Phlegmasia cerulea dolens (PCD) [literally: painful blue inflammation; not to be confused with phlegmasia alba dolens] is an uncommon severe form of lower extremity deep venous thrombosis (DVT) that obstructs venous outflow. It results from extensive thrombotic occlusion (blockage by a thrombus) of the lower extremity vein(s), most commonly an iliofemoral DVT of the iliac vein and/or common femoral vein. [Source: Wikipedia 
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