Fever with cough, sputum and chest pain is one of the symptoms of respiratory diseases. Respiratory diseases are caused by a variety of viral infections. Respiratory diseases are acute and chronic inflammatory diseases of the respiratory tract such as cold, bronchitis, bronchitis, and pneumonia, which are common and more dangerous. So, what causes fever with cough, sputum and chest pain? Here is how fever with cough, sputum, chest pain is caused: 1, the danger of atmospheric pollution and smoking Etiological studies have confirmed that the increase in respiratory disease is closely related to air pollution, smoking. Some data prove that when airborne soot or sulfur dioxide exceeds 1000ug/m3, acute attacks of chronic bronchitis increase significantly; other dusts such as carbon dioxide, coal dust, cotton dust, etc. can stimulate bronchial mucosa, impair lung clearance and natural defense functions, creating conditions for microbial invasion. The higher incidence of lung cancer in industrially developed countries than in industrially backward countries indicates that it is related to the pollution of the atmosphere by carcinogenic substances in industrial waste gas. Smoking is the main source of pollution of the small environment, smoking and chronic bronchitis and lung cancer concerns. 1994 on the World Health Organization proposed smoking is the world’s largest plague causing death, the survey showed that in developing countries in the last half century, smoking devoured 60 million lives, of which 2 / 3 is 45 to 65 years old, smokers die 20 years earlier than non-smokers. If the current smoking situation continues, by 2025, the world’s annual smoking-related deaths will reach 10 million people, three times the current mortality rate, of which China accounts for 2 million people. Now China’s total consumption of tobacco accounts for the world’s first, the obvious increase in smoking among young people, the next 20 years, indeed, the death of people due to smoking will increase sharply. 2, respiratory diseases have long failed to receive sufficient attention Because the respiratory organs have a huge physiological function of the reserve capacity, usually only 1/20 lung respiratory function can maintain normal life, so the pathological changes in the lungs, the clinical often can not be reflected truthfully; respiratory diseases such as cough, cough, hemoptysis, chest pain, shortness of breath and other symptoms lack of specificity, often mistaken by people and clinicians for the flu, bronchitis, and The diagnosis of severe pneumonia, tuberculosis or lung cancer and other diseases is delayed; or due to repeated respiratory infections, until the development of emphysema, pulmonary heart disease, respiratory failure occurred only to be paid attention to, but it is too late, its pathology and physiological function is difficult to reverse. 3, the relationship between the structure and function of the respiratory system and disease The respiratory system has the most frequent contact with the external environment and a large contact area among the various systems of the human body. In the resting state of adults, there are 12,000L of gas in and out of the respiratory tract every day, and 300-750 million alveoli (total area of about 100m2) exchange gas with the capillaries of the pulmonary circulation, absorbing oxygen from the external environment and discharging carbon dioxide to the outside of the body. In the process of breathing, organic or inorganic dust in the external environment, including various microorganisms, allergens, dust particles and harmful gases can be inhaled into the respiratory tract and lungs to cause various diseases. Primary infections are most common with viral infections, which first appear in the upper respiratory tract, followed by bacterial infections; exogenous asthma and exogenous allergic alveolitis; pneumoconiosis caused by inhalation of productive dust, with silicosis, coal silicosis and asbestosis being the most common; acute and chronic respiratory tract infections and pneumonia can occur with inhalation of irritant gases such as sulfur dioxide, chlorine and ammonia, which are highly water soluble, while Inhalation of low water-soluble gases such as nitrogen oxides, phosgene, and dimethyl sulfate damage the alveoli and pulmonary capillaries to occur in acute pulmonary edema. The lungs are supplied by two groups of blood vessels: the arteries and veins of the pulmonary circulation are functional vessels for gas exchange; the bronchial arteries and veins of the body circulation are nutrient vessels for the airways and the dirty pleura. The lungs are connected to the blood and lymphatic circulation of all organs of the body, so the bacterial embolus of skin and soft tissue boils and carbuncles, the thrombus of embolic phlebitis, and the cancer embolus of tumors can reach the lungs and cause secondary lung abscess, pulmonary infarction, and metastatic lung cancer, respectively. Lung cancer of the digestive system can also spread to the whole body, such as lung cancer and tuberculosis to bone, brain, liver and other organs; likewise, focal spread can occur in the lung itself. The vasculature of the pulmonary circulation and the trachea-bronchus are also becoming more and more divided, the cross-sectional area of the small arteries is large, and the pulmonary capillary bed is larger and easily dilated. Therefore, the lung is a low-pressure (blood pressure in the pulmonary circulation is only 1/10th of the blood pressure in the body circulation), low-resistance, high-volume organ. Interstitial pulmonary edema, or leakage of fluid from the thoracic cavity, occurs when mitral stenosis, left heart failure, cirrhosis, nephrotic syndrome, and hypoproteinemia of malnutrition are present. Some immune, autoimmune or metabolic systemic diseases such as nodular disease, systemic lupus erythematosus, rheumatoid arthritis, dermatomyositis and scleroderma can involve the lungs. The lung also has non-respiratory functions, such as endocrine syndrome produced by the production and release of ectopic hormones in lung cancer. 4.Social population aging With the rapid progress of science and medical technology, human life expectancy is also rapidly accelerating. It is recorded that two thousand years ago the average life expectancy was second only to 20 years, which increased to 30 years in the 18th century and reached 40 years by the end of the 19th century. According to the United Nations Population Division forecast, by 2025 the world’s population over 60 years of age will increase to 1.121 billion, accounting for 13.7% of the world’s population, of which 12% in developing countries and 23% in developed countries. at the end of 1993, the number of elderly people over 60 years of age in Shanghai had exceeded 2.1 million, accounting for 16% of the total population, and by 2025 the number of elderly people will reach 4 million, accounting for more than 28%. Respiratory system diseases such as chronic obstructive pulmonary disease and lung cancer are increasing with age, and their prevalence is also increasing; due to the low immune function of the elderly body, and easy to cause aspiration pneumonia, even though a variety of new antibiotics have been introduced, lung infection still ranks first in the elderly infectious diseases, often as a direct factor causing death. 5, medical science and the progress of applied technology to improve the level of diagnosis In recent years, physiology, biochemistry, immunology, pharmacology, nuclear medicine, laser, ultrasound, electronic technology and other fields of scientific research progress for the diagnosis of respiratory disease provides the conditions. New and more comprehensive understanding of the etiology, pathogenesis and pathophysiology of some respiratory diseases is now available using cellular and molecular biology techniques, which allows for more accurate and early diagnosis of diseases.