Spontaneous pneumomediastinum: are we overinvestigating?

Background: Spontaneous pneumomediastinum (SPM) is uncommon in pediatrics. Because of the growing concern about the risks of radiation in children, the authors analyzed whether an extensive radiologic workup influences management and outcome.

Methods: In a retrospective study from 1991 to 2003, 53 patients were diagnosed with SPM. Charts were reviewed for demographics, predisposing factors, presentation, investigation, and evolution. Pneumomediastinum occurring in the neonatal period or related to either pneumothorax, barotrauma, or trauma were excluded.

Results: Of 53 cases, 26 (49%) were bronchospasm related, 11 (21%) had respiratory tract infections, and 8 (15%) were idiopathic. Four (7.5%) were caused by inhaled foreign bodies while other causes accounted for the remaining 7.5%. No esophageal perforations were identified. Presentations included dyspnea (64%), subcutaneous emphysema (60%), cough (45%), cervical or chest pain (42%), and Hamman's sign (19%). Postero-anterior chest x-rays (CXR) were diagnostic in all cases except one. Mean number of CXR per hospitalization was 3. Only 3 patients subsequently had pneumothorax, and none required pleural drainage. Of the 8 patients with idiopathic SPM, 5 underwent a barium swallow, and 2 had a chest CT scan; results of all were normal.

Conclusions: More than 70% of SPMs were related to bronchospasm or respiratory tract infections. Idiopathic SPMs deserve more attention because of the concern about esophageal perforation, although most investigations will be negative. SPM usually is a self-limited condition, and prognosis is related to the underlying disorder. Consequently, with clinical improvement, aggressive investigation and follow-up x-ray rarely is warranted.