An Uncommon Cause of Spontaneous Pneumomediastinum and Subcutaneous Emphysema

Edwards, Michael; Ramappa, Arun Jeenahalli

Pneumomediastinum presents most commonly with chest pain, shortness of breath, and subcutaneous emphysema but rhinolalia, cough, neck pain, emesis, and dysphagia are also possible [4] . The diagnosis of pneumomediastinum in our patient was confirmed by computed tomography after it was initially suspected from chest x-ray. Subcutaneous emphysema was simultaneously identified by chest x-ray and clinical examination. While a majority of pneumomediastinum cases can be identified by chest x-ray, computed tomography provides confirmation in uncertain cases and clarification of its extent [2] . Pneumomediastinum has previously been associated with cases of pneumonia but often with rare strains such as P. jirovecii pneumonia in immunocompromised patients [1] . In the case described above, the patient had no known immunocompromise or pre-existing lung disease and grew no micro-organisms from culture. However, given the lack of other precipitants (e.g. penetrating chest injury, endoscopic procedure), and because the degree of severity of both pneumomediastinum and pneumonia appears to be linked, it is reasonable to conclude that the pneumomediastinum is secondary to the patient's pneumonia. In this case the patient suffered from extensive subcutaneous emphysema and eventually died of septicaemia. Spontaneous pneumomediastinum is typically associated with a benign course that resolves itself conservatively without invasive management [2] . Spontaneous pneumomediastinum is also most common in patients aged 14-35 years, which is likely to be due to slack mediastinal sheaths that allow the passage of air along vascular routes [3] . The 79-year-old gentleman in this case was not a demographically common patient for this atraumatic phenomenon. In some cases significant amounts of air may accumulate in the mediastinum due to tracheobronchial rupture, oesophageal perforation, or pneumothorax. Airway compression and tamponade may occur due to the build-up of air. Cases may require interventions such as subcutaneous needle drainage, chest drain insertion, Video-Assisted Thoracoscopic Surgery (VATS), or even thoracotomy [4] . There was no indication for invasive intervention in this case. Information surrounding the use of invasive/non-invasive ventilation in these patients is limited due to the principally benign course of the condition. Mechanical ventilation may worsen air leakage and the subsequent pneumomediastinum but may be used with caution if the patient's clinical state necessitates its use [5] . While spontaneous pneumomediastinum is often a benign condition affecting younger males and in patients with underlying airway disease, pneumonia is an uncommon cause of pneumomediastinum. Treatment of pneumomediastinum has traditionally been conservative and although options may be limited, aggressive management of any causative factor may be essential in selected cases.