Early onset children's interstitial lung diseases: Discrete entities or manifestations of pulmonary dysmaturity?

The Clinical Approach to Interstitial Lung Disease in Childhood: A Narrative Review Article

Interstitial lung disease (ILD) comprises a group of respiratory diseases affecting the interstitium of the lungs, which occur when a lung injury triggers an abnormal healing response, and an inflammatory process leads to altered diffusion and restrictive respiratory dysfunction. The term "interstitial" may be misleading, as other components of the lungs are usually also involved (epithelium, airways, endothelium, and so on). Pediatric conditions (childhood interstitial lung disease, chILD) are different from adult forms, as growing and developing lungs are affected and more diverse and less prevalent diseases are seen in childhood. Diffuse parenchymal lung disease (DPLD) and diffuse lung disease (DLD) can be used interchangeably with ILD. Known etiologies of chILD include chronic infections, bronchopulmonary dysplasia, aspiration, genetic mutations leading to surfactant dysfunction, and hypersensitivity pneumonitis due to drugs or environmental exposures. Many forms are seen in disorders with pulmonary involvement (connective tissue disorders, storage diseases, malignancies, and so on), but several conditions have unknown origins (desquamative pneumonitis, pulmonary interstitial glycogenosis, neuroendocrine cell hyperplasia in infancy, and so on). Currently, there is no consensus on pediatric classification; however, age grouping is proposed as some specific forms are more prevalent in infancy (developmental and growth abnormalities, surfactant dysfunction mutations, etc.) and others are usually seen in older cohorts (disorders in normal or immunocompromised hosts, systemic diseases, etc.). Clinical manifestations vary from mild nonspecific symptoms (recurrent respiratory infections, exercise intolerance, failure to thrive, dry cough, etc.) to a severe clinical picture (respiratory distress) and presentation related to the child's age. The diagnostic approach relies on imaging techniques (CT), but further investigations including genetic tests, BAL, and lung biopsy (VATS) are needed in uncertain cases. Pharmacological treatment is mostly empiric and based on anti-inflammatory and immunomodulatory drugs. Lung transplantation for selected cases in a pediatric transplantation center could be an option; however, limited data and evidence are available regarding long-term survival. International collaboration is warranted to understand chILD entities better and improve the outcomes of these patients.

Diagnostic workup of childhood interstitial lung disease

Childhood interstitial lung diseases (chILDs) are rare and heterogeneous diseases with significant morbidity and mortality. An accurate and quick aetiological diagnosis may contribute to better management and personalised treatment. On behalf of the European Respiratory Society Clinical Research Collaboration for chILD (ERS CRC chILD-EU), this review summarises the roles of the general paediatrician, paediatric pulmonologists and expert centres in the complex diagnostic workup. Each patient's aetiological chILD diagnosis must be reached without prolonged delays in a stepwise approach from medical history, signs, symptoms, clinical tests and imaging, to advanced genetic analysis and specialised procedures including bronchoalveolar lavage and biopsy, if necessary. Finally, as medical progress is fast, the need to revisit a diagnosis of "undefined chILD" is stressed.

Pediatric pulmonology 2021 year in review: Rare and diffuse lung disease

The field of rare and diffuse pediatric lung disease is experiencing rapid progress as diagnostic and therapeutic options continue to expand. In this annual review, we discuss manuscripts published in Pediatric Pulmonology in 2021 in (1) children's interstitial and diffuse lung disease, (2) congenital airway and lung malformations, and (3) noncystic fibrosis bronchiectasis including primary ciliary dyskinesia. These include case reports, descriptive cohorts, trials of therapies, animal model studies, and review articles. The results are put into the context of other literature in the field. Each furthers the field in important ways, while also highlighting the continued need for further studies.

A Rare Case Report of NEHI in a Preterm Infant with Review of the Literature

Background

Neuroendocrine cell hyperplasia of infancy (NEHI) is a rare respiratory disorder. During infancy, it typically presents with hypoxemia, tachypnea, and respiratory distress, and is commonly misdiagnosed as common childhood illnesses such as pneumonia, reactive airway disease, or bronchiolitis. Lack of awareness about this relatively new and rare disorder in primary care and acute care settings lead to delayed diagnosis and unnecessary use of antibiotics. Case Presentation. We present a case of a 7-month-old girl, born prematurely at 32 weeks with tachypnea and respiratory distress who was initially diagnosed with viral pneumonia, then upper respiratory infection, and finally with community-acquired bacterial pneumonia, while the child never had any fever or upper respiratory symptoms. Failure of outpatient treatment with oral antibiotic and bronchodilator, with the persistence of respiratory symptoms such as retractions, bilateral crackles, and hypoxemia led to hospitalization for intravenous antibiotics. Given persistent symptoms, further evaluation was performed, and she was diagnosed with NEHI based on characteristic chest CT findings.

