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

Childhood Interstitial Lung Disease

Childhood interstitial lung disease (chILD) is a heterogeneous group of diseases with various clinical and imaging findings. The incidence and prevalence have increased in recent years, probably due to better comprehension of these rare diseases and increased awareness among physicians. chILDs present with nonspecific pulmonary symptoms, such as tachypnea, hypoxemia, cough, rales, and failure to thrive. Unnecessary invasive procedures can be avoided if specific mutations are detected through genetic examinations or if typical imaging patterns are recognized on computed tomography. Disease knowledge and targeted therapies are improving through international collaboration. Pulmonary involvement in systemic diseases is not uncommon. Pulmonary involvement may be the first finding in connective tissue diseases. This review aims to present a systematic patient-targeted approach to the diagnosis of chILD.

Long-term evolution of neuroendocrine cell hyperplasia of infancy: the FRENCHI findings

Only few studies report long-term evolution of patients with neuroendocrine cell hyperplasia of infancy (NEHI). We report data from a 54-patient cohort followed up in the French network for rare respiratory diseases (RespiRare). Demographic characteristics and respiratory and nutritional evolution were collected at the time of the patient's last scheduled visit. The mean duration of follow-up was 68 months (5 months to 18 years). Fifteen patients (27.8%) were considered clinically cured. During follow-up, hospitalizations for wheezy exacerbations were reported in 35 patients (55%), and asthma diagnosed in 20 (37%). Chest CT scan improvement was noted in 25/44 (56.8%). Spirometry showed a persistent obstructive syndrome in 8/27 (29.6%). A sleep disorder was rare (2/36, 5.5%). Oxygen weaning occurred in 28 of the 45 patients initially treated (62.2%) and was age-dependent (35.7% under 2 years, 70.5% between 2 and 6 years, and 100% after 7 years). Oxygen duration was linked to a biopsy-proven diagnosis (p = 0.02) and to the use of a nutritional support (p = 0.003). Corticosteroids were largely prescribed at diagnosis, with no evident respiratory or nutritional effect during follow-up. Among 23 patients with an initial failure to thrive, 12 (52.2%) had no weight recovery. Initial enteral feeding (17/54, 31.5%) was stopped at a mean age of 43 months (3 to 120), with no effect on cure and oxygen liberation at the last visit.  Conclusion: Our results show that NEHI has a globally positive, but unequal, improvement over time. Further prospective studies are needed to better clarify the different trajectories of patients with NEHI. What is Known: • Neuroendocrine cell hyperplasia of infancy (NEHI) is an interstitial lung disease whose long-term outcome is considered positive from very few studies including heterogeneous populations. What is New: • The 68-month follow-up of our 54-patient cohort showed respiratory/nutritional symptom persistence in 72.2%, oxygen requiring in 34%, and asthma in 37%. When controlled, radiological or functional improvement was noted in 56.8 and 40.7%. Further prospective studies are needed to better clarify the different trajectories of patients with NEHI.

French national cohort of neuroendocrine cell hyperplasia of infancy (FRENCHI) study: diagnosis and initial management

Early diagnosis of neuroendocrine cell hyperplasia of infancy (NEHI) is crucial as, conversely to the other causes of intersititial lung disease, corticosteroids are not recommended. Diagnosis is historically based on lung biopsy (NEHI), but in current practice, a clinical and radiological approach is more and more preferred (NEHI syndrome). This national study aimed to address diagnosis and initial management of patients followed up for a NEHI pattern in pediatric centers for rare lung diseases (RespiRare, France). Data on neonatal and familial events, symptoms at diagnosis, explorations performed and results, and therapeutic management were collected by questionnaire. Fifty-four children were included (boys 63%). The mean onset of symptoms was 3.8 ± 2.6 months. The most frequent symptoms at diagnosis were tachypnea (100%), retraction (79.6%), crackles (66.7%), and hypoxemia (59.3%). The mean NEHI clinical score, evocative when ≥ 7/10, was 7.9 ± 1.4 (76% with a score ≥ 7). All chest CT-scans showed ground glass opacities evolving at least the middle lobe and the lingula. Lung biopsy was performed in 38.9% of the cases and was typical of NEHI in only 52.4%, even when the clinical presentation was typical. Initial treatments were oxygen (83.6%) and more curiously intravenous pulses of steroids (83.3%) and azithromycin (70.2%).

