Frequency, treatment, and functional outcome in children with hypersensitivity pneumonitis

ERS statement on transition of care in childhood interstitial lung diseases

Interstitial lung diseases (ILD) are a heterogeneous group of rare diffuse diseases affecting the lung parenchyma in children and adults. Childhood interstitial lung diseases (chILD) are often diagnosed at very young age, affect the developing lung, and can have different presentations and prognosis compared to adult forms of these diseases. In addition, chILD in many cases may apparently remit, and have a better response to therapy and better prognosis than adult ILD. Many affected children will reach adulthood with minimal activity or clinical remission of the disease. They need continuing care and follow-up from childhood to adulthood if the disease persists and progresses over time, but also if they are asymptomatic and in full remission. Therefore, for every chILD patient an active transition process from paediatric to adult care should be guaranteed. This European Respiratory Society (ERS) statement provides a review of the literature and current practice concerning transition of care in chILD. It draws on work in existing transition care programmes in other chronic respiratory diseases, disease-overarching transition-of-care programmes, evidence on the impact of these programmes on clinical outcomes, current evidence regarding long-term remission of chILD as well as the lack of harmonisation between the current adult ILD and chILD classifications impacting on transition of care. While the transition system is well established in several chronic diseases, such as cystic fibrosis or diabetes mellitus, we could not find sufficient published evidence on transition systems in chILD. This statement summarises current knowledge, but cannot yet provide evidence-based recommendations for clinical practice.

Masqueraders of pneumonia in children: A case series

Pneumonia remains the top most killer of under-five Indian children. Pneumonia in children is usually caused by viral or bacterial infections. However, there are some unusual causes of pneumonia that merit consideration when pneumonia is recurrent or persistent.

When to panic about a panic attack: A challenging case of hypersensitivity pneumonitis

The COVID-19 pandemic has created diagnostic difficulties with the increase in mental health illnesses that often present with nonspecific symptoms, like hypersensitivity pneumonitis. Hypersensitivity pneumonitis is a complex syndrome of varying triggers, onset, severity, and clinical manifestations that can be challenging to diagnose in many cases. Typical symptoms are nonspecific and can be attributed to other entities. There are no pediatric guidelines, which contributes to diagnostic difficulties and delays in treatment. It is particularly important to avoid diagnostic biases, have an index of suspicion for hypersensitivity pneumonitis, and to develop pediatric guidelines as outcomes are excellent when diagnosed and treated promptly. This article discusses hypersensitivity pneumonitis with a focus on the causes, pathogenesis, diagnostic approach, outcomes, and prognosis while using a case to illustrate the diagnostic difficulties worsened by the COVID-19 pandemic.

The Challenging Diagnosis of Interstitial Lung Disease in Children-One Case Report and Literature Review

Childhood interstitial lung disease (chILD) includes a heterogeneous spectrum of rare respiratory disorders in children associated with substantial morbi-mortality. Interstitial tissue, and other pulmonary structures, epithelium, blood vessels, or pleura are involved, resulting in a restrictive lung disfunction. Respiratory symptoms set in progressively and are often subtle, making thorough clinical history and physical examination fundamental. The etiology often is obscure. The clinical presentation mimics pneumonia or asthma, leading to a diagnostic delay. Challenging diagnosis may require genetic tests, bronchoalveolar lavage, or lung biopsy. Alongside general supportive therapeutic measures, anti-inflammatory, immunosuppressive or antifibrotic agents may be used, based on data derived from adult studies. However, if accurate diagnosis and treatment are delayed, irreversible chronic respiratory failure may ensue, impacting prognosis. The most frequent chILD is hypersensitivity pneumonitis (HP), although it is rare in children. HP is associated with exposure to an environmental antigen, resulting in inflammation of the airways. Detailed antigen exposure history and identification of the inciting trigger are the cornerstones of diagnostic. This article provides the current state of chILD, revealing specific features of HP, based on a clinical case report of a patient admitted in our clinic, requiring extensive investigations for diagnosis, with a favorable long-term outcome.

Pediatric hypersensitivity pneumonitis: literature update and proposal of a diagnostic algorithm

Hypersensitivity pneumonitis (HP) is a rare disease in childhood with the prevalence of 4 cases per 1 million children and an incidence of 2 cases per year. The average age of diagnosis at pediatric age is approximately 10 years. The pathogenesis of HP is characterized by an immunological reaction caused by recurrent exposure to triggering environmental agents (mostly bird antigens in children). The clinical picture of HP is complex and variable in children, often presenting in subacute forms with cough and exertion dyspnea. A diagnosis of HP should be considered in patients with an identified exposure to a triggering antigen, respiratory symptoms, and radiologic signs of interstitial lung disease. Blood tests and pulmonary function tests (PFT) support the diagnosis. Bronchoscopy (with bronchoalveolar lavage and tissue biopsy) may be needed in unclear cases. Antigen provocation test is rarely required. Of note, the persistence of symptoms despite various treatment regimens may support HP diagnosis. The avoidance of single/multiple triggers is crucial for effective treatment. No evidence- based guidelines for treatment are available; in particular, the role of systemic glucocorticoids in children is unclear. With adequate antigen avoidance, the prognosis in children with HP is generally favorable.

