Pediatric chronic lower respiratory disorders: microbiological and immunological phenotype

Exposures and coexisting conditions in pediatric nodular tracheobronchitis

BACKGROUND

The aim of our study was to investigate the prevalence of coexisting conditions and exposures in children with nodular tracheobronchitis diagnosed by flexible bronchoscopy.

METHODS

We conducted a single-center retrospective review of 100 children diagnosed with nodular tracheobronchitis by flexible bronchoscopy between 2012 and 2023.

RESULTS

Common coexisting diagnoses included gastroesophageal reflux disease (GERD, 50%), dysphagia/aspiration (40%), asthma (30%), recurrent croup (30%), tracheostomy dependence (19%) and eosinophilic esophagitis (EOE) (12%). Bronchoalveolar lavage (BAL) demonstrated cellular inflammation with elevated proportions of neutrophils in 63%, and lymphocytes in 24%. Among 88 patients in whom bacterial cultures were performed, 52% were positive, with Moraxella, Haemophilus, Streptococcal and Pseudomonas species predominating. Among 30 patients who underwent viral testing, 57% were positive, with rhinovirus (82%) and adenovirus (29%) predominating. Patients with neutrophilic inflammation were more likely to have a positive respiratory bacterial culture and/or viral polymerase chain reaction (p = 0.003, 0.005). Evaluation of the gastrointestinal tract included 79 patients with a history of esophagogastroduodenoscopy, 45 patients with a videofluoroscopic swallow study (VFSS), and 45 patients with multi-channel intraluminal impedance and pH testing. The majority of VFSS were abnormal (60%) demonstrating either laryngeal penetration (33%) or intratracheal aspiration (27%). Median pH reflux and impedance proximal reflux indices were 3.8% and 0.5% respectively.

CONCLUSION

Potential contributing factors in the pathophysiology of nodular tracheobronchitis include bacterial and viral infections, GERD, dysphagia/aspiration, and EOE. When nodular tracheobronchitis is observed during bronchoscopy, further evaluation to assess for these conditions should be considered.

Respiratory virus infections of the lower respiratory tract elevate bronchoalveolar lavage eosinophil fraction: a clinical retrospective study and case review

BACKGROUND

Eosinophilic airway inflammation caused by respiratory virus infection has been demonstrated in basic research; however, clinical investigations are lacking. To clarify the extent to which respiratory virus infection induces airway eosinophilic inflammation, we reviewed the results of bronchoalveolar lavage (BAL) and respiratory virus testing performed at our hospital.

METHODS

Among the BAL procedures performed at the University of the Ryukyu Hospital from August 2012 to September 2016, we collected cases of acute respiratory disease in which multiplex polymerase chain reaction (PCR) was used to search for respiratory viruses. The effect of respiratory virus detection on BAL eosinophil fraction was analyzed using statistical analysis. A case study was conducted on respiratory virus detection, which showed an elevated BAL eosinophil fraction.

RESULTS

A total of 95 cases were included in this study, of which 17 were PCR-positive. The most common respiratory virus detected was parainfluenza virus (eight cases). The PCR-positive group showed a higher BAL eosinophil fraction than the PCR-negative group (p = 0.030), and more cases had a BAL eosinophil fraction > 3% (p = 0.017). Multivariate analysis revealed that being PCR-positive was significantly associated with BAL eosinophil fraction > 1% and > 3%. There were nine PCR-positive cases with a BAL eosinophil fraction > 1%, of which two cases with parainfluenza virus infection had a marked elevation of BAL eosinophil fraction and were diagnosed with eosinophilic pneumonia.

CONCLUSIONS

Cases of viral infection of the lower respiratory tract showed an elevated BAL eosinophil fraction. The increase in eosinophil fraction due to respiratory virus infection was generally mild, whereas some cases showed marked elevation and were diagnosed with eosinophilic pneumonia. Respiratory virus infection is not a rare cause of elevated BAL eosinophil fraction and should be listed as a differential disease in the practice of eosinophilic pneumonia.

Influenza vaccination in children at high risk of respiratory disease

Chronic respiratory diseases (CRDs) are a heterogeneous group of diseases that can affect the pediatric population and health authorities throughout the world recommend influenza vaccination because of the significant risk of influenza-related complications. However, despite this recommendation, vaccine coverage is generally unsatisfactory. The aim of this review is to analyze the impact of influenza on children at high risk of respiratory disease, and the immunogenicity, safety and efficacy of influenza vaccination in such children. The results show that there is a significant risk of influenza-related complications in preterm neonates and infants, in whom influenza vaccines are immunogenic and safe (although their efficacy has not been specifically studied). There are conflicting data concerning the effect of influenza infection on asthma morbidity in children, and whether or not influenza vaccination helps to prevent asthma exacerbations. Recent data provide no evidence that influenza is more frequent in patients with cystic fibrosis than in healthy subjects, or that it is responsible for increased lower respiratory tract morbidity. The lack of any clear correlate of protection suggests that future studies should also consider the efficacy of the different influenza vaccines and not only evaluate them in terms of immunogenicity. Furthermore, there is a need for clinical studies to assess the effectiveness of the available vaccines in patients with other rare CRDs and other chronic underlying diseases with possibly severe respiratory involvement. It is also important to determine whether children with recurrent respiratory tract infections should be included in the list of those for whom influenza vaccination is recommended. In the meantime, given the increasing evidence of the burden of influenza on the population as a whole and the benefits associated with vaccination, annual influenza vaccinations should be recommended for all children at high risk of respiratory disease and the members of their households.