Conclusions

Viral respiratory infections are the most frequent cause of respiratory illnesses in the first years of life. Primary care providers should be aware of less frequent causes of persistent respiratory symptoms in infancy like NEHI and other interstitial lung diseases in children. This may prevent unnecessary use of antibiotics and delayed diagnosis.

Management Practices During Perinatal Respiratory Transition of Very Premature Infants

The present review considers some controversial management practices during extremely premature perinatal transition. We focus on perinatal prevention and treatment of respiratory distress syndrome (RDS) in immature infants. New concerns regarding antenatal corticosteroid management have been raised. Many fetuses are only exposed to potential adverse effects of the drug. Hence, the formulation and the dosage may need to be modified. Another challenge is to increase the fraction of the high-risk fetuses that benefit from the drug and to minimize the harmful effects of the drug. On the other hand, boosting anti-inflammatory and anti-microbial properties of surfactant requires further attention. Techniques of prophylactic surfactant administration to extremely immature infants at birth may be further refined. Also, new findings suggest that prophylactic treatment of patent ductus arteriosus (PDA) of a high-risk population rather than later selective closure of PDA may be preferred. The TREOCAPA trial (Prophylactic treatment of the ductus arteriosus in preterm infants by acetaminophen) evaluates, whether early intravenous paracetamol decreases the serious cardiorespiratory consequences following extremely premature birth. Lastly, is inhaled nitric oxide (iNO) used in excess? According to current evidence, iNO treatment of uncomplicated RDS is not indicated. Considerably less than 10% of all very premature infants are affected by early persistence of pulmonary hypertension (PPHN). According to observational studies, effective ventilation combined with early iNO treatment are effective in management of this previously fatal disease. PPHN is associated with prolonged rupture of fetal membranes and birth asphyxia. The lipopolysaccharide (LPS)-induced immunotolerance and hypoxia-reperfusion-induced oxidant stress may inactivate NO-synthetases in pulmonary arterioles and terminal airways. Prospective trials on iNO in the management of PPHN are indicated. Other pulmonary vasodilators may be considered as comparison drugs or adjunctive drugs. The multidisciplinary challenge is to understand the regulation of pregnancy duration and the factors participating the onset of extremely premature preterm deliveries and respiratory adaptation. Basic research aims to identify deficiencies in maternal and fetal tissues that predispose to very preterm births and deteriorate the respiratory adaptation of immature infants. Better understanding on causes and prevention of extremely preterm births would eventually provide effective antenatal and neonatal management practices required for the intact survival.

Neonatal interstitial lung disease in a girl with Jacobsen syndrome: a case report

BACKGROUND

We report a case of the neonatal interstitial lung disease pulmonary interstitial glycogenosis in a girl with Jacobsen syndrome. While Jacobsen syndrome is caused by a deletion on the long arm of chromosome 11 and is genetically confirmed, pulmonary interstitial glycogenosis is of unknown etiology and is diagnosed by lung biopsy. Pulmonary interstitial glycogenosis has not previously been described in association with Jacobsen syndrome.

CASE PRESENTATION

A term newborn small for gestational age Caucasian girl presented with respiratory distress, pulmonary hypertension, congenital heart defects, immunodeficiency, and thrombocytopenia. She was diagnosed with Jacobsen syndrome, but also had pulmonary interstitial glycogenosis, which contributed to significant morbidity. There was striking clinical improvement after steroid treatment of the pulmonary interstitial glycogenosis.

CONCLUSIONS

Interstitial lung disease should be considered as a differential diagnosis when respiratory distress and hypoxemia in the perinatal period worsens or persists despite standard treatment. Importantly, pulmonary interstitial glycogenosis may be treatable with corticosteroids. Whether there is a genetic link between pulmonary interstitial glycogenosis and Jacobsen syndrome is still unknown.

The improved clinical course of persistent tachypnea of infancy with inhaled bronchodilators and corticosteroids

BACKGROUND

Persistent tachypnea of infancy (PTI) is the most common interstitial lung disease in young children. As no standardized therapeutic guidelines exist, different pharmaceuticals are used to treat PTI; inhaled corticosteroids (ICS) and bronchodilators being mostly used. This observation assessed the effectiveness of bronchodilators and ICS in children with PTI enrolled in the children's interstitial lung diseases (chILD)-EU Register.

METHODS

Symptomatic children with PTI were observed according to a predetermined stepwise protocol including bronchodilators as the first choice treatment (6 weeks). In patients with incomplete response, additionally, ICS was given (12 weeks). Signs, symptoms, and pulmonary function were evaluated at three time points: at baseline, 6 (±1) weeks after initiation of bronchodilators, and 12 (±1) weeks after bronchodilators/ICS.

