Supportive care<unk>  typically reabsorbs over 1-2 weeks.
Treat underlying cause, if identified<unk>  typically reabsorbs over 1-2 weeks.
Pneumomediastinum
Acute coronary syndromes 
Hemothorax
STEMI
Chylothorax
Non-STEMI
Pneumopericardium
Unstable angina