Case Report: Gold Miner’s Lung: A Case of Chronic Hypersensitivity Pneumonia in Amazonian Forest

The hostile conditions at informal and illegal mining sites in the Amazonian forest erode the miner’s health, exposing workers to a broad range of diseases because most of the gold is extracted using mercury (Hg). The Hg vapor used daily at gold panning sites presents an environmental threat to the ecosystems and human health. We report the case of a 58-year-old man who has worked in gold panning for over 30 years, presented with diffuse interstitial pneumonia characterized by bilateral images of ground glass and mosaic opacities on the chest CT scan. Based on the negative differential diagnosis (cardiovascular, infectious, autoimmune or cancer), the context of chronic exposure to Hg in a patient who has been working for decades on illegal gold panning sites, we concluded to a chronic form of heavy metal hypersensitivity pneumonia. This hypothesis was supported by high levels of mercury in blood and urine. Mercury hypersensitivity pneumonia might be more frequent than presently thought with thousands of workers chronically exposed to high mercury concentrations among others pollutants. Medical practitioners should systematically seek for chronic respiratory illnesses associated with pollutants exposure in these vulnerable workers with poor health.

Hypersensitivity pneumonitis: Lessons from a randomized controlled trial in children

INTRODUCTION

Hypersensitivity pneumonitis (HP) in children is a severe interstitial lung disease and potentially, a chronic condition, if not treated appropriately. No evidence-based guidelines are available; in particular, the role of systemic glucocorticoid therapy is unclear.

METHODS

The aim of this randomized, double-blind, placebo-controlled, parallel-group, multi-center, phase II trial in pediatric HP was to assess the outcome of HP in children after 6 months of treatment and to compare 3 months of treatment with oral prednisolone or placebo.

RESULTS

After 1.5 years and the inclusion of only four children, we terminated the study prematurely. Two of the children randomized to prednisolone did not achieve the predefined response of FVC to normal. One child treated with placebo recovered to normal, similar to another child treated with prednisolone. All children treated with steroids developed drug-related side effects.

DISCUSSION

This uncompleted study illustrates the urgent medical need for evidence-based treatment protocols for this condition. We discuss the hurdles which were specific for completion of this trial in a rare condition. Among other options, we suggest the inclusion of children into an all-age study of HP, as in adults the same questions are unanswered.

Diagnosis and Evaluation of Hypersensitivity Pneumonitis: CHEST Guideline and Expert Panel Report

BACKGROUND

The purpose of this analysis is to provide evidence-based and consensus-derived guidance for clinicians to improve individual diagnostic decision-making for hypersensitivity pneumonitis (HP) and decrease diagnostic practice variability.

STUDY DESIGN AND METHODS

Approved panelists developed key questions regarding the diagnosis of HP using the PICO (Population, Intervention, Comparator, Outcome) format. MEDLINE (via PubMed) and the Cochrane Library were systematically searched for relevant literature, which was supplemented by manual searches. References were screened for inclusion, and vetted evaluation tools were used to assess the quality of included studies, to extract data, and to grade the level of evidence supporting each recommendation or statement. The quality of the evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach. Graded recommendations and ungraded consensus-based statements were drafted and voted on using a modified Delphi technique to achieve consensus. A diagnostic algorithm is provided, using supporting data from the recommendations where possible, along with expert consensus to help physicians gauge the probability of HP.

RESULTS

The systematic review of the literature based on 14 PICO questions resulted in 14 key action statements: 12 evidence-based, graded recommendations and 2 ungraded consensus-based statements. All evidence was of very low quality.

INTERPRETATION

Diagnosis of HP should employ a patient-centered approach and include a multidisciplinary assessment that incorporates the environmental and occupational exposure history and CT pattern to establish diagnostic confidence prior to considering BAL and/or lung biopsy. Criteria are presented to facilitate diagnosis of HP. Additional research is needed on the performance characteristics and generalizability of exposure assessment tools and traditional and new diagnostic tests in modifying clinical decision-making for HP, particularly among those with a provisional diagnosis.

Executive Summary: Diagnosis and Evaluation of Hypersensitivity Pneumonitis: CHEST Guideline and Expert Panel Report

BACKGROUND

The purpose of this summary is to provide a synopsis of evidence-based and consensus-derived guidance for clinicians to improve individual diagnostic decision-making for hypersensitivity pneumonitis (HP) and decrease diagnostic practice variability.

STUDY DESIGN AND METHODS

Approved panelists developed key questions regarding the diagnosis of HP using the PICO (Population, Intervention, Comparator, and Outcome) format. MEDLINE (via PubMed) and the Cochrane Library were systematically searched for relevant literature, which was supplemented by manual searches. References were screened for inclusion and vetted evaluation tools were used to assess the quality of included studies, to extract data, and to grade the level of evidence supporting each recommendation or statement. The quality of the evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach. Graded recommendations and ungraded consensus-based statements were drafted and voted on using a modified Delphi technique to achieve consensus.

RESULTS

The systematic review of the literature based on 14 PICO questions resulted in 14 key action statements: 12 evidence-based, graded recommendations, and 2 ungraded consensus-based statements. All evidence was of very low quality.

INTERPRETATION

Diagnosis of HP should employ a patient-centered approach and include a multidisciplinary assessment that incorporates the environmental and occupational exposure history and CT pattern to establish diagnostic confidence prior to considering BAL and/or lung biopsy. Additional research is needed on the performance characteristics and generalizability of exposure assessment tools and traditional and new diagnostic tests in modifying clinical decision-making for HP, particularly among those with a provisional diagnosis.

Clinical Features of Hypersensitivity Pneumonitis in Children: A Single Center Study

BACKGROUND

Hypersensitivity pneumonia (HP) is an interstitial lung disease (ILD) mainly involving small airways and lung parenchyma that is caused by the inhalation of antigens in susceptible people to stimulate the body's immune response.

METHODS

A total of 6 Chinese children with HP treated in our center from July 2017 to July 2021 were included in our study.

