Lower extremity swelling can be caused by kidney disease, commonly chronic nephritis, glomerulonephritis, repeated episodes of renal function abnormalities can also affect sodium metabolism, sodium storage. The common manifestation is edema of the lower extremities, usually double lower extremity edema, and may also be prone to secondary infections. In other cases, due to deep vein thrombosis of the lower extremities or iliac vein thrombosis, the patient may also present with marked swelling of the abdominal wall and lower extremities, accompanied by abdominal pain or low back pain. This condition is usually secondary to hypercoagulable state of blood or endothelial injury after trauma, both of which are prone to secondary DVT, and should be promptly intervened with the choice of inferior vena cava filter implantation. This is because thrombus dislodgement can easily circulate to the pulmonary artery, leading to pulmonary embolism, which is life-threatening in severe cases.