Swollen legs may be caused by renal insufficiency or heart failure. If you want to make a definite diagnosis, you can have an ultrasound of both lower extremities, along with BNP, kidney function and cardiac ultrasound. In addition to these two problems, there are some other problems that may also cause false swelling in the legs, such as hypothyroidism, abnormal liver function, and vascular occlusion in the lower extremities. There are also special oral medications, such as glucocorticoids, calcium channel blockers, and glycopyrrological drugs that may cause patients to develop lower extremity edema. It is recommended that patients can further check liver function and thyroid function to help further clarify the diagnosis. There are also some people who may have poor venous return to the lower extremities caused by obesity, which may also trigger the appearance of leg edema, and patients are advised to lose weight appropriately.