RESULTS

Among the children, there were 4 males and 2 females, ranging in age from 4 to 14 years. Three cases had chest tightness and shortness of breath, 2 cases had cough, 1 case had chest pain, and 1 case had fever. Two cases of children had a history of close contact with pet dogs, 1 case had a history of contact with pigeons, 2 cases lived in a moldy house recently, and 1 case recently played a saxophone that had been idle for more than 2 years. The parents of two cases also had similar symptoms recently. The specific signs of chest HRCT of 6 cases all were in line with the characteristics of HP. After avoiding the sensitization environment, 2 children quickly recovered, 4 patients received low-dose glucocorticoid oral treatment, and after symptom control the dose was gradually reduced. The course of treatment was about 3-6 months.

CONCLUSIONS

Exposure to a potential antigen has been found in all 6 HP children. The clinical manifestations are heterogeneous and easy to confuse with other diseases. A clear history of exposure to the antigens, respiratory symptoms associated with HP, signs of HP on HRCT, and improvement after removal from the antigenic environment constitute the cornerstone of the diagnosis of HP children in our unit. Avoiding exposure to antigenic environment is the first step in treatment, and glucocorticoid use is necessary in children with persistent symptoms.

[Bird fancier's disease in a child: about a rare and unusual case]

La pathologie du poumon des éleveurs d´oiseaux fait partie des pneumopathies d´hypersensibilité, elle est secondaire à une réaction immuno-allergique aux antigènes aviaires. Cette entité demeure rare chez l´enfant. Elle constitue les deux tiers des pneumopathies d´hypersensibilité. Le diagnostic de cette maladie n´est pas si aisé. Il repose sur un faisceau d´arguments. Nous rapportons une observation singulière d´une fille de 7 ans, ayant comme antécédent un terrain d´atopie familiale, traitée initialement comme asthme devant des épisodes de dyspnée sifflante et une toux sans amélioration. La symptomatologie s´est aggravée par l´installation d´une dyspnée au repos, compliquée d´une détresse respiratoire cyanosante dans un contexte d´altération de l´état général. L´examen clinique a retrouvé un enfant ayant un retard pondéral, une cyanose péribuccale avec un hippocratisme digital. L´auscultation pulmonaire a objectivé des râles crépitants bilatéraux. La radiographie du thorax a mis en évidence un syndrome interstitiel bilatéral. La tomodensitométrie (TDM) thoracique a montré un aspect en verre dépoli diffus. Le bilan biologique a révélé une hyperéosinophilie avec une hyper-IgE, et a écarté une tuberculose, une mucoviscidose, un déficit immunitaire. La reprise de l´interrogatoire a montré un contact avec les oiseaux. Les sérologies de la maladie du poumon des éleveurs d´oiseaux étaient positives. La patiente est mise sous corticothérapie inhalée avec éviction de l´expositions aux oiseaux. Après un recul de 2 mois, l´évolution était favorable. Etant donné que les signes de la maladie du poumon des éleveurs d´oiseaux sont non spécifiques, elle doit être évoquée devant toute symptomatologie respiratoire avec la notion de contact aux antigènes aviaires.

An Inflamed Human Alveolar Model for Testing the Efficiency of Anti-inflammatory Drugs in vitro

A large number of prevalent lung diseases is associated with tissue inflammation. Clinically, corticosteroid therapies are applied systemically or via inhalation for the treatment of lung inflammation, and a number of novel therapies are being developed that require preclinical testing. In alveoli, macrophages and dendritic cells play a key role in initiating and diminishing pro-inflammatory reactions and, in particular, macrophage plasticity (M1 and M2 phenotypes shifts) has been reported to play a significant role in these reactions. Thus far, no studies with in vitro lung epithelial models have tested the comparison between systemic and direct pulmonary drug delivery. Therefore, the aim of this study was to develop an inflamed human alveolar epithelium model and to test the resolution of LPS-induced inflammation in vitro with a corticosteroid, methylprednisolone (MP). A specific focus of the study was the macrophage phenotype shifts in response to these stimuli. First, human monocyte-derived macrophages were examined for phenotype shifts upon exposure to lipopolysaccharide (LPS), followed by treatment with MP. A multicellular human alveolar model, composed of macrophages, dendritic cells, and epithelial cells, was then employed for the development of inflamed models. The models were used to test the anti-inflammatory potency of MP by monitoring the secretion of pro-inflammatory mediators (interleukin [IL]-8, tumor necrosis factor-α [TNF-α], and IL-1β) through four different approaches, mimicking clinical scenarios of inflammation and treatment. In macrophage monocultures, LPS stimulation shifted the phenotype towards M1, as demonstrated by increased release of IL-8 and TNF-α and altered expression of phenotype-associated surface markers (CD86, CD206). MP treatment of inflamed macrophages reversed the phenotype towards M2. In multicellular models, increased pro-inflammatory reactions after LPS exposure were observed, as demonstrated by protein secretion and gene expression measurements. In all scenarios, among the tested mediators the most pronounced anti-inflammatory effect of MP was observed for IL-8. Our findings demonstrate that our inflamed multicellular human lung model is a promising tool for the evaluation of anti-inflammatory potency of drug candidates in vitro. With the presented setup, our model allows a meaningful comparison of the systemic vs. inhalation administration routes for the evaluation of the efficacy of a drug in vitro.

