Clinical Implications of Pneumomediastinum

Abstract

1. Background Spontaneous pneumomediastinum is a rare condition and is regarded as benign. Because of its vague clinical presentation, it is often misdiagnosed. The purpose of this study was to describe the clinical characteristics and radiologic findings of spontaneous pneumomediastinum and assess the relation between them.

2. Patients and Methods We retrospectively extracted demographics, clinical symptoms, predisposing factors, triggering events and radiologic findings from medical records of 41 patients diagnosed with spontaneous pneumothorax.

3. Results Forty-one patients (32 men, 9 women; mean body mass index, 20.6 ± 3.0) were included. The most common presenting symptoms were chest pain (61.0%) and dyspnea (56.1%). Although triggering events include physical exercise, defecation and emesis, most patients did not recall any definite triggering events (80.5%). Pneumonia (34.1%) and interstitial lung disease (19.5%) were identified as most common predisposing factors and were related to prolonged hospital stay (p<0.05). Subcutaneous emphysema was noted in 51.2% of the patients. Compared to the 100% diagnostic rate of chest computed tomography, chest X-ray had 22.0% false negative rate. This was related to the absence of subcutaneous emphysema (p=0.001).

4. Conclusion Spontaneous pneumomediastinum occurs primarily in slender, young men presenting with non-specific manifestations such as chest discomfort or dyspnea. Pathognomonic signs such as subcutaneous emphysema may not be revealed and this may be the reason for the misdiagnosis with chest X-ray. Spontaneous pneumomediastinum should be suspected in patients with these vague symptoms even in the absence of air in the mediastinum on chest X-ray; chest computed tomography is required for an accurate diagnosis of spontaneous pneumomediastinum.