Swollen ankles may be a sign of heart failure, kidney disease, cirrhosis, venous disease of the lower extremities and other diseases, and may also be caused by trauma. 1. Heart failure: heart failure, especially right heart failure, the venous return of the whole body is blocked, the hydrostatic pressure of capillaries rises, and the generation of tissue fluid increases and causes tissue edema, mostly from the feet, ankles, calves, and other low-hanging parts of the body, and then gradually spreads upward, mostly in the old people with long-term heart disease. 2. Kidney disease: all kinds of kidney disease will damage the kidney function, cause the decrease of glomerular filtration, and then cause sodium retention and tissue edema, mostly seen in glomerulonephritis, nephrotic syndrome, secondary nephropathy and so on. 3. Liver cirrhosis: Reduction of albumin synthesis and obstruction of lymphatic fluid return in liver cirrhosis can also cause tissue edema, mostly in the lower limbs. 4. Lower extremity venous diseases: varicose veins of the lower extremity, venous valve insufficiency, deep vein thrombosis of the lower extremity and other diseases can cause foot or ankle edema due to the obstruction of lower extremity reflux. 5. Trauma: ankle sprain, fracture or ankle hit by violence, ankle soft tissue injury can also cause ankle edema, usually with a clear history of trauma. Found ankle swelling, should promptly go to the hospital, timely identification of the cause of the disease to be targeted treatment.