Diagnosis of Hypersensitivity Pneumonitis in Adults. An Official ATS/JRS/ALAT Clinical Practice Guideline

Background: This guideline addresses the diagnosis of hypersensitivity pneumonitis (HP). It represents a collaborative effort among the American Thoracic Society, Japanese Respiratory Society, and Asociación Latinoamericana del Tórax.Methods: Systematic reviews were performed for six questions. The evidence was discussed, and then recommendations were formulated by a multidisciplinary committee of experts in the field of interstitial lung disease and HP using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach.Results: The guideline committee defined HP, and clinical, radiographic, and pathological features were described. HP was classified into nonfibrotic and fibrotic phenotypes. There was limited evidence that was directly applicable to all questions. The need for a thorough history and a validated questionnaire to identify potential exposures was agreed on. Serum IgG testing against potential antigens associated with HP was suggested to identify potential exposures. For patients with nonfibrotic HP, a recommendation was made in favor of obtaining bronchoalveolar lavage (BAL) fluid for lymphocyte cellular analysis, and suggestions for transbronchial lung biopsy and surgical lung biopsy were also made. For patients with fibrotic HP, suggestions were made in favor of obtaining BAL for lymphocyte cellular analysis, transbronchial lung cryobiopsy, and surgical lung biopsy. Diagnostic criteria were established, and a diagnostic algorithm was created by expert consensus. Knowledge gaps were identified as future research directions.Conclusions: The guideline committee developed a systematic approach to the diagnosis of HP. The approach should be reevaluated as new evidence accumulates.

Pulmonary function testing in children's interstitial lung disease

The use of pulmonary function tests (PFTs) has been widely described in airway diseases like asthma and cystic fibrosis, but for children's interstitial lung disease (chILD), which encompasses a broad spectrum of pathologies, the usefulness of PFTs is still undetermined, despite widespread use in adult interstitial lung disease. A literature review was initiated by the COST/Enter chILD working group aiming to describe published studies, to identify gaps in knowledge and to propose future research goals in regard to spirometry, whole-body plethysmography, infant and pre-school PFTs, measurement of diffusing capacity, multiple breath washout and cardiopulmonary exercise tests in chILD. The search revealed a limited number of papers published in the past three decades, of which the majority were descriptive and did not report pulmonary function as the main outcome.PFTs may be useful in different stages of management of children with suspected or confirmed chILD, but the chILD spectrum is diverse and includes a heterogeneous patient group in all ages. Research studies in well-defined patient cohorts are needed to establish which PFT and outcomes are most relevant for diagnosis, evaluation of disease severity and course, and monitoring individual conditions both for improvement in clinical care and as end-points in future randomised controlled trials.

Current Diagnosis and Management of Hypersensitivity Pneumonitis

Hypersensitivity Pneumonitis (HP) one of the most common interstitial lung diseases (ILDs) is characterized by exposure to an inhaled inciting antigen that leads to a host immunologic reaction determining interstitial inflammation and architectural distortion. The underlying pathogenetic mechanisms are unclear. The absence of international shared diagnostic guidelines and the lack of a "gold-standard" test for HP combined with the presence of several clinical and radiologic overlapping features makes it particularly challenging to differentiate HP from other ILDs, also in expert contests. Radiology is playing a more crucial role in this process; recently the headcheese sign was recognized as a more specific for chronic-HP than the extensive mosaic attenuation. Several classification proposals and diagnostic models have been advanced by different groups, with no prospective validation. Therapeutic options for HP have been limited to antigen avoidance and immunosuppressant drugs over the last decades. Several questions about this condition remain unanswered and there is a need for more studies.

Usefulness of bronchoalveolar lavage in a French pediatric cohort with hypersensitivity pneumonitis

BACKGROUND

Hypersensitivity pneumonitis (HP) is a rare interstitial lung disease in children, and very little data are available on the frequency, diagnosis, and outcomes of HP. In a pediatric cohort with HP, the characteristics of the CD4/CD8 lymphocyte ratio are often described as nonspecific.

METHODS

We used the National French Database (RespiRare) to collect data from the last decade on HP. The diagnosis of HP was defined by the presence of a relevant exposure, clinical symptoms, and compatible lung imaging radiology and was usually defined by positive precipitins antibodies.

RESULTS

A total of 16 children with a mean age of 10 years (4-13) presented with HP. All children presented with dyspnea on exertion. Diffuse ground-glass opacity was present in all computed tomography (CT) scans. Research guided by a questionnaire and precipitins antibodies against the corresponding antigens showed that patients were positive for contact with birds with or without fungi. Bronchoalveolar lavage (BAL) was performed in 12 children. The total cell counts were elevated in BAL fluid, with a mean value of 36% lymphocytes. The CD4/CD8 lymphocyte ratio was below one for all children.

CONCLUSION

BAL in our pediatric cohort with HP had the same characteristics as that of adults with HP. An HP diagnosis must be considered when dyspnea on exertion and diffuse ground-glass opacity are observed. Carrying out BAL and serological tests can help diagnose and avoid lung biopsy.

Early-life exposure to humidifier disinfectant determines the prognosis of lung function in children

BACKGROUND

Use of humidifier disinfectants (HD) at home leads to chemical airborne exposure, causing HD associated lung injury (HDLI) with high mortality. However, the lung function in children diagnosed with HDLI is not well studied. We investigated the effect of HD exposure on lung function, prognosis, and exposure characteristics associated with the lung function phenotype in children.

METHODS

Eighty-one children diagnosed with HDLI in a nationwide cohort were tested for spirometry and diffusing capacity of the lung for carbon monoxide (DLco) from July 2013 and followed up with at five time points over 2 years. The results were compared with 122 children without HD exposure as controls. Home investigation and questionnaire analysis were conducted to assess HD inhalation exposure.

