Clinical Significance of Spontaneous Pneumomediastinum.

Background: Spontaneous pneumomediastinum (SPM) is classified as free air in the mediastinum in the absence of any precipitating cause. It is relatively uncommon, and the clinical significance and risk associated with SPM is not well understood and has not been widely documented in the literature. Our goals were to determine the outcomes of patients who presented with SPM and to determine predictors of severe pathology associated with SPM.

Methods: From 2004 through 2013, a retrospective review was conducted of patients who presented with SPM to our institution. Patient demographics, comorbidities, laboratory tests, and esophageal perforation were recorded.

Results: In all, 249 patients were discovered to have SPM on chest radiograph or computed tomography scan. Mean age was 38.7 years (range, 17 to 81). Sixty-one percent of patients (151 of 249) were male. Ten percent of all patients (24 of 249) were ultimately discovered to have esophageal perforation, determined by upper endoscopy, upper gastrointestinal series, or intraoperatively during emergent surgery. Age (p < 0.01), pleural effusion (p < 0.01), and elevated white blood cell count (p < 0.01) were the only significant risk factors for esophageal perforation on multivariate analysis.

Conclusions: Spontaneous pneumomediastinum is usually associated with a benign clinical course. Risk factors for esophageal perforation in these patients include age, elevated white blood cell count, and a pleural effusion. In the absence of abnormal laboratory values or associated radiologic findings, the majority of patients with SPM may be safely observed without the need for further diagnostic testing.