Commentary on ‘effect of bronchoscopy on plastic bronchitis in children’

In this commentary, we would like to highlight the underlying causes of plastic bronchitis (PB) in children which is not mentioned in detail in the article by Yuan et al.1 Authors reported a retrospective study evaluating the use bronchoscopy in the treatment of PB and suggested that removal of casts by bronchoscopy is a safe procedure with no serious adverse events.1 The objective of this commentary is to discuss what the underlying causes are and its impact on the treatment and follow-up. The study put forth by Yuan et al include the patients with type-1 PB. This type of PB mostly occurs in children with infections and asthma and casts consists of inflammatory cells and fibrin.2 They exclude type-2 patients that mostly encounter in children with congenital heart diseases.1 Asthma is the second most common condition which is thought to be caused by increased mucus due to goblet cell hyperplasia and increase in inflammatory mediators.3 The co-occurrence of asthma and PB is reported to be 80% of children with PB and recurrent cast development is more common in patients with asthma.4, 5 In the mentioned cohort, only 60% of the cases managed with single bronchoscopy whereas 40% of them required second or third bronchoscopies. The detailed evaluation of patients and defining underlying pathologies has utmost importance in the treatment of PB because of high risk of recurrence in cases with asthma. Furthermore, the asthma control may prevent cast recurrence in children. The microscopic evaluation of the removed cast may show accumulation of inflammatory cells and fibrins. Charcot-Leiden crystals are common histological findings in cast samples in children with PB and asthma.6 The presence of these crystals also confirms type-1 PB. Thus, histopathologic evaluation of casts is also essential part of clinical work-up in patients with PB. Infectious disease such as Mycoplasma pneumoniae, Boca virus, influenza and adenovirus are infectious causes of PB.7 Microbiological evaluation of broncho alveolar lavage is recommended in children. It has been reported that PB due to M. pneumoniae develop more recurrence than the other infectious causes. Yuan et al reported adenovirus infection in one patient and the patient died due to multiorgan failure.1 Therefore, treatment of underlying infections has paramount importance to avoid recurrence and complications. Bronchoscopy is not only diagnostic but also therapeutic intervention in children with PB. The removal of casts eliminates the airway obstruction and allows the inhaled medications pass to the distal airways. Due to underlying diseases, recurrence of cast development is common and more than one bronchoscopy needed in most of the cases.6 Yuan et al recommended to administer acetylcysteine or mucosolvan to achieve lysis of casts in patients with severe dyspnea and multiple casts.1 However, medical lysis of the casts make them stickier and more difficult to remove with forceps. Mechanical cast removal with optical forceps and rigid suctioning is recommended instead of lysis.6 We suggest that patients with casts that are firmly adherent to bronchial mucosa may benefit from medical lysis. Otherwise, routine use of lysis agents may complicate the cast removal. Close follow-up with clinical examinations and imaging is recommended to define the optimal timing for repeated bronchoscopies in children. In conclusion, the underlying causes of PB in children should be comprehensively evaluated. Asthma and infectious disease are common causes of PB and associated with recurrent cast formation. The treatment of underlying disease prevents cast formation and avoid multiple bronchoscopy interventions. As stated by the authors, bronchoscopy is a safe procedure with favorable outcomes in the treatment of pediatric PB. Yasemin Dere Günal conceptualized the study, Tutku Soyer wrote the draft and review editing. The authors declare no conflict of interest. Data sharing is not applicable in this study. No datasets were generated or analyzed in this study.