[Bronchiolitis obliterans: outcome in the medium term]

Abstract

Background: Bronchiolitis obliterans is a chronic obstructive lung disease that follows a severe insult to the lower respiratory tract. Severity and outcome are different depending on the geographic area. The aim of this study was to communicate the results of our sample.

Methods: A retrospective study was performed in a sample of boys and girls with a medical diagnosis of bronchiolitis obliterans (BO) between December 1994 and February 2011. The diagnosis was made by high-resolution computed tomography (HRCT) scan and lung function. Lung biopsy was performed in one case. Pulmonary function testing included; forced spirometry (≥ 3 years old), plethysmography (≥ 5 years), bronchodilator tests (BDT), single-breath determination of carbon monoxide uptake in the lung (D(LCO)) (≥ 6 years) and measurement of exhaled lower respiratory nitric oxide (FE(NO)). Quantitative variables were; age at diagnosis, respiratory morbidity before the diagnosis, time from the start of the symptomatology until the diagnosis, follow-up time, respiratory morbidity after the diagnosis, airway specific resistance (sR(eff)), airway specific conductance (sG(eff)), residual volume, total lung capacity, thoracic gas volume, FEV(1), FVC, FEV(1)/FVC, FEF(25-75), D(LCO) and FE(NO). Qualitative variables were; sex, reason for consulting, viral infections, atopy, smoke exposure, HRCT scan and current treatment. Descriptive analysis was performed and pulmonary function before and after BDT was studied using paired-sample Wilcoxon and Student́s t-test.

Results: We studied a cohort of 22 cases, 10 (45.4%) boys and 12 (54.5%) girls. The mean age at the diagnosis was 4.87 ± 3, 27 years old. The follow-up period was 5 years (range 1 to 8 years). Related virus were; influenza 2 (9.09%), parainfluenza 2 (9.09%), adenovirus 3 (13.69%), syncytial respiratory virus 1 (4.5%) and rhinovirus 1 (4.54%). HRCT scan: mosaic pattern of lung attenuation 22 (100%) and bronchiectasis 8 (36.36%). Lung function at diagnosis showed fixed airflow obstruction and increased lung volumes. The global analysis showed a progressive decrease in FEV(1), FVC, FVC/FEV(1,) FEF(25-75) and increase in sR(eff) and residual volume with decrease in sG(eff). Individually, there was a tendency to stabilise the lung function comparing with initial values at diagnosis. Respiratory morbidity was low after the diagnosis.

Conclusions: In most cases, fixed air-flow obstruction and lung function stability with low respiratory morbidity were observed. HRCT scan and lung function testing supported the diagnosis.