RESULTS

Thirty-one children (median age: 44 months, interquartile range [IQR]: 15-67) were included. The therapy was associated with a significant reduction of tachypnea (53.3% of patients, p = 0.02), exercise intolerance (52.2% of patients, p < 0.001), chest retractions (43.8% of patients, p = 0.04), and crackles (29.2% of patients, p = 0.02). Also, a significant improvement in forced expiratory volume in 1 s (FEV₁ ) (median z score: -2.21 vs. -0.47, p = 0.03), residual volume (RV) (median z score 5.28 vs. 1.07, p = 0.007), RV% total lung capacity (TLC) (median z score: 6.05 vs. 1.48, p = 0.01), sRaw (median z score: 6.6 vs. 4.64, p = 0.01), R5 (median z score: 1.27 vs. 0.31, p = 0.009), and R5-R20 (median: 0.58 vs. 0.26 kPa/(l/s), p = 0.002) was demonstrated.

CONCLUSIONS

Inhaled bronchodilators and ICS may exert a positive effect on the severity of symptoms and pulmonary function test (PFT) in symptomatic children with PTI. However, a randomized control trial should be conducted to confirm their effectiveness.

Upregulation of neuropeptides and obstructive airway disorder in infancy: A review with focus on post-RSV wheezing and NEHI

Obstructive airway disorders, common in infancy and early childhood, include some entities that are recognized to have neuro immune mediators as their underlying pathogenetic mechanisms. The best characterized example amongst post-viral wheezing phenotypes is the disorder that follows respiratory syncytial virus (RSV) infection and leads to intermittent, long-term wheezing. The underlying mechanisms of the airway reactivity related to RSV infection have been extensively studies and are associated with dysregulation of the nonadrenergic-noncholinergic (NANC) system, via upregulation of neurotransmitters, typically Substance P. Neuroendocrine hyperplasia of infancy (NEHI), while a less common entity, is a disorder characterized by more severe and long-term obstructive airway disease. NEHI is pathophysiologically characterized by abundance of neuroendocrine cells in the airways containing the neuroimmune mediator bombesin, the release of which is presumed to be the driver of the persistent small airway obstruction and functional air-trapping. Here we review the NANC and neuroendocrine cells, the neurotransmitter systems and their studied roles in pulmonary diseases with a focus on their role in lung development, and subsequent various pediatric lung diseases. We focus on the juxtaposition of the separate neuroimmune mechanisms underlying the pathogenesis of post-RSV recurrent wheezing and NEHI's persistent small airway obstruction. We finally propose a unifying concept of neuropeptides in obstructive disorders that may encompass these two entities and possibly others.

Clinical, functional, and computed tomography findings in a cohort of patients with neuroendocrine cell hyperplasia of infancy

INTRODUCTION

Neuroendocrine cell hyperplasia of infancy (NEHI) is one of the most common interstitial lung diseases in children. Both the etiology and pathophysiological mechanisms of the disease are still unknown. Prognosis is usually favorable; however, there are significant morbidities during the early years of life.

OBJECTIVE

To describe the clinical course, infant pulmonary function tests and computed tomography (CT) findings in a cohort of patients with NEHI in Argentina.

METHODS

This is a observational multicenter cohort study of children diagnosed with NEHI between 2011 and 2020.

RESULTS

Twenty patients participated in this study. The median age of onset of symptoms was 3 months and the median age at diagnosis was 6 months. The most common clinical presentation was tachypnea, retractions and hypoxemia. The chest CT findings showed central ground glass opacities and air trapping. Infant pulmonary function tests revealed an obstructive pattern in 75% of the cases (10/12). Most patients (75%) required home oxygen therapy for 17 months (interquartile range 12-25). In 85% of them, tachypnea and hypoxemia spontaneously resolved between the second and third years of life.

CONCLUSION

In this cohort, the first symptoms appeared during the early months of life. The typical clinical, CT, and functional findings allowed the diagnosis without the need of a lung biopsy. Although most patients required home oxygen therapy, they showed a favorable evolution.

Children's Interstitial and Diffuse Lung Diseases (ChILD) in 2020

The term children interstitial lung diseases (chILD) refers to a heterogeneous group of rare diseases that diffusely affect the lung. ChILD specific to children younger than 2 years of age include diffuse developmental disorders, growth abnormalities, specific conditions of undefined etiology (neuroendocrine cell hyperplasia of infancy and pulmonary interstitial glycogenosis) and surfactant protein disorders. Clinical manifestations are highly variable, ranging from the absence of relevant symptoms to a severe onset. Most commonly, chILD presents with nonspecific respiratory signs and symptoms, such as dyspnea, polypnea, dry cough, wheezing, recurrent respiratory infections and exercise intolerance. In the diagnostic approach to a child with suspected ILD, chest high resolution computed tomography and genetic tests play a central role. Then, if the diagnosis remains uncertain, laryngotracheal-bronchoscopy and lung biopsy are needed. Pharmacological treatment is mostly empiric and based on anti-inflammatory and immunomodulatory drugs including corticosteroids, hydroxychloroquine and azithromycin. Despite chILD overall rarity, pediatric pulmonologists must be familiar with these diseases in order to carry out a timely diagnosis and patient treatment.