RESULTS

HDLI survivor's mean percent of predicted forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), and corrected DLco were significantly lower compared with the control group. On longitudinal assessment, FVC was within the normal range, but flattened, and spirometry showed a predominantly restrictive pattern. Corrected DLco did not normalize above 80% despite increasing age. The persistently low phenotype of lung function was associated with initial exposure age, especially less than 12 months of age. Higher density HD exposure during sleep and close distance between the bed and the humidifier were significantly associated with persistently low corrected DLco.

CONCLUSIONS

HD exposure affects prolonged decrement in lung function, especially DLco, particularly among children who are exposed within the first year of life. These results suggested that early-life HD exposure determines long-term prognosis of lung function in children.

Feather duvet lung

A 43-year-old non-smoker was referred with a 3-month history of malaise, fatigue and breathlessness. Blood avian precipitins were strongly positive. Lung function testing confirmed a restrictive pattern with impaired gas transfer. A 'ground glass' mosaic pattern was seen on CT imaging, suggestive of hypersensitivity pneumonitis. Although he had no pet birds, on closer questioning he had recently acquired a duvet and pillows containing feathers. His symptoms, chest radiograph and lung function tests improved after removal of all feather bedding, and he was also started on oral corticosteroid therapy. Our case reinforces the importance of taking a meticulous exposure history and asking about domestic bedding in patients with unexplained breathlessness. Prompt recognition and cessation of antigen exposure may prevent the development of irreversible lung fibrosis.

Lentil aspiration leading to likely hypersensitivity pneumonitis

RATIONALE

A variety of inhaled antigens have been implicated to cause hypersensitivity pneumonitis (HP). We observed that children force-fed with lentil-based weaning food had persistent respiratory symptoms and radiology similar to HP.

OBJECTIVES

To describe the clinical features of lentil HP.

METHODS

We conducted a retrospective review of records of children with lentil HP attending Pediatric Chest Clinic at a tertiary care hospital in North India from 2008-2018. We included case records with elevated immunoglobulin G (IgG) specific for lentil antigen.

MEASUREMENTS AND MAIN RESULTS

Nine children (seven boys) were identified with median (IQR) age of onset of symptoms and diagnosis at 9 (6, 12) and 11 (10, 16) months, respectively. Chronic cough (100%), shortness of breath (89%), fever (78%), vomiting (56%), and wheezing (33%) were common symptoms. Fine crackles were heard in 33% of children, none had clubbing. CT scans showed nodular opacities and consolidation in 78% and 67% children, respectively. Bronchoalveolar lavage showed increased neutrophils and lymphocytes (67% and 33%, respectively). All children showed rapid remission with systemic steroids (prednisolone), starting at a median dose of 1 (1, 1.1) mg kg^-1  day^-1 . One child had a clinical relapse which was treated with oral steroids again. IgG specific to lentil antigens was elevated in children with lentil HP (21->200 mgA/L) compared with children with other chronic respiratory illnesses (n = 7, <2-11.4 mgA/L).

CONCLUSIONS

Lentil aspiration is an important cause of HP in infants of weaning age with force-feeding practices. Further studies are needed to identify aspirated antigens which cause HP in aspiration prone children.

Incidence, comorbidity and survival rate of hypersensitivity pneumonitis: a national population-based study

Background and objectives

Hypersensitivity pneumonitis (HP) is a rare disease, which can lead to premature death. Few studies have investigated HP on a national level. The objective of this study was to investigate incidence, survival rate, and comorbidity of HP in Denmark.

Methods

Using the Danish National Patient Registry we identified all patients with a first-time diagnosis of HP between 1998 and 2010. Patients with HP were matched 1:4 with controls by sex, age and geography in this case-control study. Comorbidity 3 years prior to diagnosis was explored by the Charlson score index. Survival rates were assessed using Kaplan–Meier curves and hazard ratios.

Results

We identified 753 patients during the observation period equalling an average HP incidence of 1.16 per 100 000 citizens. Patients with HP had a significantly higher Charlson score index when compared with the matched controls and an increased risk of dying (hazard ratio 1.98, CI 1.61–2.58, se 0.14, p<0.001). Survival rates of HP were lower at all time points when compared with the matched control population. The decline in survival was observed for both male and female patients with HP with no clear sex difference. Most deaths were related to diseases of the heart and lungs.

Conclusions

In this Danish longitudinal nationwide observational study we found an increased Charlson score index combined with a higher mortality without sex difference among patients with HP compared with a healthy control group, mainly due to diseases of the heart and lungs.

Hypersensitivity pneumonitis is rare and associated with increased mortality rates especially during the first 2 years following diagnosishttp://bit.ly/2oo7tiR

[Hypersensitivity pneumonitis in children]

Hypersensitivity pneumonitis (HP) is an interstitial lung disease caused by an immune response to a variety of antigens to which patients have been previously sensitised. It can occur at any age. In children, it is a rare disease, probably under-diagnosed, with an estimated prevalence of 4 per million. The paediatric forms are not really different from those of adults but present some particularities. Avian exposure is by far the most frequent cause of HP, accounting for nearly two-thirds of cases. Although there is no current recommendation for the diagnosis of HP, it is commonly considered that the diagnosis can be made with confidence on the combination of (1) compatible respiratory symptoms, (2) exposure to a known offending antigen, (3) lymphocytic alveolitis, (4) decreased transfer factor for carbon monoxide or hypoxia on exertion and (5) compatible radiologic features. The treatment is based on antigen avoidance that must be complete and definitive. Corticosteroids can be necessary in severe forms. The prognosis of HP in children is better than in adults, with a full clinical and functional recovery in the majority of cases after complete antigenic withdrawal.

