errors of immunity

PURPOSE OF REVIEW

Our goal is to review current understanding of interstitial lung disease (ILD) affecting patients with inborn errors of immunity (IEI). This includes understanding how IEI might predispose to and promote development or progression of ILD as well as how our growing understanding of IEI can help shape treatment of ILD in these patients. Additionally, by examining current knowledge of ILD in IEI, we hope to identify key knowledge gaps that can become focus of future investigative efforts.

RECENT FINDINGS

Recent identification of novel IEI associated with ILD and the latest reports examining treatment of ILD in IEI are included. Of noted interest, are recent clinical studies of immunomodulatory therapy for ILD in common variable immunodeficiency.

SUMMARY

ILD is a frequent complication found in many IEI. This article provides a guide to identifying manifestations of ILD in IEI. We review a broad spectrum of IEI that develop ILD, including antibody deficiency and immune dysregulation disorders that promote autoimmunity and autoinflammation. This work integrates clinical information with molecular mechanisms of disease and diagnostic assessments to provide an expedient overview of a clinically relevant and expanding topic.

Pediatric Interstitial (Diffuse) Lung Disease

Interstitial (diffuse) lung diseases in infants and children comprise a rare heterogeneous group of parenchymal lung disorders, with clinical syndromes characterized by dyspnea, tachypnea, crackles, and hypoxemia. They arise from a wide spectrum of developmental, genetic, inflammatory, infectious, and reactive disorders. In the past, there has been a paucity of information and limited understanding regarding their pathogenesis, natural history, imaging findings, and histopathologic features, which often resulted in enormous diagnostic challenges and confusion. In recent years, there has been a substantial improvement in the understanding of interstitial lung disease in pediatric patients due to the development of a structured classification system based on the etiology of the lung disease, established pathologic criteria for consistent diagnosis, and the improvement of thoracoscopic techniques for lung biopsy. Imaging plays an important role in evaluating interstitial lung diseases in infants and children by confirming and characterizing the disorder, generating differential diagnoses, and providing localization for lung biopsy for pathological diagnosis. In this chapter, the authors present the epidemiology, challenges, and uncertainties of diagnosis and amplify a recently developed classification system for interstitial lung disease in infants and children with clinical, imaging, and pathological correlation.

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.

Mycoplasma pneumoniae-Associated Bronchiolitis Obliterans Following Acute Bronchiolitis

The characteristics of Mycoplasma pneumonia (M. pneumoniae)-associated bronchiolitis obliterans (BO) are not well known. We retrospectively reviewed 17 patients with M. pneumoniae–associated BO. All patients had M. pneumoniae–associated acute bronchiolitis prior to the development of BO. In the acute bronchiolitis stage, all patients had fever and cough; six patients also had wheezing and dyspnoea. BO was diagnosed approximately 1.5–8 months later based on clinical manifestations and chest high-resolution computed tomography (HRCT) findings. All patients presented with wheezing and/or dyspnoea at the time of diagnosis of BO. HRCT findings included mosaic attenuation, pronounced air trapping, central bronchiectasis and emphysema, according to disease severity. Lung function tests revealed mild to severe airway obstruction. Fourteen of 17 patients had a greater than 12% increase in forced expiratory volume in 1 second values after taking salbutamol. All patients had positive allergy test results and family or personal history of atopic disease. Four patients had a history of asthma before M. pneumonia bronchiolitis. Asthma was diagnosed before, at the time of or after the diagnosis of BO in 11 cases. M. pneumoniae–associated BO may therefore develop following M. pneumonia bronchiolitis and overlap with asthma.

Use of macrolides in lung diseases: recent literature controversies

OBJECTIVE

To review the mechanisms of action of macrolides in pediatric respiratory diseases and their clinical indications.

SOURCES

Review in the PubMed database, comprising the following terms in English: "macrolide and asthma"; "macrolide and cystic fibrosis"; "macrolide bronchiolitis and viral acute"; "macrolide and bronchiolitis obliterans" and "macrolide and non-CF bronchiectasis".

SUMMARY OF THE FINDINGS

The spectrum of action of macrolides includes production of inflammatory mediators, control of mucus hypersecretion, and modulation of host-defense mechanisms. The potential benefit of macrolide antibiotics has been studied in a variety of lung diseases, such as cystic fibrosis (CF), bronchiectasis, asthma, acute bronchiolitis, and non-CF bronchiectasis. Several studies have evaluated the benefits of macrolides in asthma refractory to therapy, but the results are controversial and indications should be limited to specific phenotypes. In viral bronchiolitis, there is no consistent benefit in acute conditions, although recent data have shown an effect in recurrent wheezing prevention. In patients with CF results are also contradictory, but the consensus states there is a small clinical benefit, especially for patients infected with P. aeruginosa. There was also no positive action of macrolides in patients with post-infectious bronchiolitis obliterans. Children with non-CF bronchiectasis seem to have clear benefits regarding the use of macrolides, which showed clinical advantages in parenchyma protection and lung function.

CONCLUSIONS

The long-term use of macrolides should be limited to highly selected situations, especially in patients with bronchiectasis. Careful evaluation of the benefits and potential damage are tools for their indication in specific groups.

Bronchiolitis obliterans: clinical and radiological profile of children followed-up in a reference outpatient clinic

OBJECTIVES

To describe the clinical and radiological characteristics of patients with bronchiolitis obliterans.

METHODS

This is a retrospective and descriptive study. Data were collected from patients diagnosed with bronchiolitis obliterans between 2004 and 2008 in the Pediatric Pulmonology Clinic of Hospital Infantil Albert Sabin, in Ceará, Northeast Brazil. Such diagnosis was based on clinical and tomographic criteria. Previous history, clinical findings at the diagnosis, complementary exams, and follow-up data were evaluated.