Persistent tachypnea of infancy: Follow up at school age

BACKGROUND

Persistent tachypnea of infancy (PTI) is a rare pediatric lung disease of unknown origin. The diagnosis can be made by clinical presentation and chest high resolution computed tomography after exclusion of other causes. Clinical courses beyond infancy have rarely been assessed.

METHODS

Patients included in the Kids Lung Register diagnosed with PTI as infants and now older than 5 years were identified. Initial presentation, extrapulmonary comorbidities, spirometry and clinical outcome were analyzed.

RESULTS

Thirty-five children older than 5 years with PTI diagnosed as infants were analyzed. At the age of 5 years, 74% of the patients were reported as asymptomatic and did not develope new symptoms during the observational period at school-age (mean, 3.9 years; range, 0.3-6.3). At the age of about 10 years, none of the symptomatic children had abnormal oxygen saturation during sleep or exercise anymore. Lung function tests and breathing frequency were within normal values throughout the entire observational period.

CONCLUSIONS

PTI is a pulmonary disease that can lead to respiratory insufficiency in infancy. As at school age most of the previously chronically affected children became asymptomatic and did not develop new symptoms. We conclude that the overall clinical course is favorable.

Variation in the bombesin staining of pulmonary neuroendocrine cells in pediatric pulmonary disorders-A useful marker for airway maturity

OBJECTIVES

Pulmonary neuroendocrine cells (NEC) increase with age due to pulmonary maturity. The aim of this study was to determine whether open lung biopsies from patients with interstitial lung diseases have increased pulmonary NEC compared with neuroendocrine cell hyperplasia of infancy (NEHI). Our second aim was to assess pulmonary NECs in the lung autopsy of children without lung disease who died from different causes.

METHODS

Lung tissue of 5 infants with NEHI; 21 patients with pediatric interstitial lung disease (chILD); 17 lung autopsies of infants at varying age without lung disease were included. The percentage of the airways containing neuroendocrine cells, the average percentage of neuroendocrine cells (NECs) per airway, and the number of neuroendocrine bodies (NEBs) in each case were analyzed.

RESULTS

The mean percentage of the airways containing neuroendocrine cells were 95% in the NEHI group, 30% in the chILD group, 89% under Intrauterine 37 weeks, 70% between intrauterine 37 to 40 weeks, 52% at postnatal 4 days to 6 months of autopsy ages. In the NEHI group, diffuse NE cell distribution and large NEBs were noticed in the lung biopsy. In the chILD group, neuroendocrine cells were dispersed, did not form clusters and NE cells showed solitary distribution. In the lung autopsy group, linear NE cells were detected at younger aged fetuses and solitary distribution of NE cells was detected with the older increasing age.

CONCLUSIONS

Our findings confirm that NECs are seen in many other childhood interstitial lung diseases; NE cell hyperplasia may be a marker of decreased pulmonary development and NE cells decrease with the increasing age of the fetus during Intrauterine life.

Lung ultrasound-a new diagnostic modality in persistent tachypnea of infancy

Lung ultrasound (LUS) has been increasingly used in diagnosing and monitoring of various pulmonary diseases in children. The aim of the current study was to evaluate its usefulness in children with persistent tachypnea of infancy (PTI). This was a controlled, prospective, cross-sectional study that included children with PTI and healthy subjects. In patients with PTI, LUS was performed at baseline and then after 6 and 12 months of follow-up. Baseline results of LUS were compared to (a) baseline high-resolution computed tomography (HRCT) images, (b) LUS examinations in control group, and (c) follow-up LUS examinations. Twenty children with PTI were enrolled. B-lines were found in all children with PTI and in 11 (55%) control subjects (P < .001). The total number of B-lines, the maximal number of B lines in any intercostal space, the distance between B-lines, and pleural thickness were significantly increased in children with PTI compared to controls. An irregularity of the pleural line was found in all patients with PTI and in none of the healthy children. There were no significant changes in LUS findings in patients with PTI during the study period. The comparison of HRCT indices and LUS findings revealed significant correlations between the mean lung attenuation, skewness, kurtosis and fraction of interstitial pulmonary involvement, and the number of B-lines as well as the pleural line thickness. LUS seems to be a promising diagnostic tool in children with PTI. Its inclusion in the diagnostic work-up may enable to reduce the number of costly, hazardous, and ionizing radiation-based imaging procedures.