Side effects of medications used to treat childhood interstitial lung disease

Interstitial lung disease in children (chILD) comprises a range of different rare diseases. There is limited evidence for the treatment of chILD and no randomised clinical trials of treatment have been undertaken. Most treatments are therefore prescribed off-label based on expert opinion. The off-label nature of prescription of drugs for chILD highlights the importance of a solid understanding of the side effects to facilitate risk-benefit assessment. The European Respiratory Society chILD guidelines recommend the use of systemic glucocorticosteroids, hydroxychloroquine and azithromycin. Side effects of these drugs will be discussed followed by consideration of other drugs used for the treatment of chILD.

Childhood interstitial lung diseases in immunocompetent children in Australia and New Zealand: a decade's experience

BACKGROUND

Childhood interstitial lung disease (chILD) represents a rare heterogeneous group of respiratory disorders. In the absence of randomized controlled clinical trials, global collaborations have utilized case series with an aim to standardising approaches to diagnosis and management. Australasian data are lacking. The aim of this study was to calculate prevalence and report the experience of chILD in Australasia over a decade.

METHODS

Paediatric pulmonologists in Australia and New Zealand involved in the care of patients aged 0-18 years with chILD completed a questionnaire on demographics, clinical features and outcomes, over a 10 year period. These data, together with data from the 2 reference genetics laboratories, were used to calculate prevalence.

RESULTS

One hundred fifteen cases were identified equating to a period prevalence (range) of 1.5 (0.8-2.1) cases/million for children aged 0-18years. Clinical data were provided on 106 patients: the <2 year group comprised 66 children, median age (range) 0.50 years (0.01-1.92); the ≥2 year group comprised 40 children, median age 8.2 years (2.0-18.0). Management approach was heterogeneous. Overall, 79% of patients had a good clinical outcome. Mortality rate was 7% in the study population.

CONCLUSION

chILD is rare in Australasia. This study demonstrates variation in the investigations and management of chILD cases across Australasia, however the general outcome is favorable. Further international collaboration will help finesse the understanding of these disorders.

Pulmonary hypertension in childhood interstitial lung disease: A systematic review of the literature

Childhood interstitial lung disease (chILD) comprises a wide heterogeneous group of rare parenchymal lung disorders associated with substantial morbidity and mortality. Pulmonary hypertension is a common comorbidity in adults with interstitial lung disease (ILD) and associated with poor survival. We aimed to systematically review the literature regarding the occurrence of pulmonary hypertension (PH) in chILD, its effect on prognosis and healthcare use, and its treatment in clinical practice. Searches of PubMed and EMBASE databases (up to February 2016), and American Thoracic Society conference abstracts (2009-2015) were conducted using relevant keywords. References from selected articles and review papers were scanned to identify further relevant articles. A total of 20 articles were included; estimates of PH in chILD ranged from 1% to 64% with estimates among specific chILD entities ranging from 0% to 43%. Comparisons between studies were limited by differences in the study populations, including the size, age range, and heterogeneous composition of the ILD case series in terms of the nature and severity of the clinical entities, and also the methods used to diagnose PH. Three studies found that among patients with chILD, those with PH had a significantly higher risk (up to sevenfold) of death compared with those without PH. Information on the treatment of pulmonary hypertension in chILD or the effect of PH on healthcare use was not available. Data on the use and effectiveness of treatments for pulmonary hypertension in chILD are required to address this area of unmet need. Pediatr Pulmonol. 2017;52:689-698. © 2016 Wiley Periodicals, Inc.

Diagnosis of Interstitial Lung Disease Caused by Possible Hypersensitivity Pneumonitis in a Child: Think CGD

Interstitial lung disease (ILD) is a rare and heterogeneous group of disorder affecting the lung parenchyma and has a detrimental effect on gas exchange. Chronic granulomatous disease (CGD), when it affects primarily lungs, may cause ILD. We report a 16-year-old patient with CGD caused by homozygous deletion of NCF1 who atypically presented with ILD. The patient had many pigeons and was a pigeon breeder. Exacerbated clinical symptoms were linked to hypersensitivity pneumonitis (HP), and the patient was suggested to keep away from pigeons. In addition to allergen avoidance and prophylactic antibacterial therapy, treatment with corticosteroids and hydroxychloroquine was started for mainly obstructive and persistant symptoms of ILD. CGD is known to cause a hyperinflammatory state and the patients present with excessive granuloma formation and HP. Control of inflammation either by avoidance of allergen exposure and by anti-inflammatory drugs is necessary for the relief of symptoms.

Pulmonary function and fitness years after treatment for hypersensitivity pneumonitis during childhood

BACKGROUND

Hypersensitivity pneumonitis (HP) is an immune-mediated diffuse lung disease. Significant improvement in lung function and diffusing capacity after treatment was previously demonstrated, while long-term data focusing specifically on peripheral airway impairment and peak oxygen uptake (fitness) are lacking. Hence, the aim of this study was to conduct a comprehensive study to determine the stability of pulmonary function and fitness in patients previously diagnosed with HP.

METHODS

We performed a cross-sectional follow-up study with inclusion of longitudinal data if available in patients previously diagnosed with biopsy and high-resolution computed tomography-verified HP during childhood. We performed multiple breath wash-out (LCI2.5 ), spirometry (FEV1 ), bronchiodilator responsiveness test, diffusing capacity (DLCO and DLCO /VA ), body-plethysmography (TLC), and peak oxygen uptake (VO2peak ). St. George Respiratory Questionnaire was used as a measure of respiratory quality of life.

