Radiological–pathological signatures of patients with COVID-19-related pneumomediastinum: is there a role for the Sonic hedgehog and Wnt5a pathways?

• Published in: ERJ open research 2021-07, Vol.7 (3), p.346
• Main Authors: Baratella, Elisa, Bussani, Rossana, Zanconati, Fabrizio, Marrocchio, Cristina, Fabiola, Giudici, Braga, Luca, Maiocchi, Serena, Berlot, Giorgio, Volpe, Maria Concetta, Moro, Edoardo, Confalonieri, Paola, Cova, Maria Assunta, Confalonieri, Marco, Salton, Francesco, Ruaro, Barbara
• Format: Article
• Language: English
• Subjects: Research Letters
• ISSN: 2312-0541; 2312-0541
• DOI: 10.1183/23120541.00346-2021

Pneumomediastinum is a rare complication of acute respiratory distress syndrome (ARDS), when air leaks into the mediastinum. An increased pneumomediastinum incidence, of up to 5–13%, was reported during the coronavirus disease 2019 (COVID-19) pandemic [1, 2] and even occurred spontaneously without a history of mechanical ventilation [3], similarly to the previous severe acute respiratory syndrome (SARS)-1 [4]. Almost half of the 30 consecutive COVID-19 patients who had prolonged invasive mechanical ventilation had full-thickness tracheal lesions and pneumomediastinum [5]. Although pronation and high positive end-expiratory pressure levels were presumed to be the putative causes of pneumomediastinum [5], the mechanism of this COVID-19 complication remains unknown. We hypothesise that sonic hedgehog (SHH) and Wnt5a signalling, crucial pathways in tracheal morphogenesis, and repair/regeneration of cartilage lesions in adulthood [6, 7], could play a role in pneumomediastinum-related COVID-19 tracheal lesions. Pneumomediastinum is a rare complication of ARDS but is more common during #COVID19. The fibrous hyaline degeneration of the tracheal rings seen in this autoptic series is an original observation that has not been previously described in COVID-19 patients. https://bit.ly/3vxTQde