The lung in inborn errors of immunity: From clinical disease patterns to molecular pathogenesis.

In addition to being a vital organ for gas exchange, the lung is a crucial immune organ continuously exposed to the external environment. Genetic defects that impair immune function, called inborn errors of immunity (IEI), often have lung disease as the initial and/or primary manifestation. Common types of lung disease seen in IEI include infectious complications and a diverse group of diffuse interstitial lung diseases. Although lung damage in IEI has been historically ascribed to recurrent infections, contributions from potentially targetable autoimmune and inflammatory pathways are now increasingly recognized. This article provides a practical guide to identifying the diverse pulmonary disease patterns in IEI based on lung imaging and respiratory manifestations, and integrates this clinical information with molecular mechanisms of disease and diagnostic assessments in IEI. We cover the entire IEI spectrum, including immunodeficiencies and immune dysregulation with monogenic autoimmunity and autoinflammation, as well as recently described IEI with pulmonary manifestations. Although the pulmonary manifestations of IEI are highly relevant for all age groups, special emphasis is placed on the pediatric population, because initial presentations often occur during childhood. We also highlight the pivotal role of genetic testing in the diagnosis of IEI involving the lungs and the critical need to develop multidisciplinary teams for the challenging evaluation of these rare but potentially life-threatening disorders.

Home Oxygen Therapy for Children. An Official American Thoracic Society Clinical Practice Guideline.

BACKGROUND: Home oxygen therapy is often required in children with chronic respiratory conditions. This document provides an evidence-based clinical practice guideline on the implementation, monitoring, and discontinuation of home oxygen therapy for the pediatric population. METHODS: A multidisciplinary panel identified pertinent questions regarding home oxygen therapy in children, conducted systematic reviews of the relevant literature, and applied the Grading of Recommendations, Assessment, Development, and Evaluation approach to rate the quality of evidence and strength of clinical recommendations. RESULTS: After considering the panel's confidence in the estimated effects, the balance of desirable (benefits) and undesirable (harms and burdens) consequences of treatment, patient values and preferences, cost, and feasibility, recommendations were developed for or against home oxygen therapy specific to pediatric lung and pulmonary vascular diseases. CONCLUSIONS: Although home oxygen therapy is commonly required in the care of children, there is a striking lack of empirical evidence regarding implementation, monitoring, and discontinuation of supplemental oxygen therapy. The panel formulated and provided the rationale for clinical recommendations for home oxygen therapy based on scant empirical evidence, expert opinion, and clinical experience to aid clinicians in the management of these complex pediatric patients and identified important areas for future research.

Obesity and Airway Dysanapsis in Children with and without Asthma.

RATIONALE: For unclear reasons, obese children with asthma have higher morbidity and reduced response to inhaled corticosteroids. OBJECTIVES: To assess whether childhood obesity is associated with airway dysanapsis (an incongruence between the growth of the lungs and the airways) and whether dysanapsis is associated with asthma morbidity. METHODS: We examined the relationship between obesity and dysanapsis in six cohorts of children with and without asthma, as well as the relationship between dysanapsis and clinical outcomes in children with asthma. Adjusted odds ratios (ORs) were calculated for each cohort and in a combined analysis of all cohorts; longitudinal analyses were also performed for cohorts with available data. Hazard ratios (HRs) for clinical outcomes were calculated for children with asthma in the Childhood Asthma Management Program. MEASUREMENTS AND MAIN RESULTS: Being overweight or obese was associated with dysanapsis in both the cross-sectional (OR, 1.95; 95% confidence interval [CI], 1.62-2.35 [for overweight/obese compared with normal weight children]) and the longitudinal (OR, 4.31; 95% CI, 2.99-6.22 [for children who were overweight/obese at all visits compared with normal weight children]) analyses. Dysanapsis was associated with greater lung volumes (FVC, vital capacity, and total lung capacity) and lesser flows (FEV1 and forced expiratory flow, midexpiratory phase), and with indicators of ventilation inhomogeneity and anisotropic lung and airway growth. Among overweight/obese children with asthma, dysanapsis was associated with severe disease exacerbations (HR, 1.95; 95% CI, 1.38-2.75) and use of systemic steroids (HR, 3.22; 95% CI, 2.02-5.14). CONCLUSIONS: Obesity is associated with airway dysanapsis in children. Dysanapsis is associated with increased morbidity among obese children with asthma and may partly explain their reduced response to inhaled corticosteroids.