RESULTS

Twenty two patients were assessed. LCI2.5 was abnormal in 47.4% compared to abnormal FEV1 in only 9.1% and without significant bronchiodilator responsiveness. DLCO and TLC were abnormal in 40.9 and 13.6%, respectively, while DLCO /VA was within normal range. Only 11.1% demonstrated abnormal VO2peak . All longitudinally assessed outcomes remained unchanged between end of treatment and time of follow up.

CONCLUSIONS

A large proportion of patients previously diagnosed with HP had abnormal LCI2.5 in contrast to normal spirometry. Spirometric outcomes, TLC, and diffusing capacity were persistently slightly reduced, but stable, and VO2peak was excellent at time of follow-up. Long-term prognosis in children with HP appears favorable although persistent peripheral airway involvement of unknown clinical significance was demonstrated in almost half of the patients. Pediatr Pulmonol. 2016;51:830-837. © 2015 Wiley Periodicals, Inc.

Update on Diffuse Lung Disease in Children

Diffuse lung diseases in children, also called children's interstitial lung disease, are a diverse group of rare disorders that cause disturbances of gas exchange in the lungs. Although individually rare, there are many different forms of diffuse lung disease in children, and collectively these disorders are associated with significant morbidity and mortality, as well as health-care resource utilization. Over the past several years, there have been many significant advances in the field, including genetic discoveries and the development of clinical practice guidelines. This review summarizes recent advances in the understanding, diagnosis, and treatment of diffuse lung diseases in children.

Childhood interstitial lung disease: A systematic review

OBJECTIVES

Childhood interstitial lung disease (chILD) is a group of rare chronic and complex disorders of variable pathology. There has been no systematic review of published chILD research. This study aimed to describe chILD classification systems, epidemiology, morbidity, treatments, outcomes, and the impact of chILD on families and the burden on health services.

METHODS

A systematic literature search for original studies on chILD was undertaken in the major biomedical databases to the end of December 2013. Epidemiological studies, case series and studies describing classification systems were included. Single case studies were excluded.

RESULTS

The search yielded 37 publications that met study criteria. Four different chILD classification systems have been proposed in the past decade. The incidence of chILD has been estimated at 0.13-16.2 cases/100,000 children/year. One to five new cases presented to individual hospitals each year. In developed countries, the median mortality was 13% (6-19%). Morbidity and outcomes were highly variable and not systematically reported. Corticosteroids and hydroxychloroquine were the most common treatments. The impact of chILD on families and the burden on health services has not been studied.

CONCLUSIONS

The heterogeneity of the chILD group of disorders, different determinations of what constitutes a chILD disorder and, a paucity of large epidemiological studies precludes consolidation of results across studies. Consensus on chILD classification is needed to support diagnosis and allow direct comparisons of research evidence. Active disease surveillance and international patient registries are required to advance understanding and management of chILD.

Interstitial lung disease with multiple microgranulomas in chronic granulomatous disease

BACKGROUND

Chronic granulomatous disease (CGD) is a primary immunodeficiency disease that is characterized by susceptibility to bacterial and fungal infections. CGD patients also suffer from immune regulatory disorders, such as CGD-associated bowel inflammation with granuloma, which could be caused by excessive inflammation without demonstrable infection.

PURPOSE

We investigated the clinical manifestation of interstitial lung disease (ILD) resulting from excessive inflammation in X-linked CGD patients.

METHODS

Pulmonary CT images and testing of serum KL-6 levels were performed to assess ILD in the patients. For this study, patients with pulmonary lesions due to demonstrable infections were excluded from among ILD patients.

RESULTS

Among 33 CGD patients, four developed ILD; they had increased reticulo-nodular opacities on CT images and elevated serum KL-6 levels. Histopathological examinations revealed multiple homogeneous microgranulomas in the lesions of inflammatory cell infiltration. Mononuclear cells obtained from their pulmonary lesions produced higher amounts of inflammatory cytokines than the peripheral blood mononuclear cells of CGD patients, suggesting that the only infiltrating cells in the pulmonary lesions were activated and produced large amounts of inflammatory cytokines in ILD patients. Interestingly, an anti-inflammatory drug, such as a corticosteroid or thalidomide, but not anti-bacterial or anti-fungal drugs, improved CT image findings and reduced their KL-6 levels.

CONCLUSIONS

CGD patients' daily exposures to inhaled antigens may induce excessive reactions with the production of inflammatory cytokines leading to the development of ILD with multiple microgranulomas, which could be due to an inadequate production of reactive oxygen species in CGD.

Pulmonary function testing in children and infants

Pulmonary function testing is performed in children and infants with the aim of documenting lung development with age and making diagnoses of lung diseases. In children and infants with an established lung disease, pulmonary function is tested to assess the disease progression and the efficacy of therapy. It is difficult to carry out the measurements in this age group without disturbances, so obtaining results of good quality and reproducibility is challenging. Young children are often uncooperative during the examinations. This is partly related to their young age but also due to the long testing duration and the unpopular equipment. We address a variety of examination techniques for lung function assessment in children and infants in this review. We describe the measuring principles, examination procedures, clinical findings and their interpretation, as well as advantages and limitations of these methods. The comparability between devices and centres as well as the availability of reference values are still considered a challenge in many of these techniques. In recent years, new technologies have emerged allowing the assessment of lung function not only on the global level but also on the regional level. This opens new possibilities for detecting regional lung function heterogeneity that might lead to a better understanding of respiratory pathophysiology in children.

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.

Diffuse lung disease in infancy and childhood: expanding the chILD classification

AIMS

Diffuse parenchymal lung diseases (DPLD) in children comprise a wide spectrum of rare disorders. In 2007 the Children's Interstitial Lung Disease (chILD) Research Cooperative proposed a classification system for DPLD in children <2 years of age. The aims of our study were to determine the utility and reproducibility of this system in children <2 years of age, and test its extension to 18 years of age.

