Abstract: Objective: To summarize the clinical characteristics of 70 cases of children with bronchiolitis obliterans(BO), and to explore the susceptibility factors of the children with BO.Methods: A total of 70 children with BO(BO group) and 200 children with pneumonia(control group) were selected.The clinical materials of the children in two groups were retrospectively analyzed.Results: Among the 70 children with BO, the ratio of male to female was 2.3:1,and the age of the diagnosed BO was concentrated in infancy and early childhood;there were 64 cases (91.4%) within 3 years in BO group,32 cases (16%) within 3 years in control group,and the difference in the age composition ratio was statistically significant between two groups (P<0.05).In region distribution,the patients in BO group and control group were mainly in rural areas.There were 41 cases in rural areas in BO group and 29 cases in urban areas,and there were 113 cases in rural areas and 87 cases in urban areas in control group;there was no significant difference in the regional composition ratio between two groups (P>0.05).In terms of medical history and underlying diseases, the proportions of patients with severe pneumonia,respiratory failure,endotracheal intubation and mechanical ventilation, and non-invasive end-expiratory positive pressure ventilation in BO group were significantly higher than those in control group (P<0.05).And the children in BO group were more likely to be associated with the basic diseases such as anemia and congenital heart disease.In pathogens,the patients in two groups were infected with Mycoplasma pneumoniae, adenovirus, and Streptococcus pneumoniae, but the proportions of adenovirus and fungal infection in BO group were significantly higher than those in control group(P<0.05).The clinical manifestations of children in BO group and control group were fever, cough, and wheezing; there were three concave signs, fine wet voices or wheezing sounds on the signs.However, the proportions of children with dyspnea, repeated wheezing (usually lasting for 6 weeks to several years) and intolerance to exercise in BO group were higher than those in control group (P<0.05).Compared with control group,the children with BO had the characteristic high-resolution CT (HRCT) changes, which showed that the proportions of children with mosaic perfusion signs and bronchial wall thickening were significantly higher than those in control group (P<0.05).Pulmonary function in most children with BO suggested persistent obstructive ventilatory dysfunction, while lung function test in of the most of the children in control group suggested normal, or only a few children had transient mild changes in lung function.Conclusion: Severe pneumonia and mechanical ventilation are the main susceptibility factors of BO.The children with underlying diseases (premature birth, congenital heart disease,and bronchopulmonary dysplasia) are prone to BO if they have a serious lung infection.

Key words: children, bronchiolitis obliterans, clinical features, susceptiblility factors