Airway microbiota across age and disease spectrum in cystic fibrosis.

Our objectives were to characterise the microbiota in cystic fibrosis (CF) bronchoalveolar lavage fluid (BALF), and determine its relationship to inflammation and disease status.BALF from paediatric and adult CF patients and paediatric disease controls undergoing clinically indicated bronchoscopy was analysed for total bacterial load and for microbiota by 16S rDNA sequencing.We examined 191 BALF samples (146 CF and 45 disease controls) from 13 CF centres. In CF patients aged <2 years, nontraditional taxa (e.gStreptococcus, Prevotella and Veillonella) constituted ∼50% of the microbiota, whereas in CF patients aged ≥6 years, traditional CF taxa (e.gPseudomonas, Staphylococcus and Stenotrophomonas) predominated. Sequencing detected a dominant taxon not traditionally associated with CF (e.gStreptococcus or Prevotella) in 20% of CF BALF and identified bacteria in 24% of culture-negative BALF. Microbial diversity and relative abundance of Streptococcus, Prevotella and Veillonella were inversely associated with airway inflammation. Microbiota communities were distinct in CF compared with disease controls, but did not differ based on pulmonary exacerbation status in CF.The CF microbiota detected in BALF differs with age. In CF patients aged <2 years, Streptococcus predominates, whereas classic CF pathogens predominate in most older children and adults.

Official American Thoracic Society technical standards: flexible airway endoscopy in children.

BACKGROUND: Flexible airway endoscopy (FAE) is an accepted and frequently performed procedure in the evaluation of children with known or suspected airway and lung parenchymal disorders. However, published technical standards on how to perform FAE in children are lacking. METHODS: The American Thoracic Society (ATS) approved the formation of a multidisciplinary committee to delineate technical standards for performing FAE in children. The committee completed a pragmatic synthesis of the evidence and used the evidence synthesis to answer clinically relevant questions. RESULTS: There is a paucity of randomized controlled trials in pediatric FAE. The committee developed recommendations based predominantly on the collective clinical experience of our committee members highlighting the importance of FAE-specific airway management techniques and anesthesia, establishing suggested competencies for the bronchoscopist in training, and defining areas deserving further investigation. CONCLUSIONS: These ATS-sponsored technical standards describe the equipment, personnel, competencies, and special procedures associated with FAE in children.

An official American Thoracic Society clinical practice guideline: classification, evaluation, and management of childhood interstitial lung disease in infancy.

BACKGROUND: There is growing recognition and understanding of the entities that cause interstitial lung disease (ILD) in infants. These entities are distinct from those that cause ILD in older children and adults. METHODS: A multidisciplinary panel was convened to develop evidence-based guidelines on the classification, diagnosis, and management of ILD in children, focusing on neonates and infants under 2 years of age. Recommendations were formulated using a systematic approach. Outcomes considered important included the accuracy of the diagnostic evaluation, complications of delayed or incorrect diagnosis, psychosocial complications affecting the patient's or family's quality of life, and death. RESULTS: No controlled clinical trials were identified. Therefore, observational evidence and clinical experience informed judgments. These guidelines: (1) describe the clinical characteristics of neonates and infants (<2 yr of age) with diffuse lung disease (DLD); (2) list the common causes of DLD that should be eliminated during the evaluation of neonates and infants with DLD; (3) recommend methods for further clinical investigation of the remaining infants, who are regarded as having "childhood ILD syndrome"; (4) describe a new pathologic classification scheme of DLD in infants; (5) outline supportive and continuing care; and (6) suggest areas for future research. CONCLUSIONS: After common causes of DLD are excluded, neonates and infants with childhood ILD syndrome should be evaluated by a knowledgeable subspecialist. The evaluation may include echocardiography, controlled ventilation high-resolution computed tomography, infant pulmonary function testing, bronchoscopy with bronchoalveolar lavage, genetic testing, and/or lung biopsy. Preventive care, family education, and support are essential.