CONCLUSION

This national cohort of patients underlines diagnosis difficulties of NEHI. A composite clinical and radiological score should help clinicians for limiting the use of anti-inflammatory drugs.

WHAT IS KNOWN

•Neuroendocrine cell hyperplasia of infancy (NEHI) is an interstitial lung disease whose diagnosis is essential to limit corticosteroids therapy.

WHAT IS NEW

•In this national cohort of 54 patients with a NEHI pattern, diagnosis is mainly based on clinical symptoms and chest CT-scan results. The newly proposed clinical score and, when performed, the lung biopsies are faulted in 25 and 50% of the cases, respectively. •Corticosteroids are widely used. Such results plead for a new composite score to formally diagnose NEHI.

Interstitial lung disease in infancy and early childhood: a clinicopathological primer

Children's interstitial lung disease (chILD) encompasses a wide and heterogeneous spectrum of diseases substantially different from that of adults. Established classification systems divide chILD into conditions more prevalent in infancy and other conditions occurring at any age. This categorisation is based on a multidisciplinary approach including clinical, radiological, genetic and histological findings. The diagnostic evaluation may include lung biopsies if other diagnostic approaches failed to identify a precise chILD entity, or if severe or refractory respiratory distress of unknown cause is present. As the majority of children will be evaluated and diagnosed outside of specialist centres, this review summarises relevant clinical, genetic and histological findings of chILD to provide assistance in clinical assessment and rational diagnostics.

ILD of childhood is comparable by name only to lung disease in adults. A dedicated interdisciplinary team is required to achieve the best possible outcome. This review summarises the current clinicopathological criteria and associated genetic alterations.https://bit.ly/3mpxI3b

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.

The Use of Infant Pulmonary Function Tests in the Diagnosis of Neuroendocrine Cell Hyperplasia of Infancy

BACKGROUND

Infant pulmonary function tests (iPFTs) in subjects with neuroendocrine cell hyperplasia of infancy (NEHI) have demonstrated significant expiratory airflow obstruction and air trapping.

RESEARCH QUESTION

Can indexes from iPFTs be used in the diagnosis of NEHI?

STUDY DESIGN AND METHODS

This is an observational case-control study evaluating iPFT results from a registry of patients assessed at the Hadassah Hebrew University Medical Center between 2008 and 2018. We used the Kruskal-Wallis H test to compare iPFT results in infants with NEHI with those in two infants in a disease control group (infants evaluated for recurrent wheezing and infants evaluated owing to prematurity) and those in a spirometry control group of infants with normal expiratory airflow. Receiver operating characteristic (ROC) curves were used to assess the diagnostic accuracy of the iPFT indexes.

RESULTS

We evaluated iPFT data in 481 infants (15, NEHI; 292, wheezing; 128, premature; and 46, control group). Infants with NEHI had significantly increased trapped air volumes (median functional residual capacity measured with baby-body plethysmograph [FRC_pleth] was 199% predicted; median ratio of residual volume to total lung capacity was 59% predicted) when compared with results in all evaluated groups of infants (P < .001), including multiple pairwise comparisons. Airflow limitation was demonstrated in infants with NEHI when compared with the infants in the spirometry control group but was similar to that in the two infants in the disease control group. FRC_pleth had the best discriminatory ability for NEHI diagnosis, with an FRC_pleth ≥ 150% predicted demonstrating a ROC of 0.91 (95% CI, 0.82-1.00), sensitivity of 86.7% (95% CI, 59.5%-98.3%), and specificity of 95.5% (95% CI, 93.2%-97.3%).

INTERPRETATION

Findings on iPFTs of markedly increased air trapping, out of proportion to the degree of airflow limitation, are characteristic of infants with NEHI. iPFT results demonstrating an FRC_pleth ≥ 150% predicted are highly specific for NEHI and may aid in early diagnosis. Further research is required to confirm these findings in a prospective cohort and to understand the pathophysiologic explanation for these findings.