METHODS AND RESULTS

Of 211 cases, 93 were <2 years of age at presentation and 58% were included in the chILD classification. In 118 cases aged between 2 and 18 years there was a wider distribution of disorders, overlapping with those seen in adults, necessitating expansion of the chILD classification types to encompass all reviewed cases, in particular patients with 'adult' diffuse lung diseases. Many cases showed mixed histological patterns, overlap often being between groups of disorders more prevalent in infancy. Concordance between reporting pathologists was 90%.

CONCLUSIONS

The chILD scheme allows classification of conditions more common in children <2 years of age. It can be applied to children of any age, although additional entities need to be included. We propose a more histologically based system for use when assessing biopsies in this context.

Hypersensitivity pneumonitis: lessons for diagnosis and treatment of a rare entity in children

Hypersensitivity pneumonitis (HP) also called exogenous allergic alveolitis = extrinsic allergic alveolitis in children is an uncommon condition and may not be recognized and treated appropriately.

To assess current means of diagnosis and therapy and compare this to recommendations, we used the Surveillance Unit for Rare Paediatric Disorders (ESPED) to identify incident cases of HP in Germany during 2005/6. In addition, cases of HP reported for reference from all over Germany to our center in the consecutive year were included.

Twenty-three children with confirmed pediatric HP were identified. All (age 9.4 y (4.4-15.1) presented with dyspnoea at rest or with exercise, mean FVC was 39% of predicted, seven of the 23 children already had a chronic disease state at presentation. IgG against bird was elevated in 20, and against fungi in 15. Bronchoalveolar lavage was done in 18 subjects (41% lymphocytes, CD4/CD8 1.99), and lung biopsy in 6. Except 2, all children were treated with prolonged courses of systemic steroids. Outcome was not favourable in all cases.

Late diagnosis in up to a quarter of the children with HP and inappropriate steroid treatment must be overcome to improve management of HP. Inclusion of children with HP into international, web-based registry studies will help to study and follow up such rare lung diseases.

Management of hypersensivity pneumonitis

Hypersensitivity pneumonitis (HP) is an interstitial lung disease due to a combined type III and IV reaction with a granulomatous inflammation, caused by cytotoxic delayed hypersensitivity lymphocytes, in a Th1/Th17 milieu, chaperoned by a deficient suppressor function of T regulatory cells. Skewing toward a Th2 phenotype is reported for chronic HP. Phenotypic expression and severity depends on environmental and/or host genetic and immune co-factors. The wide spectrum of causative antigens is continuously up-dated with new sources of airborne organic particles and drug-induced HP. The diagnosis requires a detailed history, measurement of environmental exposure, pulmonary function tests, imaging, detection of serum specific antibodies, broncho-alveolar lavage, antigen-induced lymphocyte proliferation, environmental or laboratory-controlled inhalation challenge and lung biopsy. Complete antigen avoidance is the best therapeutic measure, although very difficult to achieve in some cases. Systemic steroids are of value for subacute and chronic forms of HP, but do not influence long term outcome. Manipulation of the immune response in HP holds future promise.

Hypersensitivity pneumonitis: insights in diagnosis and pathobiology

Hypersensitivity pneumonitis (HP) is a complex syndrome resulting from repeated exposure to a variety of organic particles. HP may present as acute, subacute, or chronic clinical forms but with frequent overlap of these various forms. An intriguing question is why only few of the exposed individuals develop the disease. According to a two-hit model, antigen exposure associated with genetic or environmental promoting factors provokes an immunopathological response. This response is mediated by immune complexes in the acute form and by Th1 and likely Th17 T cells in subacute/chronic cases. Pathologically, HP is characterized by a bronchiolocentric granulomatous lymphocytic alveolitis, which evolves to fibrosis in chronic advanced cases. On high-resolution computed tomography scan, ground-glass and poorly defined nodules, with patchy areas of air trapping, are seen in acute/subacute cases, whereas reticular opacities, volume loss, and traction bronchiectasis superimposed on subacute changes are observed in chronic cases. Importantly, subacute and chronic HP may mimic several interstitial lung diseases, including nonspecific interstitial pneumonia and usual interstitial pneumonia, making diagnosis extremely difficult. Thus, the diagnosis of HP requires a high index of suspicion and should be considered in any patient presenting with clinical evidence of interstitial lung disease. The definitive diagnosis requires exposure to known antigen, and the assemblage of clinical, radiologic, laboratory, and pathologic findings. Early diagnosis and avoidance of further exposure are keys in management of the disease. Corticosteroids are generally used, although their long-term efficacy has not been proved in prospective clinical trials. Lung transplantation should be recommended in cases of progressive end-stage illness.

Bronchiolitis obliterans after allo-SCT: clinical criteria and treatment options

Bronchiolitis obliterans (BO) following allogeneic haematopoietic SCT (HSCT) is a serious complication affecting 1.7-26% of the patients, with a reported mortality rate of 21-100%. It is considered a manifestation of chronic graft-versus-host disease, but our knowledge of aetiology and pathogenesis is still limited. Diagnostic criteria are being developed, and will allow more uniform and comparable research activities between centres. At present, no randomised controlled trials have been completed that could demonstrate an effective treatment. Steroids in combination with other immunosuppressive drugs still constitute the backbone of the treatment strategy, and results from our and other centres suggest that monthly infusions of high-dose pulse i.v. methylprednisolone (HDPM) might stabilise the disease and hinder progression. This article provides an overview of the current evidence regarding treatment options for BO and presents the treatment results with HDPM in a paediatric national HSCT-cohort.