To the night there are three most common diseases of lower limb edema, the first, cardiogenic edema, cardiogenic edema is a non-sunken edema, in addition to edema will be accompanied by other symptoms, such as patients will appear exertional dyspnea, nocturnal paroxysmal dyspnea, and wheezing at night, some patients may appear corresponding symptoms of angina pectoris, chest tightness, shortness of breath, chest pain, etc. Previous patients can Provide medical history clinically can do cardiac ultrasound and BNP examination to confirm the diagnosis; second, poor venous reflux in the lower extremities or thrombosis and other vascular diseases, is also clinically more common especially in older patients, some diabetic patients are more likely to appear, edema is also generally caused by poor reflux, clinically do lower extremity venous ultrasound can see whether the blood vessels are smooth, venous valve reflux is not good; third, edema caused by the kidneys; Thirdly, edema caused by kidney is usually sunken edema, and morning rise is usually accompanied by eyelid edema, which can be clinically guided by urine routine, renal function and protein examination. There are other clinical lower limb edema diseases, but relatively speaking the above three diseases have the highest probability of occurrence.