A patient with a recent history of immobilization has a new onset of unilateral leg swelling with dependent edema. This condition is most likely due to which of the following?

The new onset of unilateral leg swelling and dependent edema in a patient with a recent history of immobilization is most indicative of deep vein thrombosis (DVT). When a patient has been immobile for an extended period, as can occur post-surgery, with immobilization due to injury, or during long flights, the blood flow in the veins can become sluggish. This creates a higher risk for clot formation in the deep veins of the legs.

DVT often presents with symptoms such as unilateral swelling, pain, warmth, and changes in skin color. The dependent edema observed indicates that fluid is accumulating in the lower extremities, which is characteristic in thrombotic conditions due to obstruction of venous return. Furthermore, the risk factors associated with recent immobilization align directly with the development of DVT.

In contrast, conditions like congestive heart failure could lead to bilateral swelling rather than unilateral, and peripheral arterial disease typically presents with symptoms related to arterial insufficiency, such as claudication and coolness rather than dependent edema. Lymphedema usually develops gradually and is related to lymphatic system dysfunction and is often bilateral or affects specific regions rather than presenting acutely after immobilization. This context emphasizes why deep vein thrombosis is the most likely