Could increased pleural fluid cause pulmonary edema, heart failure, or pneumonia?

No, but: Increased pleural fluid (effusion) may be caused by pulmonary edema and heart failure. This is because the heart is unable to pump the blood effectively and fluid backs up in the lungs and leaks out to the pleural space. The fluid can often be relieved by medication. Pneumonia can cause increased fluid as well, which is often infected (empyema). This is removed by a tube in the chest or surgery.