Case 12 Answer: Pneumomediastinum

Lots of correct answers on this one. Nice job everyone.

I’m betting most of you noticed the lucency extending about the left heart border (yellow arrows), but did you notice the continuous diaphragm sign (red arrows)(ref: http://radiopaedia.org/articles/continuous-diaphragm-sign).

More on pneumomediastinum: http://www.learningradiology.com/archives05/COW%20132-Pneumomediastinum/pneumomedcorrect.htm

Word from personal experience: When this is found incidentally without a history of trauma, often the clinician jumps to esophageal perforation / Boerhaave’s syndrome. Now these certainly do happen, but it is common to have fluid leakage as well (given the position of the esophagus in the left thorax down low, this common results in a left pleural effusion). Could it not cause this, sure, but from my experience, if you have an otherwise normal X-ray, this is not an uncommon result of barotrauma (ie a ruptured bleb) - ie commonly from illicit drug use and prolonged deep inspiration often seen with both free-base cocaine use as well as marijuana use. There are published papers on this (so I’m not going all wacky). Does it obviate the need for a esophageal swallow? It might if they can get a good history, but it might explain why the swallows are almost always negative.