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A5278 - Case Report: Pneumomediastinum, a Rare Complication of Noninvasive Ventilation Through a Descending Pathway
Author Block: K. Mohamed Ahmed1, F. G. Jamous2; 1University of South Dakota Sanford School of Medicine, Sioux Falls, SD, United States, 2Pulmonary and Sleep Medicine, Avera Medical Group, Sioux Falls, SD, United States.
Introduction: Spontaneous pneumomediastinum is an uncommon and relatively benign disorder of bronchial asthma exacerbation. We present a case of pneumomediastinum that complicated asthma exacerbation through a novel pathway and mechanism.
Case presentation: 32-year-old male, with history of bronchial asthma was admitted to our hospital with acute asthma exacerbation and respiratory failure. He initially required Noninvasive ventilation (NIV). Few days before his presentation he underwent Endodontic therapy (root canal procedure) for his left lower molar tooth, he reported that the root canal filling fall off shortly afterwards. On the second day of hospitalization patient reported fullness of his neck which prompted imaging, he was otherwise clinically improving and responding well to steroids and inhaler therapy. A subcutaneous emphysema and pneumomediastinum-that was not present on initial X-ray- was detected. CT scan confirmed the findings. NIV was discontinued and patient tolerated nasal canula, he continued to improve without any further intervention and was discharged home 3 days later. Our patient denied smoking or illicit drug use. There were no reported coughing spells or vomiting.
Discussion: pneumomediastinum is a rare complication of bronchial asthma. The pathophysiology was described by Macklin and Macklin in 1944 and is thought to be air leak from ruptured alveoli that dissects into peri bronchial vascular sheath and then travels into the hilum. Because the mediastinum is connected through vascular structures to the neck soft tissues; pneumomediastinum often leads to concomitant subcutaneous emphysema at the base of the neck through ascending pathway. Case reports of pneumomediastinum through another descending pathway (From pharyngeal tissue down to the mediastinum) has been reported mainly following dental procedures. The growing use of NIV in treating respiratory failure resulted in reduced intubation rates and-in certain conditions- reduced mortality. NIV associated barotrauma is exceedingly rare. The use of NIV in patients with recent dental procedures could result in pneumomediastinum through a descending pathway. Absence of Macklin effect on CT scan, the amount of air at the base of skull/neck tissue compared with that in the mediastinum as well as the development of pneumomediastinum while patient respiratory status is improving all supports a descending pathway in our case. Recognition of the pathophysiology in those cases is of paramount importance. Unlike alveolar space oral cavity is not sterile which increases the risk of mediastinitis in similar cases. Discontinuation of NIV in such cases is prudent and early recognition of this complication might be lifesaving.