Chronic Venous Insufficiency: This condition is a common cause of bilateral ankle swelling due to the incompetence of venous valves, leading to fluid accumulation in the lower extremities. It is often associated with a history of deep vein thrombosis, obesity, or prolonged standing.

Heart Failure: Bilateral ankle swelling can be a sign of right-sided heart failure, where the heart is unable to pump blood effectively, leading to fluid buildup in the body, particularly in the lower extremities.
Nephrotic Syndrome: A condition characterized by excessive loss of protein in the urine, leading to hypoalbuminemia, which causes fluid to shift from blood vessels to interstitial spaces, resulting in edema.
Liver Cirrhosis: Can cause fluid retention and swelling in the ankles due to hypoalbuminemia and portal hypertension.
Hypothyroidism: Sometimes presents with non-pitting edema, which can affect the ankles.

Deep Vein Thrombosis (DVT): Although DVT typically presents unilaterally, it's crucial not to miss it, as it can be bilateral and life-threatening if it leads to pulmonary embolism.
Lymphoma or Other Malignancies: Certain cancers can cause lymphatic obstruction or increased vascular permeability, leading to edema.
Sepsis: In severe cases, sepsis can cause capillary leak syndrome, leading to significant edema.

Lipedema: A chronic condition characterized by the abnormal growth of fat cells in the legs, leading to swelling and pain.
Fabry Disease: A genetic disorder that can cause edema due to the accumulation of a particular type of fat in the body's cells.
Sarcoidosis: A condition that can cause inflammation in various parts of the body, including the lymph nodes, which might lead to swelling in the ankles.
Milroy Disease: A rare genetic disorder that affects the lymphatic system, leading to chronic swelling, typically in the legs.