Phlegm in the lungs is mainly considered to be caused by respiratory infectious diseases, tumors and other diseases that stimulate the secretion of respiratory mucosa.
1. Infectious diseases of respiratory system: such as bronchitis, pneumonia, bronchial dilatation, tuberculosis, emphysema and other acute episodes, the infection produces inflammation to stimulate the respiratory mucosa, resulting in mucosal swelling, congestion, secretion increase, which leads to phlegm in the lungs, coughing, coughing up phlegm and other symptoms.
2. Tumor: such as lung cancer, the growing tumor tissues damage the mucous membrane of the respiratory tract, thus increasing the risk of infection, which may cause phlegm in the lungs under the stimulation of these factors.
3. Other reasons: such as chest trauma, poisoning, heart failure, shock and other diseases may cause pulmonary edema due to pulmonary circulation disorders, which may stimulate the mucous membrane of the respiratory tract to increase secretion, resulting in phlegm in the lungs.
It is not possible to make a diagnosis based only on the symptom of sputum in the lungs. It is recommended to consult a doctor in time, improve the chest imaging, blood biochemistry and other tests, combine with the past medical history and other symptoms to make a comprehensive judgment, and then take active treatment after clarifying the cause of the disease, so as to avoid delaying the condition.