According to WebMD, swollen ankles commonly occur when a person stands or walks a lot, but if swollen ankles persist or are accompanied by other symptoms, they could be an indication of a serious health problem, such as pregnancy complications, foot or ankle injury, lymphedema and venous insufficiency. Sudden or excessive swelling is a possible sign of preeclampsia.
Swelling of the ankles and feet normally occurs during pregnancy, notes WebMD. However, when a person experiences sudden or too much swelling, it can indicate preeclampsia, which involves the development of high blood pressure and protein in the urine after the 20th week of pregnancy. It is important to contact a doctor immediately when the swelling is severe or accompanied by other symptoms, such as headaches and abdominal pain.
An injury to the foot or ankle also tends to cause swelling, says WebMD. A sprained ankle happens when an injury stretches the ligaments that hold the ankle in place beyond their normal range. Another condition that leads to swelling is lymphedema, which is an accumulation of lymphatic fluid in the tissues that develops due to problems with the lymph vessels or when the lymph nodes are removed. Swelling of the ankles and feet is also one of the symptoms of venous insufficiency, a condition wherein blood insufficiently moves up the veins from the feet and legs toward the heart.