Long-term lung function in postinfectious bronchiolitis obliterans

Abstract

We read with great interest the paper by Colom et al 1 on pulmonary function of a paediatric cohort of patients with postinfectious bronchiolitis obliterans (BO). The authors concluded that pulmonary function remained severely impaired, showing an obstructive pattern with air trapping that slowly improved during childhood. In addition, they showed that nine (19%) patients developed thoracic deformity and seven (15.2%) bronchiectasis. On the first view, contrary to their findings, the FVC and FEV 1 increased by a mean of 11%/ year (95% CI 9.3% to 12.6%; p<0.0001) and 9%/year (95% CI 7.7% to 10.2%; p<0.0001) during childhood. This is quite difficult to understand since the authors did report the increase in lung volume in per cent only, but not in litre (L). Still, their findings are in good accordance with our findings in BO.We have recently characterised a cohort of 16 patients with BO aged median 13.3 ±4.6 years and measured their lung function prospectively over 24 months by 48 plethysmographies (three measurements in each patient). Of these patients, nine were in the period of growth.Our data confirmed that BO patients had significantly lower lung function (FVC, FEV 1 , FEV 1 /VC , MEF25 and increased residual volume (RV) and RV/ TLC (total lung capacity) values) as agematched controls.As shown in table 1, lung function of patients during growth period remained stable when expressed as predicted level of normal. But there was a significant increase in lung growth by a mean of FVC 0.3 L (14.1%) and FEV 1 0.19 L (13.3%) in the first year and FVC 0.08 L (3.98%) and FEV 1 0.03 L (2.09%) in the second year indicating that lung growth is clearly related to growth velocity. Therefore, to avoid misunderstanding, lung growth should not be expressed as mean increase per year during childhood as done in the abstract.

Short-Term Variation of Lung Function and Airway Inflammation in Children and Adolescents with Bronchiolitis Obliterans

“…Clinical improvement during the disease process is somewhat attributed to the growth of the lungs and probably does not indicate regression of the pathology in the small airways [12,13]. In the majority of the published cohort studies, the overall prognosis of pulmonary function is poor.…”

Clinical, functional, and cytological evaluation of sputum in postinfectious bronchiolitis obliterans: a possible overlap with asthma?

“…(11) The bronchodilator test turned out positive in all cytological patterns, including the exclusively neutrophilic one, corroborating studies with long-term follow-up of patients with PIBO. (12,13) Those studies have shown severe and permanent impairment of lung function, though air trapping slowly decreased with patient growth. (1,12,13) There were no significant correlations between sputum cellularity and the clinical, functional, and CT variables studied.…”

“…(12,13) Those studies have shown severe and permanent impairment of lung function, though air trapping slowly decreased with patient growth. (1,12,13) There were no significant correlations between sputum cellularity and the clinical, functional, and CT variables studied. The lack of statistical correlation between the variables in the present study was probably due to the small sample size; the low prevalence of the disease represents an analytical challenge.…”

Synthèse N° 3 : Bronchites chroniques obstructives de l’enfant : un concept émergent

“…Le point de départ est une infection virale, et les nourrissons sont les plus vulnérables. A moyen terme, ces patients gardent une altération de leur fonction respiratoire avec un syndrome obstructif sur les petites voies aériennes, une distension thoracique parfois importante, des anomalies de ventilation sans anomalies de perfusion, et une réponse aux beta-2 variable [41,42]. Certains restent symptomatiques et entrent dans la définition de la BPCO de l'adulte avec une évolution vers l'insuffisance respiratoire chronique.…”