Acute tracheobronchitis is an acute inflammation of the mucous membrane of the bronchial tree caused by biotic or abiotic pathogenic factors, and is an independent condition not intrinsically linked to chronic bronchitis. It is a common and frequent disease, especially in children and the elderly. It is mostly caused by viral infections of the upper respiratory tract, with cold as the main cause, and is more frequent in autumn and winter, as well as in colder regions, with a higher incidence in influenza epidemics. In addition, people who are often in contact with physical and chemical irritants are susceptible to this disease. The disease often starts with symptoms of upper respiratory tract infection, such as nasal congestion, runny nose, sore throat, and hoarseness. In adults, influenza virus, adenovirus, and Mycoplasma pneumoniae infections may be associated with fever and systemic toxemia symptoms such as malaise, headache, and generalized aches and pains, whereas acute bronchitis caused by rhinovirus and coronavirus often does not have these manifestations. Tracheobronchitis is an acute inflammation of the tracheobronchial mucosa caused by biological, physical or chemical irritation or allergy. The main clinical symptoms are cough and sputum. It is common in the cold season or during sudden climate changes. It can also spread from acute upper respiratory tract infection. Diagnostic points 1. Clinical manifestations: mild systemic symptoms, fever, about 38℃, mostly dropping to normal in 3-5 days. Cough and sputum, starting with irritating dry cough or a small amount of mucus sputum, with coughing increasing after 2 to 3 days and sputum changing from mucus to mucopurulent, occasionally with blood in the sputum. In severe cases, there is often a paroxysmal cough in the morning, at night, after inhalation of cold air or after activity, or a cough that lasts all day. If accompanied by bronchospasm, different degrees of shortness of breath may occur, and croup may be heard on lung auscultation. Respiratory symptoms disappear in about 2 to 3 weeks. If prolonged, it may evolve into chronic bronchitis over time. 2, auxiliary examination: white blood cell count is mostly normal or mildly elevated. Chest X-ray examination, most of the performance is normal or only increased lung texture, thickening.