Pulmonary Complications in Patients With Fontan Circulation: JACC Review Topic of the Week.

The Fontan operation has resulted in significant improvement in survival of patients with single ventricle physiology. As a result, there is a growing population of individuals with Fontan physiology reaching adolescence and adulthood. Despite the improved survival, there are long-term morbidities associated with the Fontan operation. Pulmonary complications are common and may contribute to both circulatory and pulmonary insufficiency, leading ultimately to Fontan failure. These complications include restrictive lung disease, sleep abnormalities, plastic bronchitis, and cyanosis. Cyanosis post-Fontan procedure can be attributed to multiple causes including systemic to pulmonary venous collateral channels and pulmonary arteriovenous malformations. This review presents the unique cardiopulmonary interactions in the Fontan circulation. Understanding the cardiopulmonary interactions along with improved recognition and treatment of pulmonary abnormalities may improve the long-term outcomes in this growing patient population. Interventions focused on improving pulmonary function including inspiratory muscle training and endurance training have shown a promising effect post-Fontan procedure.

The US national registry for childhood interstitial and diffuse lung disease: Report of study design and initial enrollment cohort.

INTRODUCTION: Childhood interstitial and diffuse lung disease (chILD) encompasses a broad spectrum of rare disorders. The Children's Interstitial and Diffuse Lung Disease Research Network (chILDRN) established a prospective registry to advance knowledge regarding etiology, phenotype, natural history, and management of these disorders. METHODS: This longitudinal, observational, multicenter registry utilizes single-IRB reliance agreements, with participation from 25 chILDRN centers across the U.S. Clinical data are collected and managed using the Research Electronic Data Capture (REDCap) electronic data platform. RESULTS: We report the study design and selected elements of the initial Registry enrollment cohort, which includes 683 subjects with a broad range of chILD diagnoses. The most common diagnosis reported was neuroendocrine cell hyperplasia of infancy, with 155 (23%) subjects. Components of underlying disease biology were identified by enrolling sites, with cohorts of interstitial fibrosis, immune dysregulation, and airway disease being most commonly reported. Prominent morbidities affecting enrolled children included home supplemental oxygen use (63%) and failure to thrive (46%). CONCLUSION: This Registry is the largest longitudinal chILD cohort in the United States to date, providing a powerful framework for collaborating centers committed to improving the understanding and treatment of these rare disorders.

Lobar displacement following pediatric heart-lung transplantation: case report and review of literature.

Lobar displacement (LD) after heart-lung transplantation (HLT) has been reported in adults, but there are no reported pediatric cases. Its occurrence may cause vascular compromise of the displaced lung segment leading to necrosis, infection and bronchiectasis, as well as compression of contralateral lobes. We report two cases of LD in children following HLT, treated differently and with different outcomes. Assessment of pulmonary perfusion and weighing the risk of surgical repair may be considered for optimal patient management of this condition.

Radiation exposure from diagnostic imaging in the pediatric intensive care unit.

