Pulmonary effusion in the elderly is also known as pleural effusion. There are many causes of pleural effusion, and the causes need to be clearly identified in order to know how to treat it. Common causes of pulmonary effusion include: 1, tumor, also known as cancerous pleural effusion, which requires anti-tumor treatment; 2, tuberculous pleural effusion, which requires anti-tuberculosis treatment, and anti-tuberculosis treatment generally requires treatment for one to one and a half years; 3, pleural effusion caused by bacterial infection requires anti-infection treatment; 4, pleural effusion caused by primary diseases of the kidney, liver and heart, which requires treatment of the heart, liver, kidney and other organs primary diseases and adjust the underlying diseases of liver, kidney and cardiac and cerebral insufficiency patients; 5. Pleural effusion caused by geriatric malnutrition and hypoproteinemia requires supplemental nutrition or transfusion of blood products and albumin therapy for the elderly.