1. Symptoms (1) Onset: Patients with acute lung abscess may have oropharyngeal infection foci and risk factors for aspiration, or have a history of exposure to cold and exertion. The onset of the disease can be rapid, patients with chills, high fever, 8 to 14 days after the formation of cavities in the lungs, the patient coughing a large amount of purulent sputum with a foul odor, the body temperature dropped significantly. In a few patients, the disease may be insidious, with malaise, cough and low-grade fever lasting several weeks or even longer. Lung abscess secondary to pneumonia may appear 2 to 3 weeks after the onset of the disease, when the pneumonia should have been cured, but then high fever, increased amount of purulent sputum, often with symptoms of malaise. (2) Cough, large amount of purulent sputum: at the initial stage, cough mucus or mucopurulent sputum, after 8 to 14 days of cavity formation in the lungs, 40% to 70% of cases cough up a large amount of pus-flavored sputum, foul-smelling sputum suggestive of anaerobic bacterial infection. (3) Hemoptysis: not uncommon, occasionally can cause fatal hemoptysis. (4) Chest pain: caused by inflammatory lesions involving the pleura, and the pain is aggravated during inhalation. If the abscess breaks into the chest cavity, pus chest or pus pneumothorax can be formed, and the patient’s whistling movement will be limited and shortness of breath will be aggravated. (5) Others: fatigue, emaciation, loss of appetite, etc. Hematogenous lung abscess is often preceded by symptoms caused by the primary disease. Anemia and other consumptive symptoms are common in patients with chronic lung abscess and pyothorax. Signs and symptoms There are no positive signs when the abscess is small and deep; if the abscess is large, there can be signs of lung solid changes locally, such as the abscess close to the chest wall can appear empty urn sound; patients with pyothorax have signs of pleural effusion on the affected side; pestle finger can be seen within a few weeks after the onset of the disease, which can be seen in patients with chronic lung abscess, and it sometimes suggests that there is a bronchopulmonary carcinoma possibility. Hematogenous lung abscesses often have no positive pulmonary signs because the lesions are small and scattered.