4. Edema
Unexplained swelling in the arms and legs are classic signs of pulmonary fibrosis. The longer a patient lives with the disease, the worse the scarring on the lungs becomes. As a result, there is less oxygen entering your bloodstream which causes your heart to work overtime. The right side of your heart is tasked with getting oxygen into your blood vessels.
In order to increase the amount of oxygen, your blood, your heart reduces the overall volume it pumps. This reduction is what causes swelling in the arms and legs. Edema is most often noted in the extremities, but excess blood is also pooled in the gastrointestinal tract and liver.
Fluid can also build up under the skin and in the lungs. The location of the edema is one of the main clues regarding the cause of the swelling. Swelling in the ankles, legs and other extremities can become painful if left untreated.