The causes of fever and dyspnea are complex, and need to be analyzed and judged in conjunction with clinical symptoms, because there are many diseases that can cause fever and dyspnea, as follows:1. Severe pneumonia: cause fever and dyspnea, but more often accompanied by coughing and coughing up sputum, especially in patients with viral pneumonia, for example, new coronary artery pneumonia can cause fever and dyspnea. Because these severe pneumonias can lead to ventilation and ventilation dysfunction of the lungs, thus causing fever and dyspnea at the same time.2. Large amount of pleural effusion: cause fever and dyspnea, because pleural effusion can compress the lung tissues, which can cause ventilation dysfunction of the lungs, resulting in dyspnea.3. Severe heart disease: accompanied by respiratory tract infection, fever and dyspnea can occur. Therefore, fever and dyspnea should be consulted as soon as possible, and chest X-ray or lung CT, electrocardiogram, cardiac enzymes, cardiac ultrasound and other related tests should be performed to clarify the situation.