Some of the symptoms of pulmonary tuberculosis in the elderly are not obvious, lacking typical symptoms such as afternoon fever and night sweats, and some of them are coughing, sputum production and shortness of breath. In addition, asymptomatic cases account for about 1/4 of pulmonary tuberculosis in the elderly, so the underdiagnosis rate is high. 1. Special chest X-ray performance. The chest X-ray performance of typical elderly patients with pulmonary tuberculosis is different from that of general patients. In the early stage, it shows infiltration in the middle and lower lung fields, and gradually develops into a sclerotic fibrotic lesion, sometimes with clear boundaries and high density, resembling an isolated shadow of lung cancer, which is often misdiagnosed. Sometimes in the apical fibroplasia lesions with pleural thickening, there is a hidden cellular cavity lesion. The incidence of cavities is high, even more than half; thick-walled, multiple cavities are predominant, and some of them have irregular inner walls and are suspected to be cancerous. If the lung lesions of elderly patients do not improve under reasonable anti-tuberculosis drug treatment, but deteriorate instead, or if lumpy shadow occurs in the lung area without tuberculosis lesions, the possibility of combined lung cancer should be considered, and a comprehensive examination should be conducted as soon as possible to make a correct diagnosis in time. 2.Many comorbidities. Tuberculosis in the elderly is often combined with arteriosclerosis, diabetes, heart disease, chronic obstructive pulmonary disease, especially combined with diabetes is more common. These comorbidities aggravate the condition of elderly patients with tuberculosis and complicate the treatment. 3. High rate of bacillary excretion. Nearly 50% of elderly patients with tuberculosis are sputum positive, which is significantly higher than that of young patients. 4, poor treatment effect. Clinical practice proves that the rational application of anti-tuberculosis drug therapy can completely cure almost all patients with primary sputum-positive pulmonary tuberculosis. Due to the decreased tissue repair ability of elderly patients, coupled with more comorbidities, the therapeutic effect of anti-tuberculosis drugs is significantly worse than that of adults, especially in relapsed patients. 5. High relapse rate. Due to the weak resistance of the elderly, coupled with more comorbidities, malnutrition and other factors, the elderly are prone to relapse of tuberculosis. Recurrence triggers are mainly respiratory infections. Prevention of respiratory infections is important to prevent the relapse of tuberculosis. 6. High morbidity and mortality rate. It is reported that the death rate of elderly tuberculosis is 8.1%, which is higher than the death rate of all tuberculosis patients by 5.1%. The death rate of those with a disease duration longer than 10 years is 31.5%. In addition to the deterioration of tuberculosis, infectious shock and respiratory failure are common causes of death. 7. BCG vaccination is ineffective. BCG vaccination is the most effective and important means for children to prevent tuberculosis infection. Since the immune function of the elderly has declined, it is difficult for BCG vaccination of the elderly to play a preventive role. Regular chest X-ray for the elderly can be important for early detection of tuberculosis.