In most cases, the cause of pulmonary veno-occlusive disease is unknown. The condition may be related to a viral infection. It may occur as a complication of certain diseases such as lupus, or as a complication of leukemia, lymphoma, or chemotherapy. The disorder is most common among children and young adults. As the disease gets worse, it causes narrowed pulmonary veins, pulmonary hypertension, congestion, and edema (swelling) of the lungs. |