Cocaine-Induced Pneumopericardium
Likely use of "crack" cocaine with solid contaminants in the crystalline mass could may cause a microscopic esophageal tear and eventually produce a leak of air into the pericardial sac.
See interesting case report here (Circulation. 2000;102:2792)
CXR shows linear detachment along silhouette of left ventricle and left atrium (arrows)