OBJECTIVE: To determine the range of radiation exposure from diagnostic imaging in children requiring mechanical ventilation. DESIGN: Prospective, observational. SETTING: Tertiary pediatric critical care unit. PATIENTS: We enrolled pediatric critical care unit patients requiring mechanical ventilation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Thoracic radiation exposure while the patient was in the pediatric critical care unit was measured using a small, radiolucent dosimeter secured to the anterior chest wall. Demographic data, diagnoses, and number and type of radiographic procedures were recorded. Differences between exposures by admission diagnoses were analyzed by rank sum test. Relationships between exposure and risk factors were assessed using multiple linear regression and Pearson correlation. Sixty-nine subjects were enrolled over a 175-day period. Subjects experienced a mean (± SD) of 11 ± 11 days of mechanical ventilation during which they underwent a mean of 14 ± 16 chest radiographs and 5 ± 4 other plain films. Subjects who had only plain radiographic studies (CXR group) had a median thoracic exposure of 1.02 (range, 0.13-28.26) mGy and a median daily exposure of 0.16 (range, 0.02-1.99) mGy/day. Subjects who had computed tomography and/or fluoroscopy studies in addition to plain radiographs (CXR+ group) had a median total thoracic exposure of 3.71 (range, 0.77-33.41) mGy and median daily exposure of 0.37 (range, 0.04-3.71) mGy/day, both of which were significantly higher than for subjects in the CXR group. There was no significant difference in average daily exposures according to admission diagnoses and daily exposure could not be predicted from a combination of variables, including age, body mass index, gender, or length of stay. Total number of radiologic studies was correlated, as expected, with duration of ventilation (r = 0.941, p < .0001). Exposure was significantly higher in patients who underwent computed tomography scans or fluoroscopy studies than in patients who only had plain radiography. CONCLUSIONS: Ventilated pediatric intensive care unit patients experienced an average daily thoracic radiation exposure above background environmental exposure and exposure varied widely, but exposures would not be expected to cause acute or chronic toxicity. Overall patient exposures were less than that received from 1 yr of natural background radiation.

Feasibility of laparoscopic Nissen fundoplication after pediatric lung or heart-lung transplantation: should this be the standard?

BACKGROUND: Five-year graft survival in the pediatric lung transplant (LTxp) population is less than 50%, with obliterative bronchiolitis (OB) the leading cause of death at 1, 3, and 5 years post-transplant. Bronchiolitis obliterans syndrome (BOS), defined using spirometry values, is the clinical surrogate for the histological diagnosis of obliterative bronchiolitis. Surgical correction of documented gastroesophageal reflux disease (GERD) has been proposed as a means to potentially delay the onset of BOS and prolong allograft survival in adults before or after lung transplantation but only one such study exists in children. We have examined the safety and possible benefits of laparoscopic antireflux surgery in pediatric patients following lung (LTxp) and heart-lung transplantation (HLTxp). METHODS: An Institutional Review Board (IRB)-approved retrospective chart review was performed to evaluate the outcomes and complications of laparoscopic antireflux surgery in pediatric lung and heart-lung transplant patients. Spirometry data were collected for BOS staging using BOS criteria for children. RESULTS: Twenty-five lung and heart-lung transplants were performed between January 2003 and July 2009. Eleven transplant recipients, including six double-lung and five heart-lung (HLTxp), with a median age of 11.7 years (range 5.1-18.4 years), underwent a total of 12 laparoscopic Nissen fundoplications at a median of 427 days after transplant (range 51-2310 days). GERD was determined based upon clinical impression, pH probe study, gastric emptying study, and/or esophagram in all patients. Three patients already had a gastrostomy tube in place and two had one placed at the time of fundoplication. There were no conversions to open surgery, 30-day readmissions, or 30-day mortalities. Complications included one exploratory laparoscopy for free air 6 days after laparoscopic Nissen fundoplication for a gastric perforation that had spontaneously sealed. Another patient required a revision laparoscopic Nissen 822 days following the initial fundoplication for a paraesophageal hernia and recurrent GERD. The average length of hospital stay was 4.4 ± 1.7 days. Nine of the 12 fundoplications were performed in patients with baseline spirometry values prior to fundoplication and who could also complete spirometry reliably. One of these nine operations was associated with improvement in BOS stage 6 months after fundoplication; seven were associated with no change in BOS stage; and one was associated with a decline in BOS stage. CONCLUSION: It is feasible to perform laparoscopic Nissen fundoplication in pediatric lung and heart-lung transplant recipients without mortality or significant morbidity for the treatment of GERD. The real effect on pulmonary function cannot be assessed due to our small sample size and lack of reproducible spirometry in our younger patients. Additional studies are needed to elucidate the relationship between antireflux surgery and the potential for improving pulmonary allograft function and survival in children which has been previously observed in adult patients.

