Pneumopericardium is an uncommon but potentially serious condition of which leading cause is mechanical ventilation in infants suffering respiratory distress syndrome. In adults, however, the most common causes are iatrogenic in diagnostic and therapeutic procedures, as well as traumatic lesions. We describe a case of pneumopericardium in a teenager suffering an asthma crisis. A review of the literature is presented, stressing the most relevant findings of the physical examination and habitual laboratory tests.