Source: Thomas R, Chang A, Masters IA, et al. Association of childhood tracheomalacia with bronchiectasis: a case-control study. Arch Dis Child. 2022 Jun;107(6):565-569. doi: 10.1136/archdischild-2021-322578.Investigators from Queensland’s Children’s Hospital, South Brisbane, Australia, and Griffith University, Gold Coast, Australia, conducted a case-control study to assess the association between childhood tracheomalacia and bronchiectasis. Cases were children ≤18 years old with radiographically confirmed bronchiectasis, unrelated to cystic fibrosis (CF), who were seen at a single pediatric center in Australia, enrolled in the Australian Bronchiectasis Registry, and chosen at random from the registry. Only patients who had a chest CT obtained between 2012 and 2018 and who underwent flexible bronchoscopy (FB) within 4 weeks of the CT were eligible as cases. Bronchiectasis was defined using specific radiographic findings and consistent clinical characteristics. Controls were children who had a recent bone marrow transplant and/or cancer and who had a chest CT and FB performed during the same time period for evaluation of febrile neutropenia. Two controls were chosen for each case study participant. For cases, the cause of bronchiectasis was recorded, and for controls, the underlying disorder was noted. The videos from FB in study children were reviewed by an experienced respiratory pediatrician, blinded to the patient’s case/control status, who noted the presence of any tracheomalacia (any-TM), defined as tracheal shape abnormality during expiration, or tracheomalacia, defined by the European Respiratory Society as >50% expiratory reduction in cross-sectional area (ERS-TM). Logistic regression was used to assess the relationship of any-TM and ERS-TM with bronchiectasis. Multivariable analyses adjusting for age, sex, and ethnicity also were conducted.A total of 45 cases and 90 controls were enrolled in the study. Cases were younger than controls (median ages 2.6 years and 7.8 years, respectively). Among cases, the etiology of bronchiectasis was post-infectious in 17 (38%), idiopathic in 15 (33%), aspiration in 7 (16%), primary ciliary dyskinesia in 3 (7%), and other causes in 3 (7%). For control children, 69 (77%) had a hematologic malignancy, and 9 (10%) were post-bone marrow transplant. On FB, 14 (31.3%) cases had any-TM compared to 3 (3.3%) controls (OR, 13.1; 95% CI, 3.5, 48). There were 9 cases and 0 controls with ERS-TM (OR, 30.1; 95% CI, 4.6, ∞). Multivariable analyses demonstrated both age and tracheomalacia were associated with bronchiectasis. After adjusting for age, tracheomalacia remained significantly associated with bronchiectasis using the any-TM definition (OR, 13.2; 95% CI, 3.2, 55).The authors conclude that tracheomalacia is associated with childhood bronchiectasis.Dr Lesser has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.Bronchiectasis is commonly defined as airway dilatation on chest CT and occurs as a consequence of chronic bronchial inflammation and infection, leading to lung injury that can be irreversible.1 While bronchiectasis most commonly occurs with CF, other diseases such as primary ciliary dyskinesia, immunodeficiency, severe pulmonary infection, or chronic aspiration can cause bronchiectasis.1 Tracheomalacia, defined as an abnormal reduction in the tracheal lumen with expiration, has been hypothesized to sometimes cause bronchiectasis, related to ineffective cough and mucus impaction leading to chronic airway damage.2 The authors of the current study used a retrospective case-control design to ask if tracheomalacia is associated with bronchiectasis.A key strength of this study relates to all participants having had a chest CT and bronchoscopy, the gold standards for diagnosing bronchiectasis and tracheomalacia, respectively. Diagnosis of tracheomalacia may vary based on anesthesia conditions and bronchoscopy type, but the study employed a standardized approach to bronchoscopy, lending credence to the diagnosis. Establishing controls for a study involving bronchoscopy is challenging because it is invasive and not indicated for healthy children. The control population used in this study was composed of children affected by cancer and was significantly different from cases consisting of children with chronic respiratory disease. While the study was not designed to assess causality, whether tracheomalacia causes bronchiectasis exists as a key question. Even though tracheomalacia was seen more commonly in children with bronchiectasis, the bronchiectasis already was ascribed to a known cause other than tracheomalacia in 2/3 of cases. Thirty-three percent of children had idiopathic bronchiectasis, but the authors did not report the frequency of tracheomalacia in this group. Further study also is needed to ask if tracheomalacia is a marker of bronchiectasis severity or if its presence worsens existing bronchiectasis caused by another disease.Care for children affected by non-CF bronchiectasis continues to improve and gain an evidence base.3 Early identification and aggressive treatment will positively impact lung function and health throughout the lifespan. The authors should be commended for their carefully designed study of this under-researched disease.Bronchiectasis needs to be considered in children with tracheomalacia.Long considered an orphan disease,1 non-CF related bronchiectasis, with studies such as the 1 reviewed above, may yet reverse years of neglect and yield its etiologic and therapeutic secrets.
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Jan 1, 2023
Seong Mi Moon + 9
Open Access