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.

Neuroendocrine Cell Hyperplasia of Infancy. Clinical Score and Comorbidities.

Rationale: Neuroendocrine cell hyperplasia of infancy (NEHI) is an important form of children's interstitial and diffuse lung disease for which the diagnostic strategy has evolved. The prevalence of comorbidities in NEHI that may influence treatment has not been previously assessed.Objectives: To evaluate a previously unpublished NEHI clinical score for assistance in diagnosis of NEHI and to assess comorbidities in NEHI.Methods: We performed a retrospective chart review of 199 deidentified patients with NEHI from 11 centers. Data were collected in a centralized Research Electronic Data Capture registry and we performed descriptive statistics.Results: The majority of patients with NEHI were male (66%). The sensitivity of the NEHI Clinical Score was 87% (95% confidence interval [CI], 0.82-0.91) for all patients from included centers and 93% (95% CI, 0.86-0.97) for those with complete scores (e.g., no missing data). Findings were similar when we limited the population to the 75 patients diagnosed by lung biopsy (87%; 95% CI, 0.77-0.93). Of those patients evaluated for comorbidities, 51% had gastroesophageal reflux, 35% had aspiration or were at risk for aspiration, and 17% had evidence of immune system abnormalities.Conclusions: The NEHI Clinical Score is a sensitive tool for clinically evaluating NEHI; however, its specificity has not yet been addressed. Clinicians should consider evaluating patients with NEHI for comorbidities, including gastroesophageal reflux, aspiration, and immune system abnormalities, because these can contribute to the child's clinical picture and may influence clinical course and treatment.

Comparative analysis of chest tube thoracostomy and video-assisted thoracoscopic surgery in empyema and parapneumonic effusion associated with pneumonia in children.

BACKGROUND: Controversy exists regarding the optimal management strategy for children having empyema or parapneumonic effusion as a complication of pneumonia. We hypothesized that video-assisted thoracoscopic surgery (VATS)-assisted drainage of pleural fluid and debridement of the pleural space is superior to a chest tube alone in the management of these patients. We further identified predictive factors-namely, presentation, radiographic findings, antibiotic usage, and pleural fluid features-that could predict the need for VATS rather than primary chest tube drainage. METHODS: Forty-nine pediatric patients with pneumonia complicated by parapneumonic effusion or empyema treated at the Children's Hospital of Pittsburgh (1997-2003) were divided into three groups according to the therapy instituted: Primary chest tube, chest tube followed by VATS, or primary VATS. The groups were analyzed in terms of demographics and outcome, as judged by pleural fluid analysis and hospital resource utilization. Demographic and outcome data were compared among groups using one-way analysis of variance and the Student t-test. RESULTS: All groups were similar with respect to demographics and initial antibiotic usage. Patients undergoing primary VATS had a higher initial temperature, whereas radiographic findings of mediastinal shift and air bronchograms were more likely to be found in patients who underwent primary chest tube placement. Patients undergoing primary VATS demonstrated a significantly shorter total stay and lower hospital charges than the other groups. Forty percent of children started on chest tube therapy failed even with subsequent VATS, necessitating a significantly longer hospital course (18 +/- 3 vs. 11 +/- 0.8 days; p < 0.05) and higher hospital charges ($50,000 +/- 7,000 vs. $29,000 +/- 1000) than those having primary VATS. CONCLUSIONS: Patients treated by primary VATS had a shorter stay and lower hospital charges than patients treated by chest tube and antibiotic therapy alone. There were no demographic, physiologic, laboratory, or chest radiographic data that predicted the selection of VATS as an initial treatment. These data suggest a strategy of primary VATS as first-line treatment in the management of empyema or parapneumonic effusion as a complication of pneumonia in pediatric patients.

