Evaluating the utility of serological testing in laryngotracheal stenosis

Fatal Asphyxia Potentially Caused by COVID-19-Induced Exacerbation of Pre-existing Tracheal Stenosis

We report a case of cardiac arrest due to asphyxia caused by coronavirus disease 2019 (COVID-19) in a patient with no history of tracheal intubation but with a history of subglottic stenosis. A 54-year-old man suffered a cardiac arrest at home. The patient had tracheal stenosis; therefore, it was difficult to intubate. The patient had COVID-19, which was presumed to have aggravated the existing tracheal stenosis and caused asphyxiation. The patient died seven days later. This is, to our knowledge, the first report of a patient with subglottic stenosis potentially aggravated by COVID-19, resulting in asphyxia-related cardiopulmonary arrest. The patient could not be saved, but emergency physicians should be aware that airway obstruction can be caused by viral infections, including severe acute respiratory syndrome coronavirus 2 infections. Physicians should consider the difficulty in performing oral intubation and cricothyrotomy and be aware of alternative methods to secure the airway.

GDF15 alleviates the progression of benign tracheobronchial stenosis by inhibiting epithelial-mesenchymal transition and inactivating fibroblasts

Benign tracheobronchial stenosis (BTS) is a fatal and incurable disease. Epithelial repair and matrix reconstruction play an important role in the wound repair process. If the interstitial context is not restored and stabilized in time, it can lead to pathological fibrosis. Here we attempted to identify cytokines that are involved in promoting wound repair. Growth differentiation factor 15 (GDF15) is a cytokine secreted by tracheal epithelial cells, which is indispensable for the growth of epithelial cells and inhibits the overgrowth of fibroblasts. GDF15 can counteract transforming growth factor-β (TGFβ1) stimulation of epithelial-mesenchymal transition (EMT) in tracheal epithelial cells and inhibit fibroblast activation via the TGFβ1-SMAD2/3 pathway. In a rat model of tracheal stenosis, GDF15 supplementation alleviated the degree of tracheal stenosis. These results suggest that GDF15 prevents fibroblast hyperactivation and promotes epithelial repair in injured trachea. GDF15 may be a potential therapy to improve benign tracheobronchial stenosis.

Molecular Mechanisms and Physiological Changes behind Benign Tracheal and Subglottic Stenosis in Adults

Laryngotracheal stenosis (LTS) is a complex and heterogeneous disease whose pathogenesis remains unclear. LTS is considered to be the result of aberrant wound-healing process that leads to fibrotic scarring, originating from different aetiology. Although iatrogenic aetiology is the main cause of subglottic or tracheal stenosis, also autoimmune and infectious diseases may be involved in causing LTS. Furthermore, fibrotic obstruction in the anatomic region under the glottis can also be diagnosed without apparent aetiology after a comprehensive workup; in this case, the pathological process is called idiopathic subglottic stenosis (iSGS). So far, the laryngotracheal scar resulting from airway injury due to different diseases was considered as inert tissue requiring surgical removal to restore airway patency. However, this assumption has recently been revised by regarding the tracheal scarring process as a fibroinflammatory event due to immunological alteration, similar to other fibrotic diseases. Recent acquisitions suggest that different factors, such as growth factors, cytokines, altered fibroblast function and genetic susceptibility, can all interact in a complex way leading to aberrant and fibrotic wound healing after an insult that acts as a trigger. However, also physiological derangement due to LTS could play a role in promoting dysregulated response to laryngo-tracheal mucosal injury, through biomechanical stress and mechanotransduction activation. The aim of this narrative review is to present the state-of-the-art knowledge regarding molecular mechanisms, as well as mechanical and physio-pathological features behind LTS.

Multi-disciplinary management of patients with benign airway strictures: A review

Histologically benign airway strictures are frequently misdiagnosed as asthma or COPD and may present with severe symptoms including respiratory failure. A clear understanding of pathophysiology and existing classification systems is needed to determine the appropriate treatment options and predict clinical course. Clinically significant airway strictures can involve the upper and central airways extending from the subglottis to the lobar airways. Optimal evaluation includes a proper history and physical examination, neck and chest computed tomography, pulmonary function testing, endoscopy and serology. Available treatments include medical therapy, endoscopic procedures and open surgery which are based on the stricture's extent, location, etiology, morphology, severity of airway narrowing and patient's functional status. The acuity of the process, patient's co-morbidities and operability at the time of evaluation determine the need for open surgical or endoscopic interventions. The optimal management of patients with benign airway strictures requires the availability, expertise and collaboration of otolaryngologists, thoracic surgeons and interventional pulmonologists. Multidisciplinary airway teams can facilitate accurate diagnosis, guide management and avoid unnecessary procedures that could potentially worsen the extent of the disease or clinical course. Implementation of a complex airway program including multidisciplinary clinics and conferences ensures that such collaboration leads to timely, patient-centered and evidence-based interventions. In this article we outline algorithms of care and illustrate therapeutic techniques based on published evidence.