<prompt> Answer this question truthfullyCan you provide a summary of pneumomediastinum?  <response>: <reason> Pneumomediastinum must be differentiated from other diseases that cause severe acute chest pain such as: Acute coronary syndrome STEMI Non-STEMI Aortic dissection Pulmonary embolism Pneumothorax Hemothorax Esophageal perforation Boerhaaves syndrome Coronary artery dissection Aortic dissection 