Perception of Pulmonary Function in Children with Asthma and Cystic Fibrosis.

Background: Under-perception of pulmonary dysfunction may delay appropriate treatment, while over-perception may result in unnecessary treatments. Objectives: To evaluate the ability of patients with asthma or cystic fibrosis and their subspecialty caregivers to assess changes in lung function based on their subjective clinical impressions. Methods: Patients were asked to qualitatively describe how they felt compared to their prior visit (same/better/worse) and to quantitatively estimate their forced expiratory volume in 1 s (FEV1) after being reminded of their FEV1 at the prior visit. Providers made similar estimates based on history and physical examination and knowledge of prior FEV1. After adjusting for relevant clinical covariates, lung function estimates were categorized as accurate (±5% of measured FEV1), overestimated (>5% above measured), and underestimated (>5% below measured). Results: One hundred nine patients estimated FEV1 on 179 occasions. Concordance between patient qualitative assessment and FEV1-based categories was low (κ = 0.08); 44% of patients reported feeling better than the FEV1-based category showed. Quantitatively, 56% of patient estimates were accurate, 18% were underestimated, and 26% overestimated; accuracy improved with age (odds ratio = 1.16, P = 0.01). Concordance between provider qualitative assessments and FEV1-based category was moderate (κ = 0.35); about 19% said their patient looked better than the FEV1-based category showed. Quantitatively, 65% of provider estimates were accurate, 16% were underestimated, and 19% were overestimated; accuracy improved with years of experience. Conclusions: Patients' and providers' perceptions of lung function were low to moderately accurate. Relying on subjective impression may place patients at risk for unnecessary treatments or increased morbidity. These findings highlight the importance of objective lung function assessment.

Controlled-ventilation volumetric CT scan in the evaluation of acquired pulmonary lobar emphysema: a case report.

Acquired lobar emphysema (ALE), a clinical entity often associated with bronchopulmonary dysplasia (BPD) in premature infants, carries significant morbidity and mortality. Because of compression of adjacent lung tissue and poor response to medical therapy, patients may require surgical resection of the hyperinflated region of lung. The decision of proceed to surgery is often problematic, relying upon standard chest radiographs, ventilation-perfusion scans, and high resolution CT (HRCT) scans. We report the use of controlled volume HRCT with breath-holding at TLC and FRC in an infant with severe BPD and ALE. Using reconstruction software, we could estimate total lung volume as well as the volume of the lobe affected by ALE at both lung volumes, permitting the determination of the degree of air trapping. This is turn afforded us confirmatory data of the extent of the affected lung, justifying surgical removal.

A novel surfactant protein C gene mutation associated with progressive respiratory failure in infancy.

Mutations of the Surfactant Protein C (SPC) gene (SFTPC) have been associated with childhood interstitial lung disease (chILD) with variable age of onset, severity of lung disease, and outcomes. We report a novel mutation in SFTPC [c.435G->A, p.(Gln145)] that was associated with onset of symptoms in early infancy, progressive respiratory failure with need for prolonged mechanical ventilatory support, and eventual lung transplant at 1 year of age. While the mutation was not predicted to alter the amino acid sequence of the SP-C precursor protein, analysis of SP-C transcripts demonstrated skipping of exon 4. Because of limited data about the outcomes of infants with SFTPC mutations, we conducted a systematic review of all the SFTPC mutations reported in the literature in order to define their presenting features, clinical and radiologic features, and outcomes. Further advances in our understanding of chILD and creation of an international registry will help to track these patients and their outcomes. Pediatr Pulmonol. 2017;52:57-68. © 2016 Wiley Periodicals, Inc.