What condition is characterized by a severely swollen, blue, cool lower extremity?

The condition characterized by a severely swollen, blue, cool lower extremity is Phegmasia cerulea dolens. This is a severe form of deep vein thrombosis (DVT) that involves extensive venous occlusion, leading to significant swelling and cyanosis (bluish discoloration) of the affected limb.

The clinical presentation of this condition is critical; the combination of severe swelling, a blue tint, and coolness to the touch indicates a compromised venous outflow and possibly arterial blood supply, resulting from acute venous obstruction. The term "phlegmasia" translates to inflammation of the veins, and "cerulea dolens" refers specifically to the blue and painful nature of the affected extremity.

In contrast, while deep vein thrombosis can also lead to swelling and pain, it does not typically result in the distinct severe symptoms observed in phlegmasia cerulea dolens. Chronic venous insufficiency usually manifests with chronic symptoms such as swelling and skin changes over time rather than acute presentations. Pulmonary embolism, although severe and related to DVT, presents primarily with respiratory symptoms and does not typically involve the characteristic swelling and discoloration of a lower limb.