On November 17th, data released by the National Bureau of Disease Control and Prevention showed that influenza ranked first in the number of Class C infectious diseases in China in October this year. As temperatures continue to decrease in various regions, respiratory diseases have entered a high incidence period. Influenza, mycoplasma pneumonia, respiratory diseases and other words are frequently searched. What are the typical symptoms of respiratory tract infections? How to identify and respond to severe and critical illnesses caused by respiratory infections? A reporter from Science and Technology Daily interviewed relevant experts on this matter. The types of respiratory infectious diseases have not increased. "Recently, everyone is talking about respiratory diseases. Before the discussion, at least three concepts should be clarified: respiratory infectious diseases, respiratory infectious diseases and respiratory diseases." Professor Wang Guangfa, director of the Department of Respiratory and Critical Care Medicine of Peking University First Hospital, told reporters. "Respiratory infectious diseases refer to legal infectious diseases transmitted through the respiratory tract, such as influenza, COVID-19, tuberculosis, etc. Respiratory infectious diseases include respiratory infectious diseases, which refer to respiratory diseases caused by infection of foreign pathogens invading the respiratory system. Respiratory diseases are more extensive, including infectious respiratory diseases and non infectious respiratory diseases." Wang Guangfa said, In terms of disease types, there are no new types of respiratory infectious diseases, but the number of cases may increase compared to some years. From the perspective of infection sites, respiratory infections are divided into upper respiratory tract infections and lower respiratory tract infections. The symptoms of upper respiratory tract infections mainly include runny nose, sneezing, sore throat, and can also include coughing, expectoration, hoarseness, and other symptoms. The symptoms of lower respiratory tract infections mainly include coughing, expectoration, suffocation, and wheezing. Both upper and lower respiratory tract infections can cause systemic symptoms such as fever, muscle soreness, and headache, "Wang Guangfa said. What symptoms may indicate a risk of severe or critical illness after seeking medical attention and contracting respiratory diseases as soon as possible? In response, Wang Guangfa stated that the following three signals should be seized. One is the appearance of symptoms of lower respiratory tract infection. For example, the occurrence of pneumonia, bronchiolitis, severe bronchitis, and other symptoms may affect lung ventilation, lead to hypoxia, and even lead to respiratory failure. Most upper respiratory tract infections have mild symptoms, but there may also be symptoms such as suffocation and hoarseness that can cause suffocation. The second is that infected individuals belong to a special population with severe and high-risk conditions. Usually, infants, elderly people, and people with underlying diseases have relatively poor immunity. It is necessary to closely observe the status of these populations after infection. If they experience mental depression, cyanosis (skin and mucous membranes showing cyanosis), breathing difficulties, etc., it may indicate a risk of severe and critical illness. Thirdly, the disease progression is rapid. Respiratory infections caused by some special pathogens may be more likely to cause critical illness. For example, Legionella pneumonia, pestis, etc., can progress very quickly. If you encounter severe or critical illness, you must seek medical attention at the hospital as soon as possible, "Wang Guangfa emphasized. Firstly, routine examinations should be conducted, including physical examination (respiratory rate, heart rate, blood pressure, mental state, lung rales, etc.), examination of white blood cells, measurement of finger pulse oxygen saturation, chest X-ray or CT. Not everyone needs to undergo a CT scan. Infants, elderly people, and those with underlying diseases may need to undergo a CT scan as their condition progresses rapidly