Clinical, radiological, and physiological differences between obliterative bronchiolitis and problematic severe asthma in adolescents and young adults: the early origins of the overlap syndrome?

ABSTRACT

PURPOSE: Few reports have compared chronic obstructive lung diseases (OLDs) starting in childhood. AIMS: To describe functional, radiological, and biological features of obliterative bronchiolitis (OB) and further discriminate to problematic severe asthma (PSA) or to diagnose a group with overlapping features. RESULTS: Patients with OB showed a greater degree of obstructive lung defect and higher hyperinflation (P < 0.001). The most frequent high-resolution computed tomography (HRCT) features (increased lung volume, inspiratory decreased attenuation, mosaic pattern, and expiratory air trapping) showed significantly greater scores in OB patients. Patients with PSA have shown a higher frequency of atopy (P < 0.05). ROC curve analysis demonstrated discriminative power for the LF variables, HRCT findings and for atopy between diagnoses. Further analysis released five final variables more accurate for the identification of a third diagnostic group (FVC%t, post-bronchodilator ΔFEV(1) in ml, HRCT mosaic pattern, SPT, and D. pteronyssinus-specific IgE). CONCLUSIONS: We found that OB and PSA possess identifiable characteristic features but overlapping values may turn them undistinguishable.