Cervical emphysema, pneumomediastinum, and pneumothorax following self-induced oral injury: report of four cases and review of the literature.

Spontaneous rupture of the pulmonary alveoli after a sudden increase in intra-alveolar pressure is a common cause of pneumomediastinum, which is usually seen in healthy young men. Other common causes are traumatic and iatrogenic rupture of the airway and esophagus; however, pneumomediastinum following cervicofacial emphysema is much rarer and is occasionally found after dental surgical procedures, head and neck surgery, or accidental trauma. We present four cases of subcutaneous emphysema and pneumomediastinum with two secondary pneumothoraces after self-induced punctures in the oral cavity. They constitute an uncommon clinical entity that, to our knowledge, has not been reported in the literature. Its radiologic appearance, clinical presentation, and diagnosis are described.