Tracheal Diverticulum in SARS-CoV-2 Patients on Non-Invasive Ventilation A not so “Spontaneous” Cause of Pneumomediastinum? An imaging Pictorial Presentation of Two Cases with Review of Literature

Abstract

Spontaneous pneumomediastinum is a rare but potentially life-threatening condition, the incidence of which has showed an increase in patients with SARS-CoV-2 pneumonia, especially when they are on positive pressure ventilation. None of the reported cases of covid related pneumomediastinum had an associated tracheal diverticulum. Also, to the best of our knowledge, tracheal diverticulum has not been reported in patients on NIV. We report 2 cases of COVID-19 pneumonia on NIV with pneumomediastinum, which also had associated tracheal diverticulum, one of which developed after NIV. Though the establishment of causality needs further research, early detection of a tracheal diverticulum, which might be a harbinger of pneumomediastinum, can be a timely alarm to prompt titration of the pressure settings and judicious use of NIV. The role of inverted grey scale CT images in mediastinal window is a simple, yet hardly utilised radiological tool to increase detection of ‘mediastinal air’, let it be free air or air within a diverticulum. Through this case report, we would like to highlight the role of conventional and inverted CT imaging of pneumomediastinum and tracheal diverticulum in general and in SARS-CoV-2 pneumonia in particular, and to call for more objective research to throw light on the plausible relationship between pneumomediastinum and tracheal diverticulum.

Tracheal Diverticulum Mimicking Pneumomediastinum: A Case Report Emphasizing the Importance of Differential Diagnosis in Chest Imaging Evaluation

“…The presence of TD can also complicate interventions such as tracheal intubation and administration of positive pressure ventilation since the TD is prone to perforation, giving rise to pneumomediastinum [ 17 ]. A literature review has also revealed cases reported of TD arising after non-invasive ventilation in coronavirus disease 2019 (COVID-19) patients, which had an associated pneumomediastinum [ 5 ]. Regarding this case, no complications or symptoms were reported after the incidental finding was determined to not be a pneumomediastinum but instead a TD.…”

“…Although TDs are considered benign in nature, they are occasionally symptomatic, presenting with cough, dyspnea, frequent respiratory infections, dysphonia, or hiccups [2][3][4]. Additionally, there have been several reported cases of adverse outcomes associated with TD associated with ventilatory support [5][6][7]. This is especially concerning in patients with acquired TD as they are generally a population with chronic lung problems that lead to sometimes invasive ventilatory intervention [1].…”

Positional relationships between a tracheal diverticulum and the tracheal tube under general anesthesia: a single-center observational and simulation study

“…In general anesthesia, tracheal diverticula cause failures in tracheal intubation, positivepressure ventilation, and lung isolation [2][3][4]. Additionally, positive-pressure ventilation for tracheal diverticula causes tracheal diverticula rupture, subcutaneous emphysema, and pneumomediastinum [4][5][6][7][8][9][10][11]. Thus, preventing positive-pressure ventilation to tracheal diverticula is important to avoid these adverse events.…”