Swollen legs are a very common symptom in the elderly. What are the causes of swollen legs? Are these diseases serious? Today to give you some introduction. The common causes of leg swelling are: 1. Cardiogenic edema. It refers to edema caused by heart disease, and is most common in heart failure, especially right heart failure. The edema of such patients is characterized by obvious edema in the lower part of the body. When the patient stands, the legs are in the lowest position, so the leg swelling is more obvious, and the edema will be reduced after lying down. In addition to leg edema, patients can also show symptoms of heart failure such as shortness of breath and wheezing after activity. 2. Nephrogenic edema. It is edema caused by various kidney diseases, such as chronic nephritis, chronic renal failure, nephrotic syndrome, etc. Nephrogenic edema usually starts from the eyelids and face and progresses to the whole body, and edema caused by nephrotic syndrome is often more serious. In addition to edema, it is also accompanied by hypertension, proteinuria, hematuria, abnormal kidney function and other manifestations. 3. Hepatogenic edema. It is edema caused by liver disease, and the most common disease is cirrhosis of the liver in its decompensated stage. In addition to foot swelling, ascites is also common. These patients also have abnormal liver function, jaundice and other manifestations. 4. Malnutrition edema. These patients often suffer from chronic wasting diseases with long-term nutritional deficiency, or long-term poor appetite and impaired nutrient absorption, resulting in hypoproteinemia, which can produce edema. Patients often show wasting and weight loss before the appearance of edema. 5.Oedema caused by other reasons. Such as mucinous edema (hypothyroidism), medication edema (glucocorticoids, licorice preparations, calcium ion antagonists, etc.), senile edema, etc. In addition, there is another kind of edema that should be paid attention to. This kind of edema is not symmetrical in both legs, but the leg of one limb is swollen badly, and its cause may be venous thrombosis of the lower limbs, and this thrombus can be dislodged and flow with the blood, and if it flows to the lungs, it can cause pulmonary embolism, which is a more serious disease. Of course, from the above analysis, it can be seen that the diseases that cause swollen feet are common with chronic diseases, and many chronic diseases can be effectively treated, and the swollen feet can subside or be reduced, and will not immediately threaten the life safety of the patient.