Multidimensional approach using HRCT for the diagnosis of severe asthma in children

Background: GINA defines severe asthma as a subset of difficult to treat asthma, which is uncontrolled despite adherence with maximal optimized high dose ICS-LABA and treatment of contributory factors, or that worsens when high dose treatment is decreased. The diagnosis of severe asthma is complicated, and we believe that the usage of HRCT could assist in the diagnosis of severe asthma in children. Objective: we performed a retrospective, monocentric study that his goals are to characterize the clinical and functional characteristics and describe the radiological findings of chest HRCT in children with severe asthma. Methods: we compared between a group of 20 pediatric patients (6 – 17years) with severe asthma based on the GINA guidelines, to 21 control pediatric patients (6 – 17 years) that attended our pediatric clinic for reasons other than asthma. There were no differences between the study groups in terms of age, BMI, ethnicity, and gender. Each patient in both groups followed laboratory tests (blood eosinophil count, total and specific IgE), spirometry, FeNO evaluation, conventional radiography, and chest HRCT. Based on these HRCT scans we measured different parameters, Bronchial Thickening (BT), Air Trapping (AT), Airway Wall Thickness (AWT), Bronchiectasis Grading and Severity (BG, BS), Ground Glass (GG) Opacities, Mucus Plugging (MP), and Emphysema. Results: Among the asthmatic children the mean FEV1 Z-score was -1.11, mean FVC Z-score was -0.16, with a mean lifetime hospitalization of 2. Moreover, the mean eosinophilic count was 464 cell/mcl, and the mean FeNO was 61.8 ppb. We further found that 30% of severe asthmatic children were taking biological therapy. Based on a univariate analysis, we found that several of our HRCT results were significantly associated with the severe asthmatic children group, among them, BT score (p<0.001), AWT% (p<0.001), BG and BS scores (P = 0.016), MT score (p = 0.009) and Centrilobular Emphysema (p = 0.009). Conclusions: in concordance with previous studies and based on our novel findings, among the group of children with severe asthma, HRCT findings were abnormal. We believe that these findings might contribute and assist to the multidimensional diagnosis of severe asthma in children.