Edema is not a symptom of chronic obstructive pulmonary disease (COPD); rather, it is often a complication of the disease. COPD is a general term for a group of lung conditions that obstruct the lungs, preventing oxygen-filled air from getting in and carbon dioxide-filled air from getting out. As the disease worsens, your body will get less and less oxygen. All parts of the body need oxygen in order to function correctly, so if you have COPD, your organs will slowly become damaged due to the constant lack of oxygen.
The heart and the lungs work closely together, because the heart pumps blood through the lungs in order to remove the carbon dioxide in the blood and in order to pick up oxygen for the body. However, COPD can put a lot of pressure on the heart, especially on the right side of the heart, which pumps the blood to the lungs. The pressure is created because the decreased oxygen in your blood, as a result of COPD, causes your blood vessels to constrict. In addition, many of the blood vessels in your lungs are destroyed by the disease. This means that your heart has to push against a lot of resistance in order to get blood through the fewer, constricted blood vessels of your lungs. Eventually, the right side of your heart becomes enlarged and the walls thicken, until the heart can no longer contract properly. Since the heart isn't able to properly circulate blood around your body, blood begins to build up in your extremities and puts pressure on the walls of the blood vessels. Fluid may then start to leak out of the vessels and into your body tissue, causing edema in your feet and hands. This condition is known as cor pulmonale and may be caused by any condition that causes long-term pulmonary hypertension, which is high blood pressure in the arteries of the lungs.