Idiopathic spontaneous pneumomediastinum: an uncommon emergency in children.

Spontaneous pneumomediastinum (SPM) occurs rarely in children. The diagnosis is based on physical examination and chest radiography. Conservative therapy usually leads to recovery. However, SPM in association with severe hypoxia, tachycardia, metabolic acidosis, and high ventilation pressures indicates clinically significant tension in the mediastinum. A collar mediastinotomy is the treatment of choice in these circumstances.