Pleural effusion is not tuberculosis, pleural effusion and tuberculosis belong to two concepts, two diseases. Pleural effusion is a state and change of abnormally increased fluid in the pleural cavity, while tuberculosis is a chronic infectious disease of the lungs caused by Mycobacterium tuberculosis infection, and the causes of the two are not exactly the same. TB is caused by Mycobacterium tuberculosis infection, while pleural effusion can be either infectious, such as infection with bacteria, viruses or tuberculosis. It can also be non-infectious, such as pleural effusion caused by connective tissue diseases, malignant pleural mesothelioma, bronchopulmonary cancer, and other metastatic cancers. The clinical symptoms caused by tuberculosis are not exactly the same. Tuberculosis is mostly characterized by low afternoon fever, night sweating, emaciation and cough, while pleural effusion is mostly characterized by chest tightness and dyspnea. Symptoms similar to those of tuberculosis only appear if the pleural effusion is caused by tuberculosis infection. Therefore, only pleural effusion caused by Mycobacterium tuberculosis infection belongs to the category of tuberculosis.