RESULTS

35 children diagnosed with bronchiolitis obliterans were identified. There was a predominance of male patients (3:1). The mean age at the onset of symptoms was 7.5 months, and bronchiolitis obliterans was diagnosed at a mean age of 21.8 months. The most common clinical findings were crackles/wheezing, tachypnea, dyspnea, and chest deformity. Post-infectious etiology was the main cause of bronchiolitis obliterans. Predominant findings at chest X-ray and high resolution computed tomography were peri-bronchial thickening and mosaic pattern, respectively. The treatment was variable and individualized. The majority of patients improved during follow-up, despite the persistence of respiratory symptoms.

CONCLUSIONS

In this study, the predominance of male patients and post-infectious etiology was noted, corroborating scientific literature. The most common tomographic findings were similar to those described in previous studies (mosaic pattern, peri-bronchial thickening, and bronchiectasis). Evidence about the treatment of this disease is still lacking. The diagnosis was delayed, which indicates that clinical suspicion of bronchiolitis obliterans is necessary in children with persistent and severe wheezing.

Diffuse Lung Disease

Diffuse lung disease (DLD) comprises a diverse group of disorders characterized by widespread pulmonary parenchymal pathology and impaired gas exchange. While many of these disorders are categorized under the rubric of interstitial lung disease (ILD), some of these disorders involve the airspaces or peripheral airways in addition to, or rather than, the interstitium. Some of these disorders are present primarily in infancy or early childhood, while others that are prevalent in adulthood rarely occur in childhood. This chapter will review the classification of pediatric DLD and the characteristic imaging findings of specific disorders to facilitate accurate diagnosis and guide appropriate treatment of children with these disorders.

[Bronchiolitis obliterans: outcome in the medium term]

BACKGROUND

Bronchiolitis obliterans is a chronic obstructive lung disease that follows a severe insult to the lower respiratory tract. Severity and outcome are different depending on the geographic area. The aim of this study was to communicate the results of our sample.

METHODS

A retrospective study was performed in a sample of boys and girls with a medical diagnosis of bronchiolitis obliterans (BO) between December 1994 and February 2011. The diagnosis was made by high-resolution computed tomography (HRCT) scan and lung function. Lung biopsy was performed in one case. Pulmonary function testing included; forced spirometry (≥ 3 years old), plethysmography (≥ 5 years), bronchodilator tests (BDT), single-breath determination of carbon monoxide uptake in the lung (D(LCO)) (≥ 6 years) and measurement of exhaled lower respiratory nitric oxide (FE(NO)). Quantitative variables were; age at diagnosis, respiratory morbidity before the diagnosis, time from the start of the symptomatology until the diagnosis, follow-up time, respiratory morbidity after the diagnosis, airway specific resistance (sR(eff)), airway specific conductance (sG(eff)), residual volume, total lung capacity, thoracic gas volume, FEV(1), FVC, FEV(1)/FVC, FEF(25-75), D(LCO) and FE(NO). Qualitative variables were; sex, reason for consulting, viral infections, atopy, smoke exposure, HRCT scan and current treatment. Descriptive analysis was performed and pulmonary function before and after BDT was studied using paired-sample Wilcoxon and Student́s t-test.

RESULTS

We studied a cohort of 22 cases, 10 (45.4%) boys and 12 (54.5%) girls. The mean age at the diagnosis was 4.87 ± 3, 27 years old. The follow-up period was 5 years (range 1 to 8 years). Related virus were; influenza 2 (9.09%), parainfluenza 2 (9.09%), adenovirus 3 (13.69%), syncytial respiratory virus 1 (4.5%) and rhinovirus 1 (4.54%). HRCT scan: mosaic pattern of lung attenuation 22 (100%) and bronchiectasis 8 (36.36%). Lung function at diagnosis showed fixed airflow obstruction and increased lung volumes. The global analysis showed a progressive decrease in FEV(1), FVC, FVC/FEV(1,) FEF(25-75) and increase in sR(eff) and residual volume with decrease in sG(eff). Individually, there was a tendency to stabilise the lung function comparing with initial values at diagnosis. Respiratory morbidity was low after the diagnosis.

CONCLUSIONS

In most cases, fixed air-flow obstruction and lung function stability with low respiratory morbidity were observed. HRCT scan and lung function testing supported the diagnosis.

Interstitial Lung Disease in Infants and Children: New Classification System with Emphasis on Clinical, Imaging, and Pathological Correlation

Interstitial lung diseases in infants and children comprise a rare heterogeneous group of parenchymal lung disorders, with clinical syndromes characterized by dyspnea, tachypnea, crackles, and hypoxemia. They arise from a wide spectrum of developmental, genetic, inflammatory, infectious, and reactive disorders. In the past, there has been a paucity of information and limited understanding regarding their pathogenesis, natural history, imaging findings, and histopathologic features, which often resulted in enormous diagnostic challenges and confusion. In recent years, there has been a substantial improvement in the understanding of interstitial lung disease in the pediatric patient, due to the development of a structured classification system based on etiology of the lung disease, established pathologic criteria for consistent diagnosis, and improvement of thoracoscopic techniques for lung biopsy. Imaging plays an important role in evaluating interstitial lung diseases in infants and children by confirming and characterizing the disorder, generating differential diagnoses, and providing localization for lung biopsy for pathological diagnosis. In this chapter, the authors present epidemiology, challenges and uncertainties of diagnosis, and amplify a recently developed classification system for interstitial lung disease in infants and children with clinical, imaging, and pathological correlation.