I. Definition and epidemiological etiology of geriatric tuberculosis (1) Definition: Tuberculosis patients aged 65 years or older (2) Epidemiology, etiology 1. Global epidemic One third of the world’s population (about 2 billion) has been infected by Mycobacterium tuberculosis. The prevalence of tuberculosis is broadly correlated with economic levels, with high prevalence of tuberculosis corresponding to low levels of gross national product (GDP). The World Health Organization classifies 22 countries, including India, China, Russia, South Africa, and Peru, as having a high burden and high risk of TB disease. Eighty percent of global TB cases are concentrated in these countries. Undoubtedly these countries TB control will have an important impact on the global TB situation. The current TB epidemic in China is characterized as follows: (1) High infection rate The annual infection rate of Mycobacterium tuberculosis is 0.72%. Nearly half of the country’s population, about 550 million, have been infected with Mycobacterium tuberculosis, and the infection rate in urban populations is higher than that in rural areas. (2) High prevalence of tuberculosis in the elderly In 2000, the prevalence of active elderly tuberculosis, sputum smear-positive (referred to as smear-positive) and culture-positive (referred to as bacillary-positive) elderly tuberculosis were 367/100,000, 122/10,000 and 160/100,000, respectively, and the estimated number of cases was about 5 million, 1.5 million and 2 million. The number of smear-positive elderly TB patients accounted for 61.6% of all smear-positive patients. (3) High number of deaths About 130,000 people die of tuberculosis each year. (4) Large regional differences in prevalence rates The prevalence of active elderly TB, smear-positive elderly TB and culture-positive elderly TB in the western region is significantly higher than the national average, while the eastern region is below the average. Tuberculosis remains a major infectious disease that poses a serious threat to human health in this century, a public health and social issue of global concern, and one of the major diseases that China is focusing on controlling. The transmission of tuberculosis in the population] 1. Infectious source The infectious source of tuberculosis is mainly patients with pulmonary tuberculosis. Since Mycobacterium tuberculosis is mainly disseminated with the sputum out of the body, the patient who has Mycobacterium tuberculosis detected in the sputum is infectious and is the source of infection. The degree of infectivity depends on the amount of bacilli in the sputum. Those who have Mycobacterium tuberculosis detected by direct smear method belong to a large number of bacilli, and those who have only Mycobacterium tuberculosis cultured by negative direct smear method belong to a small amount of bacilli. Mycobacterium tuberculosis is mainly spread by coughing, sneezing, laughing, talking loudly, and so on, by expelling microdroplets containing Mycobacterium tuberculosis into the air. Droplet transmission is the most important way of transmission of tuberculosis. Transmission by other routes such as the gastrointestinal tract and skin is now rare. 3, susceptible people Factors affecting the body’s natural resistance to Mycobacterium tuberculosis, in addition to genetic factors, also include living in poverty, crowded housing, malnutrition and other social factors. Infants and children with imperfect cellular immune system, the elderly, HIV-infected patients, immunosuppressant users, patients with chronic diseases and other immune deficiencies are all susceptible to tuberculosis. Factors affecting infectiousness The size of infectiousness depends on the amount of Mycobacterium tuberculosis excreted by the patient, the density of space containing Mycobacterium tuberculosis droplets and ventilation, the closeness and duration of contact, and the status of individual immunity. Ventilation to reduce the density of spatial microdroplets is an effective measure to reduce the transmission of TB in the elderly. Of course, the most fundamental way to reduce the number of spatial microdroplets is to cure TB patients. 5, the effect of chemotherapy on the infectiousness of tuberculosis After receiving chemotherapy, the mycobacterium tuberculosis in the sputum of elderly patients with tuberculosis was logarithmically reduced. After chemotherapy, the number of Mycobacterium tuberculosis in the sputum not only decreases, but also the viability is reduced or lost. The most dangerous sources of TB infection are smear-positive patients who are undetected and not managed with treatment or treated unreasonably. Second, the clinical manifestations and diagnosis of tuberculosis in the elderly The clinical manifestations of various types of tuberculosis in the elderly are different, but there are common features. The clinical features of geriatric tuberculosis include passive detection of tuberculosis in the elderly, complicated by other diseases, atypical chest X-ray, high sputum detection rate of tuberculosis, and poor compliance with treatment or non-cooperation with treatment. （The clinical manifestations of tuberculosis include fever, cough, sputum, hemoptysis, dyspnea, weight loss, poor appetite and night sweats, etc. The manifestations of elderly patients are not typical. Canada et al. compared 142 adult and 76 elderly patients with TB and found that fever was only 22 cases in the elderly group (36 cases in the young group), while cough was more common (45 cases), and the frequency of hemoptysis and night sweats was also significant. Similar results were observed by Van den Brande et al. In Belgium, Van den Brande et al. observed elderly patients with pulmonary tuberculosis and showed that cough (57 cases), dyspnea (46 cases) and dyspnea were the most common symptoms in elderly patients and were easily overlooked or confused with other coexisting conditions. In a controlled comparison between 198 elderly and 150 non-elderly patients, fatigue, dyspnea, and depression were more frequent than in young and middle-aged patients, and 89.9% had various underlying diseases. However, some authors did not find significant differences in the frequency of fever, cough, hemoptysis, and dyspepsia among different age groups. In China, Yan Biya, Zhu Ermei, and Xu Yingjie conducted a larger number of case studies respectively and found that more patients had other diseases associated with them. Such as respiratory diseases, cardiovascular diseases, diabetes mellitus, anemia, etc. The Beijing Institute of Tuberculosis and Thoracic Oncology also analyzed the incidence of various co-morbidities in the first treatment of elderly patients with TB, which was 82.8%, significantly higher than that of the middle-aged group (28.6%). In conclusion, the clinical symptoms of elderly patients with tuberculosis are complex and varied. In elderly patients, symptoms that are suggestive of TB diagnosis, such as fever and night sweats, are less frequent, while non-characteristic symptoms, such as chronic cough, coughing, loss of appetite, dyspnea, and wasting, are more likely to be overlooked by physicians or patients. Symptoms 1. Respiratory symptoms (1) Cough and sputum: The most common symptom of tuberculosis in the elderly. The cough is mild, dry or a small amount of mucus sputum. When there is cavity formation, the sputum volume increases, and if combined with other bacterial infections, the sputum may be purulent. If combined with bronchial tuberculosis, the cough may be irritating. (2) Hemoptysis: about 1/3-1/2 of patients have hemoptysis. The amount of hemoptysis is variable, with most patients having a small amount of hemoptysis and a few having a large amount of hemoptysis. (3) Chest pain: When tuberculosis involves the pleura, chest pain can be manifested as pleuritic chest pain. It is aggravated by breathing movement and coughing. (4) Dyspnea: Most commonly seen in patients with caseous pneumonia and massive pleural effusion. 2) Systemic symptoms Fever is the most common symptom, mostly prolonged afternoon flashes, i.e., starting to rise in the afternoon or evening and dropping to normal the next morning. Some patients have fatigue, night sweats, loss of appetite and weight loss. Female patients of childbearing age may have irregular menstruation.