If a patient has inexplicable swelling of the legs, it is important to rule out hypothyroidism, especially in relatively young patients with no previous history of cardiovascular disease, and consider that the lower limb edema may be caused by hypothyroidism. If a patient has had a myocardial infarction or has hypertension and has poorly controlled blood pressure on a regular basis, it is likely that the lower extremity leg swelling is due to heart failure. Some patients may also be obese, have heavy weight bearing on the lower limbs or have varicose veins, and may also have lower limb edema. Patients are advised to have their thyroid function, cardiac ultrasound and BNP checked, and they are also advised to have arteriovenous ultrasound of both lower limbs to further rule out any lower limb thrombosis.